外文翻译 建筑施工 外文文献 英文文献 文献翻译
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建筑设计中英文对照外文翻译文献On the other hand, there is a significant amount ofliterature in the field of architecture design that is writtenin foreign languages. While it may not be as readily accessible for non-native speakers, there are many benefits to exploring literature in other languages. For example, architects who are fluent in multiple languages can have a broader understanding of different cultural approaches to architecture. By reading literature in foreign languages, architects can gain insights into design concepts and practices that may not be covered in English-language sources. This can lead to a more diverse and innovative approach to design.However, one challenge with accessing literature in foreign languages is the accuracy of translations. Architecture is a technical field with specific terminology, and it is important to ensure that translations accurately convey the intended meaning. In some cases, the translation of technical terms and concepts may not accurately convey their full meaning, which can lead to misunderstandings or confusion. Architects who rely on translated literature should be cautious and ensure they verify the accuracy of the translations with experts in the field.Despite these challenges, it is essential for architects to explore literature in multiple languages to stay informed and to gain a global perspective on architecture design. By consideringboth English and foreign language translated literature, architects can access a wider range of resources and insights. Additionally, architects should consider collaborating with colleagues who are fluent in different languages to ensure accurate translation and interpretation of foreign language sources.In conclusion, architecture design is a field that benefits from accessing literature in multiple languages. English provides a wealth of resources and is the global language of academia. However, architects who can access and read literature in foreign languages can gain new perspectives and insights into different cultural approaches to design. While caution should be taken to verify the accuracy of translations, architects should explore literature in multiple languages to broaden their understanding and enhance their creative problem-solving skills.。
建筑施工质量管理体系外文翻译参考文献1. GB/T -2016 英文名称:Quality management systems--Requirements《质量管理体系要求》2. GB/T -2016 英文名称:Quality management systems--Guidelines for the application of ISO 9001:2015《质量管理体系应用指南》3. GB -2013 英文名称:Code for construction quality acceptance of building engineering《建筑工程质量验收规范》4. GB -2011 英文名称:Code for acceptance of constructional quality of masonry engineering《砌体工程施工质量验收规范》5. GB -2010 英文名称:Code for design of concrete structures《混凝土结构设计规范》6. GB -2013 英文名称:Standard for building drawing standardization《建筑施工图件编制规范》7. GB -2001 英文名称:Code for acceptance of construction quality of pile foundation engineering《桩基工程施工质量验收规范》8. /T 11-2017 英文名称:Technical specification for concrete structure of tall building《高层建筑混凝土结构技术规范》9. 63-2013 英文名称:Technical specification for strengthening of building structures using carbon fiber reinforced plastics 《建筑结构加固碳纤维布增强复合材料技术规范》10. 81-2002 英文名称:Technical specification for application of sprayed mortar in building construction and acceptance of quality 《建筑喷涂砂浆工程施工及质量验收技术规定》。
外文原文Study on Human Resource Allocation in Multi-Project Based on the Priority and the Cost of ProjectsLin Jingjing , Zhou GuohuaSchoolofEconomics and management, Southwest Jiao tong University ,610031 ,China Abstract----This paper put forward the a ffecting factors of project’s priority. which is introduced into a multi-objective optimization model for human resource allocation in multi-project environment . The objectives of the model were the minimum cost loss due to the delay of the time limit of the projects and the minimum delay of the project with the highest priority .Then a Genetic Algorithm to solve the model was introduced. Finally, a numerical example was used to testify the feasibility of the model and the algorithm.Index Terms—Genetic Algorithm, Human Resource Allocation, Multi-project’s project’s priority .1.INTRODUCTIONMore and more enterprises are facing the challenge of multi-project management, which has been the focus among researches on project management. In multi-project environment ,the share are competition of resources such as capital , time and human resources often occur .Therefore , it’s critical to schedule projects in order to satisfy the different resource demands and to shorten the projects’ duration time with resources constrained ,as in [1].For many enterprises ,the human resources are the most precious asset .So enterprises should reasonably and effectively allocate each resource , especially the human resource ,in order to shorten the time and cost of projects and to increase the benefits .Some literatures have discussed the resource allocation problem in multi-project environment with resources constrained. Reference [1] designed an iterative algorithm and proposeda mathematical model of the resource-constrained multi-project scheduling .Basedon work breakdown structure (WBS) and Dantzig-Wolfe decomposition method ,a feasible multi-project planning method was illustrated , as in [2] . References [3,4]discussed the resource-constrained project scheduling based on Branch Delimitation method .Reference [5] put forward the framework of human resource allocation in multi-project in Long-term ,medium-term and short-term as well as research and development(R&D) environment .Basedon GPSS language, simulation model of resources allocation was built to get the project’s duration time and resources distribution, as in [6]. Reference [7] solved the engineering project’s resources optimization problem using Genetic Algorithms. These literatures reasonably optimized resources allocation in multi-project, but all had the same prerequisite that the project’s importance is the same to each other .This paper will analyze the effects of project’s priority on human resource allocation ,which is to be introduced into a mathematical model ;finally ,a Genetic Algorithm is used to solve the model.2.EFFECTS OF PROJECTS PRIORITY ON HUMAN RESOUCE ALLOCATIONAND THE AFFECTING FACTORS OF PROJECT’S PRIORITYResource sharing is one of the main characteristics of multi-project management .The allocation of shared resources relates to the efficiency and rationality of the use of resources .When resource conflict occurs ,the resource demand of the project with highest priority should be satisfied first. Only after that, can the projects with lower priority be considered.Based on the idea of project classification management ,this paper classifies the affecting factors of project’s priority into three categories ,as the project’s benefits ,the complexity of project management and technology , and the strategic influence on the enterprise’s future development . The priority weight of the project is the function of the above three categories, as shown in (1).W=f(I,c,s…) (1)Where w refers to project’s priority weight; I refers to the benefits of th e project; c refers to the complexity of the project, including the technology and management; s refers to the influence of the project on enterprise .The bigger the values of the three categories, the higher the priority is.3.HUMAN RESOURCE ALLOCATION MODEL IN MULTI-PROJECTENVIRONMENT3.1Problem DescriptionAccording to the constraint theory, the enterprise should strictly differentiate the bottleneck resources and the non-bottleneck resources to solve the constraint problem of bottleneck resources .This paper will stress on the limited critical human resources being allocated to multi-project with definite duration times and priority.To simplify the problem, we suppose that that three exist several parallel projects and a shared resources storehouse, and the enterprise’s operation only involves one kind of critical human resources. The supply of the critical human resource is limited, which cannot be obtained by hiring or any other ways during a certain period .when resource conflict among parallel projects occurs, we may allocate the human resource to multi-project according to project’s priorities .The allocation of non-critical independent human resources is not considered in this paper, which supposes that the independent resources that each project needs can be satisfied.Engineering projects usually need massive critical skilled human resources in some critical chain ,which cannot be substituted by the other kind of human resources .When the critical chains of projects at the same time during some period, there occur resource conflict and competition .The paper also supposes that the corresponding network planning of various projects have already been established ,and the peaks of each project’s resources demand have been optimized .The delay of the critical chain will affect the whole project’s duration time .3.2 Model HypothesesThe following hypotheses help us to establish a mathematical model:(1)The number of mutually independent projects involved in resourceallocation problem in multi-project is N. Each project is indicated withQ i,while i=1,2, … N.(2)The priority weights of multi-project have been determined ,which arerespectively w1,w 2…w n .(3) The total number of the critical human resources is R ,with r k standingfor each person ,while k=1,2, …,R(4) Δk i = ⎩⎨⎧others toprojectQ rcer humanresou i k 01(5) Resources capturing by several projects begins on time. t E i is theexpected duration time of project I that needs the critical resources tofinish some task after time t ,on the premise that the human resourcesdemand can be satisfied .tAi is the real duration time of project I thatneeds the critical resource to finish some task after time t .(6) According to the contract ,if the delay of the project happens the dailycost loss due to the delay is △c i for pro ject I .According to the project’simportance ,the delay of a project will not only cause the cost loss ,butwill also damage the prestige and status of the enterprise .(while thelatent cost is difficult to quantify ,it isn’t considered in this articletemporarily.)(7) From the hypothesis (5) ,we can know that after time t ,the time-gapbetween the real and expected duration time of project I that needs thecritical resources to finish some task is △t i ,( △t i =t A i -t E i ). For thereexists resources competition, the time –gap is necessarily a positivenumber.(8) According to hypotheses (6) and (7), the total cost loss of project I is C i(C i = △t i * △C i ).(9) The duration time of activities can be expressed by the workload ofactivities divided by the quantity of resources ,which can be indicatedwith following expression of t A i =ηi / R i * ,.In the expression , ηi refersto the workload of projects I during some period ,which is supposed tobe fixed and pre-determined by the project managers on project planningphase ; R i * refers to the number of the critical human resources beingallocated to projects I actually, with the equation Ri * =∑=Rk ki 1δ existing. Due to the resource competition the resourcedemands of projects with higherPriorities may be guarantee, while those projects with lower prioritiesmay not be fully guaranteed. In this situation, the decrease of theresource supply will lead to the increase of the duration time of activitiesand the project, while the workload is fixed.3.3 Optimization ModelBased on the above hypotheses, the resource allocation model inmulti-project environment can be established .Here, the optimizationmodel is :F i =min Z i = min∑∑==Ni i N i Ci 11ω =min i i Ni i N i c t ∆∆∑∑==11ω (2) =min ∑∑==N i i N i 11ω )E i R i ki i t - ⎝⎛∑=1δη i c ∆ 2F =min Z 2=min ()i t ∆=min )E i R i ki i t -⎝⎛∑=1δη (3) Where wj=max(wi) ,(N j i 3,2,1,=∀) (4)Subject to : 0∑∑==≤R k ki N i 11δ=R (5)The model is a multi-objective one .The two objective functions arerespectively to minimize the total cost loss ,which is to conform to theeconomic target ,and to shorten the time delay of the project with highestpriority .The first objective function can only optimize the apparenteconomic cost ;therefore the second objective function will help to makeup this limitation .For the project with highest priority ,time delay will damage not only the economic benefits ,but also the strategy and the prestige of the enterprise .Therefore we should guarantee that the most important project be finished on time or ahead of schedule .4.SOLUTION TO THE MULTI-OBJECTIVE MODEL USING GENETICALGORITHM4.1The multi-objective optimization problem is quite common .Generally ,eachobjective should be optimized in order to get the comprehensive objective optimized .Therefore the weight of each sub-objective should be considered .Reference [8] proposed an improved ant colony algorithm to solve this problem .Supposed that the weights of the two optimizing objectives are αand β ,where α+β=1 .Then the comprehensive goal is F* ,where F*=αF1+βF2.4.2The Principle of Genetic AlgorithmGenetic Algorithm roots from the concepts of natural selection and genetics .It’s a random search technique for global optimization in a complex search space .Because of the parallel nature and less restrictions ,it has the key features of great currency ,fast convergence and easy calculation .Meanwhile ,its search scope is not limited ,so it’s an effective method to solve the resource balancing problem ,as in [9].The main steps of GA in this paper are as follow:(1)EncodingAn integer string is short, direct and efficient .According to thecharacteristics of the model, the human resource can be assigned to be acode object .The string length equals to the total number of humanresources allocated.(2)Choosing the fitness functionThis paper choose the objective function as the foundation of fitnessfunction .To rate the values of the objective function ,the fitness of then-th individual is 1/n。
建筑施工质量控制技术外文翻译参考文献1. Zhang, H., Yu, S., & Yang, C. (2019). Research on Quality Control Technology of Construction Engineering. Journal of Wuhan University of Technology. 41(9), 28-33.2. Li, J., & Wang, Y. (2018). Application of Quality Management Technology in Construction Projects. China Construction Science and Technology. 45(2), 60-64.3. Chen, X., & Li, Z. (2017). Quality Improvement Measures and Evaluation Index System for Construction Projects. Construction Engineering Technology and Design. 28(4), 65-70.4. Zhao, Y., & Liu, W. (2016). Study on Quality Control Technology of Construction Engineering based on BIM. Modern Construction Technology. 57(1), 38-42.5. Wang, L., & Zhang, Y. (2015). Application of Lean Construction in Quality Control of Construction Projects. Construction Technology and Economy. 36(6), 45-49.6. Wu, Q., & Xu, H. (2014). Research on Quality Control Technology Innovation of Construction Projects. Journal of Building Materials and Structures. 35(8), 51-55.7. Li, H., & Zhu, L. (2013). Application of Six Sigma in Quality Control of Construction Engineering. China Construction Economy.40(3), 70-75.8. Tang, J., & Guan, J. (2012). Analysis of Quality Control Measures in Construction Engineering. Construction Engineering and Technology. 33(5), 32-37.9. Zhang, G., & Zhang, Q. (2011). Study on Quality Control of Construction Engineering based on PDCA Cycle. Construction Science and Management. 51(9), 47-51.10. Liu, Y., & Wang, X. (2010). Key Points and Methods for Quality Control of Construction Engineering. Building Construction. 42(4), 34-38.。
建筑英文文献及翻译第一篇:建筑英文文献及翻译外文原文出处: NATO Science for Peace and Security Series C: Environmental Security, 2009, Increasing Seismic Safety by Combining Engineering Technologies and Seismological Data, Pages 147-149动力性能对建筑物的破坏引言:建筑物在地震的作用下,和一些薄弱的建筑结构中,动力学性能扮演了一个很重要的角色。
特别是要满足最基本的震动周期,无论是在设计的新建筑,或者是评估已经有的建筑,使他们可以了解地震的影响。
许多标准(例如:欧标,2003;欧标,2006),建议用简单的表达式来表达一个建筑物的高度和他的基本周期。
这样的表达式被牢记在心,得出标定设计(高尔和乔谱拉人,1997),从而人为的低估了标准周期。
因为这个原因,他们通常提供比较低的设计标准当与那些把设计基础标准牢记在心的人(例:乔普拉本和高尔,2000)。
当后者从已进行仔细建立的数字模型中得到数值(例:克劳利普和皮诺,2004;普里斯特利权威,2007)。
当数字估计与周围震动测量的实验结果相比较,有大的差异,提供非常低的周期标准(例:纳瓦洛苏达权威,2004)。
一个概述不同的方式比较确切的结果刊登在马西和马里奥(2008);另外,一个高级的表达式来指定更有说服力的坚固建筑类型,提出了更加准确的结构参数表(建筑高度,开裂,空隙填实,等等)。
联系基础和上层建筑的震动周期可能发生共振的效果。
这个原因对于他们的振动,可能建筑物和土地在非线性运动下受到到破坏,这个必须被重视。
通常,结构工程师和岩土工程师有不同的观点在共振作用和一些变化的地震活动。
结构工程师们认为尽管建筑物和土壤的自振周期和地震周期都非常的接近。
但对于建筑物周期而言,到底是因为结构还是非结构造成的破坏提出了疑问。
建筑施工中英文对照外文翻译文献建筑施工中英文对照外文翻译文献(文档含英文原文和中文翻译)外文:Building construction concrete crack ofprevention and processingAbstractThe crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure.Keyword:Concrete crack prevention processingForewordConcrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect, end formation we can see without the aid of instruments of macro view the crack be also the crack that the concrete often say in the engineering.Concrete building and Gou piece usually all take sewer to make of, because of crack of existence and development usually make inner part of reinforcing bar etc. material creation decay, lower reinforced concrete material of loading ability, durable and anti- Shen ability, influence building of external appearance, service life, severity will threat arrive people's life and property safety.A lot of all of crash of engineerings is because of the unsteady development of the crack with the result that.Modern age scienceresearch with a great deal of of the concrete engineering practice certificate, in the concrete engineering crack problem is ineluctable, also acceptable in certainly of the scope just need to adopt valid of measure will it endanger degree control at certain of scope inside.The reinforced concrete norm is also explicit provision:Some structure at place of dissimilarity under the condition allow existence certain the crack of width.But at under construction should as far as possible adopt a valid measure control crack creation, make the structure don't appear crack possibly or as far as possible decrease crack of amount and width, particularly want to as far as possible avoid harmful crack of emergence, insure engineering quality thus.Concrete crack creation of the reason be a lot of and have already transformed to cause of crack:Such as temperature variety, constringency, inflation, the asymmetry sink to sink etc. reason cause of crack;Have outside carry the crack that the function cause;Protected environment not appropriate the crack etc. caused with chemical effect.Want differentiation to treat in the actual engineering, work°out a problem according to the actual circumstance.In the concrete engineering the familiar crack and the prevention1.Stem Suo crack and preventionStem the Suo crack much appear after the concrete protect be over of a period of time or concrete sprinkle to build to complete behind of around a week.In the cement syrup humidity of evaporate would creation stem Suo, and this kind of constringency is can't negative.Stem Suo crack of the creation be main is because of concrete inside outside humidity evaporate degree dissimilarity but cause to transform dissimilarity of result:The concrete is subjected to exterior condition of influence, surface humidity loss lead quick, transform bigger, inner part degree of humidity variety smaller transform smaller, bigger surface stem the Suo transform to be subjected to concrete inner part control, creation more big pull should dint but creation crack.The relative humidity is more low, cement syrup body stem Suo more big, stem the Suo crack be more easy creation.Stem the Suo crack is much surface parallel lines form or the net shallow thin crack, width many between 0.05-0.2 mm, the flat surface part much see in the big physical volume concrete and follow it more in thinner beam plank short todistribute.Stem Suo crack usually the anti- Shen of influence concrete, cause the durable of the rust eclipse influence concrete of reinforcing bar, under the function of the water pressure dint would creation the water power split crack influence concrete of loading dint etc..Concrete stem the Suo be main with water ash of the concrete ratio, the dosage of the composition, cement of cement, gather to anticipate of the dosage of the property and dosage, in addition etc. relevant.Main prevention measure:While being to choose to use the constringency quantity smaller cement, general low hot water mire and powder ash from stove cement in the adoption, lower the dosage of cement.Two is a concrete of stem the Suo be subjected to water ash ratio of influence more big, water ash ratio more big, stem Suo more big, so in the concrete match the ratio the design should as far as possible control good water ash ratio of choose to use, the Chan add in the meantime accommodation of reduce water.Three is strict control concrete mix blend with under construction of match ratio, use of concrete water quantity absolute can't big in match ratio design give settle of use water quantity.Four is the earlier period which strengthen concrete to protect, and appropriate extension protect of concrete time.Winter construction want to be appropriate extension concrete heat preservation to overlay time, and Tu2 Shua protect to protect.Five is a constitution the accommodation is in the concrete structure of the constringency sew.2.The Su constringency crack and preventionSu constringency is the concrete is before condense, surface because of lose water quicker but creation of constringency.The Su constringency crack is general at dry heat or strong wind the weather