Mechanical behavior of a novel steel–concrete joint in concrete-composited hybrid continuous bridges

Abstract

The steel–concrete joint is of great importance to the hybrid girder, while its mechanical behavior has not been understood enough due to the diversity of structural forms and application areas. This paper presented a mechanical performance investigation on a novel steel–concrete joint applied in a hybrid continuous bridge. A static flexural test and numerical simulation were conducted on a 16.6-m-long full-scale segmental joint. Parametric analysis via finite element models with the material damage plasticity on the joint performance was also carried out, in which structural dimensions and pre-stress extent were analyzed. The test results revealed that the border between the concrete girder and steel–concrete joint was the most cracking-prone position, while the joint remained comparatively intact at the ultimate state. The structural safety and internal force transfer mechanism were discussed with the presented strain distributions and deflection along the test girder. The simulation results showed that the effect of joint length on the bending performance of hybrid girder was more significant than back bearing plate thickness and pre-stress extent. The calculated ultimate capacity and bending stiffness increased by 8.3% and 4.0%, respectively, as the joint length increased from 3.6 m to 4.4 m. In addition, the initial cracking mode of the hybrid girder was exhibited to be correlated with the joint length because of changing structural stiffness. The research outcomes could provide the fundamental basis for a rational design of the joint component applied in hybrid continuous bridges.