Analysis On The Static And Dynamic Characteristics Of Long-span Arch Bridge Under Water Environment

In recent years, with the development of highway and the speedup of railway,the requirements of road linienarten increasing,which leads inevitably the road across the deep canyons.Due to the terrain conditions of canyon,deck arch bridge project will be more reasonable.For the water-rich region,the canyons are always the selective terrain of water conservancy project. From the view of economic benefits,the climbing height should not be too high.Thus,the reduction of design height leads arch rings flooded by the reservoir water.Water and air belong to the fluid,but there are still some differences in certain characteristics.Based the statement above,the paper will analyze the long-span deck arch bridge in the reservoir area.Firstly, according to the long-span deck arch bridge which is different from other arch bridges in environmental characteristics, the dynamic and static force analysis will be special.Underwater part of the long-span deck arch bridge will be affected by water.In the normal environment of water,the effect of water on the structure is the lateral pressure and vertical buoyancy of water flow.When there is an earthquake,the structure will generate vibration and deformation which cause surrounding water sloshing and the water will react upon the structure in the form of hydrodynamic pressure.Both of action and reaction will exist between the structure and the water body during the earthquake.Therefore,fluid-solid coupling is the one of the main factors in earthquake.Secondly, according to researching the basic characteristics of the fluid, the formulas of flowing water pressure and water buoyancy of underwater arch ring portion has been obtained.Existing computational theory of fluid-solid coupling was studied. Furthermore,computational theory of fluid-solid coupling suitable for underwater ring structure was explored.Thirdly, the paper studied the finite element theories of arch structure.Although the curved bar unit is more suitable for arch to solve the load effects,free vibration and forced vibration.However the complexity of curved bar unit,the method of replacing curve by straight to solve the arch structure effect will always be adopted in engineering.Finally, according to an engineering example,the space finite element model of thelong-span deck arch bridge in the reservoir area was established.In static analysis,considering two main factors-flowing water pressure and water buoyancy,the paper analyzed the impact of the extent and impact of the law of the arch ring internal forces due to the two main factors.Also,the paper have explored whether the impact of flowing water pressure could be ignored under the influence of flow speed in the reservoir area and regard reservoir water as the hydrostatic.What’s more,the paper explored in the low-intensity earthquake fortified area, the submerged height of arch ring in hydrostatic environment;researching when considering the fluid-solid coupling, how the submerged depth of arch ring influence the arch bridge free vibration characteristics as well as how influence the arch ring internal forces in earthquake,investigating in high seismic intensity area,what submerged height arch ring can bear.