Effect of Steel Bracing in Progressive Collapse of Multi Storey RC Buildings

Rapid increase in manmade and natural disasters can lead to structural instability which triggers the partial or complete collapse of the building. These manmade disasters include gas cylinder explosion or terrorist attack or instant removal of the primary structural element which leads to the progressive collapse of the building. To avoid the progressive collapse of building due to man-made disasters, incorporate the mechanism which resists the man-made disaster while the design for existing or newly constructing building. In this paper, an attempt is made to understand the effect of with and without providing steel bracing at various positions column removal in multi-storey building one at a time as per General Service Administration and Unified facilities criteria codes. The propagation of progressive collapse with and without the effect of steel bracing is studied in this paper. A seven-storey RC building is modelled and analysed for various column removal scenarios in SAP 2000 software. The Loads are applied according to General Service administration and Unified facilities criteria guidelines, column removal positions namely centre, edge and corner column removal at ground floor are also considered from guidelines. The three scenarios are then analysed individually as a bare frame, bare frame with steel bracing in the wall and bare frame with steel bracing in the slab. Push down analysis is carried out on models and results of mode shapes, time periods, force Vs displacement curves, plastic hinge deformation are discussed. From results, it is observed that wall bracings have better performance in all three and can help in arresting the progressive collapse from spreading throughout the building.