Seismic response of step-back and step-back setback RC building frames

In the present study, dynamic analysis has been carried out for 4 storey and 7 storey building frames having three different configurations viz. Regular, Step-back and Step-back Setback building frames, using ETABS 2015 and the results were obtained in terms of fundamental natural period of vibration and modal mass participating ratio, and variation of column shear forces along the height of buildings. Torsion irregularity of the building frames has also been studied. The analysis was carried for out building frames with 4x3 bays and 4x4 bays in both soft soil and hard soil conditions. The building frames were analysed with and without shear walls placed at two different positions. Comparison of results among the different models has been made by the author. The analysis results have shown that the introduction of shear walls improved the performance and stability of the structures during seismic excitation. Also, torsional effects have been reduced to the permissible limits specified in the code IS 1893 (Part 1): 2002.