Analysis on Beam Over-deflection Affecting the Bearing Performance of Continuous Rigid Frame Bridge

The continuous rigid frame bridge has been applied widely in our country. But in recent years, over-deflection of beam in this bridge has become an serious problem. This may cause the redistribution of displacement and internal force of the whole structure, especially in dynamic load status. A twodimensional pile-soil-bridge model is built up in ANSYS based on a factual bridge. The over-deflection is considered as the decrease of beam elastic modulus. The displacement and internal force of key parts are analysed in static and dynamic vehicle load. The study shows that over-deflection will reduce the first three natural vibration frequency, weaken the sensitivity of bridge to dynamic load. In dynamic load status, the displacement and internal force will be influenced by rigidity of beam.