混凝土应力实验
一、实验介绍
直径很小的钢纤维用于混凝土结构可以大大的提高混凝土的抗拉承载能力。在一般情况下混凝土中掺钢纤维的体积比例在0.2％～2.0％之间。在很小比例下，钢筋混凝土的张拉响应可假设为不硬化的类型，它有加大单个裂缝扩展性质很像无钢筋的素混凝土，钢纤维对混凝土开裂之后性能的改善作用更加明显，可以通过控制裂缝的开展从而较大幅度地提高混凝土的韧性。然而它对其它性质的改进很小，因此在正常实验方法下如此低得的纤维含量很难难得到钢纤维混凝土轴拉应力——应变曲线的平稳段。为了找到一个合适易行的方法来研究SFRC轴拉性能人们做了很多工作并且有报告称可通过添加刚性组件方法来获得轴拉全曲线。
在这篇文章中,我们将用不同类型的纤维来做钢筋混凝土的单轴拉伸试验。钢筋混凝土的抗拉特型首钢纤维的强度和含量影响。另外，在强力作用下，钢筋混凝土的应力——应变曲线受多种因素的影响。对纤维混凝土增强机理进行研究，要获得钢纤维混凝土的受拉全过程曲线，采用轴拉方法最为适宜，但是要在试验方法上作一定改进，并且试验机要有足够的刚度，来保证试验过程的稳定。众所周知，在工程实践过程中，由于施工技术及经济条件的限制，SFRC中纤维体积掺率一般不超过2%，而大部分工程实例中，纤维掺量都在1%左右。为此，本文设计了轴拉SFRC材料试验，纤维掺量取1%，并采用不同种类的纤维增强形式，进行对比分析。
二、实验内容
试验在60吨万能试验机上进行。在试验装置中添加了四个高强钢杆以增大试件的卸载刚度，并通过在试件两端添加球铰来消除试件的初始偏心率。
通过调节连接试件和横梁的四个高强螺栓来保证试件的轴心受拉。试件相对两侧面之间的拉应变值之差不得大于其平均值的15％。当钢纤维掺量很低（为零或0.5％时），在荷载峰值采用低周反复加载曲线的外包络线来获得轴拉应力——应变全曲线.。
2.1材料
由四种不同类型的钢纤维用于该试验，这些纤维中三种是带钩的（和）一种是光滑的。
试验中所采用的三种混凝土配合比用于研究，见于表一。在基体强度等级为C60和C80钢纤维混凝土中分别加入了大连建科院生产的DK一5型减水剂和瑞士Sika公司生产的液体减水剂。这些被用来研究钢纤维混凝土的C30,C60,C80混凝土被制成的试件，在标准情况下养护28天。三种试件的平均强度见于表一。水泥采用大连小野田水泥厂生产的32.5级和52.5级普通硅酸盐水泥。细骨料采用细度模数2．6的河砂。粗骨料采用5～20 石灰岩碎石。
表一
2.2、试件
用建筑结构胶将轴拉试件粘贴于两端的钢垫板上。22组共110个试件的具体参数。
2.3、补充
经过28天，普通混凝土和钢纤维混凝土分别被用来做抗拉强度试验。张拉应力——应变曲线由此获得。对于高强度钢纤维混凝土诸如抗拉能力等拉伸特性也由此得到。增强类钢纤维混凝土比增韧类钢纤维混凝土的强度平均提高13%；而由基本开裂至裂缝宽度为0.5mm区间(相应的应变约2000με)的断裂能积分则显示：增韧类钢纤维混凝土比增强类钢纤维混凝土的断裂能平均提高20%.由表3还可以看出，大部分SFRC第一峰值对应的极限拉应变值与素混凝土相当，在100με左右，这说明低含率纤维的掺入对提高混凝土的极限拉应变作用不很明显。而增韧类SFRC第二峰值对应的应变则大大提高，可达1000με，由此可知第二峰值的出现大大提高了材料的韧性。DRAMIX型纤维因为长度是其它三种纤维长度的2倍，其断裂韧性更好，在试验曲线中可以看出在应变达到后，其荷载强度仍然保持较高水平，直到10000με应变时荷载仍可保持其峰值水平的50%左右。
三、试验结果和分析
3.1 劈拉强度和轴拉极限强度
不同试件的劈拉强度和轴拉极限强度查表，在混凝土中增加钢纤维的量可以提高它的劈拉强度和轴拉极限强度，两种不同参数的钢纤维钢筋混凝土和普通混凝土（它们的混合比例相同）的比率也可查表。
3.1.1基体强度及纤维类型对轴拉强度的影响
从上我们可以看出钢纤维对初裂强度的增强作用受基体强度变化的影响很小。也就是说在掺人同种钢纤维时，随着基体强度的增加，钢纤维混凝土与同配比素混凝土的初裂强度的比值基本恒定
然而，不同情况下的极限抗拉强度是不一样的，当基体强度增加时，对于不同类型的钢纤维，极限抗拉强度的分配量是不同的。另外它的增加量比劈拉恰强度大F1型钢纤维作为基体的极限抗拉强度很高，这是因为这类型的钢纤维的强度很高（大于1100MPa）试验过程中没有纤维拔断的现象出现而且当基体强度较高时(C80)，钢纤维的端部弯钩被完全拉直。由于黏结强度的提高，基体强度越高，该纤维对高强混凝土轴拉极限强度的增强效果越好。F2和F3型钢纤维的强度较高，二者均有端部弯钩，并且表面较为粗糙，当基体强度较高时(C80)，出现纤维拔断现象，该现象的出现对这两种钢纤维的增强效果产生了消极影响，因此为了最大限度的发挥这两种钢纤维的增强
作用，应将其应用于中高强度混凝土中。
F4型纤维为长直型，其与基体问的粘结力较小，因此它的增强效果耍弱于其他二种。因为其与基体问的粘结力较小因此在试验过程中没有纤维拔断现象出现。并且随着基体强度升高，由于黏结力的增大，该纤维增强效率有持续提高。
3.1.2钢纤维掺量对轴拉强度的影响
试验中重点针对F3型钢纤维研究了纤维掺量的变化对钢纤维高强混凝土轴拉初裂强度和极限强度的影响。试验中钢纤维体积掺率变化范围为0.5-1.5。可见随着纤维掺量增大，轴拉初裂强度和极限强度均有提高。两图中曲线的上升趋势很相似。也就是说纤维掺量在整个拉伸过程中对钢纤维混凝土内拉应力的影响是积极的和稳定的。
纤维序号
F1 0.642
F2 0.862
F3 0.794
F4 0.589
钢纤维钢筋混凝土轴拉极限强度可以用下式来计算：
（1）
式中：fft为钢纤维钢纤维轴拉极限强度轴拉极限强度；
ft为同配比素混凝土轴拉极限强度；
纤维类型系数有表四给出
为钢纤维体积掺率，l/d 为钢纤维长径比。
3.2 轴拉变形性能和韧性
3.2.1 初裂拉应变和峰值荷载拉应变
对试件四周四个夹式位移计测得的应变值进行平均获得试件的拉应变值。若试验中试件相对侧面的拉应变差大于平均值的15％，该试件作废。
高强SFRC的初裂拉应变和峰值拉应变要远大于同配比素混凝土(见表5)，随着基体强度或者纤维掺量增大，这个差值有所增长，钢纤维对峰值应变的提高作用要比初裂应变更加明显。
3.2.2 拉伸功和轴拉韧性指数
拉伸功为位移0-0．5 mm轴拉荷载位移全曲线下面积(图5中阴影面积)。另外，引入轴拉韧性指数。其定义为：
(2)
式中: fft为钢纤维混凝土轴拉极限强度；A为轴拉试件的破坏横截面面积。
两参数均用来评价钢纤维高强混凝土在轴拉过程中的韧性。轴拉韧性指数为无量纲系数，与轴拉功相比，在评价轴拉韧性时可在一定程度上消除轴拉极限强度的差别所带
来的影响。
从上我们可以发现，基体强度和纤维含量两种参数的有规律的改变很相似，因此我们分析的重点应放在韧性指数上。
掺有四种钢纤维及素混凝土试件基体强度与轴拉韧性指数的关系成比例，其中纤维混凝土试件中钢纤维体积掺率均为1．0％。可见高强SFRC的轴拉韧性要远远优于同配比素混凝土。
钢纤维的抗拉强度的影响是显著的，随着基体强度升高，混凝土脆性明显增加，素混凝土轴拉韧性明显下降。在掺有F1和F2型钢纤维的试件中也出现了韧性下降现象。F1型纤维从基体中拔出其实是一个纤维端钩被拉直，纤维端部周围混凝土被挤碎的过程。当纤维端钩最终被拉直时，轴拉荷载很快下降。混凝土的强度越高，基体硬度和脆性越大，上述过程历时也更短。因此当基体强度较高时，轴拉应力——应变曲线下降得更快，轴拉韧性指数也有所下降。
在四种类型纤维种F1型纤维的增韧效果最好，F2型纤维长径比最小，基体强度较高时出现了纤维拔断现象，因此当基体强度增加时韧性指数不断下降。
F3和F4型钢纤维韧性指数均随基体强度升高而增大。这两种纤维均为剪切型，表面较粗糙。在钢纤维和基体之间黏结力的各组分中，摩擦力起主导作用。摩擦力随基体强度的升高而增大，且该黏结类型的拔出破坏是一个持续过程，因此基体强度升高对掺有这两种钢纤维的混凝土韧性起积极作用。这两种纤维的不同之处是F3型的两端有弯钩。由于端钩的存在使得在基体强度不太高时(C30和C60)，F3型钢纤维的增韧作用优于F4型。当基体强度很高时(C80)，由于纤维拔断现象影响了F3型的增韧效果，F4型钢纤维的增韧效果叉反过来超过了F3型钢纤维。
3.3钢纤维钢筋混凝土单轴拉伸应力——应变曲线