appear, crack's much presenting in the center breadth, both ends be in the centerthin and the length be different, with each other not coherent appearance.Shorter crack general long 20-30 cm, the longer crack can reach to a 2-3 m, breadth 1-5 mm.It creation of main reason is:The concrete is eventually almost having no strength or strength before the Ning very small, perhaps concrete just eventually Ning but strength very hour, be subjected to heat or compare strong wind dint of influence, the concrete surface lose water to lead quick, result in in the capillary creation bigger negative press but make a concrete physical volume sharplyconstringency, but at this time the strength of concrete again can't resist its constringency, therefore creation cracked.The influence concrete Su constringency open the main factor of crack to have water ash ratio, concrete of condense time, environment temperature, wind velocity, relative humidity...etc..Main prevention measure:One is choose to use stem the Suo value smaller higher Huo sour salt of the earlier period strength or common the Huo sour brine mire.Two is strict the control water ash ratio, the Chan add to efficiently reduce water to increment the collapse of concrete fall a degree and with easy, decrease cement and water of dosage.Three is to sprinkle before building concrete, water basic level and template even to soak through.Four is in time to overlay the perhaps damp grass mat of the plastics thin film, hemp slice etc., keep concrete eventually before the Ning surface is moist, perhaps spray to protect etc. to carry on protect in the concrete surface.Five is in the heat and strong wind the weather to want to establish to hide sun and block breeze facilities, protect in time.3.Sink to sink crack and preventionThe creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;Perhaps because of template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink to decline and cause concrete structure creation crack.This kind crack many is deep enter or pierce through sex crack, it alignment have something to do with sinking to sink a circumstance, general follow with ground perpendicular or present 30 °s-45 °Cape direction development, bigger sink to sink crack, usually have certain of wrong, crack width usually with sink to decline quantity direct proportion relation.Crack width under the influence of temperature variety smaller.The foundation after transform stability sink to sink crack also basic tend in stability.Main prevention measure:One is rightness loose soft soil, return to fill soil foundation a construction at the upper part structure front should carry on necessity ofHang solid with reinforce.Two is the strength that assurance template is enough and just degree, and prop up firm, and make the foundation be subjected to dint even.Three is keep concrete from sprinkle infusing the foundation in the process is soak by water.Four is time that template tore down to can't be too early, and want to notice to dismantle a mold order of sequence.Five is at jelly soil top take to establish template to notice to adopt certain of prevention measure.4.Temperature crack and preventionTemperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete compare the earth area of the concrete structure.Concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal of of water turn hot, .(be the cement dosage is in the 350-550 kg/m 3, each sign square the rice concrete will release a calories of 17500-27500 kJ and make concrete internal thus the temperature rise to reach to 70 ℃or so even higher)Because the physical volume of concrete be more big, a great deal of of water turn hot accumulate at the concrete inner part but not easy send forth, cause inner part the temperature hoick, but the concrete surface spread hot more quick, so formation inside outside of bigger difference in temperature, the bigger difference in temperature result in inner part and exterior hot the degree of the bulge cold Suo dissimilarity, make concrete surface creation certain of pull should dint.When pull should dint exceed the anti- of concrete pull strength extreme limit, concrete surface meeting creation crack, this kind of crack much occurrence after the concrete under construction period.In the concrete of under construction be difference in temperature variety more big, perhaps is a concrete to be subjected to assault of cold wave etc., will cause concrete surface the temperature sharply descend, but creation constringency, surface constringency of the concrete be subjected to inner part concrete of control, creation very big of pull should dint but creation crack, this kind of crack usually just in more shallow scope of the concrete surface creation.The alignment of the temperature crack usually none settle regulation, big area structure the crack often maneuver interleave;The size bigger structure of the beam plank length, the crack run parallel with short side more;Thorough with pierce throughsex of temperature crack general and short side direction parallelism or close parallelism, crack along long side cent the segment appear, in the center more airtight.Crack width the size be different, be subjected to temperature variety influence more obvious, winter compare breadth, summer more narrow.The concrete temperature crack that the heat inflation cause is usually in the center the thick both ends be thin, but cold Suo crack of thick thin variety not too obvious.The emergence of the this kind crack will cause the rust eclipse of reinforcing bar, the carbonization of concrete, the anti- jelly which lower concrete melt, anti- tired and anti- Shen ability etc..Main prevention measure:One is as far as possible choose to use low hot or medium hot water mire, like mineral residue cement, powder ash from stove cement...etc..Two is a decrease cement dosage, cement dosage as far as possible the control is in the 450 kg/m 3 following.Three is to lower water ash ratio, water ash of the general concrete ratio control below 0.6.Four is improvement the bone anticipate class to go together with, the Chan add powder ash from stove or efficiently reduce water etc. to come to reduce cement dosage and lower water to turn hot.Five is an improvement concrete of mix blend to process a craft, lower sprinkle of concrete to build temperature.Six is the in addition that the Chan add a have of fixed amount to reduce water and increase Su, slow Ning etc. function in the concrete, improvement the concrete mix to match a thing of mobility, protect water, lower water to turn hot, postpone hot Feng of emergence time.Seven is the heat season sprinkle to build can the adoption take to establish to hide sun plank etc. assistance measure control concrete of Wen Sheng, lower to sprinkle temperature of build the concrete.Eight is the temperature of big physical volume concrete should the dint relate to structure size, concrete structure size more big, temperature should dint more big, so want reasonable arrangement construction work preface, layering, cent the piece sprinkle to build, for the convenience of in spread hot, let up control.Nine is at great inner part constitution of the physical volume concrete cool off piping, cold water perhaps cold air cool off, let up concrete of inside outside difference in temperature.Ten is the supervision which strengthen concrete temperature, adopt to cool off in time, protection measure.11 is to reserve temperature constringency to sew.12 is to let up to control, sprinkle proper before building concrete in the Ji rockand old concrete top build a 5 mm or so sand mat a layer or usage asphalt etc. material Tu2 Shua.13 is to strengthen concrete to protect, the concrete after sprinkle build use moist grass Lian in time, hemp slice's etc. overlay, and attention sprinkle water to protect, appropriate extension protect time, assurance the concrete surface be slow-moving cool off.At the cold season, concrete surface should constitution heat preservation measure, in order to prevent cold wave assault.14 is the allocation be a little amount in the concrete of reinforcing bar perhaps add fiber material concrete of temperature crack control at certain of scope inside.5.Crack and prevention that the chemical reaction causeAlkali bone's anticipating the crack that reaction crack and reinforcing bar rust eclipse cause is the most familiar in the reinforced concrete structure of because of chemical reaction but cause of crack.The concrete blend a future reunion creation some alkalescence ion, these ion with some activity the bone anticipate creation chemical reaction and absorb surroundings environment in of water but the physical volume enlarge, make concrete crisp loose, inflation open crack.In this kind of crack general emergence concrete structure usage period, once appear very difficult remediable, so should at under construction adopt valid the measure carry on prevention.Main of prevention measure:While being to choose to anticipate with the alkali activity small freestone bone.Two is the in addition which choose to use low lye mire with low alkali or have no alkali.Three is the Chan which choose to use accommodation with anticipate to repress an alkali bone to anticipate reaction.Because the concrete sprinkle to build, flap Dao bad perhaps is a reinforcing bar protection layer thinner, the harmful material get into concrete to make reinforcing bar creation rust eclipse, the reinforcing bar physical volume of the rust eclipse inflation, cause concrete bulge crack, the crack of this kind type much is a crack lengthways, follow the position of reinforcing bar ually of prevent measure from have:One is assurance reinforcing bar protection the thickness of the layer.Two is a concrete class to go together with to want good.Three is a concrete to sprinkle to note and flap Dao airtight solid.Four is a reinforcing bar surface layer Tu2 Shua antisepsiscoating.Crack processingThe emergence of the crack not only would influence structure of whole with just degree, return will cause the rust eclipse of reinforcing bar, acceleration concrete of carbonization, lower durable and anti- of concrete tired, anti- Shen ability.Therefore according to the property of crack and concrete circumstance we want differentiation to treat, in time processing, with assurance building of safety usage.The repair measure of the concrete crack is main to have the following some method:Surface repair method, infuse syrup, the Qian sew method, the structure reinforce a method, concrete displacement method, electricity chemistry protection method and imitate to living from heal method.Surface repair the method be a kind of simple, familiar of repair method, it main be applicable to stability and to structure loading the ability don't have the surface crack of influence and deep enter crack of processing.The processing measure that is usually is a surface in crack daubery cement syrup, the wreath oxygen gum mire or at concrete surface Tu2 Shua paint, asphalt etc. antisepsis material, at protection of in the meantime for keeping concrete from continue under the influence of various function to open crack, usually can adoption the surface in crack glue to stick glass fiber cloth etc. measure.1, infuse syrup, the Qian sew methodInfuse a syrup method main the concrete crack been applicable to have influence or have already defend Shen request to the structure whole of repair, it is make use of pressure equipments gum knot the material press into the crack of concrete, gum knot the material harden behind and concrete formation one be whole, thus reinforce of purpose.The in common use gum knot material has the cement the syrup, epoxy, A Ji C Xi sour ester and gather ammonia ester to equalize to learn material.The Qian sew a method is that the crack be a kind of most in common use method in, it usually is follow the crack dig slot, the Qian fill Su in the slot or rigid water material with attain closing crack of purpose.The in common use Su material has PVC gum mire,plastics ointment, the D Ji rubber etc.;In common use rigid water material is the polymer cement sand syrup.2, the structure reinforce a methodWhen the crack influence arrive concrete structure of function, will consideration adopt to reinforce a method to carry on processing to the concrete structure.The structure reinforce medium in common use main have the following a few method:The piece of enlargement concrete structure in every aspect accumulate, outside the Cape department of the Gou piece pack type steel, adoption prepare should the dint method reinforce, glue to stick steel plate to reinforce, increase to establish fulcrum to reinforce and jet the concrete compensation reinforce.3, concrete displacement methodConcrete displacement method is processing severity damage concrete of a kind of valid method, this method be first will damage of the concrete pick and get rid of, then again displacement go into new of concrete or other material.The in common use displacement material have:Common concrete or the cement sand syrup, polymer or change sex polymer concrete or sand syrup.4, the electricity chemistry protection methodThe electricity chemistry antisepsis is to make use of infliction electric field in lie the quality of electricity chemical effect, change concrete or reinforced concrete the environment appearance of the place, the bluntness turn reinforcing bar to attain the purpose of antisepsis.Cathode protection method, chlorine salt's withdrawing a method, alkalescence to recover a method is a chemistry protection method in three kinds of in common use but valid method.The advantage of this kind of method is a protection method under the influence of environment factor smaller, apply reinforcing bar, concrete of long-term antisepsis, since can used for crack structure already can also used for new set up structure.5, imitate to living from legal moreImitate to living from heal the method be a kind of new crack treatment, its mimicry living creature organization secrete a certain material towards suffering wound part auto, but make the wound part heal of function, join some and special composition(suchas contain to glue knot of the liquid Xin fiber or capsule) in the concrete of the tradition the composition, at concrete inner part formation the intelligence type imitate to living from heal nerve network system, be the concrete appear crack secrete a parts of liquid Xin fiber can make the crack re- heal.ConclusionThe crack is widespread in the concrete structure existence of a kind of phenomenon, it of emergence not only will lower the anti- Shen of building ability, influence building of usage function, and will cause the rust eclipse of reinforcing bar, the carbonization of concrete, lower the durable of material, influence building of loading ability, so want to carry on to the concrete crack earnest research, differentiation treat, adoption reasonable of the method carry on processing, and at under construction adopt various valid of prevention measure to prevention crack of emergence and development, assurance building and Gou piece safety, stability work.From《CANADIAN JOURNAL OF CIVIL ENGINEERING》译文:建筑施工混凝土裂缝的预防与处理混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题,本文对混凝土工程中常见的一些裂缝问题进行了探讨分析,并针对具体情况提出了一些预防、处理措施。
黄山学院毕 业 设 计系 别:_________________________班 级:_________________________姓 名:_________________________指 导 教 师:_______郭富__________________2010年5月8 日刘星 10土对本(2)班 土木工程系目录1 中文翻译 (1)1.1钢筋混凝土 (1)1.2土方工程 (2)1.3结构的安全度 (3)2 外文翻译 (6)2.1 Reinforced Concrete (6)2.2 Earthwork (7)2.3 Safety of Structures (9)1 中文翻译1.1钢筋混凝土素混凝土是由水泥、水、细骨料、粗骨料(碎石或;卵石)、空气,通常还有其他外加剂等经过凝固硬化而成。
将可塑的混凝土拌合物注入到模板内,并将其捣实,然后进行养护,以加速水泥与水的水化反应,最后获得硬化的混凝土。
其最终制成品具有较高的抗压强度和较低的抗拉强度。
其抗拉强度约为抗压强度的十分之一。
因此,截面的受拉区必须配置抗拉钢筋和抗剪钢筋以增加钢筋混凝土构件中较弱的受拉区的强度。
由于钢筋混凝土截面在均质性上与标准的木材或钢的截面存在着差异,因此,需要对结构设计的基本原理进行修改。
将钢筋混凝土这种非均质截面的两种组成部分按一定比例适当布置,可以最好的利用这两种材料。
这一要求是可以达到的。
因混凝土由配料搅拌成湿拌合物,经过振捣并凝固硬化,可以做成任何一种需要的形状。
如果拌制混凝土的各种材料配合比恰当,则混凝土制成品的强度较高,经久耐用,配置钢筋后,可以作为任何结构体系的主要构件。
浇筑混凝土所需要的技术取决于即将浇筑的构件类型,诸如:柱、梁、墙、板、基础,大体积混凝土水坝或者继续延长已浇筑完毕并且已经凝固的混凝土等。
对于梁、柱、墙等构件,当模板清理干净后应该在其上涂油,钢筋表面的锈及其他有害物质也应该被清除干净。
forced concrete structure reinforced with anoverviewReinSince the reform and opening up, with the national economy's rapid and sustained development of a reinforced concrete structure built, reinforced with the development of technology has been great. Therefore, to promote the use of advanced technology reinforced connecting to improve project quality and speed up the pace of construction, improve labor productivity, reduce costs, and is of great significance.Reinforced steel bars connecting technologies can be divided into two broad categories linking welding machinery and steel. There are six types of welding steel welding methods, and some apply to the prefabricated plant, and some apply to the construction site, some of both apply. There are three types of machinery commonly used reinforcement linking method primarily applicable to the construction site. Ways has its own characteristics and different application, and in the continuous development and improvement. In actual production, should be based on specific conditions of work, working environment and technical requirements, the choice of suitable methods to achieve the best overall efficiency.1、steel mechanical link1.1 radial squeeze linkWill be a steel sleeve in two sets to the highly-reinforced Department with superhigh pressure hydraulic equipment (squeeze tongs) along steel sleeve radial squeeze steel casing, in squeezing out tongs squeeze pressure role of a steel sleeve plasticity deformation closely integrated with reinforced through reinforced steel sleeve and Wang Liang's Position will be two solid steel bars linkedCharacteristic: Connect intensity to be high, performance reliable, can bear high stress draw and pigeonhole the load and tired load repeatedly.Easy and simple to handle, construction fast, save energy and material, comprehensive economy profitable, this method has been already a large amount of application in the project.Applicable scope : Suitable for Ⅱ, Ⅲ, Ⅳgrade reinforcing bar (including welding bad reinfor cing bar ) with ribbing of Ф 18- 50mm, connection between the same diameter or different diameters reinforcing bar .1.2must squeeze linkExtruders used in the covers, reinforced axis along the cold metal sleeve squeeze dedicated to insert sleeve Lane two hot rolling steel drums into a highly integrated mechanical linking methods.Characteristic: Easy to operate and joining fast and not having flame homework , can construct for 24 hours , save a large number of reinforcing bars and energy. Applicable scope : Suitable for , set up according to first and second class antidetonation requirement -proof armored concrete structure ФⅡ, Ⅲgrade reinforcing bar with ribbing of hot rolling of 20- 32mm join and construct live.1.3 cone thread connectingUsing cone thread to bear pulled, pressed both effort and self-locking nature, undergo good principles will be reinforced by linking into cone-processing thread at the moment the value of integration into the joints connecting steel bars.Characteristic: Simple , all right preparatory cut of the craft , connecting fast, concentricity is good, have pattern person who restrain from advantage reinforcing bar carbon content.Applicable scope : Suitable for the concrete structure of the industry , civil buil ding and general structures, reinforcing bar diameter is for Фfor the the 16- 40mm one Ⅱ, Ⅲgrade verticality, it is the oblique to or reinforcing bars horizontal join construct live.conclusionsThese are now commonly used to connect steel synthesis methods, which links technology in the United States, Britain, Japan and other countries are widely used. There are different ways to connect their different characteristics and scope of theactual construction of production depending on the specific project choose a suitable method of connecting to achieve both energy conservation and saving time limit for a project ends.钢筋混凝土结构中钢筋连接综述改革开放以来,随着国民经济的快速、持久发展,各种钢筋混凝土建筑结构大量建造,钢筋连接技术得到很大的发展。
外文文献:Construction of the competition and competition strategy Engineering and construction firms from the United States dominated the global market for many decades but recent world events have altered their position.To investigate the driving forces and trends that will affect engineering and construction competition in the next decade, a research project, called the "Anatomy of Construction Competition in the Year 2000", was sponsored by the Construction Industry Institute's Construc—tion 2000 Task Force— The project examined the factors that affect competitiveness, including the following, The shaping of corporate capabilities; vertical integration and horizontal expansion to increase corporate capabilities and market share, including acquisition and mergers by offshore conglomerates and the acquisition of foreign firms by U. S. companies.Financing options; the role of privatization, build-own-transfer projects, and the nature of project financing in future markets,Management, organization, and structure; future management and organizational approaches, structures, and techniques to attract personnel to perform in a global competitive environment.Work force characteristics; future availability of engineering and construction workers at the professional and craft levels.Technological issues:how technology will affect competition and be used to offset work force shortages.Research Objectives and ScopeThis research project's goal is to collect information, to adapt to the 2000 and the engineering construction after adjustment,formulate strategies needed to provide insight and formulate 2000 engineering construction of possible development plan. This study reviewed the project construction process of history, current development trend, to determine the impact of the industry, and the impetus to the future industrial enterprises are related to reshape the ability, privatisation and financing methods of potential function and management, organization structure, methods for future development direction。
