Isolation Aqueduct Nonlinear Seismic Response Analysis

Along with the development of our national water conservancy and city water supplying and the building of the South-to-North Water Transfer Project, lots of aqueducts will be built. The aqueducts will be an important part of lifeline engineering. So the enhancement of the aqueducts' seismic capability is a instant problem. Since J.T.P.Yao put forward the concept of civil engineering vibrate control, a number of fruits are obtained after the hard work of domestic and foreign specialists. Now construction vibrate control has been a hot spot of construction seismic field. It is a great change at the concept of earthquake preparedness and disaster mitigation from earthquake resistance to earthquake control. This exerts architects' active ability. In our country few aqueducts use seismic isolation technology and research on theory of the seismic isolation design for aqueducts is also lack. So it's very important to analysis the seismic response of the aqueducts and research the measure of seismic isolation and expending energy. At the same time it opened up the new field for the technology of seismic isolation and expending energy that be used in water conservancy projects. In this paper ,according go the technology of seismic reduction and isolation and the fundamental theory of ductile seismic design on aqueduct structure, analysis on the isolation performance of isolation bearing(LRB)and the influence of isolation bearings on anti-seismic capability of the aqueducts is made. The main contents are stated as follows:The first, a three dimensions' model with fluid-structure interaction is made. On the basis of the model, a nonlinear finite element program is written.The second, the seismic response analysis on the aqueduct of three different bearings: LRB(lead rubber bearing),RB(rubber bearing)and TSB(Teflon sliding bearing )is made. The results show the seismic force on the piers is larger when the body of the aqueduct is articulated with the piers of the aqueduct. Using the RB can reduce the seismic force on the piers and yet increase the displacement of the body. Using the LRB can reduce the bending moment and shear force at the same time. This is because LRB can prolong the structure vibration's period, and dissipate seismic energy.The third, it is qualitatively analyzed that performance parameter's changing has influenced the effect of the aqueduct's seismic isolation.The fourth, by comparing traditional ductility earthquake-resistance with seismic isolation, the results show the aqueduct remains elastic and reduce the pier's demandfor ductility.The fifth, the interactive dynamic analysis models of water and body are established. Applying the models, lateral seismic response is analyzed. The results indicate that there exists obvious sloshing action in water body remaining in the aqueduct, despite the decrease in TLD role. When rubber bearings are adopted to support the aqueduct, despite the decrease in TLD role, the co-existence system of TMD and TLD is formed. Accordingly, seismic reduction effect becomes so apparent that it is of important reference value for the aqueduct engineering design.