典型的钢纤维高强混凝土轴拉应力一应变全曲线(为了便于比较，每组试件选出条典型曲线作为代表)，表述了轴拉曲线随基体强度的变化规律；表述了轴拉曲线随钢纤维(F3型)掺量的变化规律。曲线由弹性阶段、弹塑性阶段和下降段(软化段)组成。下降段存在拐点。
从上中可以看到，基体强度越高，轴拉应力一应变全曲线下降得越快。另外，钢纤维掺量的提高可以大大地改善曲线的丰满程度。钢纤维类型对轴拉应力一应变全曲线的形状也有一定的影响。Fl型纤维的曲线是几种钢纤维中最丰满的，并且在拉应变为大约10000个微应变时出现了第二峰值。该现象体现了Fl型纤维良好的增韧效果。当基体强度较高时，由于纤维拔断的出现使得F2和F3型钢纤维试件的轴拉曲线下降端呈阶梯状。F4型纤维的曲线较为平滑，形状与素混凝土曲线相似，但是更为饱满。这是因为长直形钢纤维的拔出过程是相对连续和柔和的.
四、研究分析
由4种钢纤维混凝土的典型拉伸应力-应变曲线可以看出：在轴拉条件下，1%掺量的钢纤维远远没有达到使混凝土材料实现应变强化的地步，大部分试验曲线都在达到峰值后，出现荷载骤降段。但是，随着变形的增加，有两条曲线有明显的第二峰值出现，而另外两条则没有，正是根据这种现象，可以将其分为增强和增韧两大类钢纤维混凝土，
有第二峰值的为增韧类，无第二峰值的为增强类。
曾经有许多钢纤维混凝土轴拉应力一应变全曲线模型提出大多数为分段函数，以应力峰值点为分界点。本文中，全曲线的上升段和下降段采用不同的函数表达式。
在公式（3）中
4.1上升段的公式
上升段的数学模型为：
（4）
这里：和为与基体和钢纤维特性有关的参数。
边界条件为：
1) X=0，Y=0；
2) X=0，dy／dx=E0 ／Ep；
3)X=1，Y=1，dy／dx=0．
由边界条件可得公式(5)可以简化为：
（5）
系数可以通过试验数据回归获得
(6)
式中：E0为圆点切线模量；EP 为峰值应力点割线模量(第一峰值)。
因此公式(6)可以转换为：
(7)
4.2下降段公式
下降段数学的模型为：
（8）
式中：和为与基体和钢纤维特性有关的参数。
下降段表达式中系数值选取1.7。边界条件x=l和y=1自然满足。系数的取值通过最小二乘法回归获得：
（9）
可见基体强度和纤维参量对轴拉曲线下降段的下降速率的影响是相反的。
五、理论曲线与试验结果的比较
钢纤维高强混凝土轴拉应力一应变理论曲线和试验曲线的比较如图l2所示(以试件F3—6010为例)。可见，理论结果与试验结果符合较好。
六、实验结论
(1)试验结果表明：钢纤维高强混凝土劈拉强度略高于轴拉强度，两者有较好的相关性，钢纤维高强混凝土轴拉强度可取为劈拉强度的0.9倍。
(2)在掺入同种同量钢纤维时，随着基体强度的增加，钢纤维高强混凝土与同配比素混凝土的初裂强度的比值基本不变；轴拉极限强度的比值有所变化，且该变化对不同的纤维类型有所不同，钢纤维与基体黏结性能好，且破坏时不被拉断，则增强效果好。
(3)提高钢纤维掺量对钢纤维高强混凝土的抗拉强度特性的改善作用比对普通强度混凝土的改善作用明显。
(4)钢纤维高强混凝土的初裂应变和峰值应变要比素混凝土的增幅随基体强度和纤维掺量的升高而增大。
(5)引入了轴拉韧性指数来评价钢纤维高强混凝土的韧性，钢纤维混凝土的轴拉韧性要大大优于同配比的索混凝土，并且受基体强度和钢纤维特性和
掺量的影响。
(6)基体强度越高，钢纤维高强混凝土的轴拉应力应变曲线在峰值过后下降得越快；纤维掺量的提高可以大大改善曲线的丰满程度，钢纤维类型对曲线形状也有一定的影响。通过对实验曲线的分析与回归，给出了考虑上述影响因素的钢纤维高强混凝土轴拉应力应变全曲线表达式。
(7)综合而言，四种钢纤维中，F3型钢纤维的增强效果最好，而Fl型钢纤维的增韧效果最好。
外文翻译原文
Concrete stress test
1 Test Introduction
The tensile properties of concrete can be enhanced substantially by incorporating high strength and small diameter short steel fibers．which leads to the steel fiber reinforced concrete(SFRC)．In conventional SFRC，the steel fiber content is usually within the range of 0．2％—2％by volume．At such a low 6her content．the tensile response of SFRC would assume a nonhardening type．which is characterized by the widening of a single crack，similar to an unreinforced concrete ．The contribution of fibers is apparent in the post—cracking response, represented by an increase in post—cracking ductility due to the work associated with pullout of fibers bridging a failure crack. However，improvements in some other properties are insignificant ．Moreover，the softening segment of the stress—strain curve of SFRC with such a low fiber content under uniaxial tension is difficult to be got with normal
experimental methods．Many works have been done to find a suitable and relatively easy way to analyze the tensile characteristics ．And it was reported that the whole curve could be got on a normal testing machine with stiffening components added.
In this article，the stress—strain behavior of SFRC under uniaxial tension Was analyzed for different types of fiber．The tensile characteristics of SFRC influenced by the matrix strength and the steel fiber content were studied also．In addition，the stress—strain curves of high strength SFRC with different factors were well acquired．The mechanism of fiber reinforced concrete to enhance research, to obtain steel fiber reinforced concrete in tension curve of the whole process, using the most appropriate method of axial tension, but to make sure the testing methods improved, and the testing machine must have enough stiffness to ensure the testing process stability. Is well known in engineering practice, process, technology and economic conditions due to construction constraints, SFRC-doped fiber volume in the rate of generally not more than 2%, while most of the engineering example, the fiber fraction are about 1%. In this paper the design of the axial tension SFRC material testing, fiber dosage to take 1%, and using different types of fiber-reinforced forms, were analyzed.
