Progressive Collapse Simulation Of Isolated Structure Under Blast Load

Various kinds of research topics about disaster prevention and mitigation,or explosion prevention and explosion-proof in the field of structural engineering have been paid more and more attention by domestic and foreign researchers.With the gradual development and utilization of urban underground space,the research on the anti-blast disaster design and progressive collapse mechanism of building structures with underground space under the blast load is becoming a major research topic in engineering and scientific research.As a kind of economic,important and more widely used structure,the dynamic performance of the isolated structure suffered the blast load,especially the anti-progressive collapse performance,may become a key issue restricting its development and application.However,there are a few studies on the damage of the structural members such as rubber isolation bearings and the progressive collapse of the whole structure after the explosion in the interior of the isolation structure,especially in the basement.Therefore,this paper aims to explore the dynamic response and progressive collapse mode of the serially connected isolation structure under the blast load in the basement.The main research work and achievements are as follows:(1)Summarizing the research results about the dynamic response and progressive collapse of the structural members suffered the blast load.According to the specific requirements in this paper,the appropriate method is selected to give that the implement method in LS-DYNA about the interaction between the shock wave and the series isolation structure,which includes the selection of constitutive model of the isolation structure and the explosive,the calculation of the parameters,the handling of the boundary conditions,the contact conditions and other key issues.And the finite element analytical model of serially connected isolated structure which includes basement,explosive and air was established.(2)According to the principle of pillar removal in the GSA specification for the alternate load path method,the position of the blast load is selected.The position of the different explosive is set at the pillar in the corner,long side and inner of basement.The different numerical caculation model were operated in software through simplified direct simulation method.Based on those operations in software,the processes of progressive collapse process of the serially connected isolated structure is simulated.The progressive collapse and collapse modes of the serially connected isolation structure under different explosive positions in the basement are summarized.(3)To the phenomenon that tensile stress appears in rubber isolation bearing under the impact of explosion,the vertical displacement time history curve of several nodes in the roof of the initial explosion of three different working conditions is recorded and analyzed.Shock wave on the serially connected isolated structure does exist a” shortlift” action.(4)Compared the simulation results obtained by the alternative load path method in the existing literature and the results in this paper,which simulating the progressive collapse of the structure suffered the blast load,the collapse result obtained by the direct simulation method is more serious.Because the initial damage of the surrounding components of the key components is not negligible to the collapse of the whole structure when the structural explosion analysis is studied.Therefore,for the antiexplosion analysis of the structure,the results obtained by the alternative load path method are often less securable.