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专业资料英文原文：Building construction concrete crack ofprevention and processingAbstractThe crack problem of concrete is a widespread existence but againdifficult in solve of engineering actual problem, this text carried ona study analysis to a little bit familiar crack problem in the concreteengineering,and aim at concrete the circumstance put forward some prevention, processing measure.Keyword: Concrete crack prevention processingForewordConcrete's is 1 kind is anticipate by the freestone bone, cement,water and other mixture but formation of the in addition material ofquality 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 ofexistence 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 functionnot a creation to endanger.But after the concrete be subjected to lotus carry,difference in temperature etc.function,tiny crack wouldcontinuously of expand with connect, end formation we can see without the aid of instruments of macro view the crack be also the crack that theconcrete 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 concretematerial of loading ability, durable and anti- Shen ability, influencebuilding 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 science research with a great deal of of theconcrete engineering practice certificate, in the concrete engineeringcrack problem is ineluctable, also acceptable in certainly of the scopejust need to adopt valid of measure will it endanger degree control atcertain of scope inside. The reinforced concrete norm is also explicitprovision: Some structure at place of dissimilarity under the conditionallow existence certain the crack of width. But at under constructionshould as far as possible adopt a valid measure control crack creation,make the structure don't appear crack possibly or as far as possibledecrease 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 alreadytransformed to cause of crack: Such as temperature variety,constringency, inflation, the asymmetry sink to sink etc. reason cause of crack; Haveoutside carry the crack that the function cause; Protected environment not appropriate the crack etc. caused with chemical e ffect.Want differentiation to treat in the actual engineering, workout a problemaccording 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 overof a period of time or concrete sprinkle to build to complete behind ofaround a week. In the cement syrup humidity of evaporate would creationstem Suo, and this kind of constringency is can't negative.Stem Suo crack of the creation be main is because of concrete inside outside humidityevaporate degree dissimilarity but cause to transform dissimilarity ofresult: 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 Suotransform to be subjected to concrete inner part control, creation morebig pull should dint but creation crack. The relative humidity is morelow, 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 thenet shallow thin crack,mm, the flat surfacepart much see in the big physical volume concrete and follow it more inthinner beam plank short to distribute.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 waterpressure dint would creation the water power split crack influence concrete of loading dint etc..Concrete stem the Suo be main with waterash 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 andpowder 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 ofinfluence more big, water ash ratio more big, stem Suo more big, so inthe 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 quantityabsolute can't big in match ratio design give settle of use water quantity. Four is the earlier period which strengthen concrete to protect, andappropriate 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'smuch presenting in the center breadth, both ends be in the center thinand the length be different, with each other not coherent appearance.Shorter crack general long 20-30 cm, the longer crack can reach to a 2-3m, breadth1-5mm. It creation of main reason is:The concrete is eventually almost having no strength or strength before the Ning verysmall, perhaps concrete just eventually Ning but strength very hour, besubjected to heat or compare strong wind dint of influence,the concrete surface lose water to lead quick, result in in the capillary creationbigger negative press but make a concrete physical volume sharply constringency, but at this time the strength of concrete again can'tresist 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 valuesmaller higher Huo sour salt of the earlier period strength or commontheHuo sour brine mire. Two is strict the control water ash ratio, the Chanadd 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 evento soak through. Four is in time to overlay the perhaps damp grass matof the plastics thin film, hemp slice etc., keep concrete eventuallybefore 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 windthe 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 structurefoundation soil quality not and evenly,loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to declinewith 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 jellysoil 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 somethingto do with sinking to sink a circumstance, general follow with groundperpendicular or present 30°s-45 °Cape direction development, biggersink to sink crack, usually have certain of wrong, crack width usuallywith sink to decline quantity direct proportion relation. Crack widthunder 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, returnto fill soil foundation a construction at the upper part structure front should carry on necessity of Hang solid with reinforce.Twois the strength that assurance template is enough and just degree, and prop up firm,and makethe foundation be subjected to dint even. Three is keep concrete from sprinkle infusing the foundation in the process is soak by water. Fouris 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 toestablish template to notice to adopt certain of prevention measure.4.Temperature crack and preventionTemperature crack muchthe occurrence is in big surface or differencein temperature variety of the physical volume concrete compare the earth area of the concrete structure. Concrete after sprinkling to build, inthe hardening the process, cement water turn a creation a great deal ofof water turn hot, .(be the cement dosage is in the 350-550 kg/m 3, eachsign square the rice concrete will release a calories of 17500-27500 kJand 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 partbut not easy send forth, cause inner part the temperature hoick,but the concrete surface spread hot more quick, so formation inside outside ofbigger difference in temperature, the bigger difference in temperatureresult in inner part and exterior hot the degree of the bulge cold Suo dissimilarity, make concrete surface creation certain of pull shoulddint.When pull should dint exceed the anti- of concrete pull strengthextreme limit,concrete surface meeting creation crack, this kind of crack much occurrence after the concrete under construction 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 toinner 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 biggerstructure of the beamplank length, the crack run parallel with short side more;Thorough with pierce through sex of temperature crack general andshort side direction parallelism or close parallelism, crack along longside cent the segment appear, in the c enter width thesize be different, be subjected to temperature variety influence moreobvious,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 rusteclipse 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 lowhot 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 lowerwater ash ratio, water ash of the general concrete ratio control below0.6.Four is improvement the bone anticipate class to go together with,the Chan add powder ash from stove or efficiently reduce water etc. tocome to reduce cement dosage and lower water to turn hot.Five is an improvement concrete of mix blend to process a craft, lower sprinkle ofconcrete to build temperature.Six is the in addition that the Chan adda have of fixed amount to reduce water and increase Su, slow Ning etc.function in the concrete, improvement the concrete mix to match a thingof mobility, protect water, lower water to turn hot, postpone hot Fengof emergence time.Seven is the heat season sprinkle to build can theadoption take to establish to hide sun plank etc. assistance measurecontrol concrete of WenSheng, lower to sprinkle temperature of build the 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 is at great inner part constitution of the physical volume concrete cool off piping, coldwater perhaps cold air cool off,let up concrete of inside outside difference in is the supervision which strengthenis to reserve temperature constringency to sew.12 is to let up to control, sprinkle proper before building concrete in the Ji rock and old concrete top build a 5 mm or so sand mat a layer or usage asphalt etc. materialTu2 Shua.13 is to strengthen concrete to protect, the concrete aftersprinkle build use moist grass Lian in time, hemp slice's etc. overlay,and attention sprinkle water to protect, appropriate extension protecttime,assurance the concrete surface be slow-moving cool the cold season,concrete surface should constitution heat preservation measure, in order to prevent cold wave assault.14 is the allocation be a littleamount in the concrete of reinforcing bar perhaps add fiber materialconcrete 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 r einforced 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 thiskind of crack general emergence concrete structure usage period, onceappear very difficult remediable, so should at under construction adoptvalid the measure carry on prevention.Main of prevention measure:Whilebeing to choose to anticipate with the alkali activity small freestonebone.Two is the in addition which choose to use low lye mire with low alkaliis 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 areinforcing bar protection layer thinner, the harmful material get intoconcrete to make reinforcing bar creation rust eclipse, the reinforcingbar physical volume of the rust eclipse inflation, cause concrete bulgecrack,the crack of this kind type much is a crack lengthways,follow the position of reinforcing bar of prevent measure from have:One is assurance reinforcing bar protection the thickness of thelayer.Two is a concrete class to go together with to want good.Three isa concrete to sprinkle to note and flap Dao airtight solid.Four is areinforcing bar surface layer Tu2 Shua antisepsis coating.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 propertyof crack and concrete circumstance we want differentiation to treat, intime processing, with assurance building of safety usage.The repair measure of the concrete crack is main to have the following somemethod: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 repairmethod, it main be applicable to stability and to structure loading theability don't have the surface crack of influence and deep enter crackprocessing measure that is usually is a surface in crack daubery cement syrup, the wreath oxygen gum mire or at concrete surfaceTu2 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 glueto 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 ofrepair, it is make use of pressure equipments gumknot the material press into the crack of concrete, gum knot the material harden behind andconcrete formation one be whole, thus reinforce of purpose.The in common use gumknot 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 commonuse method in, it usually is follow the crack dig slot, the Qian fill Suin the slot or rigid water material with attain closing crack of purpose.The in commonuse Su material has PVCgummire, plastics ointment, the D Ji rubber etc.;In common use rigid water material is the polymercement sand syrup.2, the structure reinforce a methodWhenthe 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 commonuse main havethe following a few method:The piece of enlargement concrete structurein every aspect accumulate, outside the Cape department of the Gou piece pack type steel, adoption prepare should the dint method reinforce,glueto stick steel plate to reinforce, increase to establish fulcrum toreinforce and jet the concrete compensation reinforce.3, concrete displacement methodConcrete displacement method is processing severity damage concrete ofa kind of valid method, this method be first will damage of the concretepick and get rid of, then again displacement go into new of concrete orother 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 makeuse 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 ofprotection 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 thiskind 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 upstructure.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 makethe wound part heal of function, join some and special composition(such as contain to glue knot of theliquid 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 kindof phenomenon, it of emergence not only will lower the anti- Shen ofbuilding ability, influence building of usage function, and will causethe rust eclipse of reinforcing bar, the carbonization of concrete,lowerthe durable of material, influence building of loading ability, so wantto carry on to the concrete crack earnest research, differentiation treat, adoption reasonable of the method carry on processing, and at underconstruction adopt various valid of prevention measure to preventioncrack of emergence and development, assurance building and Gou piecesafety, stability work.From《CANADIAN JOURNAL OF CIVIL ENGINEERING》中文原文：建筑施工混凝土裂缝的预防与办理混凝土的裂缝问题是一个宽泛存在而又难于解决的工程实责问题，本文对混凝土工程中常有的一些裂缝问题进行了商议解析，并针对详尽情况提出了一些预防、办理措施。

