Study On The Seismic Response Of Long-span Self-anchored Suspension To Central Buckle

Self-anchored suspension bridge towards the development of large span, complex system and deeper, the seismic requirements become more prominent. But there is still a lack of a consummate theoretical guidance for the seismic design of large-span bridges over scope, so to carry out the study of the self-anchored suspension bridge’s seismic response systematically is particularly necessary.Setting central buckle connections between the main cable and stiffening beams in the mainspan across is one of the effective measures to improve the stiffness of the suspension bridges. Only a few applications in several long-span suspension bridges in domestic, since nevertheless the application and study in large-span self-anchored suspension are race. This article in conjunction with a main cross-406m of the self-anchored suspension bridge engineering examples, using the Midas/Civil procedures to establish its three finite element models of no central buckle, rigid and flexible central buckle, to study the seismic response of long-span self-anchored suspension bridges with different forms of central buckles. Aims to provide certain guiding significances to the seismic analysis for long-span self-anchored suspension bridges and the use of central buckle. The main contents are as follows:(1) Review and summarize the development of the long-span self-anchored suspension bridge, central buckle, the seismic response analysis theory. Elaborate the Newmark-β integration method used in the nonlinear time history analysis、Rayleigh damping model、 relative motion method when considering the effect of the traveling wave. Introduces the established principles of the model, and establish the three models of the self-anchored suspension bridges dynamic characteristics analysis.in addition obtain and compare the natural vibration characteristics are analyzed and calculated before the180order natural vibration frequency and vibration type.(2) In uniform excitation seismic response analysis, taking into account the vertical、 horizontal and vertical earthquakes at the same time. Firstly carried through the elastic stage response spectrum analysis of the three models under E1earthquake; then carried through the elastoplastic stage time history analysis under E2earthquake with using the typical last strong earthquake records. Come to and contrast the top of the tower displacement, stiffening beam end displacement, the main cable displacement, moment and shear of the bottom of the main tower, cross in the force and displacement and side spans span moment.(3) In the depth study of the seismic properties of the three models, also taking into account the vertical、horizontal and vertical earthquakes at the same time. When considering traveling wave effect, carried through the elastic stage time history analysis with choosing the typical last strong earthquake records. Then used the equivalent embedded solid model to consider the pile-soil-structure interaction, and reproduced modify the three models, respectively, to obtain and compare the natural vibration characteristics are analyzed and calculated before the180order natural vibration frequency and vibration type; then carried through the elastoplastic stage time history analysis with using the typical last strong earthquake records. Come to and contrast the top of the tower displacement, stiffening beam end displacement, the main cable displacement, the bottom of the main tower bending moments and shear, mid-span of the force and displacement and side spans span moment.