Static Response Assessment of the Entire Suspension Bridge under Horizontal Transverse Live Load: An Analytical Calculation Method

Abstract

Long-span suspension bridge is a flexible structure. When subjected to a horizontal transverse live load, its deck undergoes significant transverse bending deformation, jeopardizing traffic safety. This paper proposes an analytical calculation method for the static response of the entire suspension bridge with a horizontal transverse distributed live load applied to its deck. First, each component’s geometric configuration and internal force for the suspension bridge subjected only to a dead load are obtained. Next, their values under the action of horizontal transverse live load are treated as basic unknown parameters. Then, governing equations are established based on geometric compatibility conditions, conservation of unstrained length, and force balance conditions. The unknown parameters are derived by nonlinear programming, estimating the entire suspension bridge’s displacements and internal force response. The proposed analytical calculation method only considers the structural state of the suspension bridge before and after the action of the live load but not the intermediate process. Therefore, the complex problem of geometric nonlinearity involved in the stress calculation of the suspension bridge is precluded, and the calculation results are more accurate. Furthermore, the conventional treatment of all hangers as a continuous thin film is avoided. Instead, the effects of the following factors are analyzed: tower bending in the bridge-axis direction, tower torsion, hanger elongation, hanger inclination, and rigid body displacement of the deck in the bridge-axis direction. Finally, the feasibility and effectiveness of the method are verified by finite-element method (FEM) analysis of a suspension bridge with a main span of 548 m.