Structural assessment of reinforced concrete buildingsretrofitted with various schemes against progressive collapse

Primary local damage in the building spreads outward in a process known as "progressive collapse." Damages caused by removing one or more load-bearing columns lead to a sequence of failures that eventually lead to structural collapse. Multi-story reinforced concrete (RC) buildings with varying numbers of stories were investigated in this paper to observe how various retrofitting techniques affect the structures' ability to withstand progressive collapse. As a result, eight distinct scenarios involving three distinct building heights of seven, thirteen, and nineteen stories were examined. To begin with, there was an RC moment-resisting frame (bare frame) for each of the three different story numbers. The other frames included X-braces, diagonal braces, inverted V-braces, viscous dampers in the central bay and two inner-bay, viscous damper only in certain stories, and carbon fiber reinforced polymer jackets. In order to analyze the different RC frame's capacity in relation to the number of storeys, deriving each numerical model was conducted for the ultimate load- carrying ability to progressive collapse. In addition, for each case study structure, three distinct scenarios for column removal were evaluated as column failures at the ground, middle, and last floors. It was found that there was a significant improvement in the RC building's ability to withstand a collapse following a column's failure, depending on the method utilized to upgrade the structure's bare frame. It is also possible to resist the gradual collapse by raising the number of stories, which guides a rise in the number of the component that redistributes the burden after the incident.