Dynamic behavior of reinforced concrete structures irregular in elevation with and without brbs

This study investigates the dynamic response of high rise regular and irregular reinforced concrete frame buildings having buckling restrained braces (BRBs). As a case study, a twelve story reinforced concrete structure regular in elevation was designed. Then, the other three structures irregular in elevation were designed with the same geometric configuration in the lower six stories and different irregularities in the upper six stories. To improve the structural performance of both regular and irregular ones, the buckling restrained braces were introduced into the internal bays of each structure. Thus, a total of eight different cases were taken into account in the present study. All frame models considered had four bays (in the direction of earthquake) with a uniform bay width of 6 m. All frames were subjected to nonlinear dynamic time-history analysis for selected input earthquake waves of 1984 Morgan Hill and 1999 Hector Mine. Variation in displacement and inter-story drift ratio with story level, displacement time history and base shear time history responses of the regular and irregular structures with and without the BRBs were evaluated comparatively The analysis of the results showed that the BRBs caused a significant improvement in the dynamic behavior of both regular and especially irregular structures, depending on the characteristics of the ground motions used and amount of irregularity.