ABSTRACT

Most of existing concrete structures do not have suitable seismic performance due to various reasons, therefore they need seismic rehabilitation. One of the seismic rehabilitation method in structural level is using of steel bracing. New investigation of steel bracing can be referred to eccentrically bracing with single vertical link. This method of rehabilitation provides many advantages such as increasing in ductility, stiffness, lateral resistance, architectural compatibility, low weight, and the fewest changes in primary structural system. In this paper, two existing 3- and 9-story RC frames are assessed on the basis of FEMA356. Eccentrically bracing with single vertical link is used for seismic rehabilitation of these frames. The results of nonlinear time history analysis based on the maximum inter-story drift, maximum roof displacement and plastic rotation in critical elements of original and rehabilitated frames for two performance levels of Life safety (LS) and Collapse Prevention (CP) are presented. The results indicate that single vertical link can lead structures to the desired performance level with minimum cost and braced span number.