Nine PHC piles with partial normal-strength deformed bars were prepared in present study,and cyclic loading tests were implemented to evaluate these piles’seismic performance.The influence of the axial compression ra...Nine PHC piles with partial normal-strength deformed bars were prepared in present study,and cyclic loading tests were implemented to evaluate these piles’seismic performance.The influence of the axial compression ratio and the amount of normal-strength deformed bars on failure modes,crack patterns,strength,stiffness,and ductility were examined.The test findings indicate that the change of axial compression ratio has a noticeable influence on the failure mode of PHC piles.A larger axial compression ratio results in a higher cracking bending resistance,ultimate bending resistance,and initial stiffness,but the propagation heights of flexural cracks decrease as the axial compression ratio increases.Furthermore,increasing the amount of normal-strength deformed bars causes a slight decrease in ductility.Finally,a calculation formula was proposed to predict the flexural capacity of PHC piles with partial normal-strength deformed bars.展开更多
In recent earthquakes, a large number of reinforced concrete （RC） bridges were severely damaged due to mixed flexure-shear failure modes of the bridge piers. An integrated experimental and finite element （FE） anal...In recent earthquakes, a large number of reinforced concrete （RC） bridges were severely damaged due to mixed flexure-shear failure modes of the bridge piers. An integrated experimental and finite element （FE） analysis study is described in this paper to study the seismic performance of the bridge piers that failed in flexure-shear modes. In the first part, a nonlinear cyclic loading test on six RC bridge piers with circular cross sections is carried out experimentally. The damage states, ductility and energy dissipation parameters, stiffness degradation and shear strength of the piers are studied and compared with each other. The experimental results suggest that all the piers exhibit stable flexural response at displacement ductilities up to four before exhibiting brittle shear failure. The ultimate performance of the piers is dominated by shear capacity due to significant shear cracking, and in some cases, rupturing of spiral bars. In the second part, modeling approaches describing the hysteretic behavior of the piers are investigated by using ANSYS software. A set of models with different parameters is selected and evaluated through comparison with experimental results. The influences of the shear retention coefficients between concrete cracks, the Bauschinger effect in longitudinal reinforcement, the bond-slip relationship between the longitudinal reinforcement and the concrete and the concrete failure surface on the simulated hysteretic curves are discussed. Then, a modified analysis model is presented and its accuracy is verified by comparing the simulated results with experimental ones. This research uses models available in commercial FE codes and is intended for researchers and engineers interested in using ANSYS software to predict the hysteretic behavior of reinforced concrete structures.展开更多
本文基于美国陆军工程师兵团EM 1110-2-6053中提出的水工建筑物抗震性能需求能力比(DCR,demand to capacity ratio)评价方法,对某水电站沉砂池综合抗震性能进行了评价。结果表明,在OBE下,沉砂池右边墙的抗剪性能、抗弯性能、抗滑动稳定...本文基于美国陆军工程师兵团EM 1110-2-6053中提出的水工建筑物抗震性能需求能力比(DCR,demand to capacity ratio)评价方法,对某水电站沉砂池综合抗震性能进行了评价。结果表明,在OBE下,沉砂池右边墙的抗剪性能、抗弯性能、抗滑动稳定和抗倾覆稳定性均能满足设计要求。而在MDE下,尽管沉砂池截面抗弯性能良好,但其右边墙的抗剪性能难以满足设计要求,需要对结构断面或配筋进行调整;且其可能发生滑动失稳和倾覆失稳破坏,需要进一步开展非线性动力分析。展开更多
基金National Natural Science Foundation of China under Grant No.51578369the Tianjin Science and Technology Major Project under Grant No.17ZXCXSF00080。
文摘Nine PHC piles with partial normal-strength deformed bars were prepared in present study,and cyclic loading tests were implemented to evaluate these piles’seismic performance.The influence of the axial compression ratio and the amount of normal-strength deformed bars on failure modes,crack patterns,strength,stiffness,and ductility were examined.The test findings indicate that the change of axial compression ratio has a noticeable influence on the failure mode of PHC piles.A larger axial compression ratio results in a higher cracking bending resistance,ultimate bending resistance,and initial stiffness,but the propagation heights of flexural cracks decrease as the axial compression ratio increases.Furthermore,increasing the amount of normal-strength deformed bars causes a slight decrease in ductility.Finally,a calculation formula was proposed to predict the flexural capacity of PHC piles with partial normal-strength deformed bars.
基金Supported by:National Natural Science Foundation of China Under Grant No.50878033 and National Special Foundation of Earthquake Science of China Under Grant No.200808021
文摘In recent earthquakes, a large number of reinforced concrete （RC） bridges were severely damaged due to mixed flexure-shear failure modes of the bridge piers. An integrated experimental and finite element （FE） analysis study is described in this paper to study the seismic performance of the bridge piers that failed in flexure-shear modes. In the first part, a nonlinear cyclic loading test on six RC bridge piers with circular cross sections is carried out experimentally. The damage states, ductility and energy dissipation parameters, stiffness degradation and shear strength of the piers are studied and compared with each other. The experimental results suggest that all the piers exhibit stable flexural response at displacement ductilities up to four before exhibiting brittle shear failure. The ultimate performance of the piers is dominated by shear capacity due to significant shear cracking, and in some cases, rupturing of spiral bars. In the second part, modeling approaches describing the hysteretic behavior of the piers are investigated by using ANSYS software. A set of models with different parameters is selected and evaluated through comparison with experimental results. The influences of the shear retention coefficients between concrete cracks, the Bauschinger effect in longitudinal reinforcement, the bond-slip relationship between the longitudinal reinforcement and the concrete and the concrete failure surface on the simulated hysteretic curves are discussed. Then, a modified analysis model is presented and its accuracy is verified by comparing the simulated results with experimental ones. This research uses models available in commercial FE codes and is intended for researchers and engineers interested in using ANSYS software to predict the hysteretic behavior of reinforced concrete structures.
文摘本文基于美国陆军工程师兵团EM 1110-2-6053中提出的水工建筑物抗震性能需求能力比(DCR,demand to capacity ratio)评价方法,对某水电站沉砂池综合抗震性能进行了评价。结果表明,在OBE下,沉砂池右边墙的抗剪性能、抗弯性能、抗滑动稳定和抗倾覆稳定性均能满足设计要求。而在MDE下,尽管沉砂池截面抗弯性能良好,但其右边墙的抗剪性能难以满足设计要求,需要对结构断面或配筋进行调整;且其可能发生滑动失稳和倾覆失稳破坏,需要进一步开展非线性动力分析。
