Research Of Longitudinal Bending Stress Of Curved Girder Bridge

With the development of urban road and highroad traffic,the curved girders are increasingly widely applied,and become an important bridge style in modern communication engineering. The medial and lateral curvature of larger width curved girder bridge is much different, as well as the influence of the medial and lateral bending stress is very large of curved slab girder bridge. Curved bridge presents the characteristic that the force of lateral is larger than the medial as stated in mechanical characteristics of curved bridge. This paper concludes that there indeed exists the characteristics which the force of lateral is larger than the medial for rib beam bridges (T type beam or articulated plate beam) according to calculation analysis, but the situation is opposite for integral slab beam or box girder (single box) structure. In this paper, the author studies on the bending stress in the calculation process of curved girder bridge by using theoretical analysis and model test method, derives the longitudinal bending stress formula of curved girder which considering the second curvature variation, and emphatically studies on because of curvature variation along the width of the bridge, the influence of the longitudinal bending stress of various curved girder. The main research contents are as follows:â‘ This paper describes the longitudinal bending stress formula of curved girder which without considering the curvature effects, and derives the longitudinal bending stress formula of curved girder which considering first curvature and second curvature.â‘¡After analyzing the influence of the longitudinal bending torsion angle due to curvature variation along with the beam width, the author obtains the relationship between the torsion angle and curvature radius at any point of the curved beam section width, as a result, after curved beam occurs longitudinal bending deformation, the section is no longer meet the plane section assumption. Considering the effect of curvature changes along the horizontal, Bending normal stress of curved beam has the mechanical characteristics of medial stress higher than lateral stress. For large curved plate girder and box girder, its impact can not be ignored.â‘¢Through the pmma plate beam load test, the normal stress of each section is measured, the conclusion that the influence of the bending stress due to curvature variation along the beam width is correct has been verified.