Research On Shear Lag Effect And Impact Factors Of Ramp Bridges

In this paper, Nanjing 3rd Yangtze River Bridge C ramp is considered as research object.Based on ANSYS software, this paper has mapped the influence line of bending moment with unit vertical load and unit torsional moment respectively by using beam element.Then analysed shear lag effect under the action of dead load, designed temperature and designed lane load by using 3D solid element. Mainly concentrating on the factors such as curve, longitudinal gradient, cross slope and bearing type, this paper have analyzed shear lag of three-span continuous concrete curved box girder bridge with single box and double-cell section.And it has obtained the longitudinal distribution of shear lag coefficient at the junction of upperplate and web, and the transverse distribution of shear lag coefficient at the control section. It mainly obtained:1. Temperature load highly influences the shear lag of ramp bridges; between lane load and dead load, dead load is the main factor that influences the shear lag of ramp bridges; moment influence line of ramp bridges with various radius along the span is the same as straight bridge.2. The phenomena that the shear lag coefficient of outside web is larger than what of inside web is coursed by two factors, curve and cross slope. Longitudinal gradient did little impact on shear lag; the shear lag affected by the eccentricity of hinge bearing is not obvious, and the differences of shear lag at the mid pier is obvious between anti-torsional bearings and hinge bearing.According to the conclusions above, it concluded several design method as references.