Spatial Seismic Response Analysis On The Cable-stayed Bridge And The Continuous Girder Bridge

Earthquake is a kind of natural disaster which is difficult to predict and the damagedegree is very great, occurrence of the strong motion often leads to the tremendous lifeand property loss, especially for the bridge structures. Therefore, it is very necessary toconduct the comprehensive and systemic investigation on the bridge aseismic. In thispaper, the state of the art about the domestic and overseas seismic response analyses ofbridges are appraised, the following five aspects are mainly involved, i.e., the consistentexcitation input of earthquake ground motion, the FEA modeling & the responsespectrum analysis and the nonlinear time-history analysis of the cable-stayed bridge, thenon-consistent excitation random vibration analysis and isolation study on thecontinuous girder bridge. Also, based on the above-mentioned and combined with thecable-stayed bridge (main bridge) and 9-span continuous girder bridge of Macao-Taipathe 3rd bridge, the spatial seismic response analysis on the cable-stayed bridge and thecontinuous girder bridge is developed, including the following five aspects. About the consistent excitation input of the earthquake ground motion, thecomparison is made to confirm a few input methods during the bridge seismic responseanalysis, some advantages and disadvantages are indicated. The iterative fittingspecification design response spectrum method is detailedly investigated, and thecorresponding code AGM2 is programmed. In addition, the input mode of theearthquake ground motion is also discussed. About the finite element modeling and response spectrum analysis (RSA) of thecable-stayed bridge, the structural components capability is simulated through selectingdifferent finite elements, especially for the cables, surface deck and link supports. Fourfinite element models of the cable-stayed bridge are established according to thecorresponding different initial tensile stress situations, through the comparison, the finalmodel â…£ (the cables initial tensile and structure deadweight are considered) is definedto the initial equilibrium configuration of the FEA. In the RSA, the modal participationfactors, modal combination methods and input dimensions of the earthquake groundmotion are studied in order to analyze the bridge towers earthquake resistant capabilityby using the mode superposition method. About the consistent excitation nonlinear time-history analysis (THA), thecomparison and selection analysis is conducted for the input of earthquake groundmotions, The input method based on the iterative fitting specification design response IIIspectrum is discussed, furthermore, the results of the THA and the RSA are compared.The geometrical nonlinearity behaviors are investigated for the two finite elementmodels (four cases in total) of the cable-stayed bridge induced by earthquake of 50exceeding probability P1 and P2. The elastro-plastic hehaviors (set plastic hinges) oftower bottom are considered by using the single component model, the materialnonlinear deformation checking is made under the seldom earthquake. About the non-consistent excitation random vibration analysis (RVA) of thecontinous girder bridge, the modified version of the popular Kanai-Tajimi groundacceleration spectrum is adopted to simulate the power spectrum of the ground motion.And the parameters are estimated by employing the least square method according tothe power spectrum of earthquake accelerogram. The THA and RVA about a simpleframe are made to examine the reliability of the RVA. Additionally, the two 3-D finiteelement models of a continous girder bridge are established by the Penzien mode andthe modal analysis is accomplished with or without considering the interaction of thepile-soil-structure, respectively. The non-consistent excitation RVA is conducted byemploying the Closed-form solution technique of the mode superposition method,moreover, the traveling wave effect and spat...