Papers by Author: Zhen Bao Li

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Authors: Zhen Bao Li, Wen Jing Wang, Wei Jing Zhang, Yun Da Shao, Bing Zhang, Mei Guang Fan, Shuang Ping Lin
Abstract: Axial compression experiments of four full-scale reinforced concrete columns of two groups were carried out. One group of three columns used high-strength steel with the yield strength of 1000MPa as reinforcement hoops, and the second group used the ordinary-strength steel with yield strength of 400MPa. The axial compressive performances between these two groups were assessed. Compared to the specimen using the ordinary-strength steel, the axial compressive bearing capacity of using the high strength steel dose not increase significantly, while the deformation ability increases greatly. The results also indicate that the stress redistributions of the hoops and the concrete sections are obvious, and long-lasting when specimens achieve the ultimate bearing capacity after the yield of the rebar and local damage of concrete materials, at this time the strain of the specimens developes a lot, especially stress - strain curves of speciments with high-strength hoop all show a wide and flat top.
Authors: Hong Yu Zhou, Zhen Bao Li, Er Wei Guo, Jing Zhang
Abstract: Reinforced concrete calculation theories at the present stage are mainly based on experimental results of small size specimens, studies on the size effect of flexural capacity of large-scale reinforced concrete beam are not sufficient. Main research contents in this paper are the size influence on bending performance of under-reinforced beam, which can help to revise the related design theory. The paper collects test information of five different section size samples in different loading stage, including bearing capacity, deflection, section strain and so on. The total number of specimens is 13.Based on test failure process, development of cracks and deflections, analysis on section stress and strain, the safety of related bearing capacity formula is verified in research scale.It is also found that the safety reserve of calculation theory shows a trend of decrease with the specimen dimension increasing. As for large-size bending specimens, the code value of ultimate strain under non-uniform compression is bigger than test value.
Authors: Hua Ma, Hong Huan Wang, Zhen Bao Li, Xin Yu Sun, Xue Wei Zhang
Abstract: In order to study the seismic performance, of macro-synthetic fiber-reinforced concrete ductile columns, specific used as the concrete energy absorption system placed in the structure, three concrete ductile columns were constructed and tested using low-frequency cyclic loading. The damage pattern, hysteresis curve, ductile factor and equivalent viscous damping coefficient of the columns were obtained. The results show that the macro-synthetic fiber-reinforced concrete ductile column has the good ductility and the high post-crack energy absorption ability.
Authors: Zhen Bao Li, Zhen Yun Tang, Jin Bao Ji, Xiao Liang Li, Da Xing Zhou, Wei Ming Yan
Abstract: This paper presents the defects existing in shaking table control including the overshoot of displacement under low-middle frequency input using three variable parameter controls, the narrow bandwidth resulting from the performance of servo-valve and low accuracy of seismic wave reproduction because of specimen and table interaction. The effects of these factors on the stability and control accuracy of shaking table are discussed, and then the reasons of these problems existing are analyzed. The aim of this paper is to improve the stability and control accuracy of shaking table, thus, some corresponding strategies for compensation control are proposed. And a series of shaking table tests with one-story frame and two-story frame for verifying the validity of compensation control algorithm are performed.
Authors: Er Wei Guo, Zhen Bao Li, Hua Ma, Hong Yu Zhou, Xiu Li Du, Guo Hui Luo
Abstract: In order to research on seismic performance of full-scale beam-column joints of RC frames under low cyclic loading, finite element software ABAQUS is used to nonlinear analysis. Analysis results show that: the process of load carrying and fracture development of beam-column joints are simulated using concrete damage plasticity model; nonlinear finite element method is easy to obtain stress-strain relationship; and can effective analyses the complex mechanical behavior of core areas of joints.
Authors: Er Wei Guo, Zhen Bao Li, Hong Yu Zhou, Xiu Li Du
Abstract: Abstract. Size effect, referring to mechanical properties of materials change with the geometry changes, is the basic characteristic of brittle and quasi-brittle materials. Researches show that for the concrete material, compressive strength, split tensile strength and tensile strength decrease with the size of components increases, for RC structures, size effect also exists. The development and current situation in size effect are presented from three aspects, including concrete, RC members and the application of the code. And then, the developing trends of size effect of RC members are proposed.
Authors: Yong Ping Xie, Zhen Bao Li, Jia Song, Xiu Li Du
Abstract: With the development of modern constructional technique, more attention on the size effect is paid by academics and engineers. Shear failure mechanism of reinforced concrete column is analyzed firstly, and then the advances on the size effect of reinforced concrete column is introduced. the effects of sectional size on the shear behaviors of reinforced concrete column is studied by theoretical analysis and experimental summary, and the formula of the size effect of shear resistance of reinforced concrete column is proposed.
Authors: Hua Ma, Li Chun Zhou, Zhen Bao Li, Hong Huan Wang, Xiao Min Hao, Xin Yu Sun, Xue Wei Zhang
Abstract: The macro-synthetic fiber is widely used to prevent the cracking at concrete members. By the way of experiment that macro-synthetic fiber-reinforced concrete ductile columns comparing with the usual fiber-reinforced columns under the action of low-frequency cyclic loading, seismic performance of the columns in different form of bars were obtained. Meanwhile, the damage pattern, hysteresis curve, ductile coefficient and equivalent viscous damping coefficient of the columns could be also obtained. The results show that the macro-synthetic fiber-reinforced concrete ductile column has the better ductility and the higher post-crack energy absorption ability.
Authors: Lu Yan Shi, Zhen Bao Li, Zhi Yu Zhang
Abstract: The paper researched on the strain, the deformation and the failure mode of hollow latticed steel columns through two experimental conditions. They were respectively about the vertical load and the horizontal load. The results showed that for the hollow latticed steel columns with upper columns, because of the stiffness of upper columns was obviously higher than the lower ones’, the upper columns were destroyed earliest under the vertical load. In addition, the columns had good horizontal bearing and deformation capacity, and the gravity second-order effects were not obvious for the columns.
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