不同结合方式对预应力组合梁桥受力的影响

Influences of Different Combination Modes on Mechanical Performance of Pre-stressed Composite Girder Bridge

为了明确不同结合方式对预应力组合梁桥受力性能的影响,以一主跨70 m的预应力组合梁为例,选取先结合组合梁和后结合组合梁两种结构形式作为对比分析对象,采用空间有限元模型详细模拟了组合梁的施工过程,计算两种不同结合方式的组合梁的受力性能。计算结果表明:采用常规的先结合组合梁在混凝土桥面板张拉预应力后,部分预应力通过连接件传递给钢梁,而后结合组合梁的混凝土桥面板获得全部的预应力。后结合组合梁与先结合组合梁相比,在中支点截面混凝土顶面预压应力前者比后者大2.84 MPa、钢梁顶板的压应力前者比后者减少46.74 MPa、钢梁底板的拉应力前者比后者减少4.84 MPa。后结合预应力桥面板比先结合获得更多的预压应力储备,预压应力提升比例为30%,提高了桥面板在正常使用过程的抗裂性能。

In order to define the influences of the different combination modes on the mechanical performance of prestressed composite girder bridge, taking a prestressed composite girder bridge with a main span of 70 m as an example, two structural styles of pre-combined and post-combined composite girder bridges are selected for comparison. The spatial finite element model is used to simulate the construction process of the composite girder in detail. The mechanical performances of the composite girder by two different combination modes are calculated. The calculation result shows that after the conventional pre-combined composite girder is used to prestress the concrete deck slab, the partial prestress is transmitted to the steel girder through the connectors, and the concrete deck slab of the post-combined composite girder achieves all prestress. Comparing the post-combined composite girder and the pre-combined composite girder, the compressive prestress of the concrete top surface in the middle support section of the former is 2.84 MPa greater than the latter, the compressive stress of the steel girder top plate of the former is 46.74 MPa less than the latter, and the tensile stress of the steel girder baseplate of the former is 4.84 MPa less than the latter. The post-combined prestressed deck slab has more compressive prestress reserve than the pre-combined prestressed deck slab. The compressive prestress lifting ratio is 30%, which improves the crack resistance of the deck slab during the normal using process.