Anti-collapse Probabilistic Analysis Of Space Shell Structure With Damage

It has been proved in the reliability theory that material properties,properties of member cross-section and external subjection of structure are of random variables,and the variant characteristics of these random variables affect the performance of structures to some extent.Generally,alternate load path method is used to analyze the anti-collapse capacity of structure,however,this method can only show that the structure is in good or bad condition.For a structure in service,the best way to describe its condition is to calculate its failure probability of progressive collapse.In this thesis,reliability theory is incorporated into the collapse analysis of a double layer cylindrical space shell,and following four areas have been researched:(1)literature regarding reliability theory and methods for collapse analysis is reviewed and an algorithm for developing an extended SAP2000 reliability analysis program based on alternate load path and Monte Carlo method has been proposed.(2)using Matlab to develop the extended SAP2000 reliability analysis program and verifying it with real structures.(3)collapse analysis of a double layer cylindrical space shell is performed with material and geometric nonlinearity considered and key members of this structure are found,which lays a good foundation for reliability analysis.(4)anti-collapse probabilistic analysis of the cylindrical space shell is carried out using the selfdeveloped reliability analysis program.Based on the research,following conclusions can be drawn:(1)Monte Carlo method can be well combined with alternate load path method,which yields good result in the anti-collapse probabilistic analysis of structure.(2)the extended SAP2000 reliability analysis program developed by Matlab is reliable and can be used to analyze the failure probability of complicated structure.(3)initial space shell is robust in resisting collapse,however,failure of members labeled 9 and 33 can cause progressive collapse of this structure,which means the failure of key members may cause progressive structural collapse even though space shell is of redundant structure.Besides,some members with certain spatial distribution may have a more important role in anti-collapse of the structure.(4)reliability analysis shows that the double layer cylindrical space shell is in a quite good condition in resisting collapse even with regional damage.Collapse analysis and reliability analysis in combination verify that the space shell is well performed in service.Although researches have been shown that the self-developed program is accurate and reliable in calculating structural failure probability,there still are some imperfections of this program,taking time consuming for example,because this program is developed by Matlab and the codes are read by CUP one by one,which greatly affects the speed of calculation.Work described in this thesis makes contributions to the anti-collapse probabilistic analysis of space latticed structure and provides references for the development of SAP2000 calculation procedure of anti-collapse probability of cylindrical double space shell.