混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献(文档含英文原文和中文翻译) Concrete technology and developmentPortland cement concrete has clearly emerged as the material of choice for the construction of a large number and variety of structures in the world today. This is attributed mainly to low cost of materials and construction for concrete structures as well as low cost of maintenance.Therefore, it is not surprising that many advancements in concrete technology have occurred as a result of two driving forces, namely the speed of construction and the durability of concrete.During the period 1940-1970, the availability of high early strength portland cements enabled the use of high water content in concrete mixtures that were easy to handle. This approach, however, led to serious problems with durability of structures, especially those subjected to severe environmental exposures.With us lightweight concrete is a development mainly of the last twenty years.Concrete technology is the making of plentiful good concrete cheaply. It includes the correct choice of the cement and the water, and the right treatment of the aggregates. Those which are dug near by and therefore cheap, must be sized, washed free of clay or silt, and recombined in the correct proportions so as to make a cheap concrete which is workable at a low water/cement ratio, thus easily comoacted to a high density and therefore strong.It hardens with age and the process of hardening continues for a long time after the concrete has attained sufficient strength.Abrams’law, perhaps the oldest law of concrete technology, states that the strength of a concrete varies inversely with its water cement ratio. This means that the sand content (particularly the fine sand which needs much water) must be reduced so far as possible. The fact that the sand “drinks” large quantities of water can easily be established by mixing several batches of x kg of cement with y kg of stone and the same amount of water but increasing amounts of sand. However if there is no sand the concrete will be so stiff that it will be unworkable thereforw porous and weak. The same will be true if the sand is too coarse. Therefore for each set of aggregates, the correct mix must not be changed without good reason. This applied particularly to the water content.Any drinkable and many undrinkable waters can be used for making concrete, including most clear waters from the sea or rivers. It is important that clay should be kept out of the concrete. The cement if fresh can usually be chosen on the basis of the maker’s certificates of tensile or crushing tests, but these are always made with fresh cement. Where strength is important , and the cement at the site is old, it should be tested.This stress , causing breakage,will be a tension since concretes are from 9 to 11times as strong in compression as in tension, This stress, the modulus of rupture, will be roughly double the direct tensile breaking stress obtained in a tensile testing machine,so a very rough guess at the conpressive strength can be made by multiplying the modulus of rupture by 4.5. The method can be used in combination with the strength results of machine-crushed cubes or cylinders or tensile test pieces but cannot otherwise be regarded as reliable. With these comparisons,however, it is suitable for comparing concretes on the same site made from the same aggregates and cement, with beams cast and tested in the same way.Extreme care is necessary for preparation,transport,plating and finish of concrete in construction works.It is important to note that only a bit of care and supervision make a great difference between good and bad concrete.The following factors may be kept in mind in concreting works.MixingThe mixing of ingredients shall be done in a mixer as specified in the contract.Handling and ConveyingThe handling&conveying of concrete from the mixer to the place of final deposit shall be done as rapidly as practicable and without any objectionable separation or loss of ingredients.Whenever the length of haul from the mixing plant to the place of deposit is such that the concrete unduly compacts or segregates,suitable agitators shall be installed in the conveying system.Where concrete is being conveyed on chutes or on belts,the free fall or drop shall be limited to 5ft.(or 150cm.) unless otherwise permitted.The concrete shall be placed in position within 30 minutes of its removal from the mixer.Placing ConcreteNo concrete shall be placed until the place of deposit has been thoroughly inspected and approved,all reinforcement,inserts and embedded metal properly security in position and checked,and forms thoroughly wetted(expect in freezing weather)or oiled.Placing shall be continued without avoidable interruption while the section is completed or satisfactory construction joint made.Within FormsConcrete shall be systematically deposited in shallow layers and at such rate as to maintain,until the completion of the unit,a plastic surface approximately horizontal throughout.Each layer shall be thoroughly compacted before placing the succeeding layer.CompactingMethod. Concrete shall be thoroughly compacted by means of suitable tools during and immediately after depositing.The concrete shall be worked around all reinforcement,embedded fixtures,and into the comers of the forms.Every precaution shall be taken to keep the reinforcement and embedded metal in proper position and to prevent distortion.Vibrating. Wherever practicable,concrete shall be internally vibrated within the forms,or in the mass,in order to increase the plasticity as to compact effectively to improve the surface texture and appearance,and to facilitate placing of the concrete.Vibration shall be continued the entire batch melts to a uniform appearance and the surface just starts to glisten.A minute film of cement paste shall be discernible between the concrete and the form and around the reinforcement.Over vibration causing segregation,unnecessary bleeding or formation of laitance shall be avoided.The effect spent on careful grading, mixing and compaction of concrete will be largely wasted if the concrete is badly cured. Curing means keeping the concretethoroughly damp for some time, usually a week, until it has reached the desired strength. So long as concrete is kept wet it will continue to gain strength, though more slowly as it grows older.Admixtures or additives to concrete are materials arematerials which are added to it or to the cement so as to improve one or more of the properties of the concrete. The main types are:1. Accelerators of set or hardening,2. Retarders of set or hardening,3. Air-entraining agents, including frothing or foaming agents,4. Gassing agents,5. Pozzolanas, blast-furnace slag cement, pulverized coal ash,6. Inhibitors of the chemical reaction between cement and aggregate, which might cause the aggregate to expand7. Agents for damp-proofing a concrete or reducing its permeability to water,8. Workability agents, often called plasticizers,9. Grouting agents and expanding cements.Wherever possible, admixtures should be avouded, particularly those that are added on site. Small variations in the quantity added may greatly affect the concrete properties in an undesiraale way. An accelerator can often be avoided by using a rapid-hardening cement or a richer mix with ordinary cement, or for very rapid gain of strength, high-alumina cement, though this is very much more expensive, in Britain about three times as costly as ordinary Portland cement. But in twenty-four hours its strength is equal to that reached with ordinary Portland cement in thirty days.A retarder may have to be used in warm weather when a large quantity of concrete has to be cast in one piece of formwork, and it is important that the concrete cast early in the day does not set before the last concrete. This occurs with bridges when they are cast in place, and the formwork necessarily bends underthe heavy load of the wet concrete. Some retarders permanently weaken the concrete and should not be used without good technical advice.A somewhat similar effect,milder than that of retarders, is obtained with low-heat cement. These may be sold by the cement maker or mixed by the civil engineering contractor. They give out less heat on setting and hardening, partly because they harden more slowly, and they are used in large casts such as gravity dams, where the concrete may take years to cool down to the temperature of the surrounding air. In countries like Britain or France, where pulverized coal is burnt in the power stations, the ash, which is very fine, has been mixed with cement to reduce its production of heat and its cost without reducing its long-term strength. Up to about 20 per cent ash by weight of the cement has been successfully used, with considerable savings in cement costs.In countries where air-entraining cement cement can be bought from the cement maker, no air-entraining agent needs to be mixed in .When air-entraining agents draw into the wet cement and concrete some 3-8 percent of air in the form of very small bubbles, they plasticize the concrete, making it more easily workable and therefore enable the water |cement ratio to be reduced. They reduce the strength of the concrete slightly but so little that in the United States their use is now standard practice in road-building where heavy frost occur. They greatly improve the frost resistance of the concrete.Pozzolane is a volcanic ash found near the Italian town of Puzzuoli, which is a natural cement. The name has been given to all natural mineral cements, as well as to the ash from coal or the slag from blast furnaces, both of which may become cementswhen ground and mixed with water. Pozzolanas of either the industrial or the mineral type are important to civil engineers because they have been added to oridinary Portland cement in proportions up to about 20 percent without loss of strength in the cement and with great savings in cement cost. Their main interest is in large dams, where they may reduce the heat given out by the cement during hardening. Some pozzolanas have been known to prevent the action between cement and certain aggregates which causes the aggregate to expand, and weaken or burst the concrete.The best way of waterproof a concrete is to reduce its permeability by careful mix design and manufacture of the concrete, with correct placing and tighr compaction in strong formwork ar a low water|cement ratio. Even an air-entraining agent can be used because the minute pores are discontinuous. Slow, careful curing of the concrete improves the hydration of the cement, which helps to block the capillary passages through the concrete mass. An asphalt or other waterproofing means the waterproofing of concrete by any method concerned with the quality of the concrete but not by a waterproof skin.Workability agents, water-reducing agents and plasticizers are three names for the same thing, mentioned under air-entraining agents. Their use can sometimes be avoided by adding more cement or fine sand, or even water, but of course only with great care.The rapid growth from 1945 onwards in the prestressing of concrete shows that there was a real need for this high-quality structural material. The quality must be high because the worst conditions of loading normally occur at the beginning of the life of the member, at the transfer of stress from the steel to theconcrete. Failure is therefore more likely then than later, when the concrete has become stronger and the stress in the steel has decreased because of creep in the steel and concrete, and shrinkage of the concrete. Faulty members are therefore observed and thrown out early, before they enter the structure, or at least before it The main advantages of prestressed concrete in comparison with reinforced concrete are :①The whole concrete cross-section resists load. In reinforced concrete about half the section, the cracked area below the neutral axis, does no useful work. Working deflections are smaller.②High working stresses are possible. In reinforced concrete they are not usually possible because they result in severe cracking which is always ugly and may be dangerous if it causes rusting of the steel.③Cracking is almost completely avoided in prestressed concrete.The main disadvantage of prestressed concrete is that much more care is needed to make it than reinforced concrete and it is therefore more expensive, but because it is of higher quality less of it needs to be needs to be used. It can therefore happen that a solution of a structural problem may be cheaper in prestressed concrete than in reinforced concrete, and it does often happen that a solution is possible with prestressing but impossible without it.Prestressing of the concrete means that it is placed under compression before it carries any working load. This means that the section can be designed so that it takes no tension or very little under the full design load. It therefore has theoretically no cracks and in practice very few. The prestress is usually applied by tensioning the steel before the concrete in which it isembedded has hardened. After the concrete has hardened enough to take the stress from the steel to the concrete. In a bridge with abutments able to resist thrust, the prestress can be applied without steel in the concrete. It is applied by jacks forcing the bridge inwards from the abutments. This methods has the advantage that the jacking force, or prestress, can be varied during the life of the structure as required.In the ten years from 1950 to 1960 prestressed concrete ceased to be an experinmental material and engineers won confidence in its use. With this confidence came an increase in the use of precast prestressed concrete particularly for long-span floors or the decks of motorways. Whereever the quantity to be made was large enough, for example in a motorway bridge 500 m kong , provided that most of the spans could be made the same and not much longer than 18m, it became economical to usefactory-precast prestressed beams, at least in industrial areas near a precasting factory prestressed beams, at least in industrial areas near a precasting factory. Most of these beams are heat-cured so as to free the forms quickly for re-use.In this period also, in the United States, precast prestressed roof beams and floor beams were used in many school buildings, occasionally 32 m long or more. Such long beams over a single span could not possibly be successful in reinforced concrete unless they were cast on site because they would have to be much deeper and much heavier than prestressed concrete beams. They would certainlly be less pleasing to the eye and often more expensive than the prestressed concrete beams. These school buildings have a strong, simple architectural appeal and will be a pleasure to look at for many years.The most important parts of a precast prestressed concrete beam are the tendons and the concrete. The tendons, as the name implies, are the cables, rods or wires of steel which are under tension in the concrete.Before the concrete has hardened (before transfer of stress), the tendons are either unstressed (post-tensioned prestressing) or are stressed and held by abutments outside the concrete ( pre-tensioned prestressing). While the concrete is hardening it grips each tendon more and more tightly by bond along its full length. End anchorages consisting of plates or blocks are placed on the ends of the tendons of post-tensioned prestressed units, and such tendons are stressed up at the time of transfer, when the concrete has hardened sufficiently. In the other type of pretressing, with pre-tensioned tendons, the tendons are released from external abutments at the moment of transfer, and act on the concrete through bond or archorage or both, shortening it by compression, and themselves also shortening and losing some tension.Further shortening of the concrete (and therefore of the steel) takes place with time. The concrete is said to creep. This means that it shortens permanently under load and spreads the stresses more uniformly and thus more safely across its section. Steel also creeps, but rather less. The result of these two effects ( and of the concrete shrinking when it dries ) is that prestressed concrete beams are never more highly stressed than at the moment of transfer.The factory precasting of long prestressed concrete beams is likely to become more and more popular in the future, but one difficulty will be road transport. As the length of the beam increases, the lorry becomes less and less manoeuvrable untileventually the only suitable time for it to travel is in the middle of the night when traffic in the district and the route, whether the roads are straight or curved. Precasting at the site avoids these difficulties; it may be expensive, but it has often been used for large bridge beams.混凝土工艺及发展波特兰水泥混凝土在当今世界已成为建造数量繁多、种类复杂结构的首选材料。

