非对称悬臂施工曲线连续刚构桥不同施工阶段变形特性研究

Study on Deformation Characteristics of Curved Continuous Rigid Frame Bridge with Asymmetric Cantilever Construction at Different Construction Stages

曲线连续刚构桥的施工难度较大,施工过程中的受力和变形比直线桥更为复杂,所以以桐溪路景观桥为依托工程,利用有限元软件Midas/civil建立桥梁模型,研究其在不同施工阶段的变形差异情况,并与实测数据进行对比分析,以验证模型的正确性。结果表明,在桥梁对称施工过程中,箱梁竖向位移随悬臂长度的增加而增大,且边跨和中跨箱梁竖向变形不相同,边跨箱梁变形要大于中跨箱梁变形;非对称施工过程中,混凝土自重对桥梁结构变形的影响较大,会引起边跨中部附近箱梁上挠,最大上挠值达10 mm;成桥状态后,混凝土收缩徐变对桥梁结构线形影响较大,主要位于中跨跨中附近;曲线半径对桥梁结构变形有一定的影响,曲线连续刚构桥的竖向变形和横向变形随曲线半径的增大而减小。

In view of the greater difficulty in the process of curved continuous rigid frame bridge construction,as well as the greater complexity of the stress and deformation in the construction process than that of the linear bridge,a bridge model has thus been established by using the finite element software Midas/civil based on a case study of the landscape bridge of Tongxi Road,followed by a study on the deformation difference at different construction stages,to be compared with the measured data to verify the validity of the model.The results show that the vertical displacement of the box girder increases with the increase of the cantilever length in the symmetrical construction process of the bridge,and the vertical deformation of the side span box girder is different from that of the middle span box girder,with the deformation of the side span box girder greater than that of the middle span box girder;while in the asymmetric construction process,the self weight of the concrete has a greater impact on the deformation of the bridge structure,which will cause the box girder up deflection near the middle of the side span,with the maximum deflection reaching as high as 10 mm.After the completion of the bridge,the concrete shrinkage and creep have a great impact on the bridge structure alignment,mainly located near the middle of the mid span;meanwhile the curve radius has a certain influence on the deformation of the bridge structure,with the vertical deformation and transverse deformation of the curved continuous rigid frame bridge decreasing with the increase of the curve radius.