Microscopic traffic flow-bridge-expansion joint integrated analysis system and wear law of modular expansion joint

Modular expansion joint achieve overall deformation through the coordination and relative motion of multiple components. The relative motion causes wear. To explore the relative motion laws between the components, it is necessary to establish traffic loads, structural model, and analysis indicators at the component level. To achieve precise determination of traffic loads, a method of using a measured wheelbase to match the length of the front and rear suspensions to determine the size of each vehicle model and a method of using the shadow vehicle method to formalize the vehicle lane changing process are proposed. Then, using a double-layer beam as the basic structure of the expansion joint, the connection problem between the bridge and expansion joint is handled in a multipoint constraint manner, and the loading method for vehicle loads are refined, thus establishing a vehicle-bridge expansion joint analysis system. Finally, analysis indicators for the wear of modular expansion joint are established, and the wear of modular expansion joint under different traffic flows is analyzed. It is concluded that the cumulative relative displacement between the supporting crossbeam and each displacement box is not significantly different and the sliding and compression support between them can be made into uniform specifications. The cumulative relative displacement of point pairs between the middle beam and supporting crossbeam follows a W-shaped pattern, while that of the compression and stretching of the control springs between each middle beam follows a W-shaped and n-type pattern. The compression and sliding supports and the shear springs need to be differentiated design. The law of cumulative relative displacement can provide guidance for selecting materials and cross-sectional parameters in the design of expansion-joint supports and shear springs.