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为了造型新颖美观,一些市政桥梁设计采用了异形独塔斜拉桥设计,索塔形状设计上也别出心裁,如出现了桥塔纵向布置为“人字形”的异形独塔斜拉桥。为考察此类结构的受力特性,以某双肢人字形独塔斜拉桥为例,采用Midas有限元程序计算分析了在整体温度效应作用下,通过改变桥梁连接方式,对比分析了主梁、主塔与副塔结构的应力分布情况。分析结果表明:主塔、副塔固结或者竖向支撑主梁,结构整体温度效应产生的桥塔最大拉应力发生在在副塔塔底处,且均超过4 MPa;主塔固结,副塔与主梁分离的情况下,整体温度效应产生的应力较小,最大拉应力小于1MPa。即随着副塔塔梁处刚性连接的释放,主塔及主梁的整体温度应力也随之减少。因此,采用主塔与主梁固结,副塔与主梁完全分离的边界形式能有效地减小整体升温作用下桥塔的应力,是较为适宜的桥塔边界形式。
In order to create a new and beautiful appearance, some municipal bridges adopt the design of profiled single-pylon cable-stayed bridge, and the shape of the pylon is ingenious. For example, the profiled single-pylon cable-stayed bridge with “zigzag” vertical arrangement of the pylon appears. In order to investigate the mechanical characteristics of this type of structure, taking a double-decker herringbone single-pylon cable-stayed bridge as an example, the Midas finite element program was used to calculate and analyze the influence of the overall temperature effect on the bridge connection by changing the bridge connection mode. , The main tower and the tower structure stress distribution. The analysis results show that the maximum tensile stress of bridge tower caused by the temperature effect of the main tower and sub tower, or the vertical support of the main beam, occurs at the bottom of the sub tower and both exceed 4 MPa. The consolidation of the main tower and vice Under the condition that the tower is separated from the main girder, the stress caused by the overall temperature effect is small, and the maximum tensile stress is less than 1 MPa. That is, with the release of the rigid connection at the side tower tower girder, the overall temperature stress of the main tower and main girder also decreases. Therefore, using the form of the main tower and the main girder to consolidate, the complete separation between the auxiliary tower and the main girder can effectively reduce the stress of the tower under the action of the whole temperature rise, which is a suitable form of bridge tower boundary.