中墩单点铰支承小半径曲线梁桥预偏心设计研究

Research on Pre-eccentricity Design of Small Radius Curved Beam Bridges Supported by Single Point Hinge of Middle Piers

中墩单点铰支承小半径曲线梁桥弯扭耦合效应明显且抗扭能力弱,若设计不当会造成巨大的安全隐患。以湖南省长沙市机场大道改造工程某互通立交匝道桥为背景,采用Midas civil软件建立了桥梁有限元模型,分析了曲线半径分别为40、60、80、100 m时中墩预偏心设置对边墩内外侧支座反力分配、中支点和梁端扭矩以及支点和跨中扭转变形的影响,并针对不同曲线半径给出了中墩预偏心建议取值。当曲线半径为40、60、80、100 m时合理的中墩预偏心为0.50、0.35、0.30、0.25 m,分别为边墩支座反力均衡所对应中墩预偏心的45.0%、49.5%、57.6%、60.3%。相关研究结论为类似小半径曲线梁桥预偏心设计提供了借鉴。

The bending torsion coupling effect of the small radius curved beam bridge supported by single point hinge support of the middle pier is obvious and the torsional resistance is weak.Improper design can cause significant safety hazards.Taking the interchange ramp bridge in Changsha Airport Avenue Renovation Project in Hunan Province as an example,the finite element model of the bridge was established by Midas civil software.Under curve radii of 40,60,80,and 100 m,the effects of pre-eccentricity on the distribution of reaction forces between the inner and outer supports of the side piers,the torque at the middle support point and beam end,as well as the torsional deformation at the support point and mid span were analyzed to propose the reasonable pre-eccentricity values of the middle pier for curved beams.When the curve radi were 40,60,80,and 100 m,the reasonable pre-eccentricity values of the middle were 0.50,0.35,0.30,and 0.25 m,which were 45.0%,49.5%,57.6%,and 60.3%of the corresponding pre-eccentricity values for the side pier support reaction equilibrium.