Research On Performance Against Overturning Of Curved Girder Bridge On Expressway

As China’s economy continues to develop, until the end of2012, the National Highway up to95,600kilometers, ranking first in the world. Ramp Bridge is the main highway connecting the main ways to achieve one interchange, making a large number of roads connecting ramp bridge are becoming ever larger, form more and more, more and more complex mechanical characteristics. Freeway Ramp Bridge, as the highway, under two bridges connecting roads, is to achieve the highway, under the basic interworking unit body. Ramp Bridge project has become a highway, down two roads connecting the key to successful project control node. Ramp Bridge focused beam and the upper beam structure curve, compared with the direct beam, the beam plane stress performance curve has the following characteristics:①plane bending and axial deformation of the coupling;②pure vertical bending and torsion (Torsional rigidity) of the coupling;③bending, twisting, and a combination of restrained torsion section.In addition, the inner and outer curved beams supporting force is asymmetric, under dead load, was outside Ouchi small distribution outside of the curve when the live load bias, the inner support reaction force is sometimes reduced, and even produce stand negative reaction force. If the holder does not bear tension, there will be out of the beam and the bearing that "bearing separation" phenomenon. When the ramp bridge appeared bearing separation can not be achieved after a new stable equilibrium, will inevitably produce a beam overturning. For the theory of curved box girder still many imperfections and areas for improvement, many of the issues relating Curved remains to be studied. In recent years, some ramp bridge overturn phenomenon, caused many negative effects, interferes with China’s socialist modernization drive. Therefore, the question of overturning ramp bridge research is particularly important.This close freeway ramp bridge overturning this problem, the main research work carried out and conclusions are as follows:1.According to the linear beam overturning the force characteristics, using analogies, the introduction of central angle greater than180°and180°of the ramp bridge overturning the force characteristics, and through theoretical analysis results Ramp Bridge overturning failure modes;2.Through the derivation and the finite element software to calculate the arrangement of the bridge opening, the radius of curvature, bearing arrangement form, ramp bridge width, length and other factors ramp bridge cantilever bridge on the ramp overturning capacity of the analyzes;3.Summarizes the ramp bridge vehicle loads calculation methods, combined with mechanical derivation, revealing the essence of overturning ramp proposed overturning capacity ramp bridge formula;4.Through the finite element software, finite element model was analyzed based on the project in the most unfavorable loads, the mechanical behavior of the bridge ramp, and based on the situation inside the bearing void, drawn ramp bridge overturning capacity limit.