中英文资料翻译Building construction quality managementAbstract:adhere to the quality first, improve the management level, improve the quality of construction is the key, only to meet the required quality standards and user requirements under the premise of quality, time limit for a project, cost, to meet the requirements, to provide more high-quality, safe, economical and applicable building products. Based on this, the building construction quality management of.Key words: housing construction building construction quality management1 strengthen training, selection of construction personnel is laying the quality control personnel foundationEngineering quality were all participants in the project construction technology management, operating personnel coordination work results, so construction workers is to form the main factor of project quality. To control the engineering quality first is the training and selection of construction personnel, improving their comprehensive quality. We should improve their quality awareness, according to comprehensive quality regardless of idea construction personnel must establish five concepts: the concept of quality first, pre-control priority idea, talk with data concept and social benefit and enterprise benefit and comprehensive benefit idea. The second is the construction of the technical quality of personnel, management, construction personnel should have higher quality planning and management capacity, production personnel should have superb technical ability, be strict in one's demands of the style of work, strict implementation of quality standards and procedures of the legal concept, service personnel should do good technology and service life, can be with excellent service indirectly to ensure engineering quality.2 give full play to QC quality control functionAccording to "the anti-seizure combination, prevention first " principle is carried out actively " tell, help, anti, card" scientific examination method, and the constructionpersonnel together, common to the owners of construction process, responsible, quality control personnel, users, the construction personnel to establish new relations of cooperation, quality inspection staff and the construction site operations personnel is consistent, it is to provide users with high quality, satisfaction of building products. But the construction production is busy, to snatch the project schedule is loosen quality management tendency occurs. This led to check the quality of the project is checked with contradictions between. To give full play to the initiative of the staff to check the quality of the project, it is necessary to establish the authority of the quality inspection personnel, it is very necessary and important.3 following a case analysis gradually quality management, engineering survey:The territory of Hechi a building for the underground layer, on the ground twenty-two, twenty-five buildings, covers an area of 2550.4 square meters, building a total height of 79.950 meters, construction area of 4008 square meters underground, on the ground 36855 square meters, balcony area is 1570.1 square meters; the main design reasonable service life is 50 years; building fire grade two, seismic fortification intensity is 7 degrees, frame aseismic grade two; the ground floor to the ground floor three layer 2-A axis 2-6 axis and2-17 axis short limb shear wall seismic rating for a class, the rest of shear wall seismic grade two. The project uses the base form of prestressed high-strength concrete pipe pile, structure type for the cast-in-place reinforced concrete frame shear wall structure.4 construction managementOn the construction quality management, mainly involves three aspects, one is about the design, survey and document review management. On design, reconnaissance unit quality behavior and results of the activities of the supervision, the emphasis is placed on the design, survey and document review supervisory control. If the violation of the relevant laws, regulations and mandatory standards for the design and survey documents, can be through direct economic penalties and legal sanctions, enabling direct responsibility assumed by the error caused by negligence or intentional quality responsibility. Two of the activities of the bidding management, focuses on the construction bidding supervision, market supervision and quality supervision the effective integration, through the quality supervision to promote the market competition and standardization of the benign operation, effectively through market operation, to ensure the validity of quality supervision. Three isthe text of the contract supervision, is the focus of construction contract supervision, quality management standardization and legalization to fulfil the terms of the contract, the legal effect of contract binding the construction quality and results. By analyzing the three aspects of examination and supervision, to achieve the government's construction qualityof the implementation process control and supervision. Before the construction, in the final analysis is the emphasis of quality management for owners of quality behavior management, because the owner of all these activities of the organizers, decision makers, which is the standard construction owner quality behavior and results of the activities of the important measures.5 construction management5.1 Lraw materials quality controlMaterial quality engineering construction quality is the key, use of raw materials does not meet the requirements of engineering, engineering quality can not meet the requirements. Therefore, in the construction quality control of stop before construction on material quality control, to ensure the quality of materials, in order to improve construction quality. For the control of materials, first of all to the common material supply necessary audit, select qualified suppliers for the supply of materials. Secondly, to approach the necessary inspection of raw materials, including: quality inspection report of the inspection, the inspection of appearance, physical and chemical inspection inspection. Through a series of tests to ensure the quality of the raw materials entering.5.2 procedures and time limit controlTo implement the handover inspection system, on the procedures of unqualified shall enter into next working procedure construction. At the same time construction quality affected by seasons, the reasonable arrangement of construction schedule is to ensure the engineering quality are important measures, and blindly rush period will inevitably lead to serious consequences. Quality control step is to establish quality control, selected key and key technology to undertake the key is checked, the two is to strengthen the operation of the management, project quality is good or bad, depends to some extent on the construction of personnel operation level.5.3 increase on-site inspectionsQuality management in the construction site should strive to grasp first-hand information, and strive to achieve the timely control, for the occurrence of the problemmust accomplish early discovery, early correction of bad old practices die hard, avoid, avoid large loss. For example, in the masonry tie bar examination, if taken after the completion of a masonry opening examination, is not easy to check, and to identify the problems are also difficult to remedy, but in the on-site inspection in a timely manner to solve, can avoid bigger loss, but also easy to get the cooperation.The entity quality inspection methods should adopt scientific monitoring instruments and equipment, to provide accurate, reliable and convincing data, strengthen the government engineering quality supervision and inspection of scientific and authoritative. Through the supervision, to ensure the implementation of mandatory standards, ensure the construction of law, regulations and standard carry out, from macroscopical overall grasp the construction project quality and structure safety. In addition, in strengthening program management at the same time, we must strengthen the technical control. Technology control method using standard evaluation method is better. Evaluation of standard methods are mainly as follows: one is the on site quality assurance condition examination and evaluation, two is the completion of the project the detection results of the examination and evaluation, three is on site quality assurance data examination and evaluation, four of engineering entity size deviation of the measured, five is for the completion of engineering the macro visual inspection evaluation.5.4 after the completion of the managementAfter the completion of the quality management of construction projects is put into use check management. First of all to ensure that do not meet the quality standards of the project can not be put into use, avoid inferior project to the state and public users cause direct harm and influence. The second is the decoration, repair and maintenance of quality supervision in construction project whole life quality management category : one is to eliminate or reduce due to renovation, maintenance process caused by irregularities on the construction engineering foundation, body structure and environmental quality, damage, cause quality accident. Two is prevented due to repair, maintenance quality is not up to the requirements to the state and public users production and living environment caused by direct damage. At this stage of the supervision should be emphasized good two close: it is strictly for its completion and acceptance review, supervision, to ensure that the registration of the reliability, authority and effectiveness. Two is to enhance the decoration, maintenance of quality management in the process, so that construction project whole lifequality objectives are effective implementation, for users to create a safe, comfortable, healthy production, living environment, so that the construction quality and realizing the sustainable development. Advocating and implementing project quality insurance, the project quality management into economic management category, to solve engineering after the delivery of quality problem tenants to find the responsible party for any menace from the "rear".This phase is the project by construction to use or production of mark; is on engineering quality inspection the necessary link; is the guarantee contract task is finished in the round, improve project quality level of final checks. The unit after the completion of the project, must undertake the final inspection and test. Unit engineering technical person in charge should be prepared for the demands of information collected materials, equipment, component quality certificate of materials, a variety of material test data, record of concealed work, construction records records. By the technical director of project organization project technology, quality, production and other relevant professional and technical personnel to the scene inspection and evaluation. To identify the construction quality defects should be corrected, and should be corrected once again after the verification to demonstrate conformity. To ensure engineering quality accord with mandatory standard design documents and the requirements of the contract, the employer, the Ministry of supervision of the project completion report. Attended by the construction unit of the organization of the main parties involved in the completion of initial inspection, acceptance procedure.endingProject, quality, the quality of housing construction related to people's daily life and the safety of life and property. In recent years, the housing quality problems have already become the focus of public attention, annual 3.15 consumer rights day, China Consumers Association published by consumer complaints the largest of the ten major categories of commodities, the housing quality problems at the front. Therefore, construction management in many aspects, quality management is the key and core. Only do a good job in building engineering construction quality planning and housing construction quality control, to create more quality engineering.Reference.[1 ] Building Engineering ( Construction Management ) [ J]. Journal of Taizhou Polytechnic College.[2 ] Wang Yan. Paying attention to construction management" two pieces of skins" phenomenon [J ]. Management of construction enterprises.[3 ] Lin Yihong, Li Yuanying. To improve construction quality several ponders [J ]. Shanxi building, 2005, 31 ( 1): 127-128.[4 ] Bu Narui, Wang Liwen, Li Wanqin. Discussion on construction management [ J]. Journal of Hebei Institute of Architecture and Civil Engineering, 2002, ( 02).Hu Zhenghua[ 5]. The era of knowledge economy the construction management [J ]. Parathion design and powder engineering, 2005, ( 06).[ 6].Zheng Jingqiu.Infuluencing the contrcution qulity of Engineering five fsctors[J ]. Shanxi building.2005,31( 1):135-136.浅谈房屋建筑施工中的质量管理摘要:坚持质量第一、提高管理水平,是提高建筑工程质量关键之所在,只有在符合规定的质量标准和用户要求的前提下,满足质量、工期、成本等要求,才能为社会提供更多的优质、安全、经济适用的建筑产品。
土木工程建筑外文文献及翻译土木工程建筑外文文献及翻译Cyclic behavior of steel moment frame connections under varying axial load and lateral displacementsAbstractThis paper discusses the cyclic behavior of four steel moment connections tested under variable axial load and lateral displacements. The beam specim- ens consisted of a reducedbeam section, wing plates and longitudinal stiffeners. The test specimens were subjected to varying axial forces and lateral displace- ments to simulate the effects on beams in a Coupled-Girder Moment-Resisting Framing system under lateral loading. The test results showed that the specim- ens responded in a ductile manner since the plastic rotations exceeded 0.03 rad without significant drop in the lateral capacity. The presence of the longitudin- al stiffener assisted in transferring the axial forces and delayed the formation of web local buckling.1. IntroductionAimed at evaluating the structural performance of reduced-beam section(RBS) connections under alternated axial loading and lateral displacement, four full-scale specimens were tested. These tests were intended to assess the performance of the moment connection design for the Moscone Center Exp- ansion under the Design Basis Earthquake (DBE) and the Maximum Considered Earthquake (MCE). Previous research conducted on RBS moment connections [1,2] showed that connections with RBS profiles can achieve rotations in excess of 0.03 rad. However, doubts have been cast on the quality of the seismic performance of theseconnections under combined axial and lateral loading.The Moscone Center Expansion is a three-story, 71,814 m2 (773,000 ft2) structure with steel moment frames as its primary lateral force-resisting system. A three dimensional perspective illustration is shown in Fig. 1. The overall height of the building, at the highest point of the exhibition roof, is approxima- tely 35.36 m (116ft) above ground level. The ceiling height at the exhibition hall is 8.23 m (27 ft) , and the typical floor-to-floor height in the building is 11.43 m (37.5 ft). The building was designed as type I according to the requi- rements of the 1997 Uniform Building Code. The framing system consists of four moment frames in the East–West direct- ion, one on either side of the stair towers, and four frames in the North–South direction, one on either side of the stair and elevator cores in the east end and two at the west end of the structure [4]. Because of the story height, the con- cept of the Coupled-Girder Moment-Resisting Framing System (CGMRFS) was utilized.By coupling the girders, the lateral load-resisting behavior of the moment framing system changes to one where structural overturning moments are resisted partially by an axial compression–tension couple across the girder system, rather than only by the individual flexural action of the girders. As a result, a stiffer lateral load resisting system is achieved. The vertical element that connects the girders is referred to as a coupling link. Coupling links are analogous to and serve the same structural role as link beams in eccentrically braced frames. Coupling links are generally quite short, having a large shear- to-moment ratio.Under earthquake-type loading, the CGMRFS subjects its girders to wariab- ble axial forces in addition to their endmoments. The axial forces in theFig. 1. Moscone Center Expansion Project in San Francisco, CAgirders result from the accumulated shear in the link.2. Analytical model of CGMRFNonlinear static pushover analysis was conducted on a typical one-bay model of the CGMRF. Fig. 2 shows the dimensions and the various sections of the 10 in) and the ?254 mm (1 1/8 in ?model. The link flange plates were 28.5 mm 18 3/4 in). The SAP 2000 computer ?476 mm (3 /8 in ?web plate was 9.5 mm program was utilized in the pushover analysis [5]. The frame was characterized as fully restrained(FR). FR moment frames are those frames for 1170 which no more than 5% of the lateral deflections arise from connection deformation [6]. The 5% value refers only to deflection due to beam–column deformation and not to frame deflections that result from column panel zone deformation [6, 9].The analysis was performed using an expected value of the yield stress and ultimate strength. These values were equal to 372 MPa (54 ksi) and 518 MPa (75 ksi), respective ly. The plastic hinges’ load–deformation behavior was approximated by the generalized curve suggested by NEHRP Guidelines for the Seismic Rehab ilitation of Buildings [6] as shown in Fig. 3. △y was calcu- lated based on Eqs. (5.1) and (5.2) from [6], as follows: P–M hinge load–deformation model points C, D and E are based on Table 5.4 from [6] for△y was taken as 0.01 rad per Note 3 in [6], Table 5.8. Shear hinge load- load–deformation model points C, D and E are based on Table 5.8 [6], Link Beam, Item a. A strain hardening slope between points B and C of 3% of the elastic slope was assumedfor both models.The following relationship was used to account for moment–axial load interaction [6]:where MCE is the expected moment strength, ZRBS is the RBS plastic section modulus (in3), is the expected yield strength of the material (ksi), P is the axial force in the girder (kips) and is the expected axial yield force of the RBS, equal to (kips). The ultimate flexural capacities of the beam and the link of the model are shown in Table 1.Fig. 4 shows qualitatively the distribution of the bending moment, shear force, and axial force in the CGMRF under lateral load. The shear and axial force in the beams are less significant to the response of the beams as compared with the bending moment, although they must be considered in design. The qualita- tive distribution of internal forces illustrated in Fig. 5 is fundamentally the same for both elastic and inelastic ranges of behavior. The specific values of the internal forces will change as elements of the frame yield and internal for- ces are redistributed. The basic patterns illustrated in Fig. 5, however, remain the same.Inelastic static pushover analysis was carried out by applying monotonically increasing lateral displacements, at the top of both columns, as shown in Fig. 6. After the four RBS have yielded simultaneously, a uniform yielding in the web and at the ends of the flanges of the vertical link will form. This is the yield mechanism for the frame , with plastic hinges also forming at the base of the columns if they are fixed. The base shear versus drift angle of the model is shown in Fig. 7 . The sequence of inelastic activity in the frame is shown on the figure. An elastic component, a long transition (consequence of the beam plastic hinges being formed simultaneously) and a narrow yield plateaucharacterize the pushover curve.The plastic rotation capacity, qp, is defined as the total plastic rotation beyond which the connection strength starts to degrade below 80% [7]. This definition is different from that outlined in Section 9 (Appendix S) of the AISC Seismic Provisions [8, 10]. Using Eq. (2) derived by Uang and Fan [7], an estimate of the RBS plastic rotation capacity was found to be 0.037 rad:Fyf was substituted for Ry?Fy [8], where Ry is used to account for the differ- ence between the nominal and the expected yield strengths (Grade 50 steel, Fy=345 MPa and Ry =1.1 are used).3. Experimental programThe experimental set-up for studying the behavior of a connection was based on Fig. 6(a). Using the plastic displacement dp, plastic rotation gp, and plastic story drift angle qp shown in the figure, from geometry, it follows that:And:in which d and g include the elastic components. Approximations as above are used for large inelastic beam deformations. The diagram in Fig. 6(a) suggest that a sub assemblage with displacements controlled in the manner shown in Fig. 6(b) can represent the inelastic behavior of a