Vibration Control of Long-Span High-Speed Railway Bridges under Periodic Moving Loading Using Viscoelastic Damper

摘要

Steel-composite bridge is considered as a potential bridge type for the second generation of the Korean high-speed railway (KTX) bridges due to its economical efficiency and simplicity of construction compared to PC box bridges. However, its lightness and low structural damping capacity could make it dynamically unstable to resonance produced by trains running at speed below 350km/h, the maximum design speed. Therefore, the use of viscoelastic damper (VED) is proposed to reduce such dynamic responses. A Fast Nonlinear Analysis (FNA) using FEM model of bridges and moving load model for high-speed trains is performed to investigate the optimal performance of the damper-bridge system. The validation of the numerical analysis model and the damping performance evaluation of VED-bridge system are achieved by means of tests on a small-scaled model corresponding to real 40m steel-composite high-speed railway bridge. The effectiveness of VED is also verified for high-speed railway bridge spans ranging from 50m to 60m subjected to periodic moving loads. Numerical simulation shows that the VED contributed adequately to reduce resonance-induced vibrations in such long-spans independently from the natural frequency of the bridges and can offer the designer easier alternatives to design more compact and thus more economical high-speed railway bridge sections.