Analysis Of Seismic Response Of Long Span Cable-Stayed Bridge

ABSTRACT:With the speedy development of China’s economy, road transport infrastructure enterprise, as the most critical part, is booming. Long-span bridge is usually the most important part of road transport infrastructure. Because of its new structure, spanning capability, long-span cable-stayed, it became one of the protagonists in the field of bridge. Cable-stayed bridge has unique static and dynamic characteristics. Analyzing its seismic response guarantees its security in the earthquake, which is a very important engineering significance. Based on the anti-seismic research works that has been done domestic and abroad, the seismic behavior of Sutong Yangze River Highway Bridge, a long span cable-stayed bridge is investigated fully. Establish spatial dynamic model of the bridge, basing on the finite element method; and the seismic response and vibration characteristics of the bridge are in-depth analysis. The mainly research work is following:(1) Firstly, introduce the structure characteristics of current long span cable-stayed bridge and its development status; then state the status of seismic design, point out the necessity of earthquake response analysis; then propose and analyze the problems in cable-stayed bridges seismic response.(2) Followed systematically stated and summarized the seismic response analysis of bridge, describe in detail of the response spectrum method and time-history method, including their basic assumptions, derive the corresponding formulas.(3)Establish the spatial dynamic model of the Sutong Yangze River Highway Bridge, according to the structural feature of the bridge by advanced analysis program MIDAS/CIVIL under two boundary conditions:with or without energy damping device. The vibration characteristics of long-span cable-stayed bridge are summarized, by comparing and the analyzing vibration characteristics of the two models mentioned above, and the influence of energy damping device on the self-vibration characteristics of the bridge is reached.(4) By calculating the cumulative effective mode participation mass of the bridge, to certain the minimum number of modes for response spectrum analysis. Design acceleration response spectrum is selected according to the site condition of the bridge to calculate the seismic response of the bridge under five load conditions.(5) Select satisfied earthquake wave according to the site condition of the bridge for the time-history analysis. The effect of vertical component of earthquake excitation is discussed based on the calculating results.(6) Investigate the effects of non-uniform excitation of traveling wave effect on the bridge structure. The seismic response of key sections at different excitation wave velocity are calculated, and compared with the results obtained under the uniform excitation, analyze the corresponding conclusions and describes the importance of traveling wave effect.