typical beam in a CGMRF.The test set-up shown in Fig. 8 was constructed to develop the mechanism shown in Fig. 6(a) and (b). The axial actuators were attached to three 2438 mm × 1219 mm ×1219 mm (8 ft × 4 ft × 4 ft) RC blocks. These blocks were tensioned to the laboratory floor by means of twenty-four 32 mm diameter dywidag rods. This arrangement permitted replacement of the specimen after each test.Therefore, the force applied by the axial actuator, P, can beresolved into two or thogonal components, Paxial and Plateral. Since the inclination angle of the axial actuator does not exceed , therefore Paxial is approximately equal to P [4]. However, the lateral 3.0 component, Plateral, causes an additional moment at the beam-to column joint. If the axial actuators compress the specimen, then the lateral components will be adding to the lateral actuator forces, while if the axial actuators pull the specimen, the Plateral will be an opposing force to the lateral actuators. When the axial actuators undergoaxial actuators undergo a lateral displacement _, they cause an additional moment at the beam-to-column joint (P-△effect). Therefore, the moment at the beam-to column joint is equal to: where H is the lateral forces, L is the arm, P is the axial force and _ is the lateral displacement.Four full-scale experiments of beam column connections were conducted.The member sizes and the results of tensile coupon tests are listed in Table 2All of the columns and beams were of A572 Grade 50 steel (Fy 344.5 MPa). The actual measured beam flange yield stress value was equal to 372 MPa (54 ksi), while the ultimate strength ranged from 502 MPa (72.8 ksi) to 543 MPa (78.7 ksi).Table 3 shows the values of the plastic moment for each specimen (based on measured tensile coupon data) at the full cross-section and at the reduced section at mid-length of the RBS cutout.The specimens were designated as specimen 1 through specimen 4. Test specimens details are shown in Fig. 9 through Fig. 12. The following features were utilized in the design of the beam–column connection:The use of RBS in beam flanges. A circular cutout was provided, as illustr- ated in Figs. 11 and 12. For all specimens, 30% of the beam flange width was removed. The cuts were made carefully, and then ground smooth in a direct- tion parallel to the beam flange to minimize notches.Use of a fully welded web connection. The connection between the beam web and the column flange was made with a complete joint penetration groove weld (CJP). All CJP welds were performed according to AWS D1.1 Structural Welding Code Use of two side plates welded with CJP to exterior sides of top and bottom beam flan- ges, from the face of the column flange to the beginning of the RBS, as shown in Figs. 11 and 12. The end of the side plate was smoothed to meet the beginning of the RBS. The side plates were welded with CJP with the column flanges. The side plate was added to increase the flexural capacity at the joint location, while the smooth transition was to reduce the stress raisers, which may initiate fractureTwo longitudinal stiffeners, 95 mm × 35 mm (3 3/4 in × 1 3/8 in), were welded with 12.7 mm (1/2 in) fillet weld at the middle height of the web as shown in Figs. 9 and 10. The stiffeners were welded with CJP to column flanges.Removal of weld tabs at both the top and bottom beam flange groove welds. The weld tabs were removed to eliminate any potential notches introduced by the tabs or by weld discontinuities in the groove weld run out regionsUse of continuity plates with a thickness approximately equal to the beam flange thickness. One-inch thick continuity plates were used for all specimens.While the RBS is the most distinguishing feature of these test specimens, the longitudinal stiffener played an important role indelaying the formation of web local buckling and developing reliable connection4. Loading historySpecimens were tested by applying cycles of alternated load with tip displacement increments of _y as shown in Table 4. The tip displacement of the beam was imposed by servo-controlled actuators 3 and 4. When the axial force was to be applied, actuators 1 and 2 were activated such that its force simulates the shear force in the link to be transferred to the beam. 0.5_y. After The variable axial force was increased up to 2800 kN (630 kip) at that, this lo- ad was maintained constant through the maximum lateral displacement.maximum lateral displacement. As the specimen was pushed back the axialforce remained constant until 0.5 y and then started to decrease to zero as the specimen passed through the neutral position [4]. According to the upper bound for beam axial force as discussed in Section 2 of this paper, it was concluded that P =2800 kN (630 kip) is appropriate to investigate this case in RBS loading. The tests were continued until failure of the specimen, or until limitations of the test set-up were reached.5. Test resultsThe hysteretic response of each specimen is shown in Fig. 13 and Fig. 16. These plots show beam moment versus plastic rotation. The beam moment is measured at the middle of the RBS, and was computed by taking an equiva- lent beam-tip force multiplied by the distance between the centerline of the lateral actuator to the middle of the RBS (1792 mm for specimens 1 and 2, 3972 mm for specimens 3 and 4). The equivalent lateral force accounts for the additional moment due to P–△effect. Therotation angle was defined as the lateral displacement of the actuator divided by the length between the centerline of the lateral actuator to the mid length of the RBS. The plastic rotation was computed as follows [4]:where V is the shear force, Ke is the ratio of V/q in the elastic range. Measurements and observations made during the tests indicated that all of the plastic rotation in specimen 1 to specimen 4 was developed within the beam. The connection panel zone and the column remained elastic as intended by design.5.1. Specimens 1 and 2The responses of specimens 1 and 2 are shown in Fig. 13. Initial yielding occurred during cycles 7 and 8 at 1_y with yielding observed in the bottom flange. For all test specimens, initial yielding was observed at this location and attributed to the moment at the base of the specimen [4]. Progressing through the loading history, yielding started to propagate along the RBS bottom flange. During cycle 3.5_y initiation of web buckling was noted adjacent to the yielded bottom flange. Yielding started to propagate along the top flange of the RBS and some minor yielding along the middle stiffener. During the cycle of 5_y with the increased axial compression load to 3115 KN (700 kips) a severe web buckle developed along with flange local buckling. The flange and the web local buckling became more pronounced with each successive loading cycle. It should be noted here that the bottom flange and web local buckling was not accompanied by a significant deterioration in the hysteresis loops.A crack developed in specimen 1 bottom flange at the end of the RBS where it meets the side plate during the cycle 5.75_y. Upon progressing through the loading history, 7_y, the crackspread rapidly across the entire width of the bottom flange. Once the bottom flange was completely fractured, the web began to fracture. This fracture appeared to initiate at the end of the RBS,then propagated through the web net section of the shear tab, through the middle stiffener and the through the web net section on the other side of the stiffener. The maximum bending moment achieved on specimen 1 during theDuring the cycle 6.5 y, specimen 2 also showed a crack in the bottom flange at the end of the RBS where it meets the wing plate. Upon progressing thou- gh the loading history, 15 y, the crack spread slowly across the bottom flan- ge. Specimen 2 test was stopped at this point because the limitation of the test set-up was reached.The maximum force applied to specimens 1 and 2 was 890 kN (200 kip). The kink that is seen in the positive quadrant is due to the application of the varying axial tension force. The load-carrying capacity in this zone did not deteriorate as evidenced with the positive slope of the force–displacement curve. However, the load-carrying capacity deteriorated slightly in the neg- ative zone due to the web and the flange local buckling.Photographs of specimen 1 during the test are shown in Figs.14 and 15. Severe local buckling occurred in the bottom flange and portion of the web next to the bottom flange as shown in Fig. 14. The length of this buckle extended over the entire length of the RBS. Plastic hinges developed in the RBS with extensive yielding occurring in the beam flanges as well as the web. Fig. 15 shows the crack that initiated along the transition of the RBS to the side wing plate. Ultimate fracture of specimen 1 was caused by a fracture in the bottom flange. This fracture resulted in almost total loss of the beam- carrying capacity. Specimen 1 developed0.05 rad of plastic rotation and showed no sign of distress at the face of the column as shown in Fig. 15.5.2. Specimens 3 and 4The response of specimens 3 and 4 is shown in Fig. 16. Initial yielding occured during cycles 7 and 8 at 1_y with significant yielding observed in the bottom flange. Progressing through the loading history, yielding started to propagate along the bottom flange on the RBS. During cycle 1.5_y initiation of web buckling was noted adjacent to the yielded bottom flange. Yielding started to propagate along the top flange of the RBS and some minor yielding along the middle stiffener. During the cycle of 3.5_y a severe web buckle developed along with flange local buckling. The flange and the web local buckling bec- ame more pronounced with each successive loading cycle.During the cycle 4.5 y, the axial load was increased to 3115 KN (700 kips) causing yielding to propagate to middle transverse stiffener. Progressing through the loading history, the flange and the web local buckling became more severe. For both specimens, testing was stopped at this point due to limitations in the test set-up. No failures occurred in specimens 3 and 4. However, upon removing specimen 3 to outside the laboratory a hairline crack was observed at the CJP weld of the bottom flange to the column.The maximum forces applied to specimens 3 and 4 were 890 kN (200 kip) and 912 kN (205 kip). The load-carrying capacity deteriorated by 20% at the end of the tests for negative cycles due to the web and the flange local buckling. This gradual reduction started after about 0.015 to 0.02 rad of plastic rotation. The load-carrying capacity during positive cycles (axial tension applied in the girder) did not deteriorate as evidenced with the slope of the force–displacement envelope for specimen 3 shownin Fig. 17.A photograph of specimen 3 before testing is shown in Fig.18. Fig. 19 is aFig. 16. Hysteretic behavior of specimens 3 and 4 in terms of moment at middle RBS versus beam plastic rotation.photograph of specimen 4 taken after the application of 0.014 rad displacem- ent cycles, showing yielding and local buckling at the hinge region. The beam web yielded over its full depth. The most intense yielding was observed in the web bottom portion, between the bottom flange and the middle stiffener. The web top portion also showed yielding, although less severe than within the bottom portion. Yielding was observed in the longitudinal stiffener. No yiel- ding was observed in the web of the column in the joint panel zone. The un- reduced portion of the beam flanges near the face of the column did not show yielding either. The maximum displacement applied was 174 mm, and the maximum moment at the middle of the RBS was 1.51 times the plastic mom ent capacity of the beam. The plastic hinge rotation reached was about 0.032 rad (the hinge is located at a distance 0.54d from the column surface,where d is the depth of the beam).5.2.1. Strain distribution around connectionThe strain distribution across the flanges–outer surface of specimen 3 is shown in Figs. 20 and 21. The readings and the distributions of the strains in specimens 1, 2 and 4 (not presented) showed a similar trend. Also the seque- nce of yielding in these specimens is similar to specimen 3.The strain at 51 mm from the column in the top flange–outer surface remained below 0.2% during negative cycles. The top flange, at the same location, yielded in compression only Thelongitudinal strains along the centerline of the bottom–flange outer face are shown in Figs. 22 and 23 for positive and negative cycles, respectively. From Fig.23, it is found that the strain on the RBS becomes several times larg- er than that near the column after cycles at –1.5_y; this is responsible for theflange local buckling. Bottom flange local buckling occurred when the average strain in the plate reached the strain-hardening value (esh _ 0.018) and the reduced-beam portion of the plate was fully yielded under longitudinal stresses and permitted the development of a full buckled wave.5.2.2. Cumulative energy dissipatedThe cumulative energy dissipated by the specimens is shown in Fig. 24. The cumulative energy dissipated was calculated as the sum of the areas enclosed the lateral load–lateral displacement hysteresis loops. Energy dissipation sta- rted to increase after cycle 12 at 2.5 y (Fig. 19). At large drift levels, energy dissipation augments significantly with small changes in drift. Specimen 2 dissipated more energy than specimen 1, which fractured at RBS transition. However, for both specimens the trend is similar up to cycles at q =0.04 radIn general, the dissipated energy during negative cycles was1.55 times bigger than that for positive cycles in specimens 1 and2. For specimens 3 and 4 the dissipated energy during negative cycles was 120%, on the average, that of the positive cycles. The combined phenomena of yielding, strain hardening, in-plane and out- of-plane deformations, and local distortion all occurred soon after the bottom flange RBS yielded.6. ConclusionsBased on the observations made during the tests, and on the analysis of the instrumentation, the following conclusions weredeveloped:1. The plastic rotation exceeded the 3% radians in all test specimens.2. Plastification of RBS developed in a stable manner.3. The overstrength ratios for the flexural strength of the test specimens were equal to 1.56 for specimen 1 and 1.51 for specimen4. The flexural strength capacity was based on the nominal yield strength and on the FEMA-273 beam–column equation.4. The plastic local buckling of the bottom flange and the web was not accompanied by a significant deterioration in the load-carrying capacity.5. Although flange local buckling did not cause an immediate degradation of strength, it did induce web local buckling.6. The longitudinal stiffener added in the middle of the beam web assisted in transferring the axial forces and in delaying the formation of web local buckling. How ever, this has caused a much higher overstrength ratio, which had a significant impact on the capacity design of the welded joints, panel zone and the column.7. A gradual strength reduction occurred after 0.015 to 0.02 rad of plastic rotation during negative cycles. No strength degradation was observed during positive cycles.8. Compression axial load under 0.0325Py does not affect substantially the connection deformation capacity.9. CGMRFS with properly designed and detailed RBS connections is a reliable system to resist earthquakes.AcknowledgementsStructural Design Engineers, Inc. of San Francisco financially supported the experimental program. The tests were performedin the Large Scale Structures Laboratory of the University of Nevada, Reno. The participation of Elizabeth Ware, Adrianne Dietrich and of the technical staff is gratefully acknowledged.References受弯钢框架结点在变化轴向荷载和侧向位移的作用下的周期性行为摘要这篇论文讨论的是在变化的轴向荷载和侧向位移的作用下,接受测试的四种受弯钢结点的周期性行为。
forced concrete structure reinforced with anoverviewReinSince the reform and opening up, with the national economy's rapid and sustained development of a reinforced concrete structure built, reinforced with the development of technology has been great. Therefore, to promote the use of advanced technology reinforced connecting to improve project quality and speed up the pace of construction, improve labor productivity, reduce costs, and is of great significance.Reinforced steel bars connecting technologies can be divided into two broad categories linking welding machinery and steel. There are six types of welding steel welding methods, and some apply to the prefabricated plant, and some apply to the construction site, some of both apply. There are three types of machinery commonly used reinforcement linking method primarily applicable to the construction site. Ways has its own characteristics and different application, and in the continuous development and improvement. In actual production, should be based on specific conditions of work, working environment and technical requirements, the choice of suitable methods to achieve the best overall efficiency.1、 steel mechanical link1.1 radial squeeze linkWill be a steel sleeve in two sets to the highly-reinforced Department with superhigh pressure hydraulic equipment (squeeze tongs) along steel sleeve radial squeeze steel casing, in squeezing out tongs squeeze pressure role of a steel sleeve plasticity deformation closely integrated with reinforced through reinforced steel sleeve and Wang Liang's Position will be two solid steel bars linkedCharacteristic: Connect intensity to be high, performance reliable, can bear high stress draw and pigeonhole the load and tired load repeatedly.Easy and simple to handle, construction fast, save energy and material, comprehensive economy profitable, this method has been already a large amount of application in the project.Applicable scope : Suitable for Ⅱ , Ⅲ , Ⅳ grade reinforcing bar (including welding bad reinforcing bar ) with ribbing of Ф 18- 50mm, connection between the same diameter or different diameters reinforcing bar .1.2 must squeeze linkExtruders used in the covers, reinforced axis along the cold metal sleeve squeeze dedicated to insert sleeve Lane two hot rolling steel drums into a highly integrated mechanical linking methods.Characteristic: Easy to operate and joining fast and not having flame homework , can construct for 24 hours , save a large number of reinforcing bars and energy.Applicable scope : Suitable for , set up according to first and second class antidetonation requirement -proof armored concrete structure ФⅡ , Ⅲ grade reinforcing bar with ribbing of hot rolling of 20- 32mm join and construct live.1.3 cone thread connectingUsing cone thread to bear pulled, pressed both effort and self-locking nature, undergo good principles will be reinforced by linking into cone-processing thread at the moment the value of integration into the joints connecting steel bars.Characteristic: Simple , all right preparatory cut of the craft , connecting fast, concentricity is good, have pattern person who restrain from advantage reinforcing bar carbon content.Applicable scope : Suitable for the concrete structure of the industry , civil building and general structures, reinforcing bar diameter is for Фfor the the 16- 40mm one Ⅱ , Ⅲ grade verticality, it is the oblique to or reinforcing bars horizontal join construct live.conclusionsThese are now commonly used to connect steel synthesis methods, which links technology in the United States, Britain, Japan and other countries are widely used. There are different ways to connect their different characteristics and scope of the actual construction of production depending on the specific project choose a suitable method of connecting to achieve both energy conservation and saving time limit for a project ends.钢筋混凝土结构中钢筋连接综述改革开放以来,随着国民经济的快速、持久发展,各种钢筋混凝土建筑结构大量建造,钢筋连接技术得到很大的发展。
