Seismic Response Analysis Of Double-body Aqueduct Structure

China is rather abundant in total water resources, but poor in per-capita and per area resources volume. Because of this unbalanced distribution of water resources in space and time, the optimized allocation of water resources is needed. Our country has built a series of joint regulation projects and inter-basin water transfer projects to solve the serious problem of regional water shortage. Currently, the South-to-North Water Transfer Project is the greatest one, in which the East Route and Middle Route projects have already put into operation. The aqueduct, which is used as a kind of cross-linked hydraulic structure in canal system constructions, is widely applied in these large-scale water diversion projects. In order to meet the need of large flow transfer project, the structural styles of aqueduct become various. With the development of structural designs, construction techniques and material strength, the span and cross-section of aqueduct are constantly increasing, leading to the large weight of aqueduct body and water. This typical kind of Top-heavy structure is very unfavorable for the aqueduct to resist earthquake. Besides, the interaction of the structural vibration and the water sloshing should also be considered, thus the earthquake resistance of aqueduct becomes one of the theoretical and technical problems.As for the large double-body aqueduct, the analysis and research of it’s natural vibration characteristics and seismic response have a practical significance. The influence of water sloshing on the structure of a passing water aqueduct under earthquake is accurately analyzed, which will guide the earthquake resistance of aqueduct. This paper firstly introduces the research status of aqueduct seismic-resistance, and then explains the basic theory of fluid-structure coupling as well as those four common methods of simplifying structures and water bodies and its scope of application in the aqueduct structural dynamic analysis.According to the basic principles of the structural dynamics, the control equation of aqueduct structure undamped free vibration is sorted out and the aqueduct model is built through the finite element software Midas Civil. Furthermore, the additional mass method is used to simulate the water effect and the natural vibration features of aqueduct in empty and full conditions are analyzed. The result is that the aqueduct modes of vibration are basically same in these two conditions. Among these modes of vibration, the former 10 modes are mainly transverse translation and overall longitudinal translation, which means that the stiffness in these two directions are relatively low, and the natural vibration frequency of full water reduces compared with the empty aqueduct.Finally, three analysis methods of seismic response are introduced in turn, and the aqueduct models of Midas Civil and ANSYS are established. The seismic waves are selected on the basis of site features, and the Time-history analysis is used to analyze the seismic response of aqueduct structure. There is a difference between the two models on the maximum displacement, but both of them showed that the lateral displacement of full water aqueduct is greater than empty aqueduct’s. The maximum displacements of these two models are different, but all of the two show that the transverse translation in full condition is larger than in empty condition. The structural rigidity and high stress areas of aqueduct will be confirmed through the comparative analysis about the earthquake responses in these two different models and conditions and the mutual verification of displacement and stress.