2 Experimental Content
The specimens were tested on a 60 kN universal testing machine．Four high steel bars were added to enhance the stiffness of the testing machine．In addition，spherichinges were used to abate the initial axial eccentricity of the specimens．．
It was ensured that specimens should be pulled under uniaxial tension by adjusting the four high strength bolts which connect the specimens to the crossbeam．And the difference between the tensile strains of the opposite sides of the specimen should be less than 1 5％of their mean value．When the fiber content was low (0 and 0.5％by volume)，the cyclic quire the whole stress—strain.
2．1 Materials
Four types of steel fibers shown in Table were chosen for this test．Three of these fibers (F1，F2 and F3) were hooked—end and the other one(F4)was smooth．
Three concrete mixtures，shown in Table 2，were investigated．Water reducing agents were used in C60 and C80 mixes(DK一5 made by Dalian Structure Research Institute and Sika made in Switzerland respectively). The compressive strengths of these C30，C60，C80 mixes were determined according to “Test Methods Used for Steel Fiber Reinforced Concrete”(CECS 13：89)"8 3 at 28 days using 150 mm×150 mm ×150 mm cube s．Averaged results for 3 specimens are given in Table 2．0rdinary Portland cement(yielded by Dalian Huaneng Onoda Cement Company)of 32．5 and 52．5 (according to China standard) were chosen．River sand(modulus of fineness is 2.6)and crushed limestone coarse aggregates(5—20 Bin) were used．
2．2 Specimen
The tensile specimen was bonded to steel padding plates at both ends by tygoweld．A total of 1 1 0 specimens were divided into 22 groups according to certain parameters．The parameters of these specimens are shown in Table 3．
2．3 Items
At the age of 28 days．plain concrete and steel fiber concrete specimens were tested for tensile strength，respectively .The tensile stress—strain curves were acquired．Many other tensile characters of the high strength steel fiber concrete such as tensile work，etc were calculated also. Enhanced class steel fiber reinforced concrete toughness category than the strength of steel fiber reinforced concrete an average of 13%; while cracking from the basic to the crack width of 0.5mm interval (the corresponding strain of about 2000με) s howed the fracture energy integral: toughening class steel fiber reinforced concrete enhanced class than the fracture energy of steel fiber reinforced concrete an average of 20%. from Table 3 also shows that most of the SFRC first peak corresponds to the limit of tensile strain value and plain concrete rather, in the 100με around, indicating a low rate of fiber-containing incorporation in improving the role of ultimate tensile strain of concrete is not very obvious. The toughening class SFRC second peak cor responds to a much greater strain, up to 1000με, From this second peak has greatly enhanced the appearance of toughness. DRAMIX Fiber because of the length of other three kinds of fiber length of 2 times the fracture toughness and better in the test curve can be seen in the strain is attained, the load continues to maintain a high level of intensity, until the strain when the load so as to maintain 10000με its peak level of 50%.