Risk Analysis of the International Construction ProjectBy: Paul Stanford KupakuwanaCost Engineering Vol. 51/No. 9 September 2009ABSTRACTThis analysis used a case study methodology to analyse the issues surrounding the partial collapse of the roof of a building housing the headquarters of the Standards Association of Zimbabwe (SAZ). In particular, it examined the prior roles played by the team of construction professionals. The analysis revealed that the SAZ‟s traditional construction project was gener ally characterized by high risk. There was a clear indication of the failure of a contractor and architects in preventing and/or mitigating potential construction problems as alleged by the plaintiff. It was reasonable to conclude that between them the defects should have been detected earlier and rectified in good time before the partial roof failure. It appeared justified for the plaintiff to have brought a negligence claim against both the contractor and the architects. The risk analysis facilitated, through its multi-dimensional approach to a critical examination of a construction problem, the identification of an effective risk management strategy for future construction projects. It further served to emphasize the point that clients are becoming more demanding, more discerning, and less willing to accept risk without recompense. Clients do not want surprise, and are more likely to engage in litigation when things go wrong.KEY WORDS:Arbitration, claims, construction, contracts, litigation, project and risk The structural design of the reinforced concrete elements was done by consulting engineers Knight Piesold (KP). Quantity surveying services were provided by Hawkins, Leshnick & Bath (HLB). The contract was awarded to Central African Building Corporation (CABCO) who was also responsible for the provision of a specialist roof structure using patented “gang nail” roof trusses. The building construction proceeded to completion and was handed over to the ownerson Sept. 12, 1991. The SAZ took effective occupation of the headquarters building without a certificate of occupation. Also, the defects liability period was only three months .The roof structure was in place 10 years before partial failure in December 1999. The building insurance coverage did not cover enough, the City of Harare, a government municipality, issued the certificate of occupation 10 years after occupation, and after partial collapse of the roof .At first the SAZ decided to go to arbitration, but this failed to yield an immediate solution. The SAZ then decided to proceed to litigate in court and to bring a negligence claim against CABCO. The preparation for arbitration was reused for litigation. The SAZ‟s quantified losses stood at approximately $ 6 million in Zimbabwe dollars (US $1.2m) .After all parties had examined the facts and evidence before them, it became clear that there was a great probability that the courts might rule that both the architects and the contractor were liable. It was at this stage that the defendants‟ lawyers req uested that the matter be settled out of court. The plaintiff agreed to this suggestion, with the terms of the settlement kept confidential .The aim of this critical analysis was to analyse the issues surrounding the partial collapse of the roof of the building housing the HQ of Standard Association of Zimbabwe. It examined the prior roles played by the project management function and construction professionals in preventing/mitigating potential construction problems. It further assessed the extent to which the employer/client and parties to a construction contract are able to recover damages under that contract. The main objective of this critical analysis was to identify an effective risk management strategy for future construction projects. The importance of this study is its multidimensional examination approach.Experience suggests that participants in a project are well able to identify risks based on their own experience. The adoption of a risk management approach, based solely in pastexperience and dependant on judgement, may work reasonably well in a stable low risk environment. It is unlikely to be effective where there is a change. This is because change requires the extrapolation of past experience, which could be misleading. All construction projects are prototypes to some extent and imply change. Change in the construction industry itself suggests that past experience is unlikely to be sufficient on its own. A structured approach is required. Such a structure can not and must not replace the experience and expertise of the participant. Rather, it brings additional benefits that assist to clarify objectives, identify the nature of the uncertainties, introduces effective communication systems, improves decision-making, introduces effective risk control measures, protects the project objectives and provides knowledge of the risk history .Construction professionals need to know how to balance the contingencies of risk with their specific contractual, financial, operational and organizational requirements. Many construction professionals look at risks in dividually with a myopic lens and do not realize the potential impact that other associated risks may have on their business operations. Using a holistic risk management approach will enable a firm to identify all of the organization‟s business risks. This will increase the probability of risk mitigation, with the ultimate goal of total risk elimination .Recommended key construction and risk management strategies for future construction projects have been considered and their explanation follows. J.W. Hinchey stated that there is and can be no …best practice‟ standard for risk allocation on a high-profile project or for that matter, any project. He said, instead, successful risk management is a mind-set and a process. According to Hinchey, the ideal mind-set is for the parties and their representatives to, first, be intentional about identifying project risks and then to proceed to develop a systematic and comprehensive process for avoiding, mitigating, managing and finally allocating, by contract, those risks inoptimum ways for the particular project. This process is said to necessarily begin as a science and ends as an art .According to D. Atkinson, whether contractor, consultant or promoter, the right team needs to be assembled with the relevant multi-disciplinary experience of that particular type of project and its location. This is said to be necessary not only to allow alternative responses to be explored. But also to ensure that the right questions are asked and the major risks identified. Heads of sources of risk are said to be a convenient way of providing a structure for identifying risks to completion of a participant‟s part of the project. Effective risk management is said to require a multi-disciplinary approach. Inevitably risk management requires examination of engineering, legal and insurance related solutions .It is stated that the use of analytical techniques based on a statistical approach could be of enormous use in decision making . Many of these techniques are said to be relevant to estimation of the consequences of risk events, and not how allocation of risk is to be achieved. In addition, at the present stage of the development of risk management, Atkinson states that it must be recognized that major decisions will be made that can not be based solely on mathematical analysis. The complexity of construction projects means that the project definition in terms of both physical form and organizational structure will be based on consideration of only a relatively small number of risks . This is said to then allow a general structured approach that can be applied to any construction project to increase the awareness of participants .The new, simplified Construction Design and Management Regulations(CDM Regulations) which came in to force in the UK in April 2007, revised and brought together the existing CDM 1994 and the Construction Health Safety and Welfare(CHSW) Regulations 1996, into a single regulatory package.The new CDM regulations offer an opportunity for a step change in health and safety performance and are used to reemphasize the health, safety and broader business benefits of a well-managed and co-ordinated approach to the management of health and safety in construction.I believe that the development of these skills is imperative to provide the client with the most effective services available, delivering the best value project possible.Construction Management at Risk (CM at Risk), similar to established private sector methods of construction contracting, is gaining popularity in the public sector. It is a process that allows a client to select a construction manager (CM) based on qualifications; make the CM a member of a collaborative project team; centralize responsibility for construction under a single contract; obtain a bonded guaranteed maximum price; produce a more manageable, predictable project; save time and money; and reduce risk for the client, the architect and the CM.CM at Risk, a more professional approach to construction, is taking its place along with design-build, bridging and the more traditional process of design-bid-build as an established method of project delivery.The AE can review the CM‟s approach to the work, making helpful recommendations. The CM is allowed to take bids or proposals from subcontractors during completion of contract documents, prior to the guaranteed maximum price (GMP), which reduces the CM‟s risk and provides useful input to design. The procedure is more methodical, manageable, predictable and less risky for all.The procurement of construction is also more business-like. Each trade contractor has a fair shot at being the low bidder without fear of bid shopping. Each must deliver the best to get the projec. Competition in the community is more equitable: all subcontractors have a fair shot at the work .A contingency within the GMP covers unexpected but justifiable costs, and a contingency above the GMP allows for client changes. As long as the subcontractors are within the GMP they are reimbursed to the CM, so the CM represents the client in negotiating inevitable changes with subcontractors.There can be similar problems where each party in a project is separately insured. For this reason a move towards project insurance is recommended. The traditional approach reinforces adversarial attitudes, and even provides incentives for people to overlook or conceal risks in an attempt to avoid or transfer responsibility.A contingency within the GMP covers unexpected but justifiable costs, and a contingency above the GMP allows for client changes. As long as the subcontractors are within the GMP they are reimbursed to the CM, so the CM represents the client in negotiating inevitable changes with subcontractors.There can be similar problems where each party in a project is separately insured. For this reason a move towards project insurance is recommended. The traditional approach reinforces adversarial attitudes, and even provides incentives for people to overlook or conceal risks in an attempt to avoid or transfer responsibility.It was reasonable to assume that between them the defects should have been detected earlier and rectified in good time before the partial roof failure. It did appear justified for the plaintiff to have brought a negligence claim against both the contractor and the architects.In many projects clients do not understand the importance of their role in facilitating cooperation and coordination; the design is prepared without discussion between designers, manufacturers, suppliers and contractors. This means that the designer can not take advantage of suppliers‟ or contractors‟ knowledge of build ability or maintenance requirements and the impact these have on sustainability, the total cost of ownership or health and safety .This risk analysis was able to facilitate, through its multi-dimensional approach to a critical examination of a construction problem, the identification of an effective risk management strategy for future construction projects. This work also served to emphasize the point that clients are becoming more demanding, more discerning, and less willing to accept risk without recompense. They do not want surprises, and are more likely to engage in litigation when things go wrong.中文译文:国际建设工程风险分析保罗斯坦福库帕库娃娜工程造价卷第五十一期2009年9月9日摘要此次分析用实例研究方法分析津巴布韦标准协会总部(SAZ)的屋顶部分坍塌的问题。
中文译文:建筑业的竞争及竞争策略美国的工程建筑公司几十年来一直控制着国际建筑市场,但近来世界上发生的事件改变了它的主导地位。
为了调查今后十年对工程建筑竞争产生影响的推动力及趋势,由建筑工业研究院的"2000年建筑特别工作组:发起一项称为“2000年建筑市场竞争分析”的研究项目。
该研究项目考察了一些影响竞争的因素,包括下列方面:企业能力塑造:采用纵向联合,横向发展的方法,提高企业的综合能力。
扩大市场领地,这种做法包括被海外的联合企业收购或被其合并,或是由美国公司收购外国公司。
筹措资金的选择方法:私有化作用,建筑权力转让项目,未来市场中工程筹资特征。
管理、组织及结构:未来的经营管理及组织方法、组织结构、组织技巧要有利于引导职员在世界竞争环境中发挥作用。
劳力特征:未来具有专业水平和技工水平的工程建筑工人的供求情况技术问题:技术将如何影响竞争,如何用来弥补劳力不足的缺陷。
研究目标及范围这一研究项目的目标是收集信息,使之为适应2000年及以后的工程建筑业在调整、制定策略方面的需要提供真知灼见,并制定出2000年工程建筑业的可能的发展计划。
这项研究回顾了工程建筑业的历史过程,审视了当前的发展趋势,以确定影响该工业未来的推动力,与该工业相关的有重塑企业能力,私有化及筹措资金方法的潜在作用以及经营管理、组织方法、公司结构方面的未来发展方向。
研究范围包括选定一些公司,采访这些公司有专业特长的人员。
这些人员的专业涉及面很广,包括商业建筑,重工业建筑,公共事业设施建设,基础建设.轻工业建筑,电力,生产程序以及航天科学。
工程建筑业竞争特性工程建筑业的竞争特征由于下列原因在变动:80年代发生的事件,以及计划在90年代实施的项目,正在引导建筑业摆脱相互对立的局面,转向相互合作。
应该以积极的眼光看待新的公司进入国际工程建筑市场,因为它增加了全球合作的机遇。
合作关系会使所有的伙伴受益,这是因为美国公司可以在合作伙伴的国家找到机遇,同样,外国公司也会打入美国市场。
Concrete BridgesConcrete is the most-used construction material for bridges in the United States, and indeed in the world. The application of prestressing to bridges has grown rapidly and steadily, beginning in 1949 with high-strength steel wires in the Walnut Lane Bridge in Philadelphia, Pennsylvania. According to the Federal Highway Administration’s 1994 National Bridge Inventory data, from 1950 to the early 1990s, prestressed concrete bridges have gone from being virtually nonexistent to representing over 50 percent of all bridges built in the United States.Prestressing has also played an important role in extending the span capability of concrete bridges. By the late 1990s, spliced-girder spans reached a record 100 m (330 ft). Construction of segmental concrete bridges began in the United States in 1974.Curretly, close to 200 segmental concrete bridges have been built or are under construction, with spans up to 240 m (800 ft).Late in the 1970s, cable-stayed construction raised the bar for concrete bridges. By 1982, the Sunshine Skyway Bridge in Tampa, Florida, had set a new record for concrete bridges, with a main span of 365 m (1,200 ft). The next year, the Dames Point Bridge in Jacksonville, Florida, extended the record to 400 m (1,300 ft).HIGH-PERFORMANCE CONCRETECompressive StrengthFor many years the design of precast prestressed concrete girders was based on concrete compressive strengths of 34 to 41 MPa (5,000 to 6,000 psi). This strength level served the industry well and provided the basis for establishing the prestressed concrete bridge industry in the United States. In the 1990s the industry began to utilize higher concrete compressive strengths in design, and at the start of the new millennium the industry is poised to accept the use of concrete compressive strengths up to 70 MPa (10,000 psi).For the future, the industry needs to seek ways to effectively utilize even higher concrete compressive strengths. The ready-mixed concrete industry has been producing concretes with compressive strengths in excess of 70 MPa for over 20 years. Several demonstration projects have illustrated that strengths above 70 MPa can be achieved for prestressed concrete girders. Barriers need to be removed to allow the greater use of these materials. At the same time, owners, designers, contractors, and fabricators need to be more receptive to the use of higher-compressive-strength concretes.DurabilityHigh-performance concrete (HPC) can be specified as high compressive strength (e.g., in prestressed girders) or as conventional compressive strength with improveddurability (e.g., in cast-in-place bridge decks and substructures). There is a need to develop a better understanding of all the parameters that affect durability, such as resistance to chemical, electrochemical, and environmental mechanisms that attack the integrity of the material. Significant differences might occur in the long-term durability of adjacent twin structures constructed at the same time using identical materials. This reveals our lack of understanding and control of the parameters that affect durability. NEW MATERIALSConcrete design specifications have in the past focused primarily on the compressive strength. Concrete is slowly moving toward an engineered material whose direct performance can be altered by the designer. Material properties such as permeability, ductility, freeze-thaw resistance, durability, abrasion resistance, reactivity, and strength will be specified. The HPC initiative has gone a long way in promoting these specifications, but much more can be done. Additives, such a fibers or chemicals, can significantly alter the basic properties of concrete. Other new materials, such as fiber-reinforced polymer composites, nonmetallic reinforcement (glass fiber-reinforced and carbon fiber-reinforced plastic, etc.), new metallic reinforcements, or high-strength steel reinforcement can also be used to enhance the performance of what is considered to be a traditional material. Higher-strength reinforcement could be particularly useful when coupled with high-strength concrete. As our natural resources diminish, alternative aggregate sources (e.g., recycled aggregate) and further replacement of cementitious materials with recycled products are being examined. Highly reactive cements and reactive aggregates will be concerns of the past as new materials with long-term durability become commonplace.New materials will also find increasing demand in repair and retrofitting. As the bridge inventory continues to get older, increasing the usable life of structures will become critical. Some innovative materials, although not economical for complete bridges, will find their niche in retrofit and repair.OPTIMIZED SECTIONSIn early applications of prestressed concrete to bridges, designers developed their own ideas of the best girder sections. The result is that each contractor used slightly different girder shapes. It was too expensive to design custom girders for each project.As a result, representatives for the Bureau of Public Roads (now FHWA), the American Association of State Highway Officials (AASHO) (now AASHTO), and the Prestressed Concrete Institute (PCI) began work to standardize bridge girder sections. The AASHTO-PCI standard girder sections Types I through IV were developed in the late 1950s and Types V and VI in the early 1960s. There is no doubt that standardization of girders has simplified design, has led to wider utilization of prestressed concrete for bridges, and, more importantly, has led to reduction in cost.With advancements in the technology of prestressed concrete design and construction, numerous states started to refine their designs and to develop their own standard sections. As a result, in the late 1970s, FHWA sponsored a study to evaluate existing standard girder sections and determine the most efficient girders. This study concluded that bulb-tees were the most efficient sections. These sections could lead toreduction in girder weights of up to 35 percent compared with the AASHTO Type VI and cost savings up to 17 percent compared with the AASHTO-PCI girders, for equal span capability. On the basis of the FHWA study, PCI developed the PCI bulb-tee standard, which was endorsed by bridge engineers at the 1987 AASHTO annual meeting. Subsequently, the PCI bulb-tee cross section was adopted in several states. In addition, similar cross sections were developed and adopted in Florida, Nebraska, and the New England states. These cross sections are also cost-effective with high-strength concretes for span lengths up to about 60 m (200 ft).SPLICED GIRDERSSpliced concrete I-girder bridges are cost-effective for a span range of 35 to 90 m (120 to 300 ft). Other shapes besides I-girders include U, T, and rectangular girders, although the dominant shape in applications to date has been the I-girder, primarily because of its relatively low cost. A feature of spliced bridges is the flexibility they provide in selection of span length, number and locations of piers, segment lengths, and splice locations. Spliced girders have the ability to adapt to curved superstructure alignments by utilizing short segment lengths and accommodating the change in direction in the cast-in-place joints. Continuity in spliced girder bridges can be achieved through full-length posttensioning, conventional reinforcement in the deck, high-strength threaded bar splicing, or pretensioned strand splicing, although the great majority of applications utilize full-length posttensioning. The availability of concrete compressive strengths higher than the traditional 34 MPa (5,000 psi) significantly improves the economy of spliced girder designs, in which high flexural and shear stresses are concentrated near the piers. Development of standardized haunched girder pier segments is needed for efficiency in negative-moment zones. Currently, the segment shapes vary from a gradually thickening bottom flange to a curved haunch with constant-sized bottom flange and variable web depth.SEGMENTAL BRIDGESSegmental concrete bridges have become an established type of construction for highway and transit projects on constrained sites. Typical applications include transit systems over existing urban streets and highways, reconstruction of existing interchanges and bridges under traffic, or projects that cross environmentally sensitive sites. In addition, segmental construction has been proved to be appropriate for large-scale, repetitive bridges such as long waterway crossings or urban freeway viaducts or where the aesthetics of the project are particularly important.Current developments suggest that segmental construction will be used on a larger number of projects in the future. Standard cross sections have been developed to allow for wider application of this construction method to smaller-scale projects. Surveys of existing segmental bridges have demonstrated the durability of this structure type and suggest that additional increases in design life are possible with the use of HPC. Segmental bridges with concrete strengths of 55 MPa (8,000 psi) or more have been constructed over the past 5 years. Erection with overhead equipment has extended applications to more congested urban areas. Use of prestressed composite steel and concrete in bridges reduces the dead weight of the superstructure and offers increased span lengths.LOAD RATING OF EXISTING BRIDGESExisting bridges are currently evaluated by maintaining agencies using working stress, load factor, or load testing methods. Each method gives different results, for several reasons. In order to get national consistency, FHWA requests that all states report bridge ratings using the load factor method. However, the new AASHTO Load and Resistance