Perfomance analysis of a retrofitted existing reinforce concrete structure considering soil-structure interaction

Abstract

In this thesis, performance evaluations of a 3D existing reinforced concrete structure and its strengthening by columns jacketing and shear-walls addition are presented. The performance evaluations are made according to Ch. 6 of FEMA440. The column jacketing is applied on three different ways. They are jacketing of 1st floor columns; 1st and 2nd floor columns and all columns of the structure. Shear-walls are added and represented as column elements. In addition, the soil-structure interaction is included in the nonlinear static analysis of the building to realize how the modelization of the soil can affect to the response. A mat foundation is considered and different kinds of soils that are presented in TEC2007 are represented through it. The mat foundation is represented as a thick shell element. Tensionless elastic-plastic Winkler soil is used for soil idealization, which is represented by equivalent frame elements subjected only to axial forces and equivalent axial stiffness is defined for these elements. Performance evaluations and comparisons for the actual existing building and its strengthened cases are presented in detail for fixed soil condition case and for different soil conditions represented by the modelization of the foundation. The nonlinear pushover analyses and performance evaluations are obtained by SAP2000 computer package. Finally, damage evaluation according to the criteria presented in FEMA356 is performed to compare the different retrofitting techniques and to try to find out which is the most suitable in an engineering context.