PERFORMANCE OF FLAT SLAB COLUMN BUILDING DURING EARTHQUAKE

Abstract

Flat slab building system performs well in resisting gravity or vertical loads but perform poorly during cyclic loading and hence Building codes around the world has rejected the application of this building system in active earthquake zones keeping in mind the past failures of these types of buildings during major earthquakes. Pushover analysis or nonlinear static analysis procedure is simple tool to determine the performance of this system. In this method the structure is pushed with a predefined loading pattern up to certain level of roof displacement to get various performance levels. Indian code doesn't have provisions for this type of analysis and we rigidly follow ATC-40 and FEMA-356 guidelines for performing such analysis. Performance levels are defined in terms of amount of damage to the structure. In present study the flat plate buildings have analyzed which was designed only . for gravity loading and its capacity curve is drawn with SAP2000. The buildings have been studied with effects of various parameters as effects of edge beam, stiffer perimeter columns, . grade of concrete and number of storey etc. The performance of building in terms of ultimate base shear capacity and roof drift has been compared for 4-storey and 8-storey buildings. The pushover analysis clearly shows that the slab column connections are weak and: : are the first point of yielding. The shear capacity of this connection reduces drastically, in lateral loading and hence in all buildings these should be carefully design.