Improvement the Response for Tall R.C Building Under Lateral Loads by Using the Damped Outrigger Systems

Abstract

The use of high-rise buildings has seen significant growth in recent years, however, the realization of such buildings faces many challenges in study

and design due to the crucial role that lateral loads, whether wind loads or seismic loads, given that the outrigger system is one of the best ways to improve the response of tall buildings in resisting lateral loads. This research depends on that to examine the process of integrating viscous fluid dampers with the outrigger system to add complementary damping to the structure, which improves the accuracy of the dynamic response by providing a higher level of damping to the structure while also improving performance, in which two models were examined For high-rise reinforced concrete buildings consisting of 36 and 48 floors that were studied using the ETABS 19 program and the ASCE 7-05 code for both the static and dynamic states during modeling under the influence of seismic loads. The equivalent lateral forces (ELF) method was applied to the static state, and the response spectrum analysis method was applied to the dynamic state to account for the impact of time history records. the study focused on the performance of the structural outrigger systems during seismic lateral loads, where the linear analysis of the two studied buildings 36 and 48 floors was studied for the following cases: (building without outriggers and dampers, building with outriggers - building with outriggers and linked with fluid viscous dampers in their locations), the analysis includes lateral displacement, story drifts, shear forces, frequencies, and periods. The study results showed that the addition of outrigger systems to the structure significantly improved the lateral stiffness, which in turn improved the structure's response to resisting effective lateral loads. They also showed that the addition of fluid viscous dampers to the outrigger system can perform better than an outrigger without dampers. As a result, the damped outrigger system offers a practical and cost-efficient method of enhancing the structure's ability to withstand lateral loads.