Assessment Of Progressive Collapse Potential Of Multi-storey Reinforced Concrete Frames

For the past 40 years, there has been several famous records of building failures with the phenomenon"one or several structural members suddenly fail and then other adjacent structural elements fail in turn until the complete failure of the building or a major part of it", such as the 1968 Ronan Point collapse in Britain, the 1995 Alfred P. Murrah building terrorist attack and the collapse of the World Trade Center towers and of a portion of the Pentagon, each of them accompanied by significant human loss and economic consequences, and the engineering professionals including many national codes and standards have considered different techniques to simulate such phenomenon to identify the structure's behavior after tolerating local damage and to design them for best resistance to such collapse. Historically, every time after the catastrophic event, some foreign building codes and reference standards(mainly of British and North America)attempted to incorporate provisions to address the matter of progressive collapse following structural failures by enhancing general structural integrity, and the extent to which it is addressed within them was constantly evolving.But until now, research in the realm of progressive collapse in China is still very insufficient. This thesis provides a review of the current state of knowledge in the area of progressive collapse, introduces into the current international proceeding study products, and summarizes the existing foreign codes and design strategies against progressive collapse thoroughly. Three analysis methods are adopted including linear static analysis, nonlinear static analysis and nonlinear dynamic analysis.A plane RC frame model for testing is analyzed according to the alternate path method to assess the ability of the current finite element analysis software SAP2000 for predicting the RC frames'behavior after local damage has occurred. The author discusses the acceptance criteria specified in the progressive collapse design guidelines, and then tries to assess the progressive collapse potential of a four-storey typical frame designed according to the current China design codes and two eight-story plane frames with or without considering seismic design mainly by two alternate analysis techniques, including linear static procedure and nolinear static procedure, as well as conduct a nonlinear dynamic analysis procedure for the eight-storey plane frame with seismic design in the second column removel scenario to verify the results obtained from the linear and nonlinear static analysis, and at last investigates and discusses the susceptible factors of the alternate lod path analysis method, including the size of the span, the number of story, the column removal situation, and the scturcture systems on the internal loadings of plane frames during the alternate load path method analysis with certain vertical critical element removel. The goal of the thesis is to identify the behavior of the RC frames with initial damage caused by abnormal loads without considering the direct effect of the abnormal loading with the hope of providing basic reference to the progressive collapse design in China.