毕业设计（论文）外文文献翻译文献、资料中文题目：预应力混凝土文献、资料英文题目：Prestressed Concrete文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计（论文）外文资料翻译外文出处：The Concrete structure附件：1、外文原文；2、外文资料翻译译文。

1、外文资料原文Prestressed ConcreteConcrete is strong in compression, but weak in tension: Its tensile strength varies from 8 to 14 percent of its compressive strength. Due tosuch a Iow tensile capacity, fiexural cracks develop at early stages ofloading. In order to reduce or prevent such cracks from developing, aconcentric or eccentric force is imposed in the longitudinal direction of the structural element. This force prevents the cracks from developing by eliminating or considerably reducing the tensile stresses at thecritical midspan and support sections at service load, thereby raising the bending, shear, and torsional capacities of the sections. The sections are then able to behave elastically, and almost the full capacity of the concrete in compression can be efficiently utilized across the entire depth of the concrete sections when all loads act on the structure.Such an imposed longitudinal force is called a prestressing force,i.e., a compressive force that prestresses the sections along the span ofthe structural elementprior to the application of the transverse gravitydead and live loads or transient horizontal live loads. The type ofprestressing force involved, together with its magnitude, are determined mainly on the basis of the type of system to be constructed and the span length and slenderness desired.~ Since the prestressing force is applied longitudinally along or parallel to the axis of the member, the prestressing principle involved is commonly known as linear prestressing.Circular prestressing, used in liquid containment tanks, pipes,and pressure reactor vessels, essentially follows the same basic principles as does linear prestressing. The circumferential hoop, or "hugging" stress on the cylindrical or spherical structure, neutralizes the tensile stresses at the outer fibers of the curvilinear surface caused by the internal contained pressure.Figure 1.2.1 illustrates, in a basic fashion, the prestressing action in both types of structural systems and the resulting stress response. In(a), the individual concrete blocks act together as a beam due to the large compressive prestressing force P. Although it might appear that the blocks will slip and vertically simulate shear slip failure, in fact they will not because of the longitudinal force P. Similarly, the wooden staves in (c) might appear to be capable of separating as a result of the high internal radial pressure exerted on them. But again, because of the compressive prestress imposed by the metal bands as a form of circular prestressing, they will remain in place.From the preceding discussion, it is plain that permanent stresses in the prestressed structural member are created before the full dead and live loads are applied in order to eliminate or considerably reduce the net tensile stresses caused by these loads. With reinforced concrete,it is assumed that the tensile strength of the concrete is negligible and disregarded. This is because the tensile forces resulting from the bending moments are resisted bythe bond created in the reinforcement process. Cracking and deflection are therefore essentially irrecoverable in reinforced concrete once the member has reached its limit state at service load.The reinforcement in the reinforced concrete member does not exert any force of its own on the member, contrary to the action of prestressing steel. The steel required to produce the prestressing force in the prestressed member actively preloads the member, permitting a relatively high controlled recovery of cracking and deflection. Once the flexural tensile strength of the concrete is exceeded, the prestressed member starts to act like a reinforced concrete element.Prestressed members are shallower in depth than their reinforced concrete counterparts for the same span and loading conditions. In general, the depth of a prestressed concrete member is usually about 65 to 80 percent of the depth of the equivalent reinforced concrete member. Hence, the prestressed member requires less concrete, and,about 20 to 35 percent of the amount of reinforcement. Unfortunately, this saving in material weight is balanced by the higher cost of the higher quality materials needed in prestressing. Also, regardless of the system used, prestressing operations themselves result in an added cost: Formwork is more complex, since the geometry of prestressed sections is usually composed of. flanged sections with thin-webs.In spite of these additional costs, if a large enough number of precast units are manufactured, the difference between at least the initial costs of prestressed and reinforced concrete systems is usually not very large.~ And the indirect long-term savings are quite substantial, because less maintenance is needed; a longer working life is possible due to better quality control of the concrete, and lighter foundations are achieved due to the smaller cumulative weight of the superstructure.Once the beam span of reinforced concrete exceeds 70 to 90 feet (21.3 to 27.4m), the dead weight of the beam becomes excessive, resulting in heavier members and, consequently, greater long-term deflection and cracking. Thus, for larger spans, prestressed concrete becomes mandatory since arches are expensive to construct and do not perform as well due to the severe long-term shrinkage and creep they undergo.~ Very large spans such as segmental bridges or cable-stayed bridges can only be constructed through the use of prestressing.Prestressd concrete is not a new concept, dating back to 1872, when P. H. Jackson, an engineer from California, patented a prestressing system that used a tie rod to construct beams or arches from individual blocks [see Figure 1.2.1 (a)]. After a long lapse of time during which little progress was made because of the unavailability of high-strength steel to overcome prestress losses, R. E. Dill of Alexandria, Nebraska, recognized the effect of the shrinkage and creep (transverse material flow) of concrete on the loss of prestress. He subsequently developed the idea that successive post-tensioning of unbonded rods would compensate for the time-dependent loss of stress in the rods due to the decrease in the length of the member because of creep and shrinkage. In the early 1920s,W. H. Hewett of Minneapolis developed the principles of circular prestressing. He hoop-stressed horizontal reinforcement around walls of concrete tanks through the use of turnbuckles to prevent cracking due to internalliquid pressure, thereby achieving watertightness. Thereafter, prestressing of tanks and pipes developed at an accelerated pace in the United States, with thousands of tanks for water, liquid, and gas storage built and much mileage of prestressed pressure pipe laid in the two to three decades that followed.Linear prestressing continued to develop in Europe and in France, in particular through the ingenuity of Eugene Freyssinet, who proposed in 1926--1928 methods to overcome prestress losses through the use of high-strength and high-ductility steels. In 1940, he introduced thenow well-known and well-accepted Freyssinet system.P. W. Abeles of England introduced and developed the concept of partial prestressing between the 1930s and 1960s. F. Leonhardt of Germany, V. Mikhailov of Russia, and T. Y. Lin of the United States also contributed a great deal to the art and science of the design of prestressed concrete. Lin's load-balancing method deserves particular mention in this regard, as it considerably simplified the design process, particularly in continuous structures. These twentieth-century developments have led to the extensive use of prestressing throughoutthe world, and in the United States in particular.Today, prestressed concrete is used in buildings, underground structures, TV towers, floating storage and offshore structures, power stations, nuclear reactor vessels, and numerous types of bridge systems including segn~ental and cable-stayed bridges, they demonstrate the versatility of the prestressing concept and its all-encompassing application. The success in the development and construction of all these structures has been due in no small measures to the advances in the technology of materials, particularly prestressing steel, and the accumulated knowledge in estimating the short-and long-term losses in the prestressing forces.~2、外文资料翻译译文预应力混凝土混凝土的力学特性是抗压不抗拉：它的抗拉强度是抗压强度的8％一14％。