3 Results and Discussion
3．1 Crack stress and ultimate tensile strength
The crack stress and ultimate tensile strength of different specimens are listed in Table 3．The addition of steel fibers into concrete increased its crack stress an d ultimate tensile strength．And the ratios of these two parameters of SFRC to those of plain concreue (with the same mix proportion)are given in Table 3，too．
3．1．1 Effect of matrix strength an(1 fiber type
From table 3．It can be seen that the effects of steel fibers 0n crack stress are little influenced by the matsix strength．That is to say．When the matrix strength increases, the ratios of crack stresses of SFRC ( with the same type of fibers contained)to those of plain concrete ones with the same mix proportion are invariable．
However，the condition for ultimate tensile strength is different．When the matrix strength increases．these ratios of ultimate tensile strengths(shown in Table 3)vary dissimilarly according to the type of steel fiber．Moreover．the increments are bigger than those of crack stress．
The heightening efficiency of fiber F1 for ultimate tensile strength rises as matrix strength increases．It is because that the strength of this kind of fiber is very high(>1 100 MPa)．No fiber broken was observed during the test and the hooked—ends of the fibers were straightened when the matrix strength was high(C80)．The higher the matrix strength．this kind of steel fiber takes on its strengthening effect more efficiently for the increasing of bond stress．The strengths of fibers F2 and F3 are mid—high(>700 MPa)．They all have hooked ends and both of their surfaces are coarse．When the matrix strength was high(C80)．fiber breaking occurred in the test．And this phenomenon impaired the heightening efficiency of these two kinds of steel fiber．So they should be used in middle strength concrete to exert their strengthening effect more efficiently．Fiber F4 is smooth．and its bond stress with matrix is
comparatively low．T}1erefore．its strengthening effect is 1ess notable than those of other kinds of fiber．Because of the low bond stress．no fiber broken was found during the test and its heightening efficiency for ultimate tensile strength rises as matrix strength increases．3．1．2 Effect of fiber content
The effect of fiber content on the crack stress and u1．ultimate tensile strength was investigated for SFRC contained fiber F3．And the fiber content varied from 0．5％to 1．5％by volume(shown in Table 3)．It can be seen from Fig．1 and Fig．2 that as the fiber content increases．
The crack stress and ultimate strength of SFRC improve obviously．Moreover．the rising trends of the curves in these two figures are stupendously similar．In other words，the effect of fiber content on the characters of tensile stress of SFRC is positive and consistent．
Table 4 Fiber type factors
Fiber code at
F1 0.642
F2 0.862
F3 0.794
F4 0.589
The tensile strength of SFRC can be calculated with the follow formula：
(1)
where，f ft is the ultimate tensile strength of SFRC；the ultimate tensile strength of plain concrete with the same mixing proportion；a，the fiber type factor，
which is shown Table 4；is the fiber content 0f volume and l/d is the aspect ratio of steel fibers.
3．2 Tensile strain and toughness characters
3．2．1 Crack strain and the strain at peak tensile load
The tensile strains were acquired by averaging the readings of the four displacement sensors fixed around the specimen．In addition，the specimens whose difference between the tensile strains of its opposite sides is larger than 15％of their mean value were blanked out．The crack strain or the strains at peak tensile load of SFRC are much bigger than those of plain concrete(as shown in Table 5)．And the increments go up as the matrix strength or the fiber content increases．Compared to that on crack strain．the increscent effect of steel fiber on the strain at peak tensile load is more remarkable．
3．2．2 Tensile work and toughness modulus
The tensile work was defined as the area under the load-displacement curve from 0 to 0．5 rain．More—over，a tensile toughness modulus was introduced(shown in Table 5)．
It was defined as：
(2)
where，f ft is the ultimate tensile strength of SFRC；A，the area of the cross section of specimen．
Both these two parameters were quoted to evaluate the toughness characters of SFRC under uniaxial tension．The tensile toughness modulus is a dimensionless factor．Compared to what the tensile work does．it can avoid the influence of the ultimate tensile strength when studying the toughness of SFRC．
It call be found from Table 5 that the altering regularities of these two factors along with the changes of matrix strength and fiber content are approximate．Therefore，the emphasis of analysis was put on the toughness modulus．
The relationship between the matrix strength and toughness modulus of SFRC with four kinds of steel fiber are shown in Fig．3．whose fiber contents are all 1．O％by volume．together with that relationship of plain concrete．The tensile toughness of SFRC is much better than that of plain concrete．The tensile toughening effect of steel fiber is remarkable．As the matrix strength rises．The brittleness of concrete increases obviously，and then the tensile toughness of plain concrete falls down．This phenomenon was also found on specimens containing fiber F1and F2．The pulling out of fiber F1 from concrete is in fact a process of hook-end’s being straightened and the matrix’s being crushed around the hook-end．When the hooked end is straightened at last．the tensile load falls down quickly．The higher the concrete strength. the larger the rigidity of the matrix and the shorter the time that the process mentioned above lasts．Thus．the stress-strain curve falls down more quickly，and then the toughness modulus decreases．However，the toughening effect of fiber F1 is the best among these four kinds of steel fiber．The aspect ratio of fiber F2 is the least。and when the matrix strength is high，fiber breaking occurs．Therefore，the toughness modulus falls down continually as the matrix strength rises.
The toughness modului of fibers F3 and F4 rise together with the matrix strength．Both the two kinds of fiber are snipped and their surfaces are coarse．Therefore．the friction is dominant in the proportions of bond stress．Because the friction between fiber and matrix increases along with the matrix strength，and the whole pulling out of these kinds of bond status is a continuous process，the rising of matrix strength plays a positive role in improving the toughness of SFRC containing these two kinds of fiber．The difference between the two kinds of fibers is that fiber F3 has hooked ends，which makes fiber F3 have better toughening effects than fiber F4 when the matrix strength is comparatively low(C30 and C60)．When the matrix strength is high(C80)，fiber breaking impaires the toughening effect of fiber F3．And the function of fiber F4 exceeds that of fiber F3 in reverse．
3．3 Stress-strain curves of SFRC under uniaxial tension
The typical stress--strain curves of SFRC under uniaxial tension are shown in Figs．4—11(one curve is chosen for each group of specimen to keep the graphs orderly)．Figs．4—8 express the variation of curves along with the increasing of the matrix strength，and Figs．9一l1 express the variation along with the change of the fiber content of fiber F3．The curve consists of elastic section．elastic—plastic section and falling section(softening section)．Points of contra flexure exit in the falling section of the curve．It can be seen from these figures that the matrix strength is higher，the stress—strain curves fall down faster，and the rising of the fiber content can much improve the chubbiness of these curves．Moreover，the type of steel fiber has some effect on the shape of the stress—strain curve．The curves of fiber F1 are the plumpiest of them al1．The second peak was observed in the curves of fiber F1 at the strain of about 10 000 ue．This phenomenon expresses a good toughening effect of fiber F1．The curves of fibe1s F2 and F3 are ladder—like when the matrix strength is high because of fiber breaking．The curves of fiber F4 ale smooth and like those of plain concrete in shape ．That is because the pullout process of smooth steel fiber is rather gentle．
4 Analytical Investigation
Four kinds of typical steel fiber concrete tensile stress - strain curves can be seen: in axial tension conditions, the 1% dosage of the steel fiber is far short of strain hardening of the concrete materials to the point where most of the experimental curves are in reach After the peak, there loads sag section. However, as deformation increases, there are two curves have a clear second peak appeared, while the other two do not, it is the basis of this phenomenon can be divided into two major categories of strengthening and toughening of steel fiber reinforced concrete, there is a second peak for the toughening class, no second peak to enhance the class. Many tensile stress—strain models have been brought forward一1、2、4、6、9、10，Most of their formats are sectiona1．taking the peak load as the divisional point．In this paper，the formula of the rising section and that of the fa11ing section are different．
In the formulas：
（3）
4．1 Formula of rising section
The digital model for the rising section is
（4）
where，are parameters related to the characters of matrix an d steel fibers．
The boundary conditions are as following：
1) X=0，Y=0；
2) X=0，dy／dx=E0 ／Ep；
3)X=1，Y=1，dy／dx=0．
It can be drawn from the boundary'.
