共查询到20条相似文献，搜索用时 15 毫秒
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Due to the large stirrup ratio and reinforcement congest in beam-column joints, the ordinary reinforced concrete beam-column joints take inconvenience to construction. Cracked fiber renforced concrete (FRC) has strong bridge ability and better tensile performance so that it can replace part or all of the stirrups. Based on previous researches on resistance mechanism of reinforced concrete joints, a new model using FRC materials in the core zone of beam-column joints is presented. It is a kind of model in which horizontal shear supported by the diagonal strut mechanism and softening truss mechanism with a certain percentage. The calculation results of the model is compared with the existing test results. It is a bit conservative to specimens with low axial load ratio. However, the results are in line with the specimens with high axial load ratio. Therefore, the results totally demonstrate the rationality of the proposed model in this paper. Meanwhile, according to the proposed model, the shear capacity of beam-column joints can be not only calculated, it also check whether FRC compressive strength in core zone of joints and horizontal stirrup ratio meets design requirements, which has a higher practicability. 相似文献
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The mechnical characteristics of concrete is sensitive to the strain rate and it is crucial to consider the effect of load rates on the behavior of reinforced concrete (RC) structures subjected to dynamic loads such as severe earthquakes. In this study, numerical simulations on the dynamic behavior of typical RC column specimens under dynamic loadings with different load rates were performed. Concrete constitutive model considering the strain rate effects proposed by the CEB code was employed with a fiber model to characterize the nonlinear strain rate dependent behavior of RC columns. The developed dynamic fiber element model was validated by comparing the simulated results of four RC column specimens with the fast loading test results. Results show that the developed fiber element model can predict the behavior of RC columns with acceptable accuracy. After valiating the proposed fiber elemen model considering the strain rate effect, the load carrying capacity of different RC columns with various longitudinal reinforcement ratios and volumetric stirrup ratios were simulated. Results show that the trends of the influences of longitudinal reinforcement ratios and volumetric stirrup ratios on the load carrying capacity of the RC columns under dynamic loadings are different. 相似文献
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Because the factors that affect the behavior of the beam-column joints are complicated,an experimental study alone is not sufficient.Therefore,a nonlinear finite element analysis was conducted to provide better understanding of the performance of the beam-column joints.The authors intend to do the parameter study with nonlinear finite element method after a lot of high-strength concrete beam-column joints have been experimented.In this paper,the analytical model firstly was applied to simulate the experimental joint behavior and the comparison results were very well.Based on this,the parametric analysis of concrete strength on seismic performance of beam-column joints has been conducted. 相似文献
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Adopting the element SOLID65 and LINK8 in the general finite element analysis software ANSYS and fiber model beam-column element based on finite element flexibility method respectively, the comparative analysis of the cross, L and T-shaped RC columns under compression, bending, shear and torsion with flange width-thickness ratio of 4:1 is carried out. The applicability of plane section assumption in the nonlinear analysis is discussed primarily, which shows that it is feasible on the whole for shaped RC columns with flange width-thickness ratio equal to or smaller than 4:1. 相似文献
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In this paper,four models are selected as the representatives and applied to nonlinear dynamic analysis program for space frames which is based on the beam-column elements using the finite element flexibility method and the fiber model.Park's test on combined axial and bending columns under cyclic loading are taken as the calibrations,comparisons to material and structural member level are drawn and the analytical results of various models are discussed. 相似文献
