单箱多室波形钢腹板组合箱梁斜拉桥抗剪特性研究

Study of Shear Characteristics of PC and Corrugated Steel Web Composite Girder Cable-Stayed Bridge Having Multiple Cells and Single Box

为了解单箱多室波形钢腹板组合箱梁斜拉桥在施工过程中的剪应力分布情况,以某单箱五室波形钢腹板PC组合箱梁斜拉桥为背景,采用MIDAS Civil软件建立全桥空间有限元模型和边塔主梁施工过程精细模型,并结合实桥施工监测数据,研究单箱多室波形钢腹板组合箱梁在不同施工阶段的抗剪特性。结果表明:波形钢腹板组合箱梁的挠度实测值与精细模型计算值基本吻合;斜拉索张拉时,组合箱梁的剪切变形会显著增大组合箱梁的挠度;单箱多室波形钢腹板PC组合箱梁的腹板剪应力沿高度方向变化较小,呈等值分布;各腹板的剪应力分布与施工工况有关,在斜拉索张拉阶段剪应力主要由中腹板承担,但后续节段施工会改善腹板间的剪应力不均匀现象。

To investigate the shear stress distribution of the prestressed concrete （PC） and cor-rugated steel web composite girder cable-stayed bridge having multiple cells and single box in the construction process, a composite girder cable-stayed bridge of the same kind having five cells and single box was cited as an example, the software MIDAS Civil was used to establish the spatial fi-nite element model for the whole bridge of the bridge and the refined model for the construction process of the side pylon and main girder. With reference to the data of the construction monitoring of the actual bridge, the shear characteristics of the composite girder having the multiple cells and single box at the different construction stages were studied. The results of the study demon-strate that the measured values of the deflection of the composite girder are basically agreeable with the calculated values of the refined model. At the time the stay cables are tensioned, the shear de-formation of the composite girder obviously increases the deflection of the girder. The changing of the shear stress of the webs of the composite girder along the height is little and the shear stress exhibits the equivalent value distribution. The shear stress distribution of the different webs is re-lated to the construction load cases. At the stage the stay cables are tensioned, the shear stress is mainly resisted by the middle webs,however, the construction of the successive segments of the composite girder will improve the nonuniformity of the shear stress of the webs.