Study On The Practical Analysis Method For Progressive Collapse Of Multi-storey RC Frame Structure

Since the collapse of Ronan Point Tower in the United Kindom in 1968, the study on progressive collapse of structures has been continuously interested the researchers for more than forty years and lots of relevant codes and guide lines have been developed in foreign countries, such as the GSA 2003,DoD UFC 4-023-03、EuroCode 1 and BS8110, ect. However, the study on this topic started rather late in China and relevant standards are rare and far behind our international counterparts, and until 2011, the new code for concrete structures GB 50010-2010 listed a few guidelines regarding progressive collapse. Currently, the study on progressive collapse is still a hot topic for researchers both domestic and abroard and the code for prevention of progressive collapse is urgently required in China.This paper summarizes the research results and the main codes developed in the field of progressive collapse study, introduces the main design methods provided in the existing foreign codes.In this article, a 6-story RC frame structure subjected to conventional loads in different seismic resistant zone is designed according to current design code, and then, the ability to resist progressive collapse of this structure is analized based on main international design codes, using linear static alternative load path method.The analysis assumes that the corner coumn and the middle column along the long side of the building is removed respectively, and then the Demand-capcity Ratio of the residual structural memebers is calculated. By comparing the calculation result with the allowable DCR values given in the code, the scope of potential collapsing is predicted. The structure is also analized using linear dynamic method and the calculation result is compared with the output of linear static design.The following conclusion is drawn from the analysis: conventional structures that designed to resist higher seismic load demonstrate higher ability to resist progressive collapse after the failure of local structural members, however, for structures designed for low seismic zones, the risk of progressive collapse is high after local member failure.This paper also discussed non-linear design methods regarding progressive collapse.Take the complexity and cost of structural analysis and engineering work into consideration, the author concludes that in the near futhre, the linear-static method is an effective and practical analysis method for resistance of progressive collapse design.