Seismic Performance Evaluation of Essential Facilities Building in Dhaka City by Pushover Analysis

Abstract

Bangladesh is situated in moderate earthquake prone region. Major metropolitan cities of our country are under serious threat because of faulty design and construction of structures. Buildings designed without seismic consideration could be vulnerable to damage even under low levels of ground shaking from distant earthquakes. So the structural engineers now-a-days are more concerned about the different earthquake analysis procedures. According to Bangladesh National Building Code (BNBC 1993), the buildings are designed according to equivalent static force method, response spectrum method and time history analysis. But the actual performance of a structure can be hardly found by these methods. Nonlinear inelastic pushover analysis provides a better understanding about the actual behaviour of the structures during earthquake and hence, the application of pushover analysis to evaluate the seismic performance of Secretariat Clinic Building located at Secretarial of Government of Bangladesh, Dhaka is the focus of this thesis. The analysis has been performed in two orthogonal direction of the building based on ATC-40 procedure and it was found that building base shear capacity in shorter direction is about 30% higher than the capacity in longer direction. The inter-storey drift in two orthogonal directions is below 1% (0.38% and 0.74%) at performance point, which corresponds to Immediate Occupancy performance level as per ATC-40 guideline of global acceptability of buildings.