建筑土木工程外文翻译外文文献英文文献混凝土桥梁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 industrywell 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 improved durability (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 asresistance 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 MATERIALS Concrete design specifications have in the past focusedprimarily 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 eachproject.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 to reduction 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 spancapability. 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 spanrange 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 beasked 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. T o 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. DECKS Cast-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 on rapid replacement of bridge decks has provided a proposed full-depth panel system with panels pretensioned in the transverse direction and posttensioned in the longitudinaldirection.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 orpolymeric 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 the structural 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 ofdeck 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。

一、外文原文Talling building and Steel construction Although there have been many advancements in building construction technology in general. Spectacular archievements have been made in the design and construction of ultrahigh-rise buildings.The early development of high-rise buildings began with structural steel framing.Reinforced concrete and stressed-skin tube systems have since been economically and competitively used in a number of structures for both residential and commercial purposes.The high-rise buildings ranging from 50 to 110 stories that are being built all over the United States are the result of innovations and development of new structual systems.Greater height entails increased column and beam sizes to make buildings more rigid so that under wind load they will not sway beyond an acceptable limit.Excessive lateral sway may cause serious recurring damage to partitions,ceilings.and other architectural details. In addition,excessive sway may cause discomfort to the occupants of the building because their perception of such motion.Structural systems of reinforced concrete,as well as steel,take full advantage of inherent potential stiffness of the total building and therefore require additional stiffening to limit the sway.In a steel structure,for example,the economy can be defined in terms of the total average quantity of steel per square foot of floor area of the building.Curve A in Fig .1 represents the average unit weight of a conventional frame with increasing numbers of stories. Curve B represents the average steel weight if the frame is protected from all lateral loads. The gap between the upper boundary and the lower boundary represents the premium for height for the traditional column-and-beam frame.Structural engineers have developed structural systems with a view to eliminating this premium.Systems in steel. Tall buildings in steel developed as a result ofseveral types of structural innovations. The innovations have been applied to the construction of both office and apartment buildings.Frame with rigid belt trusses. In order to tie the exterior columns of a frame structure to the interior vertical trusses,a system of rigid belt trusses at mid-height and at the top of the building may be used. A good example of this system is the First Wisconsin Bank Building(1974) in Milwaukee.Framed tube. The maximum efficiency of the total structure of a tall building, for both strength and stiffness,to resist wind load can be achieved only if all column element can be connected to each other in such a way that the entire building acts as a hollow tube or rigid box in projecting out of the ground. This particular structural system was probably used for the first time in the 43-story reinforced concrete DeWitt Chestnut Apartment Building in Chicago. The most significant use of this system is in the twin structural steel towers of the 110-story World Trade Center building in New York Column-diagonal truss tube. The exterior columns of a building can be spaced reasonably far apart and yet be made to work together as a tube by connecting them with diagonal members interesting at the centre line of the columns and beams. This simple yet extremely efficient system was used for the first time on the John Hancock Centre in Chicago, using as much steel as is normally needed for a traditional 40-story building.Bundled tube. With the continuing need for larger and taller buildings, the framed tube or the column-diagonal truss tube may be used in a bundled form to create larger tube envelopes while maintaining high efficiency. The 110-story Sears Roebuck Headquarters Building in Chicago has nine tube, bundled at the base of the building in three rows. Some of these individual tubes terminate at different heights of the building, demonstrating the unlimited architectural possibilities of this latest structural concept. The Sears tower, at a height of 1450 ft(442m), is the world’s tallest building.Stressed-skin tube system. The tube structural system was developed for improving the resistance to lateral forces (wind and earthquake) and thecontrol of drift (lateral building movement ) in high-rise building. The stressed-skin tube takes the tube system a step further. The development of the stressed-skin tube utilizes the façade of the building as a structural element which acts with the framed tube, thus providing an efficient way of resisting lateral loads in high-rise buildings, and resulting in cost-effective column-free interior space with a high ratio of net to gross floor area.Because of the contribution of the stressed-skin façade, the framed members of the tube require less mass, and are thus lighter and less expensive. All the typical columns and spandrel beams are standard rolled shapes,minimizing the use and cost of special built-up members. The depth requirement for the perimeter spandrel beams is also reduced, and the need for upset beams above floors, which would encroach on valuable space, is minimized. The structural system has been used on the 54-story One Mellon Bank Center in Pittburgh.Systems in concrete. While tall buildings constructed of steel had an early start, development of tall buildings of reinforced concrete progressed at a fast enough rate to provide a competitive chanllenge to structural steel systems for both office and apartment buildings.Framed tube. As discussed above, the first framed tube concept for tall buildings was used for the 43-story DeWitt Chestnut Apartment Building. In this building ,exterior columns were spaced at 5.5ft (1.68m) centers, and interior columns were used as needed to support the 8-in . -thick (20-m) flat-plate concrete slabs.Tube in tube. Another system in reinforced concrete for office buildings combines the traditional shear wall construction with an exterior framed tube. The system consists of an outer framed tube of very closely spaced columns and an interior rigid shear wall tube enclosing the central service area. The system known as the tube-in-tube system , made it possible to design the world’s present tallest (714ft or 218m)lightweight concrete bu ilding( the 52-story One Shell Plaza Building in Houston) for the unit price of a traditional shear wall structure of only 35 stories.Systems combining both concrete and steel have also been developed, an examle of which is the composite system developed by skidmore, Owings &Merril in which an exterior closely spaced framed tube in concrete envelops an interior steel framing, thereby combining the advantages of both reinforced concrete and structural steel systems. The 52-story One Shell Square Building in New Orleans is based on this system.Steel construction refers to a broad range of building construction in which steel plays the leading role. Most steel construction consists of large-scale buildings or engineering works, with the steel generally in the form of beams, girders, bars, plates, and other members shaped through the hot-rolled process. Despite the increased use of other materials, steel construction remained a major outlet for the steel industries of the U.S, U.K, U.S.S.R, Japan, West German, France, and other steel producers in the 1970s.二、原文翻译高层结构与钢结构近年来，尽管一般的建筑结构设计取得了很大的进步，但是取得显著成绩的还要属超高层建筑结构设计。

