Seismic Evaluation and Preliminary Design of Regular Setback Masonry Infilled Open Ground Storey RC Frame

Current seismic code presents certain stringent factors for defining frame as regular and irregular. Thereby these stringent factors only decide the type of analysis (i.e. equivalent static analysis or dynamic analysis) to be done. On the contrary, development of new simplified methods such as pushover analysis can give lateral load capacity of any structure (e.g. regular or irregular frame etc.) easily. Design by iterative procedure with the help of pushover analysis for serviceability requirement (i.e. inter storey drift limitation) provided by present seismic code, can provide an alternative to present practicing procedure. Present paper deals with regular setback frame in combination with vulnerable layout of masonry infill walls over the frame elevation (i.e. probable case of “Vertical Stiffness Irregularities”). Nonlinear time history analysis and Capacity Spectrum Method have been implemented to investigate the seismic performance of these frames. Finally, recently developed preliminary design procedure satisfying the serviceability criterion of inter storey drift limitation has been employed for the preliminary design of these frames.