The Nonlinear Seismic Response Characteristics Of Bridge Considering Pounding Effects

The research is supported by the Open Fund of Aseismic Engineering Technology Key Laboratory of Sichuan Province (Contract No. SKZ200907). The short to moderate span bridges with high piers in strong earthquake areas are chosed, and the seismic response characteristics of these bridges considering pounding effects are studied. The main contents include:1. The research achievements of the seismic pounding responses of bridges are reviewed and summarized from the aspects of the bridge damage induced by seismic pounding in strong earthquakes, various analytical models used to simulate impact effect between bridge decks, the pounding response mechanism of bridge, the influence of pounding on the seismic behavior of structure components, the valid measure to prevent pounding and span collapse and the experimental studies on earthquake-induced pounding.2. Double-column highway bridge with high piers in southwest mountain area is studied, and its spatial dynamic model is established, in which the coupling of bearings, superstructures and substructures is considered. Some structural parameters influencing bridge seismic responses are studied in detail respectively. These parameters include the height of piers, pile-soil interaction, single-segment and multi-segments model, single-segment model with different span numbers, single-segment and single-pier model and terrain conditions.3. According to the characteristics of short to moderate span bridges with high piers, the rational analysis models considering the pounding effects between adjacent span are discussed in detail. The rational simulation methods and its influence on analysis results are discussed, which mainly include:the influence of various bearing features on the seismic performance of bridge; the select and evaluation of various pier element types; the influence of longitudinal stiffness of abutment on the whole response of bridge; the influence of pile-soil interaction; the simulation methods for the pounding effects between adjacent span at expansion joint; restrainers and the measures to prevent span collapse.4. Double-column highway bridges with high piers in southwest mountain area are studied, and the spatial dynamic analysis models of representative bridge span are established. The seismic response characteristics of bridge considering the pounding effects are studied in detail, nonlinear dynamic time history analysis method is used in this study. The influence of some nonlinear boundary conditions are discussed, including the value of contact element stiffness, the gap width, the longitudinal stiffness of abutment and the sliding performance of bearings. 5. The characteristics of pounding response for simply supported beam bridge and continuous bridge with high pier and long span are analyzed under traveling wave input conditions. The seismic response performance of bridge influenced by various types of restrainers and its design parameters are discussed.6. Finally, ten span irregular girder bridges with high piers constructed in southwest mountain area are analyzed. The influence of some nonlinear boundary conditions are discussed, including the pounding effects between adjacent span, the sliding performance of bearings, the longitudinal stiffness of abutment and the elastic-plastic property of pier element. Nonlinear dynamic time history analysis method is used in this study and the seismic performance of bridges are synthetically evaluated.