Seismic Protection Of An Existing Irregular Tall Building Using Fluid Viscous Dampers

In Tanzania,many existing buildings have moderate or high seismic risk but originally did not consider earthquakes due to lack of seismic standard,so seismic retrofitting techniques should be adopted for seismic protection of these buildings.This paper presents seismic upgrading of one of such a building with in-plane irregularities using fluid viscous dampers.The following work has been conducted:1.The three-dimensional finite element model of the irregular building structure was developed by SAP2000 software.Results from modal analysis well demonstrated that the dependence of the translational-torsional coupled mode on the irregularities in in-plane layout of the structure.2.Three components of the El Centro record were used as the seismic input.The arrangement and parameter selection of dampers were discussed for the purpose to effectively control the seismic response of the structure.3.The seismic responses of both the original structure and the structure with dampers was solved through time-history analysis.The comparative study on seismic performance between the uncontrolled and controlled cases were conducted.4.In the presented case study,the suggested damper arrangement significantly reduces the torsional response of the floors and floor displacement,and moderately suppresses interstory drifts of the structure.However,the base shear may increase a bit because the damper force may contribute the base shear.Thus,foundations should be checked for the sake for safety in the real application.