Formula(4)can be simplified as：
(5)
And the value of can be calculated from experimental data as ：
(6)
where，Eo is the origin tan gent modulus；E p，secant modulus at peak load(the first peak) Thus，Formula(5)Call be inverted as：
(7)
4．2 Formula of falling section
The digital model for the falling section is：
(8)
where，are parameters related to the characters of matrix an d steel fibers ．
The value of is chosen as 1.7 in the formula of falling section 9、10．the boundary condition X= 1，y= 1 is satisfied inherently．In addition．the value of a could be regressed with the method of least squares as：
(9)
it can be seen from the expression that the effects of the matrix strength and fiber content on the curve’s falling rate are opposite．
5. Comparison of Predictions and Experimental Results
The comparison of predictions and experimental results for stress—strain curves are shown in Fig．1 2 (take the curves of F3—6010 as an example)．The theoretical curve and the experimental ones fit wel1．
6. Conclusions
a)When the matrix strength increases，the ratios of crack stresses of SFRC (with the same type of fiber)to those of plain concrete ones with the saii3e mix proportion are invariable．These ratios of ultimate tensile strengths vary dissimilarly according to the type of steel fiber．Moreover，the increments ale bigger than those of crack stress and are influenced by fiber type．
b)As the fiber content increases．the crack stress and ultimate tensile strength of SFRC improve obviously and the effect of the fiber content on the characters of tensile strength of SFRC is positive an d consistent．
c)The crack strain or the strains at peak tensile load 0f SFRC are much bigger than these of plain concrete．In addition，the increments go up as the matrix strength or the fiber content increases．
d)A tensile toughness modulus was introduced to evaluate the toughness characters of SFRC under uniaxial tension．The tensile toughness of SFRC is much better than that of plain concrete．In addition．it is influenced by the matrix strength and characters of steel fiber．e)The matrix strength is higher，the stress—strain curves fall down faster．Otherwise，the rising of the fiber content can much improve the chubbiness of these curves．Moreover．the type of steel fiber has some effect on the shape of the stress—strain curve．
f)The formula of the tensile stress—strain curve of SFRC was regressed．The theoretical curve and the experimental ones fit wel1．T}1is model may be helpful in the further research of SFRC under uniaxial tension．
PA VEMENT PROBLEMS CAUSED BY COLLAPSIBLE SUBGRADES By Sandra L. Houston,1 Associate Member, ASCE (Reviewed by the Highway Division) ABSTRACT: Problem subgrade materials consisting of collapsible soils are com- mon in arid environments, which have climatic conditions and depositional and weathering processes favorable to their formation. Included herein is a discussion of predictive techniques that use commonly available laboratory equipment and testing methods for obtaining reliable estimates of the volume change for these problem soils. A method for predicting relevant stresses and corresponding collapse strains for typical pavement subgrades is presented. Relatively simple methods of evaluating potential volume change, based on results of familiar laboratory tests, are used. INTRODUCTION When a soil is given free access to water, it may decrease in volume, increase in volume, or do nothing. A soil that increases in volume is called a swelling or expansive soil, and a soil that decreases in volume is called a collapsible soil. The amount of volume change that occurs depends on the soil type and structure, the initial soil density, the imposed stress state, and the degree and extent of wetting. Subgrade materials comprised of soils that change volume upon wetting have caused distress to highways since the be- ginning of the professional practice and have cost many millions of dollars in roadway repairs. The prediction of the volume changes that may occur in the field is the first step in making an economic decision for dealing with these problem subgrade materials. Each project will have different design considerations, economic con- straints, and risk factors that will have to be taken into account. However, with a reliable method for making volume change predictions, the best design relative to the subgrade soils becomes a matter of economic comparison, and a much more rational design approach may be made. For example, typical techniques for dealing with expansive clays include: (1) In situ treatments with substances such as lime, cement, or fly-ash; (2) seepage barriers and/ or drainage systems; or (3) a computing of the serviceability loss and a mod- ification of the design to "accept" the anticipated expansion. In order to make the most economical decision, the amount of volume change (especially non- uniform volume change) must be accurately estimated, and the degree of road roughness evaluated from these data. Similarly, alternative design techniques are available for any roadway problem. The emphasis here will be placed on presenting economical and simple methods for: (1) Determining whether the subgrade materials are collapsible; and (2) estimating the amount of volume change that is likely to occur in the 'Asst. Prof., Ctr. for Advanced Res. in Transp., Arizona State Univ., Tempe, AZ 85287. Note. Discussion open until April 1, 1989. To extend the closing date one month,
