Failure assessment of skew RC bridges with FRP piers based on damage indices

Abstract Extensive damage to skew bridges during last earthquakes highlighted the vulnerability of these bridges to seismic loads and led researchers to study on damage assessment and rehabilitation methods of skew bridges. Using damage indices is a conventional approach to quantify the level of seismic damage in structures. Damage indices are defined as functions of structural parameters and are of great importance in retrofit decision-making in seismic zones. The main objective of present study is to quantify seismic damage of skew reinforced concrete (RC) bridge piers, retrofitted with carbon fiber reinforced polymer (CFRP) using displacement-based, energy-based and stiffness-based damage indices. To this end, numerical models of continuous-span RC bridges with skew angles of 0°, 10°, 20° and 30° are developed and nonlinear time-history analysis is performed using a series of selected ground motion records. The damage indices are calculated for bridge piers to study effects of the skew angle, pier height, CFRP-retrofitting and different PGA of earthquake records. Results indicate that the increase in the skew angle increases the damage level of bridge piers, particularly for bridge with taller piers. On the other hand, damage indices show that effect of CFRP-confinement increases significantly for bridges with taller piers at higher skew angles.