Factor Design (LRFD) bridge design specifications are different from load factor method. A discrepancy exists, therefore, between bridge design and bridge rating.A draft of a manual on condition evaluation of bridges, currently under development for AASHTO, has specifications for load and resistance factor rating of bridges. These specifications represent a significant change from existing ones. States will be asked to compare current load ratings with the LRFD load ratings using a sampling of bridges over the next year, and adjustments will be proposed. The revised specifications and corresponding evaluation guidelines should complete the LRFD cycle of design, construction, and evaluation for the nation's bridges.LIFE-CYCLE COST ANALYSISThe goal of design and management of highway bridges is to determine and implement the best possible strategy that ensures an adequate level of reliability at the lowest possible life-cycle cost. Several recent regulatory requirements call for consideration of life-cycle cost analysis for bridge infrastructure investments. Thus far, however, the integration of life-cycle cost analysis with structural reliability analysis has been limited. There is no accepted methodology for developing criteria for life-cycle cost design and analysis of new and existing bridges. Issues such as target reliability level, whole-life performance assessment rules, and optimum inspection-repair-replacement strategies for bridges must be analyzed and resolved from a life-cycle cost perspective. To achieve this design and management goal, state departments of transportation must begin to collect the data needed to determine bridge life-cycle costs in a systematic manner. The data must include inspection, maintenance, repair, and rehabilitation expenditures and the timing of these expenditures. At present, selected state departments of transportation are considering life-cycle cost methodologies and software with the goal of developing a standard method for assessing the cost-effectiveness of concrete bridges. DECKSCast-in-place (CIP) deck slabs are the predominant method of deck construction in the United States. Their main advantage is the ability to provide a smooth riding surface by field-adjustment of the roadway profile during concrete placement. In recent years automation of concrete placement and finishing has made this system cost-effective. However, CIP slabs have disadvantages that include excessive differential shrinkage with the supporting beams and slow construction. Recent innovations in bridge decks have focused on improvement to current practice with CIP decks and development of alternative systems that are cost-competitive, fast to construct, and durable. Focus has been on developing mixes and curing methods that produce performance characteristics such as freeze-thaw resistance, high abrasion resistance, low stiffness, and low shrinkage, rather than high strength. Full-depth precast panels have the advantages of significant reduction of shrinkage effects and increased construction speed and have been used in states with high traffic volumes for deck replacement projects. NCHRP Report 407 onrapid replacement of bridge decks has provided a proposed full-depth panel system with panels pretensioned in the transverse direction and posttensioned in the longitudinal direction.Several states use stay-in-place (SIP) precast prestressed panels combined with CIP topping for new structures as well as for deck replacement. This system is cost-competitive with CIP decks. The SIP panels act as forms for the topping concrete and also as part of the structural depth of the deck. This system can significantly reduce construction time because field forming is only needed for the exterior girder overhangs. The SIP panel system suffers from reflective cracking, which commonly appears over the panel-to-panel joints. A modified SIP precast panel system has recently been developed in NCHRP Project 12-41.SUBSTRUCTURESContinuity has increasingly been used for precast concrete bridges. For bridges with total lengths less than 300 m (1,000 ft), integral bridge abutments and integral diaphragms at piers allow for simplicity in construction and eliminate the need for maintenance-prone expansion joints. Although the majority of bridge substructure components continue to be constructed from reinforced concrete, prestressing has been increasingly used. Prestressed bents allow for longer spans, improving durability and aesthetics and reducing conflicts with streets and utilities in urban areas. Prestressed concrete bents are also being used for structural steel bridges to reduce the overall structure depth and increase vertical clearance under bridges. Precast construction has been increasingly used for concrete bridge substructure components. Segmental hollow box piers and precast pier caps allow for rapid construction and reduced dead loads on the foundations. Precasting also enables the use of more complex forms and textures in substructure components, improving the aesthetics of bridges in urban and rural areas. RETAINING WALLSThe design of earth retaining structures has changed dramatically during the last century. Retaining wall design has evolved from short stone gravity sections to concrete structures integrating new materials such as geosynthetic soil reinforcements and high-strength tie-back soil anchors.The design of retaining structures has evolved into three distinct areas. The first is the traditional gravity design using the mass of the soil and the wall to resist sliding and overturning forces. The second is referred to as mechanically stabilized earth design. This method uses the backfill soil exclusively as the mass to resist the soil forces by engaging the soil using steel or polymeric soil reinforcements. A third design method is the tie-back soil or rock anchor design, which uses discrete high-strength rods or cables that are drilled deep into the soil behind the wall to provide a dead anchorage to resist the soil forces.A major advancement in the evolution of earth retaining structures has been the proliferation of innovative proprietary retaining walls. Many companies have developed modular wall designs that are highly adaptable to many design scenarios. The innovative designs combined with the modular standard sections and panels have led to a significant decrease in the cost for retaining walls. Much research has been done to verify thestructural integrity of these systems, and many states have embraced these technologies. RESEARCHThe primary objectives for concrete bridge research in the 21st century are to develop and test new materials that will enable lighter, longer, more economical, and more durable concrete bridge structures and to transfer this technology into the hands of the bridge designers for application. The HPCs developed toward the end of the 20th century would be enhanced by development of more durable reinforcement. In addition, higher-strength prestressing reinforcement could more effectively utilize the achievable higher concrete strengths. Lower-relaxation steel could benefit anchor zones. Also, posttensioning tendons and cable-stays could be better designed for eventual repair and replacement. As our natural resources diminish, the investigation of the use of recycled materials is as important as the research on new materials.The development of more efficient structural sections to better utilize the performance characteristics of new materials is important. In addition, more research is required in the areas of deck replacement panels, continuity regions of spliced girder sections, and safe,durable, cost-effective retaining wall structures.Research in the areas of design and evaluation will continue into the next millennium.The use of HPC will be facilitated by the removal of the implied strength limitation of 70 MPa (10.0 ksi) and other barriers in the LRFD bridge design specifications. As our nation’s infrastructure continues to age and as the vehicle loads continue to increase, it is important to better evaluate the capacity of existing structures and to develop effective retrofitting techniques. Improved quantification of bridge system reliability is expected through the calibration of system factors to assess the member capacities as a function of the level of redundancy. Data regarding inspection, maintenance, repair, and rehabilitation expenditures and their timing must be systematically collected and evaluated to develop better methods of assessing cost-effectiveness of concrete bridges. Performance-based seismic design methods will require a higher level of computing and better analysis tools.In both new and existing structures, it is important to be able to monitor the “health” of these structures through the development of instrumentation (e.g., fiber optics) to determine the state of stresses and corrosion in the members.CONCLUSIONIntroduced into the United States in 1949, prestressed concrete bridges today represent over 50 percent of all bridges built. This increase has resulted from advancements in design and analysis procedures and the development of new bridge systems and improved materials.The year 2000 sets the stage for even greater advancements. An exciting future lies ahead for concrete bridges!混凝土桥梁在美国甚至在世界桥梁上,混凝土是最常用的建设材料。
中英文对照外文翻译文献(文档含英文原文和中文翻译)Construction stage safety civilization management1 Research content and purposeAt present China's production safety situation is still grim, especially the building area of the multiple casualties situation has not fundamentally reversed, construction safety is extremely stern; production safety foundation is weak, guarantee system and mechanism is not perfect; safety production supervision and management mechanism, team construction and supervision work also needs to be strengthened.With China's implementation of the "going out" strategy, the overseas engineering construction requirements of construction enterprises toward the safety and high quality fast and efficient direction, but the due to the overseas projects in surveying, design, competitive bidding system and construction exists some defects or mistakes, especially the construction environment and conditions for overseas and domestic different is formed many unsafe factors. Some governments of developed countries on safe and civilized construction management and supervision ineffective, at the same time, the security incident victimscompensation is relatively low, so as to project management are real will "safety first" self psychological suggestion and safe and civilized management psychological orientation proposed higher requirements. And in the preparation of the overseas project safety assurance program, sometimes due to lack of understanding in the engineering field, easy to cause the of dangerous source judgement is not accurate or not in place, and psychologically cannot accurately to ensure the safety of the positioning of the feasibility of the program.By exploring the harmful factors in the construction process and construction process was studied in unsafe, uncivilized between factors and employee of contradiction and the law of the unity of opposites, making better use of these rules to formulate a scientific, reasonable, effective all safe and civilized production tube system, to improve and perfect the measures of safety and technological civilization, to prevent and eliminate various harmful factors in the process of construction to the conversion of the casualty of a series of management work, to protect workers' safety and health, ensure safety in production. Due to the construction of the unsafe factor is relatively more, a little careless, it may occur accident. In recent years, occurred throughout the country in the construction work accidents and serious casualty statistics tells us that construction of the security situation is still very grim. However, construction safety problems with everything else, has its own objective law. It objectively resides in the entire construction activity. Since so, naturally, be it analysis to understand, master rules of it, take the organizational and technical measures to pre control, in order to achieve the purpose of construction safety. However, there are still many problems in the management of the security civilization.Therefore, we focus on the construction stage of the construction safety civilization management, the construction of the various aspects of the construction plan, the status quo of the safety and civilization management. Through the safety awareness of the management, the system of planning, to the project safety detailed analysis of the content. There are some unpredictable problems during the process of preparation, which is the main problem in the management of safety civilization.. Lay a good foundation for further implementation.. According to the occurrence of the settlement of the accident, there is no accident occurred, record the safety civilization management improvement measures, improve the safety and civilization management. As generally work arrangements properly was period of management is relatively lax, cross process serious and complicated, and safety problems inthis period is often risks and security alert frigidity, may not out of the big problem, but small problems and small risks constantly. So strengthen safety education and training, the unknown engineering safety civilization management summary, learning.Through the research on the safety civilization management of the construction stage, the danger identification, the risk assessment and the risk control of the modern safety civilization management are discussed in three aspects.. The aim is to better and more secure the work done. Do early work after the reduction of risk, and further strengthen the construction project risk management, and thus promote the faster development of China's construction projects.2 Status quo of safety civilization managementIn recent years, with the continuous improvement of the market economy and the common improvement of people's life, construction industry has become one of the fastest developing industries. The competition of the market is increasingly fierce, so that the benefit of the enterprise to compete in the target, so to the management to benefit has become the consensus of entrepreneurs. And safety is the premise of the benefit, because the safety results determine the size of the benefit. End over the years the party and the government attaches great importance to production safety work, determine the safety production policy of "safety first, prevention first", promulgated a series of production safety laws and regulations and standards, the purpose is to protect the safety and health of laborers, control and reduce all kinds of accidents, improve the level of safety management, promote the establishment of harmonious society.The construction industry is the risk of production activities, unsafe factors, is the accident prone industry. In recent years, the death rate of China's construction industry is the highest in all industries, after the mining industry, the loss is huge, distressing. Although the mandatory implementation of the construction enterprise safety production license system, strengthen the construction market access control, and to further strengthen the construction enterprise construction site safety inspections, but accidents still occur from time to time. I believe that the number of casualties mainly determined by the characteristics of the construction industry. The safety civilization management is a science, is a professional, policy, mass, and a very strong work. The safety civilization management of the enterprise is mainly embodied in the following aspects:(1) Safety awareness. Due to the leading enterprises for a long time the importance ofconstruction safety understanding does not reach the designated position, grasping safety formalism serious, disregard for workers in the production of the legitimate interests of labor and social security, is not equipped with the necessary labor protection supplies, arbitrary extension of working time, workers in the long run, the working state of the overload, high strength, will lead to accidents. In addition, the leadership of the security work seriously enough, the staff of the corresponding security awareness, it is easy to cause illegal command, illegal operations, violation of labor discipline and safety accidents caused by.(2) The weak base of security civilization management. The weak security and civilization management is mainly due to the weak safety consciousness of some people, the relationship between the safety and the speed, safety and the relationship between safety and benefit, security and stability.. The weak safety management is mainly reflected in the weak: first, the research work of building safety technology is weak, and the key technology of building safety production is relatively lagging behind. The wide application of safety scientific and technological achievements is lack of market-oriented policy guidance and economic incentive measures. Study on the construction of new technology, new products, new technology application and safety protection measures of synchronization; second, compared with the developed countries, our country security protection technology, protective equipment and machinery and equipment is still relatively backward. Standardization, stereotypes and industrialization degree is very low; three is the construction enterprise safety civilization management and construction team quality is generally low. The safety of the low quality of the cultural quality, safety and civilization management knowledge, safety and technical specifications, safety procedures, safety precautions and so on do not understand. Can't manage the construction team.(3) The construction safety laws and regulations system is not perfect. There are some limitations to implement its security responsibilities; terms of punishment for violations of the law is not specific enough, operability is not strong; laws and regulations are not perfect, there is a problem of duplication and overlapping management; safety rules and regulations of the responsibility is not clear, management objectives is not clear, resulting in production safety responsibility of implementation is not in place etc..(4) The mechanism of the construction safety supervision and production is not perfect. At present, the mechanism of the effective construction safety supervision and management inChina has not been formed, and there is a big gap compared with the international advanced security management mode.. The safety supervision mode and management means can't adapt to the growing scale of construction, and it is difficult to carry out the construction safety supervision work further.. Mainly in the following three aspects:Construction unit safety civilization management problemThe exploration, design, construction and supervision of the construction engineering to the entity or individual contractor who is not qualified or qualified or even illegal. Due to the layers of subcontracting, resulting in the construction management is not strict, security training is not in place and security investment or basic no. And it will also make lower profits, and contractors in order to pursue the maximal profit will reduce his all unnecessary amount of spending, leading to safety hazards and accidents continue to occur.Investigation, design, engineering supervision and other units of the major security issuesSurvey, design units not in accordance with the requirements were survey or design, or change the survey and design documents, laws, regulations and mandatory standards, to survey the design defects, can not guarantee the building and construction personnel safety engineering supervision units not to the construction unit safety technical measures or special construction safety program for careful review, in the engineering construction nor of construction units to implement security measures of supervision seriously, find the hidden accident, nor does it take decisive measures to be rectification and elimination; detection unit to produce a false report.Safety problem of construction unitWith the increasing investment in infrastructure, the construction enterprise access policy adjustment, making the number of construction enterprises continues to increase, the construction team continues to expand. Especially in recent years, the rapid development of individual construction industry, the construction enterprise has changed fundamentally. But because the construction unit is the main body and the core position in the construction safety activity, the construction safety problem is mainly in the construction unit body.2.1 Government laws and regulations(1) The lack of building safety and civilization management system for the market economyConstruction of China's investment system changes the original building a safe and civilized production management has not adapt to the current construction methods, so has been dominated by the government of safe and civilized management appeared many loopholes in management, coupled with the construction safety laws and regulations is not perfect, the low efficiency of government supervision, social supervision system is not perfect, resulting in a safe and civilized management is not in place, suited to the laws of market economy, legal and economic means parallel building a safe and civilized management system has not been formed. Therefore, the initiative construction safety civilization management initiative construction safety civilization management work first, early planning, early arrangement, do the whole process supervision and inspection. Before the construction we put the project in the province Shuangyou site as the target management, improving the safety management measures and system in the project, accomplish beforehand to prevent. Employees entering the construction site, the first production safety education and follow the operating rules of education; followed by a safety technical disclosure and each segment and sub engineering safety technical disclosure, so that all staff familiar with the rules and regulations, consciously abide by the safety regulations and operating rules, improve the sense of self-protection. Strengthen the intensity and extent of the supervision of the safety and civilization management objectives for effective control.