Analysis Of U-shaped Bridge Aqueduct Structure With Thin Shell

As the implementation of south-north water diversion project,water resources projects in China in recent years get fast development.Recently the project of the middle route the eastern route of the south-to-north water diversion project have been completed and transferred water for more provinces and cities in north,which can benefit hundreds of millions of people and effectively solve the difficult problems of industrial water tension and draft.So as the main buildings in the water diversion project,aqueduct is involved in years of effort of the engineering technical staffs.Today,both in the aqueduct design theory and the technology of using computer to simulate the actual situation of aqueduct tends to be a more perfect stage,but aqueduct forms are changing,how to increase the span aqueduct,increase the water flow,how to reduce the material usage,reduce cost and so on is still a problem to be solved.At present,the function of aqueduct is relatively single,which mostly only for the use of water,but from the power of the cross section size,large span aqueduct is very close to bridge,which is an advantage made full use of by adding a cover on top of thin wall and provide transportation and enlarge the advantage of aqueduct,enhance the practical value of aqueduct,but also reduce traffic congestion to a certain extent.At that time,aqueduct not only has the function of water conveyance,but also has the function of bridge.So this paper regards U-shaped aqueduct with a cover as the research object and analysis the structure of aqueduct with considering the characteristic of aqueduct "thin".Although the matter of whether or not to add a cover plate on aqueduct has no great effect on the type of aqueduct structure,it has a change in the structural stress,through using structure mechanics theory and finite element software ANSYS to analyze its structure.Compared the results,it can be found that both the structure internal force and the maximum internal force and displacement of position structure change,by comparing the two methods at the same time,it can be seen that the end rib of the aqueduct have a certain influence to the distribution of internal forces.To be thin is a trend in the development of aqueduct,however,the problem of "thin" to aqueduct structure design is unstable,especially for large aqueduct with U shape,the constrained torsion can occur,Therefore,it is necessary to consider the warping stress caused by torsion.this paper regards aqueduct as a walled bar and use relevant theories of structural mechanics deduced the formula of warping stress.Through the analysis of engineering examples,it is concluded that the warping stress produced by the constraint torsion is not ignored.Earthquake is a big disaster,So seismic analysis is one of the factors that must be considered in structural analysis of many large buildings.Because of the large water quality in aqueduct,aqueduct-fluid interaction will occur under the dynamic action of the earthquake,in order to simulate the interaction more convenient and effective,athree-dimensional dynamic analysis model is established by using the finite element software ANSYS to calculate natural vibration characteristics of aqueduct under different water level,the calculation results the natural frequency of aqueduct decreases with the increase of water quality,the more water increases,the more the frequency decreases;Whether there is water inside the aqueduct has a little influence on the main formation of aqueduct.This paper uses time history analysis method to calculate the dynamic displacement and dynamic stress response of aqueduct under the action of Tianjin wave.The calculation results show the lateral displacement and stress of aqueduct structure increase with the increase of water level,this is due to the quality of the water in aqueduct increases the weight of the upper structure,which increases the seismic force on the structure;In the dynamic analysis of large aqueduct,the influence of water quality in aqueduct must be considered.