四索面钢箱梁斜拉桥合理成桥状态下的空间受力研究

Study of Spatial Force Conditions of Steel Box Girder Cable-Stayed Bridge with Four Cable Planes Under Reasonable Completed Bridge State

为了探讨四索面钢箱梁斜拉桥横桥向内外侧索力比对结构的影响,使得结构空间受力最合理,以嘉绍大桥主航道桥斜拉桥(主跨428m的六塔四索面分幅钢箱梁斜拉桥)为背景,采用ANSYS软件建立了嘉绍大桥横桥向内外侧等索力、空间索力2种计算模型,利用综合能量法,对2种模型合理成桥状态下的斜拉索索力和主梁、桥塔、横梁内力与线形等进行了研究。结果表明:四索面钢箱梁斜拉桥恒载索力空间效应显著,内侧与外侧斜拉索索力比值分布不规律;空间索力分配对主梁扭矩及横梁弯矩影响较大,对主梁和桥塔应力、变形影响较小;在进行四索面钢箱梁斜拉桥结构初步设计或仅需计算主梁、桥塔应力及线形时,可近似采用平面模型;在技术设计和施工图设计时,应采用空间分析模型,并考虑主梁及横梁等的空间受力情况。

To study the influences of the ratios of the transverse inner and outer stay cable forces of the steel box girder cable-stayed bridge with four cable planes on the structure of the bridge and to make the spatial force conditions of the structure the most reasonable, the main ship channle bridge （a separated steel box girders cable-stayed bridge with six pylons, four cable planes and with a main span of 428 m） of the Jiashao Bridge was cited as an example. 2 kinds of the calcu- lation models for the transverse inner and outer equivalent stay cable forces and the spatial stay ca- ble forces of the main ship channle bridge were established, using the software ANSYS and the stay cable forces, the internal forces and geometric shapes of the main girder, pylons and cross beams of the two models under the reasonable completed bridge state were studied, using the com- prehensive energy method. The results of the study demonstrate that the spatial effect of the dead load stay cable forces of the steel box girder cable-stayed bridge with four cable planes is significant and the distribution of the ratios of the inner and outer stay cable forces is not regular. The distri bution of the spatial stay cable forces has great influences on the torsion moment of the main girder and bending moment of the cross beams, but the influences on the stress and deformation of the main girder and pylons are little. In the preliminary design of the cable-stayed bridge struc- ture with four cable planes or in case the stress and geometric shapes of the main girder and py= lons of the structure are to be calculated only, the plane model can be approximately applied and in the technical design and construction drawing design, the spatial analysis model should be ap- plied and the spatial force conditions of the main girder and cross beams should be taken into ac- count.