Live Load Structural Index study on Small and Medium Span Steel‐Concrete Composite Bridges

Steel plate and truss composite bridges are evaluated by Live Load Structural Index (LLSI) aiming on the balance between structural integrity and cost. In the span range of 20‐60m, four‐girder steel plate scheme and five‐girder steel plate scheme's LLSI are obtained based on probabilistic theory. The stress ratio of service to design status decreases in a power exponential law with the ascendance of LLSI. In terms of the steel truss concrete bridge, an optimized algorithm has been applied to analyze the composite truss bridge's LLSI, which suggests 160‐200 m · KN^‐1 as appropriate values for the engineering practice.