External Prestressing Concrete Columns for Improved Seismic Shear Resistance

Abstract

Lateral prestressing of concrete columns was investigated as a method of seismic retrofit. Experimental research was conducted to develop a design procedure for shear deficient concrete columns. The technology consists of external prestressing of columns in transverse direction by means of individual hoops that consist of prestressing strands and specially designed anchors. Seven full-scale columns were tested under constant axial compression and incrementally increasing lateral deformation reversals. The results, presented and discussed in this paper, indicate that the retrofit methodology can suppress shear failure, promote flexural behavior, and increase inelastic column deformability substantially. A design procedure is presented for seismic retrofit of shear-deficient columns to achieve two different levels of performance.