毕业设计（论文）外文文献翻译文献、资料中文题目：钢筋混凝土结构设计文献、资料英文题目：DESIGN OF REINFORCED CONCRETE STRUCTURES 文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：土木工程班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计（论文）外文参考资料及译文译文题目：DESIGN OF REINFORCED CONCRETE STRUCTURES原文：DESIGN OF REINFORCED CONCRETESTRUCTURES1. BASIC CONCERPTS AND CHARACERACTERISTICS OF REINFORCED CONCRETEPlain concrete is formed from hardened mixture of cement, water , fine aggregate , coarse aggregate (crushed stone or gravel ) , air and often other admixtures . The plastic mix is placed and consolidated in the formwork, then cured to accelerate of the chemical hydration of hen cement mix and results in a hardened concrete. It is generally known that concrete has high compressive strength and low resistance to tension. Its tensile strength is approximatelyone-tenth of its compressive strength. Consequently, tensile reinforcement in the tension zone has to be provided to supplement the tensile strength of the reinforced concrete section.For example, a plain concrete beam under a uniformly distributed load q is shown in Fig .1.1(a), when the distributed load increases and reaches a value q=1.37KN/m , the tensile region at the mid-span will be cracked and the beam will fail suddenly . A reinforced concrete beam if the same size but has to steel reinforcing bars (2φ16) embedded at the bottom under a uniformly distributed load q is shown in Fig.1.1(b). The reinforcing bars take up the tension there after the concrete is cracked. When the load q is increased, the width of the cracks, the deflection and thestress of steel bars will increase . When the steel approaches the yielding stress ƒy , thedeflection and the cracked width are so large offering some warning that the compression zone . The failure load q=9.31KN/m, is approximately 6.8 times that for the plain concrete beam.Concrete and reinforcement can work together because there is a sufficiently strong bond between the two materials, there are no relative movements of the bars and the surrounding concrete cracking. The thermal expansion coefficients of the two materials are 1.2×10-5K-1 for steel and 1.0×10-5~1.5×10-5K-1 for concrete .Generally speaking, reinforced structure possess following features :Durability .With the reinforcing steel protected by the concrete , reinforced concreteFig.1.1Plain concrete beam and reinforced concrete beamIs perhaps one of the most durable materials for construction .It does not rot rust , and is not vulnerable to efflorescence .(2)Fire resistance .Both concrete an steel are not inflammable materials .They would not be affected by fire below the temperature of 200℃when there is a moderate amount of concrete cover giving sufficient thermal insulation to the embedded reinforcement bars.(3)High stiffness .Most reinforced concrete structures have comparatively large cross sections .As concrete has high modulus of elasticity, reinforced concrete structures are usuallystiffer than structures of other materials, thus they are less prone to large deformations, This property also makes the reinforced concrete less adaptable to situations requiring certainflexibility, such as high-rise buildings under seismic load, and particular provisions have to be made if reinforced concrete is used.(b)Reinfoced concrete beam(4)Locally available resources. It is always possible to make use of the local resources of labour and materials such as fine and coarse aggregates. Only cement and reinforcement need to be brought in from outside provinces.(5)Cost effective. Comparing with steel structures, reinforced concrete structures are cheaper.(6)Large dead mass, The density of reinforced concrete may reach2400~2500kg/pare with structures of other materials, reinforced concrete structures generally have a heavy dead mass. However, this may be not always disadvantageous, particularly for those structures which rely on heavy dead weight to maintain stability, such as gravity dam and other retaining structure. The development and use of light weight aggregate have to a certain extent make concrete structure lighter.(7)Long curing period.. It normally takes a curing period of 28 day under specified conditions for concrete to acquire its full nominal strength. This makes the progress of reinforced concrete structure construction subject to seasonal climate. The development of factory prefabricated members and investment in metal formwork also reduce the consumption of timber formwork materials.(8)Easily cracked. Concrete is weak in tension and is easily cracked in the tension zone. Reinforcing bars are provided not to prevent the concrete from cracking but to take up the tensile force. So most of the reinforced concrete structure in service is behaving in a cracked state. This is an inherent is subjected to a compressive force before working load is applied. Thus the compressed concrete can take up some tension from the load.2. HISTOEICAL DEVELPPMENT OF CONCRETE STRUCTUREAlthough concrete and its cementitious(volcanic) constituents, such as pozzolanic ash, have been used since the days of Greek, the Romans, and possibly earlier ancient civilization, the use of reinforced concrete for construction purpose is a relatively recent event, In 1801, F. Concrete published his statement of principles of construction, recognizing the weakness if concrete in tension, The beginning of reinforced concrete is generally attributed to Frenchman J. L. Lambot, who in 1850 constructed, for the first time, a small boat with concrete for exhibition in the 1855 World’s Fair in Paris. In England, W. B. Wilkinson registered a patent for reinforced concrete l=floor slab in 1854.J.Monier, a French gardener used metal frames as reinforcement to make garden plant containers in 1867. Before 1870, Monier had taken a series of patents to make reinforcedconcrete pipes, slabs, and arches. But Monier had no knowledge of the working principle of this new material, he placed the reinforcement at the mid-depth of his wares. Then little construction was done in reinforced concrete. It is until 1887, when the German engineers Wayss and Bauschinger proposed to place the reinforcement in the tension zone, the use of reinforced concrete as a material of construction began to spread rapidly. In1906, C. A. P. Turner developed the first flat slab without beams.Before the early twenties of 20th century, reinforced concrete went through the initial stage of its development, Considerable progress occurred in the field such that by 1910 the German Committee for Reinforced Concrete, the Austrian Concrete Committee, the American Concrete Institute, and the British Concrete Institute were established. Various structural elements, such as beams, slabs, columns, frames, arches, footings, etc. were developed using this material. However, the strength of concrete and that of reinforcing bars were still very low. The common strength of concrete at the beginning of 20th century was about 15MPa in compression, and the tensile strength of steel bars was about 200MPa. The elements were designed along the allowable stresses which was an extension of the principles in strength of materials.By the late twenties, reinforced concrete entered a new stage of development. Many buildings, bridges, liquid containers, thin shells and prefabricated members of reinforced concrete were concrete were constructed by 1920. The era of linear and circular prestressing began.. Reinforced concrete, because of its low cost and easy availability, has become the staple material of construction all over the world. Up to now, the quality of concrete has been greatly improved and the range of its utility has been expanded. The design approach has also been innovative to giving the new role for reinforced concrete is to play in the world of construction.The concrete commonly used today has a compressive strength of 20~40MPa. For concrete used in pre-stressed concrete the compressive strength may be as high as 60~80MPa. The reinforcing bars commonly used today has a tensile strength of 400MPa, and the ultimate tensile strength of prestressing wire may reach 1570~1860Pa. The development of high strength concrete makes it possible for reinforced concrete to be used in high-rise buildings, off-shore structures, pressure vessels, etc. In order to reduce the dead weight of concrete structures, various kinds of light concrete have been developed with a density of 1400~1800kg/m3. With a compressive strength of 50MPa, light weight concrete may be used in load bearing structures. One of the best examples is the gymnasium of the University of Illinois which has a span of 122m and is constructed of concrete with a density of 1700kg/m3. Another example is the two 20-story apartment houses at the Xi-Bian-Men in Beijing. The walls of these two buildings are light weight concrete with a density of 1800kg/m3.The tallest reinforced concrete building in the world today is the 76-story Water Tower Building in Chicago with a height of 262m. The tallest reinforced concrete building in China today is the 63-story International Trade Center in GuangZhou with a height a height of 200m. The tallest reinforced concrete construction in the world is the 549m high International Television Tower in Toronto, Canada. He prestressed concrete T-section simply supported beam bridge over the Yellow River in Luoyang has 67 spans and the standard span length is 50m.In the design of reinforced concrete structures, limit state design concept has replaced the old allowable stresses principle. Reliability analysis based on the probability theory has very recently been introduced putting the limit state design on a sound theoretical foundation. Elastic-plastic analysis of continuous beams is established and is accepted in most of the design codes. Finite element analysis is extensively used in the design of reinforced concrete structures and non-linear behavior of concrete is taken into consideration. Recent earthquake disasters prompted the research in the seismic resistant reinforced of concrete structures. Significant results have been accumulated.3. SPECIAL FEATURES OF THE COURSEReinforced concrete is a widely used material for construction. Hence, graduates of every civil engineering program must have, as a minimum requirement, a basic understanding of the fundamentals of reinforced concrete.The course of Reinforced Concrete Design requires the prerequisite of Engineering Mechanics, Strength of Materials, and some if not all, of Theory of Structures, In all these courses, with the exception of Strength of Materials to some extent, a structure is treated of in the abstract. For instance, in the theory of rigid frame analysis, all members have an abstract EI/l value, regardless of what the act value may be. But the theory of reinforced concrete is different, it deals with specific materials, concrete and steel. The values of most parameters must be determined by experiments and can no more be regarded as some abstract. Additionally, due to the low tensile strength of concrete, the reinforced concrete members usually work with cracks, some of the parameters such as the elastic modulus I of concrete and the inertia I of section are variable with the loads.The theory of reinforced concrete is relatively young. Although great progress has been made, the theory is still empirical in nature in stead of rational. Many formulas can not be derived from a few propositions, and may cause some difficulties for students. Besides, due to the difference in practice in different countries, most countries base their design methods on their own experience and experimental results. Consequently, what one learns in one country may be different in another country. Besides, the theory is still in a stage of rapid。

