Seismic Performance Investigation of RC Piers with Lap-Spliced Longitudinal Bars as to Aspect Ratio

摘要

A survey of previous studies for the seismic performance investigation of existing non-seismic bridges in Korea revealed that numerous studies have been made on piers failing in bending, but studies on piers failing in shear were rather neglected despite their large presence. Accordingly, full scale specimens with aspect ratios of 2.67 and 2.25, being prone to behave respectively in flexure-shear and shear modes, and reduced scale specimens with an aspect ratio of 2.67 were fabricated and subjected to a seismic performance test. The failure behaviour of the specimens was then examined with respect to the amount of lap-spliced longitudinal steels in the plastic hinge region, the aspect ratio, and the scale factor. Test results verified that piers with an aspect ratio expecting flexure-shear behaviour showed flexure failure mode due to the reduced scale factor, and also showed the flexural failure of bond failure of the longitudinal steels according to the lap-spliced details. Based on the experimental results, formulas for the yield and ultimate displacements of circular reinforced concrete bridge piers without seismic details are proposed to evaluate the seismic performance of existing non-seismic bridge piers. These formulas will be useful for the repair and strengthening of non-seismic bridge piers by rationally evaluating their seismic performance.