Assessing Temperature-Induced Deflections in Cable-Stayed Bridges during Construction: An Elastic Foundation Beam Model Approach

Abstract

To assess temperature-induced deflections in cable-stayed bridges under cantilever construction, the girder and tower of bridges were modeled as elastic foundation beams, with supported stiffness dependent on the tensile stiffness of the cables. An analytical solution for the temperature-induced deflections was derived, accounting for internal force equilibrium and boundary conditions. In this approach, temperature actions were treated as equivalent loads on the beam, and the responses of the main girder under four types of temperature actions were analyzed. The effectiveness of the approach was verified using temperature and deflection measurements from the Zengjiang Bridge. The results demonstrated that the vertical-temperature gradient along the girder’s section and the cable-temperature variation induce significant downward deflections of the girder during cantilever construction, resulting in the lowest elevation of the girder occurring at approximately 15:00 during a day period, coinciding with the peak temperature actions. As the cantilever length increases, the effect of the cable-temperature variation becomes more pronounced, while the effect of the vertical-temperature gradient diminishes. This analytical approach provides accurate predictions of these deflections while streamlining computational complexity.