隧道设计考虑应力释放的影响摘要：在隧道设计中，支护时间的确定和刚性的支护体系对于维持隧道稳定是非常重要的，该研究所采用的收敛—约束法来确定的隧道的应力和位移，同时考虑到了地基承载力反压力曲线的位移、应力释放的影响以及隧道衬砌和岩石隧道周边洞室的相互作用，这个结论可以确定支护的时间和支护结构的强度和刚度。

这种方法曾适用于in the Ban Ve Hydroelectric Power Plant．in Nghe An Province．Vietnam 引水隧道。

结果表明，当位移u0在0.0865米到0.0919米之间时取一个合适的位移值，我们就可以通过架设支护结构来满足隧道的稳定性和经济的要求。

关键词：隧道支撑结构稳定性反压力曲线应力释放的影响1、引言岩石在自然环境中，特别是在深部地层当中，常常受到上部地层和重力的影响，由于这些因素的影响在岩体当中二次应力的发展是非常复杂，难以界定的。

隧道开挖过程中，一部分的岩石通常会受到来自隧道洞顶岩石的去除而产生的力—拉应力，有时拉应力会相当高，都会在隧道围岩的周边产生，由于岩石开挖洞周应力的释放会导致周边围岩的变形，从三向应力状态转变为双向应力状态。

在隧道施工过程中，架设支护结构的目的是为了提高和维持岩体的自承能力，以最大程度的发挥岩体的承载能力，并且在岩体内产生有利于发展的内应力场。

1938年，芬纳进行了上部地层和水力结构相互作用方面的研究，并发现了基础的特殊变化曲线和弹塑性介质的解决方案。

1963年，Pacher进行了同样的研究，并取得了同样的结果。

当隧道设计考虑上部地层和水工结构之间的相互作用时，其结果采用新奥法（NATM）施工和实际结构是比较适合的。

此外，在隧道设计中，隧道衬砌和洞室周围地层之间的相互作用，以及相应的地基反压力曲线，通常被考虑在内（Panet和Guenot1982; Panet1995年）。

在隧道设计中收敛—约束法通常被认为是有效的。

土木工程混凝土论文中英文资料外文翻译文献外文资料STUDIES ON IMPACT STRENGTH OF CONCRETESUBJECTED TO SUSTAINEDELEVATED TEMPERATUREConcrete has a remarkable fire resisting properties. Damage in concrete due to fire depends on a great extent on the intensity and duration of fire. Spalling cracking during heating are common concrete behaviour observed in the investigation of the fire affected structures. Plenty of literature is available on the studies of concrete based on time temperature cures. In power, oil sectorsand nuclear reactors concrete is exposed to high temperature for considerable period of time. These effects can be reckoned as exposure to sustained elevated temperature. The sustained elevated temperature may be varying from a few hours to a number of years depending upon practical condition of exposures. The knowledge on properties under such conditions is also of prime importance apart from the structures subjected to high intensity fire. Impact studies of structure subjected to sustained elevated temperature becomes more important as it involves sensitive structures which is more prone to attacks and accidents. In this paper impact studies on concrete subjected to sustained elevated temperature has been discussed. Experiments have been conducted on 180 specimens along with 180 companion cube specimens. The temperatures of 100°C, 200°C and 300°C for a duration of exposure of 2 hours 4 hours and 6 hours has been considered in the experiments. The results are logically analyzed and concluded.1. INTRODUCTIONThe remarkable property of concrete to resist the fire reduces the damage in a concrete structure whenever there is an accidental fire. In most of the cases the concrete remains intact with minor damages only. The reason being low thermal conductivity of concrete at higher temperatures and hence limiting the depth of penetration of firedamage. But when the concrete is subjected to high temperature for long duration the deterioration of concrete takes place. Hence it is essential to understand the strength and deformation characteristics of concrete subjected to temperature for long duration. In this paper an attempt has been made to study the variation in Impact Strength of concrete when subjected to a temperature range 100oC, 200oC and 300oC sustained for a period of 2 hrs, 4 hrs and 6 hrs.The review of the literature shows that a lot of research work [1 – 3] has taken place on the effect of elevated temperature on concrete. All these studies are based on time –temperature curves. Hence an attempt has been made to study the effect of sustained elevated temperature on impact strength of concrete and the results are compared with the compressive strength. The experimental programme has been planned for unstressed residual strength test based on the available facilities. Residual strength is the strength of heated and subsequently cooled concrete specimens expressed as percentage of the strength of unheated specimens.2. EXPERIMENTAL INVESTIGATION2.1. TEST SPECIMEN AND MATERIALSA total of 180 specimens were tested in the present study along with 180 companion cubes. An electric oven capable of reaching a maximum temperature of 300oC has been used for investigation. Fine and coarse aggregates conforming to IS383 has been used to prepare the specimen with mix proportions M1 = 1:2.1:3.95 w/c = 0.58, M2 = 1:1.15:3.56 w/c = 0.53, M3 = 1:0.8:2.4 w/c = 0.4.2.2 TEST VARIABLESThe effects of the following variables were studied.2.2.1 Size sSize of Impact Strength Test Specimen was 150 mm dial and 64 mm thickness and size of companion cube 150 x 150 x 150 mm.2.2.2 Maximum TemperatureIn addition to room temperature, the effect of three different temperatures (100oC, 200oC and 300oC) on the compressive strength was investigated.2.2.3 Exposure Time at Maximum TemperatureThree different exposure times were used to investigate the influence of heat on compressive strength; they are 2 hrs, 4 hrs and 6 hrs.2.2.4 Cooling MethodSpecimens were cooled in air to room temperature.3. TEST PROCEDUREAll the specimens were cast in steel moulds as per IS516 and each layer was compacted. Specimens were then kept in their moulds for 24 hours after which they were decoupled and placed into a curing tank until 28 days. After which the specimens were removed and were allowed to dry in room temperature. These specimens were kept in the oven and the required target temperature was set. Depending on the number of specimen kept inside the oven the time taken to reach the steady state was found to vary. After the steady state was reached the specimens were subjected to predetermined steady duration at the end of which the specimens are cooled to room temperature and tested.ACI drop weight impact strength test was adopted. This is the simplest method for evaluating impact resistance of concrete. The size of the specimen is 150 mm dial and 64 mm thickness. The disc specimens were prepared using steel moulds cured and heated and cooled as. This consists of a standard manually operated 4.54 kg hammer with 457 mm drop. A 64 mm hardened steel ball and a flat base plate with positioning bracket and lugs. The specimen is placed between the four guides pieces (lugs) located 4.8 mm away from the sample. A frame (positioning bracket) is then built in order to target the steel ball at the centre of concrete disc. The disc is coated at the bottom with a thin layer of petroleum jelly or heavy grease to reduce the friction between the specimen and base plate. The bottom part of the hammer unit was placed with its base upon the steel ball and the load was applied by dropping weight repeatedly. The loading was continued until the disc failed and opened up such that it touched three of the four positioning lugs. The number of blows that caused this condition is recorded as the failure strength. The companion cubes were tested for cube compression strength (fake).4. ANALYSIS AND RESULTS4.1 RESIDUAL COMPRESSIVE STRENGTH VS. TEMPERATUREFrom Table 1, at 100°C sustained elevated temperature it is seen that the residual strength of air cooled specimens of mixes M1, M2 and M3 has increased in strength 114% for M1 mix, 109% for M2 mix and 111% for M3 mix for 6 hours duration of exposure. When the sustained elevated temperature is to 200°C for air cooled specimens there is a decrease in strength up to 910% approximately for M1 mix for a duration of 6 hours, but in case of M2 mix it is 82% and for M3 mix it is 63% maximum for 6 hours duration of exposure. When the concrete mixes M1, M2 and M3 are exposed to 300°C sustained temperature there is a reduction in strength up to 78% for M1 mix for 6 hour duration of exposure.4.2 RESIDUAL COMPRESSIVE STRENGTH VS DURATION OF EXPOSUREFrom Table 1, result shows that heating up to 100°C for 2 hours and 4 hours, the residual strength of mix M1 has decreased where as the residual strength of mix M2 and M3 has increased. The residual strength is further increased for 6 hours duration of exposure in all the three mixes M1, M2 and M3 even beyond the strength at room temperature. When the specimens of mixes M1, M2 and M3 are exposed to 200°C for 2,4 and 6 hours of duration, it is observed that the residual strength has decreased below the room temperature and has reached 92% for M1 mix, 82 and 73% for M2 and M3 mix respectively. Concrete cubes of mixes M1, M2 and M3 when subjected to 300°C temperature for 2,4 and 6 hours the residual strength for mix M1 reduces to 92% for 2 hours up to 78% for six hours duration of exposure, for M2 mix 90% for 2 hours duration of exposure up to 76% for six hour duration of exposure, for M3 mix 88% up to 68% between 2 and 6 hours of duration of exposure.5. IMPACT STRENGTH OF CONCRETE5.1 RESIDUAL IMPACT STRENGTH VS TEMPERATUREFrom the table 1, it can be observed that for the sustained elevated temperature of 100°C the residual impact strength of all the specimens reduces and vary between 20 and 50% for mix M1, 15 to 40% for mix M2 and M3. When the sustained elevated temperature is 200°C the residual impact strength of all the mixes further decreases. The reduction is around 60-70% for mix M1, 55 to 65% for M2 and M3 mix. When the sustained elevated temperature is 300°C it is observed that the residual impact strength reduces further and vary between 85 and 70% for mix M1 and 85 to 90% for mix M2 and mix M3.5.2 RESIDUAL IMPACT STRENGTH VS DURATION OF EXPOSUREFrom the Table 1 and Figures 1 to 3, it can be observed that there is a reduction in impact strength when the sustained elevated temperature is 100°C for 2 hrs, 4 hrs and 6 hrs, and its range is 15 to 50% for all the mixes M1, M2 and M3. The influence of duration of exposure is higher for mix M1 which decreases more rapidly as compared to mix M2 and mix M3 for the same duration of exposure. When the specimens are subjected to sustained elevated temperature of 200°C for 2,4 and 6 hour of duration, further reduction in residual impact strength is observed as compared to at 100°C. The reduction is in the range of 55-70% for all the mixes. The six hour duration of exposure has a greater influence on the residual impact strength of concrete. When the sustained elevated temperature is 300°C for 2,4 and 6 hours duration of exposure the residualimpact strength reduces. It can be seen that both temperature and duration of exposure have a very high influence on the residual impact strength of concrete which shows a reduction up to 90% approximately for all the mixes.6. CONCLUSIONThe compressive strength of concrete increases at 100oC when exposed to sustained elevated temperature. The compressive strength of concrete decreases when exposed to 200°C and 300°C from 10 to 30% for 6 hours of exposure. Residual impact strength reduces irrespective of temperature and duration. Residual impact strength decreases at a higher rate of 20% to 85% as compared to compressive strength between 15% and 30 % when subjected to sustained elevated temperature. The impact strength reduces at a higher rate as compared to compressive strength when subjected to sustained elevated temperature.混凝土受持续高温影响的强度的研究混凝土具有显着的耐火性能。

