Seismic Retrofit for Existing Low-Strength Concrete Buildings Using Framed Steel Brace System Concentrically Jointed with Post-Installed Anchors

Abstract

The authors developed a seismic retrofitting method for existing RC buildings that employs a framed steel brace system that uses post-installed anchors in a concentrated layout that can be designed for either interior or exterior application. This method is being applied primarily for the seismic retrofitting of elementary school buildings. In many instances, strengthening of buildings that employ concrete of low compressive strength (less than 13.5N/mm²) or while preserving bay windows is desired. Using an elementary school building that uses concrete of low-compressive strength as the model, this paper reports the results of horizontal loading tests on 2-bay, 2-storey frame specimens that provide reinforcement through the application of steel braces on the outside of bay windows. The results demonstrate the applicability of the proposed method for the seismic retrofit design of said building by using exterior steel framed braces with the concentrated placement of post-installed anchors.