Seismic Performance and Vulnerability Analysis of Code - Conforming RC Buildings

摘要

This paper investigates seismic performance and vulnerability analysis of 4-storey and 6-storey code-conforming (IS: 456-2000, Indian standard for plain and reinforced concrete code and IS: 1893-2002, Indian standard criteria for earthquake resistant design of structures) reinforced concrete (RC) buildings. The buildings are designed for two different cases such as ordinary moment resisting frame (OMRF) and special moment resisting frame (SMRF). The nonlinear static analysis (pushover analysis) is used to capture initial yielding and gradual progressive plastic behaviour of elements and overall building response under seismic excitations. The deformation characteristics of structural elements are essential to simulate the plastic hinge formation in the process of generation of capacity curve during the pushover analysis. An analytical procedure is developed to evaluate the yield, plastic and ultimate rotation capacities of beams and columns along with different plastic hinge lengths. In the present study, user defined plastic hinge properties of beams and columns are modeled using analytical expressions developed based on Eurocode 8 and incorporated the same in pushover analysis using SAP2000. The pushover analysis is carried out for load patterns proportional to fundamental mode. A 100% dead load plus 50% live load is applied prior to the lateral load in the pushover analysis. The building performances are assessed with the capacity curve generated. Performance levels are used to describe the limiting damage condition, which may be considered satisfactory for a building under specific earthquake. The performance levels are expressed in terms of target displacement, defined by limiting values of roof drift, as well as deformation of structural elements. The three performance levels considered in the present study are immediate occupancy, life safety and collapse prevention. The vulnerability of the buildings is estimated in terms of vulnerability index to assess the performance of the building.