Progressive collapse is a catastrophic partial or total failure of a structure that mostly occurs when a structure loses a primary component like a column. Some international standards have started to consider progressive collapse resistance in various approaches. In this study, the ‘Unified Facilities Criterion’ guidelines were used in assessing the structure; these guidelines represent one of the codes that discuss progressive collapse using sophisticated approaches. Three-dimensional nonlinear dynamic analyses using the ‘Applied Element Method’ were performed for a structure that lost a column during a seismic action. A parametric study was made to investigate the effect of different parameters on progressive collapse. In this study, a primary structural component was assumed lost during an earthquake. The studied parameters were the location of the removed column in plan, the level of the removed column, the case of loading, and the consideration of the slabs. For the study cases, it was concluded that the buildings designed according to the Egyptian code satisfies the progressive collapse requirements stated by ‘Unified Facilities Criteria’ (UFC) guidelines requirements with a safety factor of 1.97. Also, it was found that losing a column during a seismic action is more critical for progressive collapse than under gravity load. Finally, this study elaborated the importance of considering the slab in progressive collapse analysis of multistory buildings in order to include the significant catenary action developed by the slabs.

A building is subjected to progressive collapse when a primary vertical structural element fails, resulting in the failure of adjoining structural elements, which cause further structural failure, leading eventually to partial or total collapse of the structure. The failure of a primary vertical support might occur because of extreme loadings such as a bomb explosion in a terrorist attack, a car colliding with supports in a parking garage, an accidental explosion of explosive materials, or a severe earthquake. Different design codes address the progressive collapse of structures attributable to the sudden loss of a main vertical support such as the General Services Administration (GSA) code and the Unified Facilities Criteria (UFC). The alternative path method (APM) is the main analysis method for evaluating the hazard of progressive collapse in the two codes. The APM requires that the structure be capable of bridging over a missing structural element, with the resulting extent of damage being loc...

In March 2011, the Tohoku tsunami swept over the east coast of Japan killing more than 15,000 people and missing more than 2,500 people. The tsunami resulted in collapsing of more than 400,000 buildings and washing away of more than 250 coastal bridges. In this study, the collapse of Tsuyagawa bridge damaged by the Tohoku tsunami is numerically investigated using the applied element method (AEM) because of its advantages for simulating structural progressive collapse. The AEM is a discrete crack approach that allows the elements separation, fall, and collision with each other in a fully nonlinear dynamic scheme of computations. The analysis was demonstrated to efficiently simulate the bridge collapse, showing that the bridge collapsed at a water speed of 6.6 m/s initiated by flexural failure of its piers. The study of bridge strengthening showed that the collapse water speed could be increased by 22 and 29% compared to Tohoku tsunami if piers are strengthened by a 100-mm RC jacket and 20-mm thick...