Mechanical Analysis On Highly Skewed Integral Abutment Bridges

Seamless bridge has natural advantages in dealing with the problems of small and medium inclined Bridges.The integral abutment bridge has the most extensive application in the seamless bridge.Because of the elimination of telescopic devices and supports,the abutment and main beam are cast into a whole,which has a stronger disaster tolerance capacity.At present,there are few studies on the large Angle in the research of seamless bridge,and there are many researches in the range of 0° ～45°.There is no accepted and accurate calculation theory for considering abutment-pile-soil interaction under temperature.It is assumed that if seamless Bridges can be fully extended to small and medium inclined Bridges in seismically active areas,great social and economic benefits will be generated.In order to better understand the integral abutment bridge of even large Angle in different angles of the stress performance of the whole bridge,this paper takes Edward states near the highway 60 Shelton bridge as the engineering background of different oblique Angle of the whole bridge finite element model is established,considering soil-structure interaction on monolithic skew bridge temperature stress performance,moving load bearing performance,seismicperformance is analyzed.The main research work and results are as follows:(1)This paper introduces the research status and development status of the mechanical performance of integral abutment bridge and inclined integral abutment seamless bridge at home and abroad,and summarizes the deficiencies of the current research.Based on Shelton Bridge near Highway 60 in Edwards,USA,the finite element model of integral bridge with different skew angles is established by considering abutment,deck and soil interaction,and the accuracy of the model is verified by comparing with the field measured data.(2)Under the load of dead weight and temperature,the temperature rise of integral inclined bridge is more unfavorable to the pile at obtuse Angle,and the temperature drop is more unfavorable to the pile at acute Angle.The transverse displacement of the main beam increases with the linear increase of Angle under the action of temperature and dead weight.Under the action of heating and dead weight load,the bridge deck has rotated when the oblique Angle is 40°.By changing the height of the platform,the length of the pile and the span,the mechanical properties of the skew bridge under the condition of large Angle are further analyzed.(3)Under the action of moving load,the maximum deflection at the obtuse Angle is greater than that at the acute Angle.When the moving load is closer to the end span,the coupling effect of the integral skew bridge is more obvious.It is suggested that the difference between the force at the obtuse Angle and the force at the acute Angle should be taken into account when the overall bridge over 40° is built.In particular,corresponding protection measures should be set at the obtuse Angle.The combined loads are used to further analyze the mechanical properties of the skew bridge at large angles.(4)Under the action of earthquake,the frequency of all modes decreases with the increase of skew Angle,and the trend is gentle and the fluctuation is small.The response spectrum analysis shows that under the action of lateral earthquake E1,the lateral and longitudinal displacements of the whole bridge end and pier top at a small Angle(0°～30°)grow slowly,while the lateral and longitudinal displacements of the whole bridge end and pier top at a large Angle(30°～40°)grow rapidly,while those of the whole bridge end and pier top at a large Angle(40°～60°)grow rapidly.Time history analysis results show that the maximum longitudinal and transverse displacement increased with the increase of skew Angle increases,and the biggest is slightly greater than the maximum longitudinal displacement,transverse displacement Suggestions in earthquake-prone areas mainly thinking of building small Angle(0 ° ～30 °)skew the overall bridge,if you need to build large Angle(30° ～ 40°)overall bridge should be controlled excessive transverse and longitudinal displacement and the obtuse Angle setting certain protection,construction of large Angle(40° ～ 60°)must strictly limit the deck when the whole bridge pile obtuse Angle rotation and constraints.