架设方法对组合桥面板受力的影响分析

为了分析在桥面板架设阶段采用临时拉索对桥面板施加预应力的效果,并比较不同数量桥面板同时张拉预应力对桥面板受力的影响,采用有限元方法建立了架设阶段组合桥面板节段的有限元模型和全桥有限元模型,模拟了对桥面板横桥向施加预应力的方法和具体施工过程。计算结果表明:对1块桥面板施加预应力时桥面板的横桥向压应力分布不均匀,主要是由于结构的不对称产生的。当对2块及以上数量的桥面板施加预应力时桥面板的应力分布比较均匀,2块板同时张拉预应力与5块板同时张拉预应力的效果相差为5%,因此实桥中可以采用2块板同时张拉预应力。根据钢横梁的强度限值、混凝土的强度限值和斜撑的稳定限值,计算分析了拉索的最大张拉力,得到了组合桥面板中混凝土可施加的横桥向预压力最大值。计算结果表明,采用合理的组合桥面板架设方法可以使组合桥面板的混凝土产生较大的预压应力。

Analysis of Influence of Erection Methods on Stress of Composite Bridge Deck

In order to analyze the effect of applying prestress on the bridge deck by using temporary cables during the erection stage and compare the stress of the bridge deck when different number of the bridge deck segments are applied prestress simultaneously,several finite element models were established,including the finite element models of composite bridge deck segments and the finite element model of whole bridge.The method of applying transverse prestress to the bridge deck and the detailed construction process were simulated.The results show that distribution of the transverse compressive stress of the bridge deck is uneven when prestress is applied to only one bridge deck segment,which is due to asymmetry of the structure.The stress distribution of the bridge deck is relatively even when two or more bridge deck segments are applied prestress simultaneously,and the difference of the effect of applying prestress to two segments and five segments is 5%.Therefore,the method of applying prestress to two segments simultaneously can be adopted in the construction of the bridge.According to the limited strength value of the steel beam,the limited strength value of concrete and the limited stability value of the inclined brace,the maximum tensile force of the cables was analyzed.The maximum transverse compressive prestress which could be applied to the composite bridge deck was obtained.The results show that a reasonable method of bridge deck erection enables concrete of the bridge deck to gain greater compressive prestress.