Seismic evaluation and retrofit with steel jackets of reinforced concrete bridge piers detailed with lap-splices

Recent earthquakes around the world have confirmed the poor seismic behavio r of reinforced concrete bridge piers incorporating typical pre-1971 reinfo rcement details. Since the 1971 San Fernando earthquake in California, proc edures to evaluate accurately the flexural and shear behavior of reinforced concrete bridge piers, as well as retrofit techniques to address economica lly the most common deficiencies, have been elaborated. In eastern Canada, the majority of reinforced concrete bridge structures incorporate piers wit h similar reinforcement details as those that suffered severe damage, or co llapse, during recent earthquakes in California and Japan. Very little rese arch, however, has been conducted on the seismic behavior of these structur es, which often exhibit complex cross-sectional geometries and lap-splices in the plastic hinge region. This paper presents a contribution towards a b etter understanding of the seismic behavior and retrofit of reinforced conc rete bridge piers in eastern Canada through quasi-static tests performed on five 1/3.65-scale pier models of an existing bridge structure in the Montr eal region. The first specimen was tested in its existing conditions, while the four others were retrofitted with steel jackets. The geometry of the j acket, the size of the gap at the base of the pier, and the properties of t he fill material between the jacket and the original cross section were inv estigated in these last four tests. A numerical model, considering the bond -slip between the concrete and the longitudinal reinforcement, is proposed to simulate the experimental results.