Study On Spatial Mechanical Behavior Of Curved Steel Box Girder Bridge

Curved girder bridge has become increasingly important because of its beautiful shape,good adaptability to terrain and excellent driving conditions.However,the structure and internal forces of curved girder bridge are complex than that of straight beam bridge and there is no explicit specification for the design of curved girder bridges in China.In addition,in recent years,the accidents of curved girder bridges often happen in China.Therefore,it is necessary to further study the spatial stress characteristics of curved girder bridges.With the population of steel bridge construction and the particularity of steel material,it is particularly necessary to study the small radius steel curve bridge.In this thesis,a 24 meters' small radius steel box girder bridge is investigated,and the effects of different temperature modes and support arrangements on its spatial mechanical characteristics are fully explored in order to get a more profound understanding of the mechanical behavior of the steel box curved bridge,so as to make a positive work on the design of the steel curved bridge.The main research works of this thesis include:(1)Through systematic review of the literature,the development and classification of curved girder bridges,the special mechanical characteristics of curved bridge compared with the straight bridge and the related analysis theories are introduced.(2)By the finite element models with different radius and different temperature modes,the laws of the internal force and of the deformation of the curved beam bridge are introduced in this thesis,which is expected to provide reference for the design of the actual curved beam.The Midas/FEA plate finite element model is set up to investigate the effects of transverse temperature gradients on the stress and deflection of curved girder bridge.(3)The internal forces and deformation of the curved beam bridge under three different bearing arrangements are investigated.The conclusion is that the full torsion bearing system has the best torsion-resistant ability.Besides,changing the eccentricity value to 0.1m,0.3m,0.5m,and 0.7m,the influence of different eccentricity values on the force of the curved beam and the support force is studied,and the conclusion is that the support eccentricity can adjust the torque distribution of the curved bridge and reduce the risk of the damage of inner bearings.For the bridge studied in this thesis,0.3m is the most suitable bearing eccentricity value among the described eccentricity values.(4)For the negative support force in the fourth chapter,the measures to reduce and avoid it are introduced,including adding weight at the beam end,setting tensile support,increasing the inner distance of the torsion support and consolidating the beam to piers.Moreover,the suggestions on how to more effectively use these methods are given.