Abstract:

The wear of modular expansion joints was essentially regarded as the cumulative result of continuous intercomponent interactive responses under external loads， with wind loading and traffic flow being identified as the primary external drivers of their motion. To enable precise wear analysis， a coupled "load-bridge-expansion joint" analysis system that integrates the evolutionary processes of the driving loads was established. First， the two operational scenarios， namely the wind environment and the traffic flow evolution around the bridge-expansion joint structure， were independently simulated by separate programs. For the purpose of expansion joint response analysis， a main-direction vehicle wind load estimation method and a unified simplified aerodynamic interference treatment were proposed， forming the wind-field and traffic-flow evolution scenarios along with their load-correlated association patterns. Subsequently， same-scale bridge and expansion joint models were connected through multi-point constraint couplings. By means of programmatic cyclic calls， the operational scenarios and their load-correlated processes were linked with the response analysis of the same-scale bridge-expansion joint model， and an integrated wind-traffic-bridge-expansion joint analysis system was developed， which provided a computational platform for wear analysis of the expansion joint. Finally， a cable-stayed bridge equipped with a modular expansion joint was selected， and wear parameter analyses under combined wind and evolving traffic flows were conducted based on prescribed wear indices. The results indicate that the design parameters of the sliding bearings and compression bearings inside the displacement box can be uniformly configured， whereas those of the shear spring and the sliding and compression bearings between the upper and lower beams require differentiated designs. Wear inside the displacement box increases with wind speed on the windward side but decreases on the leeward side， while the wear of the shear spring and the bearings between the upper and lower beams decreases as wind speed rises. The sum of bi-directional traffic flow densities plays a controlling role in wear： the greater the total density， the more severe the wear， and the more uniform the traffic distribution， the greater the wear. Compared with wind speed variations， traffic flow exerts a more significant influence on the wear of the expansion joint.

Key words: bridge engineering, modular expansion joint, wear, wind environment, evolutionary traffic flow, analytical framework