Design Strategies for the Seismic Retrofit of Reinforced Concrete Frames

Abstract

Due to economical and practical considerations, the seismic rehabilitation of buildings is generally confined to strategic areas of the structure in which only selected elements are modified or new elements are added. While these modified or new elements can be designed to have substantial strength and ductility, studies have shown that unless the retrofit scheme is stiff enough to control lateral drifts, significant damage to existing non-strengthened elements can be expected. This paper summarizes some of the results of a series of analytical studies conducted on prototype reinforced concrete frames strengthened with some of the most commonly used rehabilitation techniques. Based on the results of these studies, a design strategy that uses lateral drift rather than lateral strength as the main criterion for the design of retrofit schemes is presented.