Collapse-Resisting Mechanisms of Planar Trusses Following Sudden Member Loss

Abstract

Progressive collapse incidents of truss structures are often reported; however, studies on the collapse resistance of truss structures are comparatively few. In order to investigate the collapse-resisting mechanisms of truss structures, this paper presents a comprehensive and detailed study on the collapse-resisting performance of planar trusses subjected to local damage at various locations, using both finite-element (FE) and analytical approaches. An improved FE analysis procedure is proposed to improve the computational efficiency. The main conclusions include the following: (1) in the case of a sudden loss of a top chord member or a diagonal member, catenary action will be the primary mechanism to provide the bridging-over capacity of the remaining structure, and severer damage can result when the removed member locates in the midspan; and (2) if a bottom chord member is suddenly lost, arch action will be the main mechanism to provide the bridging-over capacity of the remaining structure, and severer damage can result when the removed member locates next to the support or in the midspan.