Abstract：Based on the three-component ultimate displacement model, principal influence factors of plastic hinge length are analyzed considering the bending,shear and bar-slip deformations．The theoretical formula and empirical formula for equivalent plastic hinge length of bridge column are suggested based on the test results of 40 circular reinforced concrete bridge columns. The formulae of plastic hinge length proposed by authors and other specifications are validated by scale and full-scale reinforced concrete bridge column experiments. The results show that the equivalent plastic hinge length of bridge column increases most consistently with specimen length, section height, fydb/fc′ and longitudinal reinforcement ratio, while independent on the axial-load ratio and the transverse reinforcement ratio. From the point of the average statistical meaning, these expressions of plastic hinge length of existing specifications are conservative but discrete. The recommended expression in JRA specification is most conservative, and JTG/T B02-01—2008 Specification gives more conservative results compared with Caltrans and Eurocode8 specifications. The proposed theoretical plastic hinge length is approximate to that in JRA specification. The proposed empirical expression is statistically close to Caltrans and Eurocode8 with smaller variation coefficient and higher guaranteed rate.