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A nonlinear finite element analysis using ANSYS is applied to the vertical mechanical behaviors of three specimens of reinforced concrete transferring joints with inchned columns, which are used in high - rise buildings. A comparison is made between the analytical achievements and the test results, including the mechanical behaviors, load - transferring path and the failure modes, and a good agreement is obtained. The reliability of the software ANSYS in the nonlinear analysis of such reinforced concrete structures is verified and developed. 相似文献
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Zhong Shusheng Chongqing Institute of Architecture EngineeringGuo Jianhua Wnhan Institute of Municipal EngineeringWang Zuhua South China University of Technology 《保鲜与加工》1992,(1)
In order to probe into the shear resistant behaviors ofsteel reinforced concrete(SRC)restrained beams,three test beams underconcentrated loads have been tested.A full range analysis of the testbeams is conducted by using nonlinear finite element(NLFE)techique,and a good agreement with the experimental results is achieved.Theshear resistant mechanism of SRC restrained beam and the main factorsaffecting its shear strength are analysed.It is found that when theavailable shear strength formula for simply supported SRC beams is usedto calculate the shear strength of SRC restrained beams,the result turnsout to be conservative,so it is suggested that the shear strength of SRCrestrained beam could be calculated by the corresponding formula ofsimply supported SRC beam,adopting calculation shear span ratio.Thepractical formula is proposed in the paper. 相似文献
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On the basis of testing results of shear behavior from 18 super high strength reinforced concrete restrained beams with web reinforcement, with the cube compressive strength ranging from over 100Mpa, in this paper, the nonlinear finite element analysis procedure was formulated and the analysis of the specimen tests was carried out with the parameters obtained from the experiments and improved constitutive model and failure criteria of materials. Based on the simulated shear resistance test results and practical measured data of eighteen super high strength concrete restrained beams under point load, the equation to compute the shear resistance capacity of such beams was thus obtained by regression. The analytical results agree well with those of experiments. 相似文献
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A finite element model based on the flexibility method and a fiber section model of nonlinear beam column elements was adopted within the OpenSees framework. A typical multistory reinforced concrete 3D frame designed in accordance with the Chinese building code and a representative plane frame parallel to the X axis were used as examples. The relationships of the responses obtained from the plane and 3D models were studied by comparing global and local seismic responses of the frame, and by taking the responses of the 3D model under unidirectional earthquake action as a medium for comparison. Because the results show the global responses of the plane model are similar to those of the 3D model, it is reasonable to replace the 3D model with the plane model when examining global seismic responses. The local responses are evidently different. For the plane model under unidirectional action, numerous plastic hinges develop at the beam ends. Many more plastic hinges at column ends exist than in beams for the 3D model under bi directional action. Column ductility demands obviously exceed those of beams. The frame tends to develop a column sway mechanism, implying that simplified plane analysis model significantly underestimates the seismic responses of the 3D frame column. 相似文献
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In order to ensure that the T shaped steel reinforced concrete short-pier shear wall ductile shear failure occurs, the failure mechanism on the basis of experimental research, using ANSYS finite element analysis software to simulate the failure mode. In the process of analysis considered the influence factors of horizontal steel reinforcement ratio, concrete strength, axial compression ratio and the content of steel. The results show: the level of reinforced volume reinforcement ratio, concrete strength and the content of steel can obviously change the the bearing capacity and ductility of components. 相似文献
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RC加气混凝土砌块组合墙加固框架抗震性能试验研究 总被引：1，自引：0，他引：1
RC加气混凝土砌块组合墙（简称组合墙）是由混凝土梁柱网格与加气混凝土砌块组合形成的一种轻型网格式抗震墙,可用于框架结构的抗震加固。笔者进行了1/2比例空框架试件、组合墙试件和组合墙加固框架试件的低周反复荷载试验,分析了各试件的主要破坏过程,对比了组合墙加固框架前后试件承载能力、刚度等抗震性能变化。试验结果及分析表明：组合墙加固框架后承载力、抗侧刚度有较大幅度提高,中大震及大震阶段其承载力、等效刚度约为空框架和组合墙单独受力之和的0.9倍,两者具有良好的协同工作性能;加固试件的破坏过程基本上遵循填充砌块混凝土框格外框架的破坏顺序,能够发挥组合墙多重抗震防线的特点,采用RC加气混凝土砌块组合墙加固框架是一种较为经济实用的加固方法。 相似文献
