Investigation and Analysis of Total Collapse of a Portal Frame Structure with Large Span

Subjected to heavy snow load,a double span portal frame structure totally collapsed.The collapse investigation is carried.The failure shape and mode of purline,tension steel,portal beams and columns,etc.are investigated.And some typical phenomena related to failure shape and mode is discussed in this paper.According to the snow load and design parameters,the collapse process and the reasons inducing the collapse of the structures are analyzed and discussed.It proves that some imperfections which were neglected in design and construction are the fatal factors responsible for the failure of structural members,and the collapse of total structure as well.Learning from the collapse event,some design regulations in different design code are studied and compared.Some key problems related to the safety and reliability of portal frame structures are highlighted. In design and construction,these problems must be taken into consideration carefully.