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Comparison of various procedures for progressive collapse analysis of cable-stayed bridges

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第5期13卷 323-334页

作者： Jian-guo CAI Yi-xiang XU Li-ping ZHUANG Jian FENG Jin ZHANG Key Laboratory of C&PC Structures of Ministry of Education Southeast University Nanjing 210096 China Department of Civil Engineering Strathclyde University Glasgow UK

Alternate path(AP) method is the most widely used method for the progressive collapse analysis,and its application in frame structures has been well proved.However,the application of AP method for other structures,especially for cable-stayed structures,should be further developed.The four analytical procedures,i.e.,linear static,nonlinear static,linear dynamic,and nonlinear dynamic were firstly improved by taking into account the initial state.Then a cable-stayed structure was studied using the four improved methods.Furthermore,the losses of both one cable and two cables were discussed.The results show that for static and dynamic analyses of the cable-stayed bridges,there is large difference between the results obtained from simulations starting with either a deformed or a nondeformed configuration at the time of cable loss.The static results are conservative in the vicinity of the ruptured cable,but the dynamic effect of the cable loss in the area farther away from the loss-cable cannot be considered.Moreover,the dynamic amplification factor of 2.0 is found to be a good estimate for static analysis procedures,since linear static and linear dynamic procedures yield approximately the same maximum vertical deflection.The results of the comprehensive evaluation of the cable failure show that the tread of the progressive failure of the cable-stayed bridges decreases when the location of the failed cables is closer to the pylon.

关键词： Progressive failure Structural failures Collapse linear analysis Nonlinear analysis Dynamic analysis Cable-stayed bridges

NUMERICAL STUDIES OF 2D FREE SURFACE WAVES WITH FIXED BOTTOM

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Journal of Computational Mathematics 2002年第4期20卷 391-412页

作者： Ping-wen Zhang Xiaoming Zheng School of Mathematics Sciences Peking UniversityBeijing100871China Department of AMS State University of New YorkStony BrookNY 11794-3600USA

The motion of surface waves under the effect of bottom is a very interesting and challenging phenomenon in the nature. we use boundary integral method to compute and analyze this problem. In the linear analysis, the linearized equations have bounded error increase under some compatible conditions. This contributes to the cancellation of instable Kelvin-Helmholtz terms. Under the effect of bottom, the existence of equations is hard to determine, but given some limitations it proves true. These limitations are that the swing of interfaces should be small enough, and the distance between surface and bottom should be large enough. In order to maintain the stability of computation, some compatible relationship must be satisfied like that of [5]. In the numerical examples, the simulation of standing waves and breaking waves are calculated. And in the case of shallow bottom, we found that the behavior of waves are rather singular.

关键词： fixed bottom 2D surface wave boundary integral method linear analysis energy analysis

Ultimate Strength analysis of Offshore Jacket Platform

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China Ocean Engineering 1995年第3期10卷 263-274页

作者： Xu Bin Shen Zhonghan Research Associate, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080 . Associate Professor, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080

The ultimate strength analysis of offshore jacket platforms is a research project which has been developed in recent years. With the rapid development of marine oil industry, the departments of design and IMR (Inspection, Maintenance and Repair) in the offshore engineering have attached great importance to this project. The research procedure applies to both the stress check of new design platforms and the whole safety assessment of existing platforms. In this paper, we combine the pseudo non-linear technique with the linear analysis program and successfully analyze the ultimate strength of the space frame structure subject to the concentrated load and a real jacket platform subject to the dead load and environmental load.

关键词： offshore platform ultimate strength linear analysis pseudo non-linear platform collapse