钢桁腹组合梁桥剪力滞效应分析

Shear Lag Effect Analysis of Steel Truss-web Composite Bridge

钢桁腹组合梁桥作为一种新型组合结构桥梁,具有自重轻、侧向通透性好、便于施工等众多优点。但与其他箱梁相似,同样存在较为明显的剪力滞效应。为精确分析剪力滞效应产生规律,本文通过建立实体有限元模型分析钢桁腹组合梁桥的弯曲应力分布状况,并着重分析混凝土顶底板厚度和钢桁腹杆壁厚等参数对剪力滞效应的影响。通过计算结果可看出,钢桁腹组合梁桥在全桥范围内均存在较为明显的剪力滞效应,靠近支座处较跨中的剪力滞效应更为显著;顶底板厚和腹杆壁厚均对组合梁剪力滞效应有较大影响,顶板厚度影响最大,实际设计中应予以注意。

As a new type of composite structure bridges, steel truss-web composite bridge has several ad- vantages such as lighter self-weight, better lateral permeability, convenient for construction. Similar to the other box girder, it also produce significant shear-lag effect. In order to accurately analyze the regularity of shear lag effect, the paper analyzes the bending stress distribution of steel truss-web composite bridge, and especially anal- yzes the effect of top＆bottom thickness and steel truss-web thickness on shear-lag effect using finite element so- lid models. Results show that it exists significant shear-lag effect within the whole bridge,and more obvious near the support.The three parameters mentioned above have significant effect on shear-lag effect for composite bri- dge,while the effect of top thickness is the greatest impact,so it should be paid attention in practical design.