EVALUATION OF RESPONSE REDUCTION FACTOR FOR SPECIAL MOMENT RESISTING FRAMES WITH SHEAR WALL

Abstract

Earthquake generally affects the developing countries than the developed countries .This is due to the lack of seismic guidelines used in design. Ordinary moment resisting frames has to be designed in a special way andhas to make it more ductile for the seismic zones ( III, IV & V)of high intensity earthquakes . Special Moment Resisting Frame (SMRF) is expected to be more ductile in a higher intensity earthquake. So they is specially detailed with a response reduction factor which is taken to be 5.Including shear wall to the special moment resisting frame, lateral load carrying capacity is increased. The present day seismic design method is primarily based on elastic and force based design approaches as suggested in different international standard codes. However, as per the philosophy of seismic design, the structures are expected to be deformed beyond their elastic deformation capacity.To reduce the elastic seismic demand on the structure response reduction factor is taken into account. Values of this R factor, given in many existing standards, are empirical in nature and are typically based on experience obtained and the observation of structures performancein past earthquakes. Various researchers stressed upon the need to evaluate exact R factor through analytical methods, which are based on different parameters governing the structural performance under earthquake shaking. The report presented here focuses at evaluating the R factor for ‘ductile’ RC framed structures with shear walls with two different configuration designed and detailed as per the latest Indian standards IS 1893,IS 456 and IS 13920. The R factor for these structures is evaluated using pushover analysis which gives capacity curve i.e. base shear versus displacement curve using Etabs15.2.2. The R factor thus obtained is compared with the IS code recommended Response reduction value.