PROGRESSIVE COLLAPSE ANALYSIS OF THIN-PLATED STRUCTURES USING ISUM

Abstract

Box columns are often used as main strength members of various types of thin-plated structures such as ships, ship-shaped offshore structures, and aerospace structures. Until and after the ultimate limit state is reached, box columns exhibit highly nonlinear structural behaviour in terms of geometrical and material aspects. In particular, the effects of local buckling, global buckling, and their interaction play a significant role in the resulting consequences of box columns under extreme actions. In order to calculate the maximum load carrying capacity of box columns, it is thus highly required to perform the progressive collapse analysis to take into account progressive failures of individual components and their interacting effects. The aim of the present study is to investigate the applicability of ISUM to the progressive collapse analysis of box columns which are typical examples of main strength members in landbased structures. Theoretical outline of the method is addressed. Short, medium and long box columns in length are studied in terms of interacting effects between local component failure modes and global system failure modes. A comparison of ISUM with more refined nonlinear finite element method (FEM) computations is also made.