Common Causes of Collapse of Metal‐Plate—Connected Wood Roof Trusses

Abstract

Metal‐plate‐connected wood roof trusses are a popular structural system for light‐framed structures. They are extremely flexible and unstable until set in place and adequately braced. Though truss‐plate manufacturers have developed handling and bracing recommendations, many truss installers ignore these guidelines. This paper discusses three roof‐truss collapses that the writer has investigated and points out how the failure to properly brace the trusses is a common source of collapse. In one case, a collapse occurred twice during the truss erection. In another case, collapse occurred six years after completion. In a third case, mishandling of trusses during erection was also a contributing factor. In these cases, design and erection responsibilities were in the hands of the construction contractor. It is suggested that building‐code changes are needed to ensure that there is a rational bracing plan detailed for the use of the truss installer.