DYNAMIC COMPUTATION OF COMPOSITE BRIDGE STRUCTURES WITH MEMBRANE-EMBEDDED MODEL EXCITED BY MOVING VEHICLE

Bridges are typically composed of reinforced concrete composite, with numerous rebar embedded in the concrete in a layered manner. Traditional methods often use two-dimensional beam elements to compute bridge dynamics, which have high solving efficiency but low calculation accuracy. In this paper, the membrane-embedded composite model is proposed, the bridge is modeled uniformly, the finite element solution model of the bridge structure excited by moving vehicles is established, and the vehicle-bridge coupling dynamic problem is computed. The volume of rebar layers is equivalently represented as membrane structures. Concrete solid structures and membrane structures are discretized separately using finite elements, with embedded constraint equations established for solid and membrane elements, describing the interaction between rebar and concrete. The method for computing moving loads is provided, the position of the moving load loading element is identified by the ray method, and the dynamic equations of the coupled vehicle-bridge system for solid bridges and vehicle models are derived. The HHT-α method is employed to construct the dynamic equation solving scheme. The effectiveness of the method is validated through numerical examples. In this paper, the embedded membrane method is used to model the bridge composite structure finely, enabling accurate dynamic responses of vehicles and bridges under moving vehicle excitations. It is expected to have significant applications in bridge dynamic impact analysis, bridge damage identification, and health monitoring.