Potential collapse of a roof structure averted by quick repair

The paper describes the analysis and repair of an accidentally damaged long-span roof structure in a large storage warehouse; these were successfully performed in order to avert potential progressive collapse. The damage was caused by the impact of the open bed of a moving truck against one of the exposed primary load-carrying steel girders of the gable roof of the building. The impact caused serious dislocation and cross-sectional deformation of the girder, as well as rupturing several purlin-to-girder connections. As a result, the girder was not only damaged in itself, but its lateral-torsional stability was also compromised. The structural analysis of the damaged roof structure is reviewed, and two versions of repair of the damaged elements are described, including temporary support by three-dimensional modern shoring towers for both gravity and wind loads. It is demonstrated that, at least in this case, the damage – however serious – to a single structural element does not necessarily impact the global safety and result in immediate failure of the entire structure. Prudent timely repair can avert a disaster.