中等分辨率制备分离的 快速色谱技术 W. Clark Still,* Michael K a h n , and Abhijit Mitra Departm(7nt o/ Chemistry, Columbia Uniuersity,1Veu York, Neu; York 10027 ReceiLied January 26, 1978 我们希望找到一种简单的吸附色谱技术用于有机化合物的常规净化。这种技术是适于传统的有机物大规模制备分离，该技术需使用长柱色谱法。尽管这种技术得到的效果非常好，但是其需要消耗大量的时间，并且由于频带拖尾经常出现低复原率。当分离的样本剂量大于1或者2g时，这些问题显得更加突出。近年来，几种制备系统已经进行了改进，能将分离时间减少到1-3h，并允许各成分的分辨率ΔR f≥（使用薄层色谱分析进行分析）。在这些方法中，在我们的实验室中，媒介压力色谱法1和短柱色谱法2是最成功的。最近，我们发现一种可以将分离速度大幅度提升的技术，可用于反应产物的常规提纯，我们将这种技术称为急骤色谱法。虽然这种技术的分辨率只是中等（ΔR f≥），而且构建这个系统花费非常低，并且能在10-15min内分离重量在的样本。4 急骤色谱法是以空气压力驱动的混合介质压力以及短柱色谱法为基础，专门针对快速分离，介质压力以及短柱色谱已经进行了优化。优化实验是在一组标准条件5下进行的，优化实验使用苯甲醇作为样本，放在一个20mm*5in.的硅胶柱60内，使用Tracor 970紫外检测器监测圆柱的输出。分辨率通过持续时间（r）和峰宽（w,w/2）的比率进行测定的（Figure 1），结果如图2-4所示，图2-4分别放映分辨率随着硅胶颗粒大小、洗脱液流速和样本大小的变化。
The smart grid Smart grid is the grid intelligent (electric power), also known as the "grid" 2.0, it is based on the integration, high-speed bidirectional communication network, on the basis of through the use of advanced sensor and measuring technology, advanced equipme nt technology, the advanced control method, and the application of advanced technology of decision support system, realize the power grid reliability, security, economic, efficient, environmental friendly and use the security target, its main features include self-healing, incentives and include user, against attacks, provide meet user requirements of power quality in the 21st century, allow all sorts of different power generation in the form of access, start the electric power market and asset optimizatio n run efficiently. The U.S. department of energy (doe) "the Grid of 2030" : a fully automated power transmission network, able to monitor and control each user and power Grid nodes, guarantee from power plants to end users among all the nodes in the whole process of transmission and distribution of information and energy bi-directional flow. China iot alliance between colleges: smart grid is made up of many parts, can be divided into:intelligent substation, intelligent power distribution network, intelli gent watt-hourmeter,intelligent interactive terminals, intelligent scheduling, smart appliances, intelligent building electricity, smart city power grid, smart power generation system, the new type of energy storage system.Now a part of it to do a simple i ntroduction. European technology BBS: an integration of all users connected to the power grid all the behavior of the power transmission network, to provide sustained and effective economic and security of power. Chinese academy of sciences, institute of electrical: smart grid is including all kinds of power generation equipment, power transmission and distribution network, power equipment and storage equipment, on the basis of the physical power grid will be modern advanced sensor measurement technology, network technology, communication
转型衰退时期的土木工程研究 Sergios Lambropoulosa[1], John-Paris Pantouvakisb, Marina Marinellic 摘要 最近的全球经济和金融危机导致许多国家的经济陷入衰退，特别是在欧盟的周边。这些国家目前面临的民用建筑基础设施的公共投资和私人投资显著收缩，导致在民事特别是在民用建筑方向的失业。因此，在所有国家在经济衰退的专业发展对于土木工程应届毕业生来说是努力和资历的不相称的研究，因为他们很少有机会在实践中积累经验和知识，这些逐渐成为过时的经验和知识。在这种情况下，对于技术性大学在国家经济衰退的计划和实施的土木工程研究大纲的一个实质性的改革势在必行。目的是使毕业生拓宽他们的专业活动的范围，提高他们的就业能力。 在本文中，提出了土木工程研究课程的不断扩大，特别是在发展的光毕业生的潜在的项目，计划和投资组合管理。在这个方向上，一个全面的文献回顾，包括ASCE体为第二十一世纪，IPMA的能力的基础知识，建议在其他：显著增加所提供的模块和项目管理在战略管理中添加新的模块，领导行为，配送管理，组织和环境等；提供足够的专业训练五年的大学的研究；并由专业机构促进应届大学生认证。建议通过改革教学大纲为土木工程研究目前由国家技术提供了例证雅典大学。 1引言 土木工程研究（CES）蓬勃发展，是在第二次世界大战后。土木工程师的出现最初是由重建被摧毁的巨大需求所致，目的是更多和更好的社会追求。但是很快，这种演变一个长期的趋势，因为政府为了努力实现经济发展，采取了全世界的凯恩斯主义的理论，即公共基础设施投资作为动力。首先积极的结果导致公民为了更好的生活条件（住房，旅游等）和增加私人投资基础设施而创造机会。这些现象再国家的发展中尤为为明显。虽然前景并不明朗（例如，世界石油危机在70年代），在80年代领先的国家采用新自由主义经济的方法（如里根经济政策），这是最近的金融危机及金融危机造成的后果（即收缩的基础设施投资，在技术部门的高失业率），消除发展前途无限的误区。 技术教育的大学所认可的大量研究土木工程部。旧学校拓展专业并且新的学校建成，并招收许多学生。由于高的职业声望，薪酬，吸引高质量的学校的学生。在工程量的增加和科学技术的发展，导致到极强的专业性，无论是在研究还是工作当中。结构工程师，液压工程师，交通工程师等，都属于土木工程。试图在不同的国家采用专业性的权利，不同的解决方案，，从一个统一的大学学历和广泛的专业化的一般职业许可证。这个问题在许多其他行业成为关键。国际专业协会的专家和机构所确定的国家性检查机构，经过考试后，他们证明不仅是行业的新来者，而且专家通过时间来确定进展情况。尽管在很多情况下，这些证书虽然没有国家接受，他们赞赏和公认的世界。 在试图改革大学研究（不仅在土木工程）更接近市场需求的过程中，欧盟确定了1999博洛尼亚宣言，它引入了一个二能级系统。第一级度（例如，一个三年的学士）是进入
姓名： 学号： 10447425 X X 大学 毕业设计（论文）外文翻译 （2014届） 外文题目Developments in excavation bracing systems 译文题目开挖工程支撑体系的发展 外文出处Tunnelling and Underground Space Technology 31 (2012) 107–116 学生XXX 学院XXXX 专业班级XXXXX 校内指导教师XXX 专业技术职务XXXXX 校外指导老师专业技术职务 二○一三年十二月
开挖工程支撑体系的发展 1.引言 几乎所有土木工程建设项目（如建筑物，道路，隧道，桥梁，污水处理厂，管道，下水道）都涉及泥土挖掘的一些工程量。往往由于由相邻的结构，特性线，或使用权空间的限制，必须要一个土地固定系统，以允许土壤被挖掘到所需的深度。历史上，许多挖掘支撑系统已经开发出来。其中，现在比较常见的几种方法是：板桩，钻孔桩墙，泥浆墙。 土地固定系统的选择是由技术性能要求和施工可行性（例如手段，方法）决定的，包括执行的可靠性，而成本考虑了这些之后，其他问题也得到解决。通常环境后果（用于处理废泥浆和钻井液如监管要求）也非常被关注（邱阳、1998）。 土地固定系统通常是建设项目的较大的一个组成部分。如果不能按时完成项目，将极大地影响总成本。通常首先建造支撑，在许多情况下，临时支撑系统是用于支持在挖掘以允许进行不断施工，直到永久系统被构造。临时系统可以被去除或留在原处。 打桩时，因撞击或振动它们可能会被赶入到位。在一般情况下，振动是最昂贵的方法，但只适合于松散颗粒材料，土壤中具有较高电阻（例如，通过鹅卵石）的不能使用。采用打入桩系统通常是中间的成本和适合于软沉积物（包括粘性和非粘性），只要该矿床是免费的鹅卵石或更大的岩石。 通常，垂直元素（例如桩）的前安装挖掘工程和水平元件（如内部支撑或绑回）被安装为挖掘工程的进行下去，从而限制了跨距长度，以便减少在垂直开发弯矩元素。在填充情况下，桩可先设置，从在斜坡的底部其嵌入悬挑起来，安装作为填充进步水平元素（如搭背或土钉）。如果滞后是用来保持垂直元素之间的土壤中，它被安装为挖掘工程的进行下去，或之前以填补位置。 吉尔- 马丁等人（2010）提供了一个数值计算程序，以获取圆形桩承受轴向载荷和统一标志（如悬臂桩）的单轴弯矩的最佳纵筋。他们开发的两种优化流程：用一个或两个直径为纵向钢筋。优化增强模式允许大量减少的设计要求钢筋的用量，这些减少纵向钢筋可达到50％相对传统的，均匀分布的加固方案。 加固桩集中纵向钢筋最佳的位置在受拉区。除了节约钢筋，所述非对称加强钢筋图案提高抗弯刚度，通过增加转动惯量的转化部分的时刻。这种增加的刚性可能会在一段时间内增加的变形与蠕变相关的费用。评估相对于传统的非对称加强桩的优点，对称，钢筋桩被服务的条件下全面测试来完成的，这种试验是为了验证结构的可行性和取得的变形的原位测量。 基于现场试验中，用于优化的加强图案的优点浇铸钻出孔（CIDH）在巴塞罗那的