(2) The law and regulations are more and more incomplete and the execution is not enoughOur country law "environment and health" is too weak. The emphasis on "environment and health" in the activity of architecture has become a common topic of international concern. The target system of engineering construction has been shifted from the traditional "cost - cost - quality - time - to - Project" system to "cost - quality - time - environment and health" system.. The international standard organization has also developed the environmental management system.(3) The functional changes of the management department are lagging behind and the management of the vacuum isWith the deepening of the reform of our political system, the reform of the national institution, the enterprise reform, the enterprise has gradually separated from the industry administrative management, and has become the independent action subject in the market.With this adaptation, Ministry of construction and local construction administrative departments to become the national construction safety special supervision of the performer, state production safety supervision and administration and the local production safety supervision and management institutions become discharger of the state production safety supervision functions.The unsafe state of the unsafe behavior and the unsafe state of the material are the direct cause of the accident, which are directly related to the management. So the management is the indirect cause of the accident.. The unsafe behavior of human can be reduced or even eliminated through safety education, safety production responsibility system and security mechanism. The unsafe state of the material can be controlled by improving the scientific and technological content of the safety, establishing the perfect equipment maintenance system, promoting the construction and safety of the civilization. To strengthen the safety inspection on the job site, we can find and stop the unsafe behavior and the unsafe state of the thing, so as to avoid the accident. One of the most common defect management system is not perfect, the responsibility is not clear, abiding by the law, the illegal command, safety education is not enough, punishment is not strict, safety technical measures are not comprehensive, security check enough.(4) The construction safety production management and professional construction safety production management separateAt present, China's construction safety civilization management is actually decentralized management, did not really do the industry management. This has formed the construction safety civilization management standard, the management pattern is different, the casualty statistics data distortion, the management work responsibility is not clear.Pay attention to safety behavior norms according to the laws of science organization construction, comply with construction safety rules and standards, as a code of conduct to organize the construction of construction site to be constrained, regulate their behavior from two aspects: one is to require managers to strictly implement the construction administrative departments of the state and local issued by the construction safety and civilized management regulations and standards the implementation of the management system of the enterprise, before the construction of the relevant technical requirements for the construction safety to the crew and workers in detail, and signed by both parties confirmed that security staff dailyinspections of implementation; two is to require the operation layer; safety protection for the outstanding construction site could cause accident.2.2 The characteristics of the construction safety civilization managementThe characteristics of construction are mainly determined by the characteristics of architectural products. Compared with other industrial products, building products is huge in size, complexity and diversity, overall hard, not easy to mobile, so that construction in addition to the basic characteristics of industrial production, but also has the following main features:(1) The fluidity of productionOne is the body construction with the buildings or structures located position change and the transfer of production sites; the second is in the process of the construction of a project construction personnel and all kinds of machinery, electrical equipment with the construction site and along the construction of the object up, down, left and right flow, continue to turn shift operation places.(2) The product form is diverseDue to the natural conditions and uses of the building, the structure, modeling and material of the building are also different, and the construction method will be changed, it is difficult to realize the standardization.(3) Construction technology complexConstruction often need according to the structure of the building for many types of work with the operation, multi unit (earthwork, civil engineering, hoisting, installation, transportation, etc.) cross tie construction, the supplies and equipment are different, thus the construction organization and construction technology management has a higher request. Most of the construction industry is still manual operation, easy to make people fatigue, attention dispersion, so improper operation or mistakes more prone to occur, Rong Yi lead to accidents security. This is manual labor and heavy manual labor and more.(4) Open and aloft operationsThe building product is huge, the production cycle is long, the construction is carried on frequently in the open air and the high place, is often influenced by the natural climate condition. According to the national standard "high job classification" provides that there are more than 90% of the construction of higher operations. The open operation of buildingsaccounts for about 70% of the total workload, and the impacts and hazards of natural conditions such as spring, summer, autumn and winter, and sunshine, wind, rain, snow and snow etc.(5) Low mechanizationAt present, the construction mechanization degree of our country is still very low, still depend on a lot of manual operation.. Construction machinery and machinery in the factory compared to the mechanical equipment is very different, its safety is much higher than the factory equipment, the probability of injury is naturally much higher. There are several aspects of the following features:A. Use of different environmental conditions;B. Operating object is different;C. Operating location and operator;Take the crane as an example to discuss the mechanization of safety civilization management.In our country, with the increase of the number of the heavy machinery, the proportion of the injury accidents in the total industrial accidents is also increasing year by year. The common accidents of hoisting machinery are: the hanging falls, the impact of extrusion, the accident, the electric shock accident, the body dump accident.. The total number of crane crashes accounted for about 33%, the impact of extrusion accounted for about 30%, electric shock accounted for about 10%, the accident accounted for about 8%, the body dumping accounts for about 5%. The total number of the total number of injuries from the accident of the highest percentage of falling accident analysis:A. Off the rope accidents: due to the load from a bundle of the hoisting rope shedding collapsibility casualties damage.B.Weight loss accident from heavy lifting rope or special sling from hook caused by prolapse.C. Broken rope accident: hoisting rope and hoisting rope broken down due to the weight loss accident.D. Hook broken accident: weight loss accident fracture caused by hook.E. Hoisting wire rope problem.2.3 The work content of the construction safety civilization managementConstruction enterprises to do a good job security construction should pay attention to do the following several work:(1)Thinking;(2) Establishment of a safety production management system;(3) Establishing the safety and professional bodies and with full-time safety technicians;(4) Ensure that the workers are safe and secure;(5) Take the targeted safety measures;Safety technical measures should be aimed at the engineering features, in depth investigation and study. Also do a good job of work safety technical disclosure.3 Security checkThe security check is found in time, eliminate hidden dangers of accidents, an effective way to nip in the bud. The construction product volume is huge, the height operation is high, and then combined with the construction period, the technology complex and other factors, to the construction production brings a lot of unsafe factors. Through the combination of leadership and mass security checks, can effectively find the problem, take measures to eliminate the accident before the occurrence of the accident. Safety inspection can also summarize the good experience of the exchange of safety production, establish a typical, to promote the level of safety and civilization management. Mobilize the masses for security checks, both to encourage the masses to participate in the enthusiasm of safety and civilization management, and can educate the masses to enhance awareness of the safety awareness of production, and consciously improve the safety of production. In addition, the safety inspection can often give the neglect of the safety of the idea of knocking the alarm, and promptly correct illegal command, illegal operations behavior.4 SummarySafety civilization management is a science, is a professional, policy, mass, and a very strong work. With the continuous development of the economy, the continuous improvement of people's living standards, employees in the construction industry and the whole society are on the construction process of safe and civilized management level proposed requirements more and more high, the traditional management mode has not adapted to the requirements of the times. It is now in need of scientific and modern enterprise security and civilization management mode, and continuously improve the level of safety civilization management, thereal safety civilization management work well. The scientific use of PDCA circulation method, the pair of leaders of all levels of safety education and construction plan possible accident, the implementation of safe and civilized management plan, make safe and civilized management is better in the construction of perfect embodiment. To inspect the construction process of the construction management plan, and find the problem that hidden and haven't met to solve, analyze and record, and put the security plan into the program. To reach a circular process. Therefore, as the construction enterprise, we should study the status quo of the construction industry safety civilization, establish the new idea of safety civilization management, and establish new accord with the.Construction safety management civilization is the first human management, to strengthen the safety education and training, continuously improve the quality of security business, enhance security awareness, and to take effective measures to regulate people's behavior, to implement standardized operation, in construction process due to the complexity of the construction site personnel, dynamic and frequent, in project management, to take admission to tertiary education and the change of production and construction, timely safety education; combination of production safety skills training, in order to enhance staff safety consciousness of responsibility and security capabilities.Through the safety civilization management education and training, strengthen the construction safety and the implementation of the guarantee. Safety education is the most effective method in the safety civilization management. Both time and greatly reduce the cost. On the construction enterprise personnel, from the leadership to the construction workers are admitted to the education and training, the whole aspect to strengthen safety awareness. A clear division of labor and management, the construction project without mistake, reduce the mistake. Building a safe and civilized management is a very complex system engineering, we must use of scientific management methods, management methods, the establishment of new safe and civilized management mode to improve worker safety execution. Only in this way, we can really make a safe and civilized management level to a new level.施工阶段的安全文明管理1.研究内容与目的目前我国的安全生产形势依然严峻,特别是建筑领域伤亡事故多发的状况尚未根本扭转,建筑施工安全极其严竣;安全生产基础比较薄弱,保障体系和机制不健全;安全生产监督管理机构、队伍建设以及监管工作还待加强。
建筑施工安全管理外文翻译参考文献1. Chen, J., & Skibniewski, M. J. (2017). Construction project safety management in China: A 2004–2014 research review. Safety Science, 93, 96-105.2. Yang, Y., Leung, Y. T., Chan, A. P., & Lu, W. (2018). Research trends and topics in construction safety management literature: A bibliometric analysis. Safety Science, 103, 255-264.3. Abdou, D. E. S., & Hassanein, M. K. (2019). Assessment of construction safety management factors affecting safety performance in Egypt. Alexandria Engineering Journal, 58(2), 767-777.4. Ling, F. Y., Chong, H. Y., Lan, Y., & Lu, W. (2020). A reviewof safety climate research from 2012 to 2018: Bibliometric analysis considering the construction industry's perspective. Safety Science, 125, .5. Zhang, Q., Jia, R., Zuo, J., & Hu, Y. (2019). Exploring the effects of construction workers’ safety behavior and safety climate onsafety performance: A multilevel analysis approach. Safety Science, 118, 502-512.6. Alazemi, K., & Kartam, N. (2014). Assessing safety performance index for construction projects in Kuwait. Journal of Construction Engineering and Management, 140(1), .7. Ardeshir, A., & Mohammadfam, I. (2015). Safety climate improvement framework for construction industry. International Journal of Injury Control and Safety Promotion, 22(1), 47-58.9. Lingard, H., & Rowlinson, S. (2015). Occupational health and safety in construction project management. Routledge.10. Sumner, N. (2019). Construction project management: An integrated approach. Routledge.11. Chikumba, T. (2017). Construction health and safety management systems in developing countries: The case of Zimbabwe. Journal of Civil Engineering and Management, 23(2), 163-175.12. Hadipriono, F. C., & Stamatis, D. H. (2016). Construction safety management. John Wiley & Sons.以上是一些关于建筑施工安全管理的外文翻译参考文献,涵盖了安全管理研究、安全氛围、安全绩效等方面的内容,有助于进一步了解该领域的研究动态和相关理论。
反思前瞻规划优化施工流程Farook Hamzeh Glenn Ballard Iris D. Tommelein摘要研究的问题:如何改善前瞻规划在建设行业的做法来提高生产计划的可靠性?目的:为了评估前瞻规划的性能,寻找一个标准化的做法,使前瞻规划与活动执行有紧密的联系,来提高生产计划的可靠性。
研究设计/方法:本研究采用案例分析,行业访谈,和行业调查,以评估目前在北美、南美和欧洲的建设项目执行的前瞻规划。
研究结果:研究结果显示存在与去年规划系统规则的不符合,前瞻规划与标准化做法的不足,识别和清除限制的迟缓,而且没有对计划失败的分析。
关键词:前瞻规划,生产计划,生产控制,精益建设,最后的规划系统,规划建设。
简介建筑、工程与施工是受变化问题的困扰的,即破坏项目绩效和扰乱施工流程导致对项目时间、成本和质量造成的不利影响(Hamzeh等,2007年,霍普和Spearman2008年,萨利姆等。
2006年,克莱顿1966年)。
组织使用许多种不同的方法来维持生产流程的一致性和屏蔽产量内部业务流程以及外部环境的变化。
汤普森(1967)着重介绍了这些方法,其中包括:•预测•缓冲•平滑各种预测方法是用于预测在内部流程和生产原料中的变化。
然而,预测不能满足所有的变化,并且有许多限制:越详细的预测越不准确,越遥远的预测越容易出错。
(纳米亚斯2009年)。
缓冲用于减轻同时在输入侧和输出侧的工艺变化。
输入通常需要成功执行的任务包括:信息,先决条件工作,人力资源,空间,材料,设备,外部条件和资金(巴拉德&Howell公司1994年,科斯基拉2000年)。
缓冲区可以采取的三种主要形式:时间,库存和产能。
时间缓冲是分配松弛的活动,利用额外的库存缓冲库存以应对供应的变化,以及用容量缓存,保留额外的容量,如加班或只在需要的时候维持机器工作,以适应激增的负荷。
平滑的供应和需求的变化是另一种方法,组织申请由于缓冲可能的不足,以满足所有的变化,是昂贵的,并可能导致满荷。
平滑需求的一个例子在丰田生产系统中平稳的工作负荷或平准化的倡导(莱克2004年)。
虽然变化破坏了项目的绩效,生产系统可以通过设计减少这种变化,并且可以通过上述提到的方法的组合来管理这种残差。
一个生产系统可以被定义为人员和资源的集合。
(例如,机械,设备,信息),被安排设计和制造产品(“货物”或“服务”)的价值给客户(Ballard等人,2007年)。
一个生产系统的基石是生产管理,例如最近的一个规划系统已成功实施建设项目(2004年巴拉德和Howell),以提高规划的可靠性,提高生产性能,在设计和施工作业中创建可以预测的工作流程。
在任何项目中,规划过程中可能遇到各种问题的困扰。
规划涉及到的越远的项目可能越不准确(纳米亚斯2009)。
当规划师把计划推向前线专家而不涉及他们的计划发展时是很难执行的工作日程。
在一厢情愿的想法的基础上开发的短期工作计划,贸易专家没有可靠的承诺,这种短期计划就会变得更短。
如果计划失败的原因并不在识别和处理不及时,进一步的失败是必然要发生的(哈姆泽2009年)。
此外,可靠的规划依赖于有效的约束分析与排除。
约束是一个活动启动前必须存在的先决条件(例如,以前的工作,信息,劳动力,材料,设备,工具,空间,天气等)。
管理约束条件可以通过识别资源冲突和提前解决这些问题帮助优化工作计划使工作开始。
如果没有约束,是难以管理和减少工作流程不确定性的,这往往导致过程的变化(蔡等,2003)。
考虑到上述挑战,最后规划系统主张项目规划中的以下步骤:•计划越详细情,执行工作越细致(科恩,2006年)•制定工作计划要执行工作的人制定工作计划•提前识别和消除工作的限制,作为一个团队,做好工作准备,提高工作计划的可靠性•在与项目参与方协调和积极谈判的基础上,做出可靠的承诺和工作执行•从失败的计划中学习经验,找出错误的根源,并采取预防措施(巴拉德,等。
2009年)尽管该系统的优点(阿拉尔孔和克鲁兹1997年,冈萨雷斯等人,2008),在许多建设项目目前的做法显示了执行不力前瞻规划,在较大差距长期规划(主阶段附表)和短期规划(承诺/每周的工作计划),降低了可靠性规划系统,并能够建立先见之明。
本文提出了一种前瞻规划实施的一种评估,为最新规划系统的一个过程,其重点介绍了统营规划系统一些不足之处,强调的前瞻规划每周工作规划成功的一个主要驱动力的作用,并建议进行前瞻规划的指导方针有关的活动故障,操作设计,及制约因素分析。
最新的规划系统最新规划系统开发者是格伦·巴拉德和格雷格·豪威尔,其是一生产计划和控制建设工作的系统,以协助平滑的变化流,发展规划先见之明,并减少施工作业中的不确定性。
系统最初是每周的工作计划水平,但很快就把处理工作流程中的变化扩大到覆盖整个计划和进度开发过程中,从主调度,通过前瞻规划,逐步调度达到每周工作规划中。
计划完成百分比(PPC)是一个度量,用于跟踪每周的工作计划水平的性能可靠性,通过测量相对于那些计划完成任务的百分比。
因此,它有助于评估的可靠性工作计划,并开始准备工作,以执行工作计划。
PPC并不是直接衡量项目的进展,而是承诺保持在何种程度上的措施,因此在何种程度上未来的工作负载可能是可预测的。
以前的研究发现PPC和劳动生产率之间的相关性(2008年刘和巴拉德)。
PPC上提高可能产生的二次冲击工作安全和质量需要进一步的研究(1998年,巴拉德和Howell Ballard等。
2007)。
有研究表明,尽管在LPS的优势,许多企业实施系统时都面临重大障碍。
(Ballard 等人,2007;哈姆泽,2009年维亚纳等)。
为建设项目的最新规划系统的成功实施提出了一个框架。
然而,当整个规划系统(主生产计划,阶段调度,前瞻的规划,每周工作规划)执行和更新设计,PPC 项目进展情况的指标,PPC和进步应随对方。
这可以表示为如权利要求一个复杂的假设,即:H1:如果前瞻任务是从一个阶段计划结构实现到项目的结束日期和中间里程碑,如果前瞻规划是准备应该怎样做,如果每周选择什么,可以做什么工作计划由应该做在临界的顺序没有游戏的系统,PPC将随项目的进展情况而不同。
如果我们接受这个假设,那么,如果不随PPC项目的进展情况,在虚拟链的某个地方就有一个破碎的链接。
图1显示了活动打破阶段的规划系统(砾石)的过程(岩石),然后在四个规划过程中的操作(卵石)不同的按时间跨度:主生产计划,阶段调度,前瞻规划和每周工作规划。
主生产计划是一个前端的规划过程中产生的时间表描述工作在进行整个项目的持续时间。
它涉及到项目级活动,并确定重要的里程碑日期主要集中在有关合同文件和拥有者的价值主张(Tommelein和Ballard,1997)。
相调度产生的时间表,覆盖项目的每个阶段,如地基,结构框架,或完成。
在协作规划设置项目团队:(1)定义项目阶段或里程碑,(2)将其分解成组成活动,(3)时间表向后的里程碑。
合并后从不同的项目方输入和在重要的阶段识别专家和团队执行之间逆相调度的平衡,从重要的阶段里程碑(哈姆泽2009年,巴拉德和豪威尔2004)。
前瞻规划是在生产控制(执行时间表)的第一步,通常包括一个为期6周的时间。
前瞻时段随正在执行的工作类型和上下文的不同而不同。
(例如,因为这种现象的出现,在概念设计,任务可以不在详细的预见水平很远的水平。
在工厂停工时,前瞻期延伸到年底关机。
在这项研究中,重点是正常的建设项目,并在这些4至6周的时间框架是常用的前瞻规划)。
在此阶段,活动被分解成水平的生产过程/操作,约束被识别,操作的设计,和准备作业就绪(巴拉德1997年,哈姆泽2009年)。
每周工作规划(WWP)也被称为承诺计划是最系统的详细计划,展现了工作的各专业组织之间的相互依存,和直接驱动的生产过程。
计划在这个级别的可靠性促进了质量分配和可靠的承诺,使生产单元从上游业务中的不确定性被屏蔽。
这个工作任务是一个详细的测量完成可的计划。
每个计划期结束时,作业被评论,评估它们是否是完整的,从测量规划中的可靠性。
对于不完整的任务,对计划失败的原因进行分析,并采取行动,这些原因是学习和持续改进的基础(巴拉德2000年)。