土木工程专业毕业设计外文文献翻译2篇XXXXXXXXX学院学士学位毕业设计（论文）英语翻译课题名称英语翻译学号学生专业、年级所在院系指导教师选题时间Fundamental Assumptions for Reinforced ConcreteBehaviorThe chief task of the structural engineer is the design of structures. Design is the determination of the general shape and all specific dimensions of a particular structure so that it will perform the function for which it is created and will safely withstand the influences that will act on it throughout useful life. These influences are primarily the loads and other forces to which it will be subjected, as well as other detrimental agents, such as temperature fluctuations, foundation settlements, and corrosive influences, Structural mechanics is one of the main tools in this process of design. As here understood, it is the body of scientific knowledge that permits one to predict with a good degree of certainly how a structure of give shape and dimensions will behave when acted upon by known forces or other mechanical influences. The chief items of behavior that are of practical interest are (1) the strength of the structure, i. e. , that magnitude of loads of a give distribution which will cause the structure to fail, and (2) the deformations, such as deflections and extent of cracking, that the structure will undergo when loaded underservice condition.The fundamental propositions on which the mechanics of reinforced concrete is based are as follows:1.The internal forces, such as bending moments, shear forces, and normal andshear stresses, at any section of a member are in equilibrium with the effect of the external loads at that section. This proposition is not an assumption but a fact, because any body or any portion thereof can be at rest only if all forces acting on it are in equilibrium.2.The strain in an embedded reinforcing bar is the same as that of thesurrounding concrete. Expressed differently, it is assumed that perfect bonding exists between concrete and steel at the interface, so that no slip can occur between the two materials. Hence, as the one deforms, so must the other. With modern deformed bars, a high degree of mechanical interlocking is provided in addition to the natural surface adhesion, so this assumption is very close to correct.3.Cross sections that were plane prior to loading continue to be plan in themember under load. Accurate measurements have shown that when a reinforced concrete member is loaded close to failure, this assumption is not absolutely accurate. However, the deviations are usually minor.4.In view of the fact the tensile strength of concrete is only a small fraction ofits compressive strength; the concrete in that part of a member which is in tension is usually cracked. While these cracks, in well-designed members, are generally so sorrow as to behardly visible, they evidently render the cracked concrete incapable of resisting tension stress whatever. This assumption is evidently a simplification of the actual situation because, in fact, concrete prior to cracking, as well as the concrete located between cracks, does resist tension stresses of small magnitude. Later in discussions of the resistance of reinforced concrete beams to shear, it will become apparent that under certain conditions this particular assumption is dispensed with and advantage is taken of the modest tensile strength that concrete can develop.5.The theory is based on the actual stress-strain relation ships and strengthproperties of the two constituent materials or some reasonable equivalent simplifications thereof. The fact that novelistic behavior is reflected in modern theory, that concrete is assumed to be ineffective in tension, and that the joint action of the two materials is taken into consideration results in analytical methods which are considerably more complex and also more challenging, than those that are adequate for members made of a single, substantially elastic material.These five assumptions permit one to predict by calculation the performance of reinforced concrete members only for some simple situations. Actually, the joint action of two materials as dissimilar and complicated as concrete and steel is so complex that it has not yet lent itself to purely analytical treatment. For this reason, methods of design and analysis, while using these assumptions, are very largely based on the results of extensive and continuing experimental research. They are modified and improved as additional test evidence becomes available.钢筋混凝土的基本假设作为结构工程师的主要任务是结构设计。