New technique of the computer network Abstract The 21 century is an ages of the information economy, being the computer network technique of representative techniques this ages, will be at very fast speed develop soon in continuously creatively, and will go deep into the people's work, life and study. Therefore, control this technique and then seem to be more to deliver the importance. Now I mainly introduce the new technique of a few networks in actuality live of application. keywords Internet Network System Digital Certificates Grid Storage 1. Foreword Internet turns 36, still a work in progress Thirty-six years after computer scientists at UCLA linked two bulky computers using a 15-foot gray cable, testing a new way for exchanging data over networks, what would ultimately become the Internet remains a work in progress. University researchers are experimenting with ways to increase its capacity and speed. Programmers are trying to imbue Web pages with intelligence. And work is underway to re-engineer the network to reduce Spam (junk mail) and security troubles. All the while threats loom: Critics warn that commercial, legal and political pressures could hinder the types of innovations that made the Internet what it is today. Stephen Crocker and Vinton Cerf were among the graduate students who joined UCLA professor Len Klein rock in an engineering lab on Sept. 2, 1969, as bits of meaningless test data flowed silently between the two computers. By January, three other "nodes" joined the fledgling network.
Computer Program 1 Introduction Computer Program, set of instructions that directs a computer to perform someprocessing function or combination of functions. For the instructions to be carried out, a computer must execute a program, that is, the computer reads the program, and then follow the steps encoded in the program in a precise order until completion. A program can be executed many different times, with each execution yielding a potentially different result depending upon the options and data that the user gives the computer. Programs fall into two major classes: application programs and operating systems. An application program is one that carries out somefunction directly for a user, such as word processing or game-playing. An operating system is a program that manages the computer and the various resources and devices connected to it, such as RAM,hard drives, monitors, keyboards, printers, and modems,so that they maybe used by other programs. Examples of operating systems are DOS, Windows 95, OS\2, and UNIX. 2 Program Development Software designers create new programs by using special applications programs, often called utility programs or development programs. A programmer uses another type of program called a text editor to write the new program in a special notation called a programming language. With the text editor, the programmer creates a text file, which is an ordered list of instructions, also called the program source file. The individual instructions that make up the program source file are called source code. At this point, a special applications program translates the source code into machine language, or object code— a format that the operating system
项目成本控制 一、引言 项目是企业形象的窗口和效益的源泉。随着市场竞争日趋激烈，工程质量、文明施工要求不断提高，材料价格波动起伏，以及其他种种不确定因素的影响，使得项目运作处于较为严峻的环境之中。由此可见项目的成本控制是贯穿在工程建设自招投标阶段直到竣工验收的全过程，它是企业全面成本管理的重要环节，必须在组织和控制措施上给于高度的重视，以期达到提高企业经济效益的目的。 二、概述 工程施工项目成本控制，指在项目成本在成本发生和形成过程中，对生产经营所消耗的人力资源、物资资源和费用开支，进行指导、监督、调节和限制，及时预防、发现和纠正偏差从而把各项费用控制在计划成本的预定目标之内，以达到保证企业生产经营效益的目的。 三、施工企业成本控制原则 施工企业的成本控制是以施工项目成本控制为中心，施工项目成本控制原则是企业成本管理的基础和核心，施工企业项目经理部在对项目施工过程进行成本控制时，必须遵循以下基本原则。 3.1 成本最低化原则。施工项目成本控制的根本目的，在于通过成本管理的各种手段，促进不断降低施工项目成本，以达到可能实现最低的目标成本的要求。在实行成本最低化原则时，应注意降低成本的可能性和合理的成本最低化。一方面挖掘各种降低成本的能力，使可能性变为现实；另一方面要从实际出发，制定通过主观努力可能达到合理的最低成本水平。 3.2 全面成本控制原则。全面成本管理是全企业、全员和全过程的管理，亦称“三全”管理。项目成本的全员控制有一个系统的实质性内容，包括各部门、各单位的责任网络和班组经济核算等等，应防止成本控制人人有责，人人不管。项目成本的全过程控制要求成本控制工作要随着项目施工进展的各个阶段连续 进行，既不能疏漏，又不能时紧时松，应使施工项目成本自始至终置于有效的控制之下。 3.3 动态控制原则。施工项目是一次性的，成本控制应强调项目的中间控制，即动态控制。因为施工准备阶段的成本控制只是根据施工组织设计的具体内容确
（ 二 〇 一 二 年 六 月 外文文献及翻译 题 目： About Buiding on the Structure Design 学生姓名： 学 院：土木工程学院 系 别：建筑工程系 专 业：土木工程(建筑工程方向) 班 级：土木08-4班 指导教师：
英文原文： Building construction concrete crack of prevention and processing Abstract The crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure. Keyword:Concrete crack prevention processing Foreword Concrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect, end formation we can see without the
英文翻译 A comprehensive overview of substations Along with the economic development and the modern industry developments of quick rising, the design of the power supply system become more and more completely and system. Because the quickly increase electricity of factories, it also increases seriously to the dependable index of the economic condition, power supply in quantity. Therefore they need the higher and more perfect request to the power supply. Whether Design reasonable, not only affect directly the base investment and circulate the expenses with have the metal depletion in colour metal, but also will reflect the dependable in power supply and the safe in many facts. In a word, it is close with the economic performance and the safety of the people. The substation is an importance part of the electric power system, it is consisted of the electric appliances equipments and the