Seismic Response And Stability Analysis Of High-pier Rigid-frame Bridge Under Hydrodynamic Pressure

In recent years,with the rapid development of domestic and foreign infrastructure projects,more and more high-pier bridges have been used in the transportation network in deep water areas.However,due to the special environment of the deep water area,the construction and design of high-pier bridges are facing more difficult problems than land bridges.To ensure the normal operation of high-pier bridges in deep-water,the structure should have sufficient theoretical application and data support for the analysis of earthquake resistance and stability.The current code is not clear about the calculation process of seismic response and stability of various types of high-pier bridges in deep-water.At the same time,the test data on seismic response of large-scale deep-water bridges in China is insufficient,and it cannot provide a strong foundation for the deep development of bridges.Therefore,in this paper,the numerical simulation test is carried out for the thin-walled high-pier bridges under waterless and different water depths,and the following contents are studied around the seismic response and stability:1.For the pier-water coupling structure,the action mechanism of the hydrodynamic pressure on the large column structure is introduced,and the calculation principle of the extended Morison equation used in the fluid-structure coupling calculation is discussed.At the same time,the ?-format potential fluid unit based on velocity potential used in the simulation calculation of this order is introduced in detail.2.To establish a fluid-structure coupling model for double-limb high-pier rigid-frame bridges based on three different construction stages.The environmental simulation of different coupled structures is described in detail.The dynamic characteristics of vertical structures,T-shaped structures and Π-shaped structures under seven water depths and the dynamic time-history response under different seismic waves are calculated.The various analysis states are studied by comparative analysis The calculated difference of the following structure.The study found that the high-order dynamic characteristics of high-pier structures change significantly with the increase of water depth.The seismic response of deep-water structures has different amplitudes compared with the waterless state,especially the shear force at the bottom of the pier.The effect of hydrodynamic effect on the performance of deep water high piers cannot be ignored.3.Introduce the analysis method of the stability of the pier-shaped structure.Before the numerical calculation of the stability of the high-pier model,use the planar rod element to simulate the single-limb bare pier,and analyze its ultimate load.Then the linear buckling analysis under different working conditions is carried out for the three stages of the high-pier rigid frame bridge,and the geometric nonlinearity,material nonlinearity and double nonlinear stability analysis are carried out for the second stage of the rigid frame bridge.The shell elements in ADINA are used to establish high pier models with different pier body width-to-thickness ratios,and the stability safety factor under the state is calculated.4.Taking the structural difference of the pier structure with or without pier body as the high pier structure,the dynamic characteristics,seismic response and stability of the two sets of models are analyzed in three aspects.The analysis results show that the difference in dynamic characteristics of the high pier structure with or without diaphragms is small;the setting of the diaphragm has a significant reduction in the peak value of the earthquake-internal force response of the high pier without water,and the response to the high pier in deep water is not more obvious effect.