曲线箱梁桥悬臂施工应力与线形现场测试研究

通过现场监测和数值模拟手段,分析了预应力混凝土曲线箱梁桥悬臂施工过程中的应力和线形变化规律,讨论了曲线箱梁弯扭耦合效应及日照温度梯度对曲线箱梁桥内力和线形的影响。研究结果表明,曲线箱梁两侧翼缘板应力差值、竖向位移差值及箱梁径向位移随着箱梁曲率、墩身高度和悬臂长度的增大而增大;日照温度应力随温度梯度、约束条件和悬臂长度的变化而变化,其量级可能超过结构的活荷载水平,温度对箱梁标高的影响也不容忽视,且温度应力和温度位移具有滞后效应。研究结论可为预应力混凝土曲线箱梁桥的设计和施工提供有益的参考。

Field Test of Stress and Alignment of Curved Box Girder Bridges in Cantilever Construction

Field test and numerical analysis were conducted to investigate the variation laws of the stress and alignment of prestressed concrete curved box girder bridges in cantilever construction process.The bending-torsion coupling effect was discussed.Furthermore,temperature effect on the inner force and alignment of curved box girder bridges were also discussed based on field monitoring.The results show that(1) the differential stress between two flange slabs,the differential deflection between two edges of top slab and the radial displacement increases with the curvature of box girder,the height of pier and the length of cantilever respectively;(2)thermal stress incurred by daily atmosphere temperature gradient may exceed live load,it changes with the variation of temperature gradient,constraint conditions and the length of cantilever;(3)thermal stress has lagging effect,the daily atmosphere temperature effect on elevation of box girder cannot be ignored.The deflection of box girder increases with the atmosphere temperature gradient and the cantilever length.The influence of daily atmosphere temperature on the elevation of box girder also has lagging effect.The conclusions can be a reference for the design and construction of prestressed concrete curved box girder bridges.