Abstract

Earthquake being one of the unpredictable natural disaster has caused extensive collapse of elevated buildings with large scale unrecoverable damages such as risk of life, occupancy and economy to the nations. Absence of earthquake resistance structures and non-implementation of seismic practices are found as the root cause behind the above damages. Designing and constructing an earthquake resistant reliable structure is the need of the time which will protect it against all natural disasters. Response reduction factor (R) is one of the most vital parameter in designing of such buildings. This study focuses on comparison of seismic provisions of different countries around the world in order to highlight the variations in response reduction factor in seismic designs dealing with steel lateral load resisting systems. In this review paper, an attempt has been made to survey the past papers associated in the field of evaluation of response reduction factor. Observations reveals that the ‘R’ values intended to conform for reserve strength, ductility and redundancy. Several researchers have proved that value of ‘R’ is affected by many parameters like building height, number of bays in building, irregularity (both vertical and horizontal) of structure, seismic region of structure, number of bracings etc. As this ‘R’ factor for inelastic state of system is merely based on professional judgement, numerical study and very little experimental test on small scaled models of lateral load resisting systems, a further attention is required to overcome these unreliable facts for safe and economic design.

Keywords— Response modification factor, Seismic design, design codes