Seismic Evaluation of Step-Back Building and Regular Building by Using Nonlinear Static and Nonlinear Dynamic Analysis

Abstract The structural configuration of hill slope buildings differs from that of flat land buildings. During previous earthquakes, buildings located on a hill slope suffer severe damage/collapse even in moderate earthquakes. In comparison to flat land buildings, in both plan and elevation, these hillside structures are highly uneven. Under lateral loading, these buildings may subjected to severe torsion, and collapse may occur. The Indian Standards code, like many other national codes, does not provide the necessary insight into the expected performance and associated vulnerability of hill slope buildings. Hence, the purpose of this research was to compare the seismic behaviour of structures on hill slopes to that of buildings on level ground. To estimate the seismic performance and vulnerability of the step-back building, it is modelled in software SAP 2000 v.20.2.0 and NLSA and NLTHA are performed as per FEMA-356 and ATC-40. The seismic response of hill slope buildings is compared to flat land regular buildings in terms of capacity curve, ductility demand, hinge pattern and inter-storey drift at different PGAs. It has been noted that the story directly above the uppermost foundation level is where step-back buildings typically fail. The uphill side of the step-back buildings sustains significant damage. In general, the least vulnerable buildings are those on flat land, whereas those on hill slopes are considered to be the most vulnerable.