Impact of structure height on retrofitted RC structures for progressive collapse prevention

The term "progressive collapse" denotes the gradual spread of damage throughout a building from its initial, localized source. Loss of support after removing one or more load-bearing columns, causes a domino effect of failures that ultimately destroys the building. This research examines the effects of numerous retrofitting strategies on the progressive collapse resistance of multi-story reinforced concrete (RC) buildings with various heights. Consequently, an unretroffitied building, and seven retrofitting concepts with two different building heights of seven and nineteen storeys were examined. Each two-story building contains an RC moment-resisting frame. Other frames consisted of X-braces, diagonal braces, inverted V-braces, viscous dampers in the center bay and two inner bays, viscous dampers exclusively on specific storeys, and carbon fiber-reinforced polymer jackets. Moreover, to examine the capacity of various RC frames in relation to the number of storeys, numerical models were developed for the ultimate load-carrying capacity to progressive collapse. Furthermore, three unique column removal scenarios were assessed for each case study structure, including column failures on the bottom, intermediate, and top levels. Depending on the approach used to upgrade the bare frame of the RC building, it was discovered that the building's capacity to survive a collapse after a column failure was significantly improved. Increasing the building's height may prevent progressive collapse by channeling more of the components required for stress dispersion following an incident. When viscous damping is applied to two inner bays of a 19-story frame, the number of plastic hinges is dramatically decreased in comparison to previous bracing processes. Moreover, is supported that, the application of CFRP to modify buildings improved overall performance, increased chain performance, and effectively distributed force.