Research On ImPact Effect Of Skew Bridge Based On Explicit Dynamic Analysis Method

Because skewed bridges can adapt to the constraints of terrain and terrain,skew beams have been widely used in high-grade highways,urban roads,and interchanges.However,due to the irregular plane a rrangement and asymmetrical support characteristics of the main beam of the skew bridge,the seismic response of the skew bridge is more complex than that of the orthogonal bridge.In the past strong earthquakes that occurred in the past,the skew bridge was severely damaged and caused great harm to the society.Therefore,based on the existing shaking table tests,the effectiveness of the dynamic analysis method in the simulation of the collision response under the action of the earthquake of the skew-beam bridge was verified.Based on the results,the slope was numerically simulated using the display dynamic analysis method.The collision response under the action of the earthquake of the girder bridge was studied to discuss the characteristics of the collision response of the simply supported diagonal girder bridge with single span and the effective method of setting the buffer device.The main research contents and achievements of this article are as follows:(1)Based on the shaking table test of the collapsing impact model of the existing skew-beam bridge,the numerical analysis model of the test object was established by the explicit dynamic finite element software,and the comparative analysis of the shake table test and the explicit dynamic analysis of the scale model.The method simulates the acceleration and displacement responses of the main girder of the skew-girder bridge,and the accuracy of the impact response of the skew girder bridge under simulated seismic action based on the explicit dynamic analysis method is determined.In addition,by analyzing the finite element simulation results,it is concluded that the collision will increase the lateral displacement of the skewed beam bridge,which has an inhibitory effect on the longitudinal displacement.(2)Based on the orthogonal test method,16 single-span skew bridge specimens were built using explicit finite element software,and the effect of bridge span,deck width,and slope on the effect of single-span simply supported skew girder bridges on different site waves was discussed.Impact degree of collision force between the lower beam and the abutment back wall,beam and transverse baffle,and collision degree of the skew beam bridge under different site waves.It is concluded that under the site conditions of ?,? and ?,the main influence of the maximum impact force on the beam and the back wall,beam and baffle is the bridge span.The longitudinal maximum collision force between the beam and the back wall increases first with the increase of the span,and it is the largest when the span is 30m,and it decreases with the increase of the span after exceeding 30m.The maximum transverse force between the beam and the baffle increases first with the increase of the span,and it is the largest when the span is 20m,and decreases with the increase of the span after exceedin g 20m.(3)Based on the above studies,the single-span skeined girder bridge model with 30m span,15.5m bridge width,and 30° slope was used to study the increase in the back wall of the abutment under seismic action.Between the main beam and different thickness of soft rubber,hard rubber,vibration isolation rubber,low pressure polyethylene four kinds of shock absorbing material on the collision between th e beam and the back wall,beam and baffle.It is concluded that the optimal damping thickness for different shock absorbing materials is different.Only adding damping material to the abutment back wall and the main girder can effectively reduce the transverse maximum impact force between the beam and the baffle,and the optimal damping thickness along with the material stiffness.Increase and increase.Comprehensive comparison of 10cm of isolation rubbe r at the back wall has the best vibration damping effect.