Transmission and the Distribution. It obtains the electric power from the electric power system, through its function of transformation and assign, transport and safety. Then transport the power to every place with safe, dependable, and economical. As an important part of power’s transport and control, the transformer substation must change the mode of the traditional design and control, then can adapt to the modern electric power system, the development of modern industry and the of trend of the society life. Electric power industry is one of the foundations of national industry and national economic development to industry, it is a coal, oil, natural gas, hydropower, nuclear power, wind power and other energy conversion into electrical energy of the secondary energy industry, it for the other departments of the national economy fast and stable development of the provision of adequate power, and its level of development is a reflection of the country's economic development an important indicator of the level. As the power in the industry and the importance of the national economy, electricity transmission and distribution of electric energy used in these areas is an indispensable component.。Therefore, power transmission and distribution is critical. Substation is to enable superior power plant power plants or power after adjustments to the lower load of books is an important part of power transmission. Operation of its functions, the capacity of a direct impact on the size of the lower load power, thereby affecting the industrial production and power consumption.Substation system if a link failure, the system will protect the part of action. May result in power outages and so on, to the production and living a great disadvantage. Therefore, the substation in the electric power system for the protection of electricity reliability,
专业资料 学院： 专业：土木工程 姓名： 学号： 外文出处：Structural Systems to resist (用外文写) Lateral loads 附件：1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文 抗侧向荷载的结构体系 常用的结构体系 若已测出荷载量达数千万磅重，那么在高层建筑设计中就没有多少可以进行极其复杂的构思余地了。确实，较好的高层建筑普遍具有构思简单、表现明晰的特点。 这并不是说没有进行宏观构思的余地。实际上，正是因为有了这种宏观的构思，新奇的高层建筑体系才得以发展，可能更重要的是：几年以前才出现的一些新概念在今天的技术中已经变得平常了。 如果忽略一些与建筑材料密切相关的概念不谈，高层建筑里最为常用的结构体系便可分为如下几类： 1.抗弯矩框架。 2.支撑框架，包括偏心支撑框架。 3.剪力墙，包括钢板剪力墙。 4.筒中框架。 5.筒中筒结构。 6.核心交互结构。 7. 框格体系或束筒体系。 特别是由于最近趋向于更复杂的建筑形式，同时也需要增加刚度以抵抗几力和地震力，大多数高层建筑都具有由框架、支撑构架、剪力墙和相关体系相结合而构成的体系。而且，就较高的建筑物而言，大多数都是由交互式构件组成三维陈列。 将这些构件结合起来的方法正是高层建筑设计方法的本质。其结合方式需要在考虑环境、功能和费用后再发展，以便提供促使建筑发展达到新高度的有效结构。这并
不是说富于想象力的结构设计就能够创造出伟大建筑。正相反，有许多例优美的建筑仅得到结构工程师适当的支持就被创造出来了，然而，如果没有天赋甚厚的建筑师的创造力的指导，那么，得以发展的就只能是好的结构，并非是伟大的建筑。无论如何，要想创造出高层建筑真正非凡的设计，两者都需要最好的。 虽然在文献中通常可以见到有关这七种体系的全面性讨论，但是在这里还值得进一步讨论。设计方法的本质贯穿于整个讨论。设计方法的本质贯穿于整个讨论中。 抗弯矩框架 抗弯矩框架也许是低，中高度的建筑中常用的体系，它具有线性水平构件和垂直构件在接头处基本刚接之特点。这种框架用作独立的体系，或者和其他体系结合起来使用，以便提供所需要水平荷载抵抗力。对于较高的高层建筑，可能会发现该本系不宜作为独立体系，这是因为在侧向力的作用下难以调动足够的刚度。 我们可以利用STRESS，STRUDL 或者其他大量合适的计算机程序进行结构分析。所谓的门架法分析或悬臂法分析在当今的技术中无一席之地，由于柱梁节点固有柔性，并且由于初步设计应该力求突出体系的弱点，所以在初析中使用框架的中心距尺寸设计是司空惯的。当然，在设计的后期阶段，实际地评价结点的变形很有必要。 支撑框架 支撑框架实际上刚度比抗弯矩框架强，在高层建筑中也得到更广泛的应用。这种体系以其结点处铰接或则接的线性水平构件、垂直构件和斜撑构件而具特色，它通常与其他体系共同用于较高的建筑，并且作为一种独立的体系用在低、中高度的建筑中。
7 Rigid-Frame Structures A rigid-frame high-rise structure typically comprises parallel or orthogonally arranged bents consisting of columns and girders with moment resistant joints. Resistance to horizontal loading is provided by the bending resistance of the columns, girders, and joints. The continuity of the frame also contributes to resisting gravity loading, by reducing the moments in the girders. The advantages of a rigid frame are the simplicity and convenience of its rectangular form.Its unobstructed arrangement, clear of bracing members and structural walls, allows freedom internally for the layout and externally for the fenestration. Rig id frames are considered economical for buildings of up to' about 25 stories, above which their drift resistance is costly to control. If, however, a rigid frame is combined with shear walls or cores, the resulting structure is very much stiffer so that its height potential may extend up to 50 stories or more. A flat plate structure is very similar to a rigid frame, but with slabs replacing the girders As with a rigid frame, horizontal and vertical loadings are resisted in a flat plate structure by the flexural continuity between the vertical and horizontal components. As highly redundant structures, rigid frames are designed initially on the basis of approximate analyses, after which more rigorous analyses and checks can be made. The procedure may typically inc lude the following stages: 1. Estimation of gravity load forces in girders and columns by approximate method. 2. Preliminary estimate of member sizes based on gravity load forces with arbitrary increase in sizes to allow for horizontal loading. 3. Approximate allocation of horizontal loading to bents and preliminary analysis of member forces in bents. 4. Check on drift and adjustment of member sizes if necessary. 5. Check on strength of members for worst combination of gravity and horizontal loading, and adjustment of member sizes if necessary. 6. Computer analysis of total structure for more accurate check on member strengths and drift, with further adjustment of sizes where required. This stage may include the second-order P-Delta effects of gravity loading on the member forces and drift.. 7. Detailed design of members and connections.