Civil engineering introduction papers[英语原文]Abstract: the civil engineering is a huge discipline, but the main one is building, building whether in China or abroad, has a long history, long-term development process. The world is changing every day, but the building also along with the progress of science and development. Mechanics findings, material of update, ever more scientific technology into the building. But before a room with a tile to cover the top of the house, now for comfort, different ideas, different scientific, promoted the development of civil engineering, making it more perfect.[key words] : civil engineering; Architecture; Mechanics, Materials.Civil engineering is build various projects collectively. It was meant to be and "military project" corresponding. In English the history of Civil Engineering, mechanical Engineering, electrical Engineering, chemical Engineering belong to to Engineering, because they all have MinYongXing. Later, as the project development of science and technology, mechanical, electrical, chemical has gradually formed independent scientific, to Engineering became Civil Engineering of specialized nouns. So far, in English, to Engineering include water conservancy project, port Engineering, While in our country, water conservancy projects and port projects also become very close and civil engineering relatively independent branch. Civil engineering construction of object, both refers to that built on the ground, underground water engineering facilities, also refers to applied materials equipment and conduct of the investigation, design and construction, maintenance, repair and other professional technology.Civil engineering is a kind of with people's food, clothing, shelter and transportation has close relation of the project. Among them with "live" relationship is directly. Because, to solve the "live" problem must build various types of buildings. To solve the "line, food and clothes" problem both direct side, but also a indirect side. "Line", must build railways, roads, Bridges, "Feed", must be well drilling water, water conservancy, farm irrigation, drainage water supply for the city, that is direct relation. Indirectly relationship is no matter what you do, manufacturing cars, ships, or spinning and weaving, clothing, or even production steel, launch satellites, conducting scientific research activities are inseparable from build various buildings, structures and build all kinds of project facilities.Civil engineering with the progress of human society and development, yet has evolved into large-scale comprehensive discipline, it has out many branch, such as: architectural engineering, the railway engineering, road engineering, bridge engineering, special engineering structure, waterand wastewater engineering, port engineering, hydraulic engineering, environment engineering disciplines. [1]Civil engineering as an important basic disciplines, and has its important attributes of: integrated, sociality, practicality, unity. Civil engineering for the development of national economy and the improvement of people's life provides an important material and technical basis, for many industrial invigoration played a role in promoting, engineering construction is the formation of a fixed asset basic production process, therefore, construction and real estate become in many countries and regions, economic powerhouses.Construction project is housing planning, survey, design, construction of the floorboard. Purpose is for human life and production provide places.Houses will be like a man, it's like a man's life planning environment is responsible by the planners, Its layout and artistic processing, corresponding to the body shape looks and temperament, is responsible by the architect, Its structure is like a person's bones and life expectancy, the structural engineer is responsible, Its water, heating ventilation and electrical facilities such as the human organ and the nerve, is by the equipment engineer is responsible for. Also like nature intact shaped like people, in the city I district planning based on build houses, and is the construction unit, reconnaissance unit, design unit of various design engineers and construction units comprehensive coordination and cooperation process.After all, but is structural stress body reaction force and the internal stress and how external force balance. Building to tackle, also must solve the problem is mechanical problems. We have to solve the problem of discipline called architectural mechanics. Architectural mechanics have can be divided into: statics, material mechanics and structural mechanics three mechanical system. Architectural mechanics is discussion and research building structure and component in load and other factors affecting the working condition of, also is the building of intensity, stiffness and stability. In load, bear load and load of structure and component can cause the surrounding objects in their function, and the object itself by the load effect and deformation, and there is the possibility of damage, but the structure itself has certain resistance to deformation and destruction of competence, and the bearing capacity of the structure size is and component of materials, cross section, and the structural properties of geometry size, working conditions and structure circumstance relevant. While these relationships can be improved by mechanics formula solved through calculation.Building materials in building and has a pivotal role. Building material is with human society productivity and science and technologyimproves gradually developed. In ancient times, the human lives, the line USES is the rocks andTrees. The 4th century BC, 12 ~ has created a tile and brick, humans are only useful synthetic materials made of housing. The 17th century had cast iron and ShouTie later, until the eighteenth century had Portland cement, just make later reinforced concrete engineering get vigorous development. Now all sorts of high-strength structural materials, new decoration materials and waterproof material development, criterion and 20th century since mid organic polymer materials in civil engineering are closely related to the widely application. In all materials, the most main and most popular is steel, concrete, lumber, masonry. In recent years, by using two kinds of material advantage, will make them together, the combination of structure was developed. Now, architecture, engineering quality fit and unfit quality usually adopted materials quality, performance and using reasonable or not have direct connection, in meet the same technical indicators and quality requirements, under the precondition of choice of different material is different, use method of engineering cost has direct impact.In construction process, building construction is and architectural mechanics, building materials also important links. Construction is to the mind of the designer, intention and idea into realistic process, from the ancient hole JuChao place to now skyscrapers, from rural to urban country road elevated road all need through "construction" means. A construction project, including many jobs such as dredging engineering, deep foundation pit bracing engineering, foundation engineering, reinforced concrete structure engineering, structural lifting project, waterproofing, decorate projects, each type of project has its own rules, all need according to different construction object and construction environment conditions using relevant construction technology, in work-site.whenever while, need and the relevant hydropower and other equipment composition of a whole, each project between reasonable organizing and coordination, better play investment benefit. Civil engineering construction in the benefit, while also issued by the state in strict accordance with the relevant construction technology standard, thus further enhance China's construction level to ensure construction quality, reduce the cost for the project.Any building built on the surface of the earth all strata, building weight eventually to stratum, have to bear. Formation Support building the rocks were referred to as foundation, and the buildings on the ground and under the upper structure of self-respect and liable to load transfer to the foundation of components or component called foundation. Foundation, and the foundation and the superstructure is a building of three inseparable part. According to the function is different, but in load, under the action of them are related to each other, is theinteraction of the whole. Foundation can be divided into natural foundation and artificial foundation, basic according to the buried depth is divided into deep foundation and shallow foundation. , foundation and foundation is the guarantee of the quality of the buildings and normal use close button, where buildings foundation in building under loads of both must maintain overall stability and if the settlement of foundation produce in building scope permitted inside, and foundation itself should have sufficient strength, stiffness and durability, also consider repair methods and the necessary foundation soil retaining retaining water and relevant measures. [3]As people living standard rise ceaselessly, the people to their place of building space has become not only from the number, and put forward higher requirement from quality are put car higher demands that the environment is beautiful, have certain comfort. This needs to decorate a building to be necessary. If architecture major engineering constitutes the skeleton of the building, then after adornment building has become the flesh-and-blood organism, final with rich, perfect appearance in people's in front, the best architecture should fully embody all sorts of adornment material related properties, with existing construction technology, the most effective gimmick, to achieve conception must express effect. Building outfit fix to consider the architectural space use requirement, protect the subject institutions from damage, give a person with beautifulenjoying, satisfy the requirements of fire evacuation, decorative materials and scheme of rationality, construction technology and economic feasibility, etc. Housing construction development and at the same time, like housing construction as affecting people life of roads, Bridges, tunnels has made great progress.In general civil engineering is one of the oldest subjects, it has made great achievements, the future of the civil engineering will occupy in people's life more important position. The environment worsening population increase, people to fight for survival, to strive for a more comfortable living environment, and will pay more attention to civil engineering. In the near future, some major projects extimated to build, insert roller skyscrapers, across the oceanBridges, more convenient traffic would not dream. The development of science and technology, and the earth is deteriorating environment will be prompted civil engineering to aerospace and Marine development, provide mankind broader space of living. In recent years, engineering materials mainly is reinforced concrete, lumber and brick materials, in the future, the traditional materials will be improved, more suitable for some new building materials market, especially the chemistry materials will promote the construction of towards a higher point. Meanwhile, design method of precision, design work of automation, information and intelligent technology of introducing, will be people have a morecomfortable living environment. The word, and the development of the theory and new materials, the emergence of the application of computer, high-tech introduction to wait to will make civil engineering have a new leap.This is a door needs calm and a great deal of patience and attentive professional. Because hundreds of thousands, even hundreds of thousands of lines to building each place structure clearly reflected. Without a gentle state of mind, do what thing just floating on the surface, to any a building structure, to be engaged in business and could not have had a clear, accurate and profound understanding of, the nature is no good. In this business, probably not burn the midnight oil of courage, not to reach the goal of spirit not to give up, will only be companies eliminated.This is a responsible and caring industry. Should have a single responsible heart - I one's life in my hand, thousands of life in my hand. Since the civil, should choose dependably shoulder the responsibility.Finally, this is a constant pursuit of perfect industry. Pyramid, spectacular now: The Great Wall, the majestic... But if no generations of the pursuit of today, we may also use the sort of the oldest way to build this same architecture. Design a building structure is numerous, but this is all experienced centuries of clarification, through continuous accumulation, keep improving, innovation obtained. And such pursuit, not confined in the past. Just think, if the design of a building can be like calculation one plus one equals two as simple and easy to grasp, that was not for what? Therefore, a civil engineer is in constant of in formation. One of the most simple structure, the least cost, the biggest function. Choose civil, choosing a steadfast diligence, innovation, pursuit of perfect path.Reference:[1] LuoFuWu editor. Civil engineering (professional). Introduction to wuhan. Wuhan university of technology press. 2007[2] WangFuChuan, palace rice expensive editor. Construction engineering materials. Beijing. Science and technology literature press. 2002[3] jiang see whales, zhiming editor. Civil engineering introduction of higher education press. Beijing.. 1992土木工程概论 [译文]摘要：土木工程是个庞大的学科，但最主要的是建筑，建筑无论是在中国还是在国外，都有着悠久的历史，长期的发展历程。