Effect of irregular plan on seismic vulnerability of reinforced concrete buildings

Abstract

In the modern world many buildings have irregular configurations both in elevation and plan. Such types of buildings are more susceptible in earthquake forces. Structural irregularities are more important factors which decrease the seismic behavior of the structures. Buildings with slab openings are often vulnerable to damages, when subjected to lateral loads. The influence of diaphragm openings on the seismic response of multi-storied buildings played a major role in reducing the base shear, hence attracting lesser seismic forces. Correct location of openings can offer efficient strength and serviceability to the structure. It is necessary to identify performance of the structures to withstand against disaster for both new and existing buildings. Opening in the floors is common for many reasons like stair cases, lighting architectural etc., these openings in diaphragms cause stresses at discontinues joints with building elements. Discontinuous diaphragms are designed without stress calculations and are thought about to be adequate ignoring any gap effects. In this study an attempt has been made to know the difference in seismic response of two building having diaphragm discontinuity and without diaphragm discontinuity. In the present study existing building with diaphragms irregularity has been modeled and seismic response will be compared with building without diaphragm discontinuity using CSI SAP200 software. Linear static and dynamic analysis has been carried out. Results of two building have been compared for modal time period, base shear, storey drift and joint displacement.