RESPONSE REDUCTION FACTOR OF BUILDINGS RESTING AT DIFFERENT ELEVATION LEVELS

Abstract

A research was carried out to inspect the Response Reduction Factor for the buildings resting in different elevations. The buildings were initially designed detailed based on seismic provisions given by IS 1893:2016 (Part 1) and IS 1893:2002 (Part 1) with a general assumption of Special Moment Resisting Frames (SMRFs). NBC 105:2020, on the other hand, suggests the separate criteria of Response Reduction Factor for Ultimate Limit State and Serviceability State. Five buildings resting on different elevation levels were chosen and the lowermost semi-basement part was removed for all buildings for comparative study. The analysis was done for both linear and non-linear cases and from the study it was obtained that the ductility reduction factor is lower in the stepback buildings, especially in the direction parallel to the slope. Furthermore, the overstrength factor is very high for such buildings due to the presence of basement walls. Redundancy Factor is obtained to be more than 1, which indicates that it is not obligatory to reduce Response Reduction Factor by Redundancy Factor. The huge variation in the value of response reduction factor suggests that the Response Reduction Factor is not always consistent within the structural engineering community because of the variation in design philosophy, assumptions and methodology followed.