千米级混合梁斜拉桥无应力索长及几何线形控制

Unstressed Cable Length and Geometric Linear Control of Hybrid Girder Cable-Stayed Bridge with 1000 m Sale Span

针对千米级混合梁斜拉桥施工期结构受力特点及制造加工和安装阶段面临的主要问题,基于几何控制理论,以主跨926 m的鄂东长江公路大桥为依托,研究斜拉索无应力长度及主梁几何线形控制方法。结果表明:以理想成桥线形、索力为目标,通过对制造及安装阶段全过程无应力状态量的调整,安装阶段将无应力线形、无应力索长的控制转换成夹角、引伸量的控制,该方法易规避不良施工效应、施工误差,高效快捷、精度高,同时能降低环境带来的不良影响。施工实践表明实测数据与理论计算吻合很好,证实了该方法的有效性和可靠性。

In the light of the mechanical behavior and the major problems in manufacture and erection phase of hybrid girder cable-stayed bridge with 1 000 m scale span during construction stage,the control methods of unstressed cable length and geometric profile were studied on the base of the geometry control method,according to the construction control of Edong Bridge with a main span of 926 m.Based on the studies mentioned above,unstressed constants were adjusted both in manufacture and erection stage.Besides,the control of unstressed cable length and geometric profile were converted to the control of tension amount and girder angle,which was to be in accordance with ideal profile and cable force.The proposed method was an efficient method with high precision for bridge construction control.With this method,undesirable influence caused by natural environment can be reduced,and some construction errors can be avoided as well.Construction experience indicates that the theoretical calculation is in well accordance with the field results,which proves that the method presented is pretty effective and reliable.