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In this paper, a study is carried out on large-span prestressed concrete structure system in residence analyzed by specially - shape column equivalent frame model. Applying fiber model column-beam element and shell element, a large amount of comparative analyses about large-span prestressd concrete structure under horizontal and vertical load is carried out. The parameter of the equivalent frame is confirmed based on comparison with the result of the man-sized structural experiment. It is proved that the equivalent frame model has high efficiency and precision especially for nonlinear analysis. 相似文献
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The active confinement for the core concrete can be provided by lateral pre-tensioned FRP, the stress hysteresis of FRP can be avoided, and good confinement effect for concrete columns can be got. It must cause large error if adopt the calculated model and constitute model of concrete columns confined with non-pretentioned FRP. The initial confined stress and effective confined stress associated with the lateral pre-stress were introduced. According to the test results and finite element simulation, the calculated model on peak stress, peak strain, ultimate stress and ultimate strain of circular concrete columns confined with lateral pre-tensioned FRP were proposed, and the initial elastic modulus of circular concrete columns confined with lateral pre-tensioned FRP was analyzed. Based the exiting stress-strain models of circular concrete columns confined with FRP, the three linear stress-strain model of circular concrete columns confined with lateral pre-tensioned FRP was recommended, and good agreement between theoretical and test results is achieved. 相似文献
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采用非线性有限元分析程序ABAQUS对无粘结体外预应力CFRP片材加固简支钢筋混凝土T形梁后进行数值模拟,该模拟梁共4根分别为3根梁侧对称加固,1根为梁底加固均为四点波形齿锚固预应力CFRP带。对比结果显示,数据模拟与试验结果在构件屈服以前的承载力、变形以及极限承载力吻合程度较好,构件屈服以后的变形差别较大,因此,可在一定程度上有效替代试验分析方法。依据吻合程度最好的TL3参数设计了“两点锚固”和“四点锚固”的模型进行模拟分析。通过对锚固点数及加固量改变的对比分析可知,依据加固构件的弯矩改变各段加固量及布置锚固点数的方法既可以保证加固效果不降低,又可以节约CFRP材料。 相似文献
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The accurate calculation of the deformation capacity of structures is very important to performance-based seismic design, which satisfies the explicit deformation demands. The method to evaluate drift capacity of fiber reinforced polymer (FRP) confined reinforced concrete circular columns under simulated seismic loading is focused. Firstly, the moment-curvature relationship of FRP confined sections of reinforced concrete (RC) circular columns is simulated by numerical analysis. It is found that the calculated ultimate curvature is significantly less than the test result, and the difference is controlled by the axial load ratio of the tested columns. According to the numerical and the test results, an equation is proposed to modify the calculated ultimate curvature. Based on this, the drift capacity can be predicted with the equivalent plastic hinge method. The calculated result agrees well with the test result when FRP amount is low, but it is significantly larger when FRP amount increases. Finally, the main parameters exerting influences on the drift capacity of the FRP-confined RC circular column are analyzed. 相似文献
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Shear Capacity Calculation Analysis of Reinforced Concrete Beams Based on Truss-arch Model 总被引：1，自引：0，他引：1
According to the theory of truss-arch model, the shear mechanism of reinforced concrete beam was analyzed, and formula of shear bearing capacity was proposed. In this formula, softening effect of concrete and the arch function were taken into account, and the coefficients in the formula were amended with experimental data. When the performance difference between the structural material and the original material is huge, the code formula of shear bearing capacity calculation is inapplicable. After the computation, the ratio of the results calculated by truss-arch model theory formula and the results calculated by the current code formula was close to 1, and the standard deviation coefficient and coefficient of variation were smaller than those of standard formula results, and the results calculated by truss-arch model formula were in good agreement with the experimental results. The collected experimental data was calculated with the shear capacity formula in ACI318-08, and the calculation results showed that United States building code was more conservative than the standard of China. The results indicate that the shear bearing capacity formula based on truss-arch model can be used for computation of shear bearing capacity of reinforced concrete beams. 相似文献
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采用简化的纤维增强混凝土应力应变关系,根据截面变形的平截面假定和截面力的平衡方程,推导出塑性铰区采用纤维增强混凝土柱在不同极限状态时的曲率。根据各极限状态点曲率,求得截面上各分布力,对截面形心轴取距,到塑性铰区采用FRC柱的开裂、屈服、峰值和极限点的弯矩表达式。与试验结果对比表明,计算值与试验值吻合较好。 相似文献