Farook Hamzeh, Glenn Ballard & Iris D. Tommelein(2012) Rethinking Lookahead Planning to OptimizeConstruction Workflow. Lean Construction Journal 2012pp 15-34 Lean Construction Journal 2011/licenses/by-nc-nd/3.0/15 Rethinking Lookahead Planning to Optimize Construction WorkflowFarook Hamzeh1; Glenn Ballard2; Iris D. Tommelein3AbstractResearch Question: How to improve lookahead planning practices in the constructionindustry to increase the reliability of production planning?Purpose: To assess the performance of lookahead planning, advise a standardized practice tosupport a strong linkage between Lookahead planning and activity execution, and improve the reliability of production planning.Research Design/Method: This study employs case study analysis, industry interviews, and anindustry survey to assess the current implementation of lookahead planning on construction projects in North America, South America, and Europe.Findings: The study findings indicate the existence of non-compliance with Last Planner®System rules, inadequate lookahead planning and standardized practices, sluggish identification and removal of constraints, and absence of analysis for plan failures. Limitations: The authors’ active role on the projects used as case studies may constitute alimitation to the research methods and tools used. The industry survey may have not covered all companies applying the Last Planner System. The suggested framework should be custom tailored to different projects to cater for size, culture, etc. Implications: This research provides a framework for applying the Last Planner System rulesduring lookahead planning. It aims at increasing the success of the making activities ready, designing operations, and ultimately improving PPC.Value for practitioners: The study presents to industry practitioners applying the LastPlanner System a standardized framework for implementing lookahead planning on construction projects. The paper also highlights the use of two metrics to assess the performance of lookahead planning at a given point in time and to monitor performanceover a period of time or between projects.Keywords: Lookahead planning, production planning, production control, lean construction,the Last Planner System, construction planning.1 Corresponding Author- Assistant Professor, Department of Civil and Environmental Engineering, 406E Bechtel,American University of Beirut, Riad El Solh, Beirut 1107 2020, Lebanon, Farook.Hamzeh@.lb2 Research Director, Project Production Systems Laboratory andAssociate-AdjunctProfessor, Civil and Environmental Engineering Department, 215 McLaughlin Hall, University. of California,Berkeley, CA 94720-1712,USA, ballard@3 Professor, Dept. of Civil and Environmental Engineering, and Director, Project Production Systems Laboratory, 215-A McLaughlin Hall, University of California, Berkeley, CA 94720-1712, USA ,tommelein@Hamzeh, Ballard, & Tommelein: Rethinking Lookahead Planning to Optimize Construction WorkflowLean Construction Journal 2011/licenses/by-nc-nd/3.0/page 16 Paper type: Full PaperIntroductionArchitecture, Engineering, and Construction (AEC) processes are plagued with problemsassociated with variations that undermine project performance and disrupt workflow leadingto detrimental impacts on project’s duration, cost, and quality (Hamzeh et al. 2007, Hoppand Spearman 2008, Salem et al. 2006, and Crichton 1966). Organizations use a number ofdifferent methods to maintain consistency in production flow and to shield production fromvariations in internal business processes as well as the external environment. Thompson(1967) highlighted some of these methods including:•Forecasting•Buffering•SmoothingVarious forecasting methods are used to anticipate variations in internal processes andin inputs to production. However, forecasts cannot cater for all variations and have manylimitations: the more detailed a forecast is the more off it will be, the farther a forecastlooks into the future the less accurate it becomes, and forecasts are always wrong (Nahmias2009).Buffering is used to mitigate process variations on both the input and output sides. Inputs typically needed for successful execution of tasks include: information, prerequisitework, human resources, space, material, equipment, external conditions, and funds (Ballard& Howell 1994, Koskela 2000).Buffers can take on one of three main forms: time, inventory and capacity. Time buffersallocate slack to an activity, inventory buffers utilize extra stock to account for supplyvariations, and capacity buffers reserve extra capacity such as using overtime or maintainingmachinery used only when needed to accommodate surges in load.Smoothing variations in supply and demand is another method that organizations applysince buffering may not be enough to cater for all variations, is costly to apply, and may leadto complacency. An example of smoothing demand is leveling the work load or heijunka asadvocated in the Toyota Production System (Liker 2004).Although variation undermines project performance, production systems can be designed to reduce them and to manage residuals utilizing a combination of the abovementioned methods.A production system can be defined as a collection of people and resources (e.g., machinery, equipment, information) arranged to design and make a product (“goods” or“services”) of value to customers (Ballard et al. 2007). A cornerstone of a production systemis production management such as the Last Planner System, which has been successfullyimplemented on construction projects (Ballard and Howell 2004) to increase the reliability ofplanning, improve production performance, and create predictable workflow indesign andconstruction operations.On any project, the planning process can be plagued by various problems. Planning involves forecasts that can be inaccurate the further they project into the future (NahmiasHamzeh, Ballard, & Tommelein: Rethinking Lookahead Planning to Optimize Construction WorkflowLean Construction Journal 2011/licenses/by-nc-nd/3.0/page 17 2009). It is hard to execute work schedules when Planners push plans to frontline specialistswithout involving them in plan development. Short-term work plans developed on the basis ofwishful thinking and in absence of reliable promises from trade experts are more likely to fallshort during execution. And if causes of plan failures are not identified and dealt with in atimely fashion, further failures are bound to happen (Hamzeh 2009). Moreover, reliableplanning depends on effective constraint analysis and removal. Constraints are those prerequisites required to be present before an activity can start (e.g., previous work,information, labor, material, equipment, tools, space, weather, etc.). Managing constraintscan help optimize work plans by identifying resource conflicts and resolving them prior towork start. Without constraint removal, it is hard to manage and reduce work flow uncertainties that often cause process variations (Chua et al. 2003).Taking into account the challenges mentioned above, the Last Planner System advocatesthe following steps in project planning:•Plan in greater detail as you get closer to performing the work (Cohn 2006) •Develop the work plan with those who are going to perform the work•Identify and remove work constraints ahead of time as a team to make work ready andincrease reliability of work plans•Make reliable promises and drive work execution based on coordination and active negotiation with project participants•Learn from plan failures by finding root causes and taking preventive actions (Ballard,et al. 2009)Despite the advantages of this system (Alarcón and Cruz 1997, Gonzalez et al. 2008), the current practice on many construction projects shows a poor implementation oflookahead planning resulting in a wide gap between long-term planning (master and phaseschedules) and short-term planning (commitment/weekly work plans) reducing the reliabilityof the planning system and the ability to establish foresight.This paper presents an assessment of lookahead planning implementation as one processin the Last Planner System, highlights some inadequacies in operating the planning system,emphasizes the role of lookahead planning as a prime driver to the success of weekly workplanning, and suggests guidelines for performing lookahead planning pertaining to activitybreakdown, operation design, and constraint analysis.The Last Planner SystemThe Last Planner System as developed by Glenn Ballard and Greg Howell is a system forproduction planning and control used to assist in smoothing variations in construction workflow, developing planning foresight, and reducing uncertainty in construction operations. Thesystem originally tackled variations in workflow at the weekly work plan level but soonexpanded to cover the full planning and schedule development process from master scheduling to phase scheduling through lookahead planning to reach weekly work planning.Percent Plan Complete (PPC) is a metric used to track the performance of reliable promising at the weekly work plan level by measuring the percentage of tasks completedrelative to those planned. It thus helps assess the reliability of work plans and initiatesHamzeh, Ballard, & Tommelein: Rethinking Lookahead Planning to Optimize Construction WorkflowLean Construction Journal 2011/licenses/by-nc-nd/3.0/page 18 preparations to perform work as planned. PPC is not a direct measure of project progress, butrather a measure of the extent to which promises are kept, and hence the extent to whichfuture work load may be predictable. Previous research has found a correlation between PPCand labor productivity (Liu and Ballard 2008). Possible secondary impacts of PPC onimprovingwork safety and quality require further research (Ballard and Howell 1998, Ballard et al.2007). Despite the advantages of the LPS, research has shown that many organizations facesignificant hurdles when implementing the system (Ballard et al. 2007; Hamzeh, 2009; Vianaet al. 2010). Hamzeh (2011) presented a framework for successful implementation of the LastPlanner System on construction projects.However, when the entire Last Planner System (master scheduling, phase scheduling,lookahead planning, and weekly work planning) is executed and updated as designed, PPCshould be an indicator of project progress; i.e., PPC and progress should vary with each other.This claim can be expressed as a complex hypothesis; namely:H1: If lookahead tasks are drawn from a phase schedule structured toachieve the project end date and intermediate milestones, and iflookahead planning makes ready what SHOULD be done, and if weeklywork plans are formed from what CAN be done selected from whatSHOULD be done in the order of criticality without gaming the system, PPCwill vary with project progress.If we accept this hypothesis as an assumption, it follows that if PPC does not vary withproject progress, there is a broken link somewhere in the hypothesized chain. Figure 1 shows the Last Planner System where activities are broken down from phases(boulders) to processes (rocks) then to operations (pebbles) across four planning processeswith different chronological spans: master scheduling, phase scheduling, lookahead planning,and weekly work planning.Master scheduling is a front-end planning process that produces a schedule describingwork to be carried out over the entire duration of a project. It involves project-level activities and identifies major milestone dates mostly in relation to contract documents andthe owner’s value proposition (Tommelein and Ballard 1997).Phase scheduling generates a schedule covering each project phase such as foundations, structural frame, or finishing. In a collaborative planning setup the projectteam: (1) defines a project phase or milestone, (2) breaks it down into constituent activities,and (3) schedules activities backward from the milestone. After incorporating input fromdifferent project parties and identifying hand-offs between specialists, the team performsreverse phase scheduling back from important phase milestones (Hamzeh 2009, Ballard andHowell 2004).Lookahead planning is the first step in production control (executing schedules) and usually covers a six week time frame. Lookahead time periods vary with the type of workbeing performed and the context. (For example, in conceptual design, tasks cannot beforeseen at a detailed level very far in advance because of the phenomenon of emergence. Inplant shutdowns, the lookahead period extends to the end of the shutdown. In this research,the focus is on normal construction projects, and on those 4 to 6 week time frames arecommonly used in lookahead planning). At this stage, activities are broken down into theHamzeh, Ballard, & Tommelein: Rethinking Lookahead Planning to Optimize Construction WorkflowLean Construction Journal 2011/licenses/by-nc-nd/3.0/page 19 level of production processes/operations, constraints are identified, operations are designed,and assignments are made ready (Ballard 1997, Hamzeh 2009).Weekly work planning (WWP) also known as commitment planning represents the mostdetailed plan in the system, shows interdependence between the works of various specialistorganizations, and directly drives the production process. Plan reliability at this level ispromoted by making quality assignments and reliable promises so that the production unitwill be shielded from uncertainty in upstream operations. The work assignment is a detailedmeasurable commitment of completion. At the end of each plan period, assignments arereviewed to assess whether they are complete or not, thus measuring the reliability of theplanning. For incomplete assignments, analyzing the reasons for plan failures and acting onthese reasons is the basis of learning and continuous improvement (Ballard 2000). Figure 1: Planning processes in the Last Planner System.The Last Planner System relates to deliberative and situated action planning as described by Senior (2007) combining aspects of both worlds. On one hand, deliberativeplanning takes place at the master and phase scheduling level where a premeditated courseof action is specified in setting milestones and identifying handoffs. On the other hand, thelookahead and weekly work plans are closer to the situated planning model where plans takeHamzeh, Ballard, & Tommelein: Rethinking Lookahead Planning to Optimize Construction WorkflowLean Construction Journal 2011/licenses/by-nc-nd/3.0/page 20 into account changes in the environment affecting inputs and outputs of constructionactivities.However, a question remains unanswered: how can the AEC industry advance the implementation of the lookahead planning within the Last Planner System to improveconstruction workflow and the reliability of planning?Accordingly, this paper reports an assessment of the current implementation of the LastPlanner System in construction, presents analytical data, highlights concerns with the currentpractice, and lays out recommended procedures to perform lookahead planning aiming atproducing more reliable production plans.MethodologyThis paper summarizes research conducted to study the role of lookahead planning within the Last Planner System in improving construction workflow and increasing thereliability of planning. Research involves results from two construction projects and preliminary results from a survey addressing Last Planner implementation (Hamzeh 2009).Case study research was the methodology adopted in this study because:1. It is appropriate for answering questions pertaining to ‘how’ and ‘why’ whe n no control for behavioral events is required and when research focuses on contemporaryaffairs.2. It uses both quantitative and qualitative methods to explain phenomena.3. It utilizes multiple sources of evidence in a natural setting that encompasses temporaland contextual facets of the variables monitored.4. It uncovers the dynamics of events explaining the phenomenon under study.5. It provides qualitative understanding when arriving at conclusions and analyzing results (Meredith 1998, Stuart et al. 2002, Yin 2003).The case studies involve two health care projects in the United States. Both projects employed the Last Planner System for production control investing heavily in employeetraining and in different aspects of lean construction. The owner on both projects is a strongadvocate of lean and integrated project delivery systems. The authors also conducted someinterviews with industry practitioners who worked on these projects.The first author spent fourteen months on project one working for ten months as a researcher and four months as an intern. While he was more of an observer in the researcherposition, he had more input into the process while working as an intern helping the development of a planning process. The first author also spent around eight months onproject two helping in the implementation of the Last Planner System and applying a newsoftware application to manage the planning process.Prior to case study research, an industry-wide survey was conducted among Last PlannerSystem industry users in the US, south America, and Europe. The survey addressed engineersand managers working for owners, architects/engineers, and contractors. The companieswere identified with help of the Lean Construction Institute (LCI). The survey aimed atassessing the implementation of the system, informing research on obstacles faced in theHamzeh, Ballard, & Tommelein: Rethinking Lookahead Planning to Optimize Construction WorkflowLean Construction Journal 2011/licenses/by-nc-nd/3.0/page 21 current practice, and providing feedback required in shaping the formation of guidelines forimprovement.The research process follows an inductive reasoning scheme adjusted to the specific situation. Accordingly the research process comprised multiple steps of evaluating andassessing the current practice, developing guidelines for improvements, and testing thesesuggested guidelines. In collecting data (e.g., PPC historical project data, master scheduledata) several methods were employed such as: conducting short interviews, attending weeklyor pull/phase scheduling sessions, attending value stream planning sessions, and performingexercises to assess the performance of the lookahead process and weekly work planning.Case Study OneThe first case study is a 555-bed hospital and medical campus in San Francisco, California. The $1.7 billion project comprises a 16-story hospital including two below-gradefloors. This is a project to study because of:•implementing integrated project delivery (IPD) and integrated form of agreement (IFOA)•engaging project partners who are interested in experimenting with lean practices •applying Last Planner System for production planning and control,•utilizing target value design (TVD) to steer design towards meeting the owner’s valueproposition•using building information modeling (BIM) extensivelyAs explained above, we assume for the moment that if the Last Planner System is implemented correctly, PPC and project progress should vary together. To determine if theyin fact do vary together, and hence if implementation is correct, an investigation wasperformed to compare slips or gains on the master schedule with each update to weekly workplanning performance expressed in percent plan complete (PPC). This investigation comprisedan in-depth study of the master schedule built in Primavera P6 scheduling software including:•Monitoring project milestones with each update.•Tracking changes to the schedule in terms of rescheduling, adding activities, addingdetail into current activities, changing sequence/logic, altering durations, and addingmodules suggested during phase planning sessions.•Analyzing the incremental slip or gain on schedule with each update. Assessing the weekly work planning performance was performed by monitoring PPC witheach weekly update. To adequately compare weekly PPC and incremental schedule changeson the master schedule, an aggregate PPC figure was calculated over 3 or 4 weeks, which isthe average cycle for master schedule updates.Figure 2 shows the relationship between percent plan complete (PPC) and the incremental schedule difference in days (+ is schedule delay and – is schedule gain). If systemimplementation was correct (drawing tasks into the weekly work plan that are critical withoutgaming the system), the higher the PPC the lower the schedule slip should be. However,results show a weak correlation of 0.28 and a covariance of 1.01 between PPC and negativeHamzeh, Ballard, & Tommelein: Rethinking Lookahead Planning to Optimize Construction WorkflowLean Construction Journal 2011/licenses/by-nc-nd/3.0/page 22 incremental schedule difference. Therefore, a clear relationship between weekly performance and overall schedule performance was not found.Moreover, the highlighted area in Figure 2 shows an increase in project delays (+ increment) for a higher PPC when more work was actually completed on the weekly schedule3. These results suggest that in Case 1 project, there is no evidence that variation inthe incremental schedule difference can be explained by PPC. This may indicate a poorlinkage between weekly work plans and the master schedule.Since earned value analysis is used to measure progress it may sometimes tempt teamsto work out of sequence to maximize progress gains in a certain period. While this may havean impact on the relationship between PPC and incremental schedule difference, it is still inviolation of the caveats stipulated in hypothesis H1 and a result of an incorrect developmentof the master schedule into a lookahead plan and an incorrect development of the lookaheadplan into a weekly work plan. That is why both working out of sequence and gaming thesystem are indications of poor implementation of the LPS and a poor linkage between weeklywork plans and the master schedule.‐80‐60‐40‐20204060800%10%20%30%40%50%60%70%80%90%100%25‐Oct‐2007 8‐Nov‐2007 22‐Nov‐2007 6‐Dec‐2007 20‐Dec‐2007 3‐Jan‐2008 17‐Jan‐2008 31‐Jan‐2008 14‐Feb‐2008 28‐Feb‐2008 13‐Mar‐2008 27‐Mar‐2008 10‐Apr‐2008 24‐Apr‐2008 8‐May‐2008 22‐May‐2008 5‐Jun‐2008 19‐Jun‐2008 3‐Jul‐2008 17‐Jul‐2008 31‐Jul‐2008 14‐Aug‐2008 28‐Aug‐2008 11‐Sep‐2008 25‐Sep‐20089‐Oct‐200823‐Oct‐2008 PPC Incremental Schedule Difference (days)Figure 2: The relationship between Percent Plan Complete (PPC) and incrementalschedule difference for case study 1Case Study TwoThe second case study project involved rehabilitation of 23 buildings, new constructionof 14 buildings, and landscape works for Fort Baker Retreat Group LLC at Fort Baker, Sausalito, California (Quakenbush 2008). The project budget was $103 million. This project3 While the two negative increments may be due to optimistic updating at the user level, the positive and negativeincrements do not correlate with PPC figures.Hamzeh, Ballard, & Tommelein: Rethinking Lookahead Planning to Optimize Construction WorkflowLean Construction Journal 2011/licenses/by-nc-nd/3.0/page 23 was chosen because the schedule was broken down into separate phases that were monitoredand recorded.This study focuses on the production management practices performed on the rehabilitation section of the project where the general contractor (GC) used the Last PlannerSystem to manage production. The GC developed the master schedule for the project usingphase scheduling sessions in collaboration with trade contractors and subcontractors. Theteam focused on the project handover and everything in between project start and projecthandover was decided using pull sessions. The GC continuously incorporated results fromthese sessions into the master schedule that was built in Microsoft Project and updated on aweekly basis. This schedule was developed to allow for a flow of construction trades from onebuilding to another. The project team used the Last Planner System to develop and manageweekly work planning based on the master schedule. Although the team did not applylookahead planning, they conducted weekly meetings for last planners who。