Pushover Analysis of Existing Asymmetrical Building Using Modal Load Pattern, Soil Flexibility and Infill Walls—A Case Study

This work studies seismic vulnerability of an irregular block of Jorhat Engineering College old building, constructed in 1960 with predated code situated in Seismic Zone-V. Non-linear Static Pushover Analysis performed in SAP 2000^® using modal load pattern with infill walls modelled as strut as per IS IS1893 (Part-I):2016. Sub-soil exploration is conducted and stiffness of the spring for the spring base structure is calculated as per ATC-40 guidelines. Detail plan of the structure showing different beams and column dimension is made using Autodesk AutoCAD^®. The structure is simulated in SAP2000. Infill walls are designed as per IS1893 (Part-I):2016. Modeling of infill is done as Equivalent Strut, pin-jointed to the RC frame. Plastic hinges are assigned to the members as per FEMA-356, to identify the critical members which have exceeded their capacities. Non-linear analyses are performed for both the fixed and flexible base conditions. Inter-storey drift ratios and plastic hinge locations were selected as response parameters. From the analysis, it is observed that the pushover curves at the calculated target displacements are linear for both the cases, which indicate that the deformation of the structure is in elastic range.