Retrofitting of Bridge Columns Using UHPC

The National Bridge Inventory reports indicate that a noticeable portion of the United States bridge infrastructure is drastically approaching the end of its intended design life, mainly due to environmental effects such as corrosion. This necessitates developing new techniques and materials for the rehabilitation of these deficient structures in a timely manner. To address this issue, a repair method has been developed at Florida International University (FIU) using ultrahigh-performance concrete (UHPC). This paper investigates the performance of the proposed retrofit method through experimental studies. A total of 11 1/4-scale columns with equal height-to-diameter ratios (H/D = 5) were cast and intentionally damaged to simulate a deficient column. Three columns with different transverse reinforcement ratios were considered as the baseline, seven of the columns were repaired using UHPC, and one was repaired with normal strength concrete (NSC) to compare. The retrofitted columns were subjected to combined constant vertical axial and cyclic lateral loads. The obtained experimental results revealed that the UHPC shell increased the strength of the damaged elements without increasing their size.