Fatigue performance of an innovative shallow-buried modular bridge expansion joint

Bridge expansion joint can accommodate the deformation under the effects of vehicle load and temperature. Fatigue damage readily occurs because it is directly subjected to repeated load. In this paper, fatigue and static loading tests were conducted on modular bridge expansion joint (MBEJ). This is an innovative type of shallow-buried modular bridge expansion joint, and the anchoring depth is reduced by 40%-50% compared with traditional ones. The reduced overall height can well adapt to the slide shutter rapid construction method in practical engineering. A loading device was designed to simulate vertical and horizontal load. The load-deflection relationship after fatigue loading were discussed. The fatigue crack types, crack initiation locations, failure criteria, and fatigue failure modes of MBEJs were also studied. Following that, a finite element model was established to calculate the internal force of welded connections. Structural analysis on MBEJs was used to calculate the stress range within center beam and support bars under the test conditions. A theoretical fatigue performance assessment method on MBEJs was introduced, which is based on the nominal stress method and a linear Miner damage accumulation rule. The theoretical prediction agreed well with the experimental observations.