TESTS ON CONCRETE SQUARE COLUMNS CONFINED BY COMPOSITE WRAPS

ABSTRACT

Fiber reinforced plastic (FRP) jacketing has emerged as a very effective way to retrofit concrete columns in recent years. The existing experimental work on FRP confined concrete column is mainly concentrated on concrete columns under concentric axial loading. This research involves the study of FRP confined square concrete columns under axial compressive loading with small eccentricities. The effects of the FRP jacket thickness and various eccentricities on concrete columns confined by the FRP jacket were investigated experimentally. The experimental results of square concrete columns under eccentric loading with and without FRP jacket were compared. It has been found that the strain gradient reduces the retrofit efficiency of the FRP jacket on concrete column, and the retrofit efficiency is proportional to the stiffness of the FRP jacket. Results indicate that, even in the case of small eccentricity, a lower enhancement factor should be used in designing FRP confined concrete columns.