Retrofit of existing steel structures against progressive collapse through roof-truss

The paper presents the results of a comprehensive study on evaluation effectiveness retrofit strategy existing steel buildings against progressive collapse. In this respect, it investigates performance and design solution to increase robustness Moment Resisting Frame buildings. A truss system added at building's rooftop level (i.e., ‘roof-truss’), intended define an alternative load path, was investigated as solution. numerical model key components, including plastic hinges beam-column connections, were validated available experimental results. models then used structure under column loss scenarios by means non-linear static dynamic analyses performed in OpenSees. simulations allowed for identification possible failure modes paths together with definition Dynamic Increase Factor (DIF). regard, is shown that buckling critical selected case study. Moreover, outcomes showed how proposed allows effective when subjected informs details should be checked employing system.