焊钉布置对钢-超高性能混凝土组合桥面板收缩效应影响

Influence of Welding Stud Arrangement on Shrinkage of Steel-Ultra-High Performance Concrete Composite Bridge Deck

摘要:

为探究不同焊钉布置对钢?超高性能混凝土（UHPC）组合桥面板收缩效应的影响规律，进行了常温养护条件下焊钉间距分别为200 mm和300 mm的足尺节段组合桥面板收缩监测试验，并利用有限元分析软件对试验模型进行了收缩模拟，在此基础上开展了不同焊钉间距下组合桥面板收缩效应的参数化分析。试验监测结果表明：试验中UHPC初凝时间约为17 h。钢?UHPC组合桥面板边缘区域UHPC收缩量较中心区域更大，前72 h最大收缩量约为450×10⁶；当焊钉间距从200 mm增加到300 mm后，UHPC受整体约束减弱，其中钢板约束作用下降，最大压应变减小约51.6 %；钢筋约束作用增强，最大压应变值增加约42.9 %。有限元分析表明：UHPC与钢板端部界面处应变差增加20.9 %，滑移最大处焊钉剪应力增加64.7 %。参数化分析可知：当焊钉间距从100 mm增加至400 mm时，跨中UHPC拉应力减小3.7 %；跨中钢板压应力减小17.8 %，钢筋压应力增加86.3 %。以上结果表明焊钉间距增加使钢与UHPC之间组合作用减弱的同时，引起了结构次内力的分布变化，UHPC与钢结构的次内力减小，钢筋承担的约束作用增强，压应力增大。适当地增加焊钉间距可以减小收缩引起UHPC拉应力和钢结构次内力，但需要注意组合作用减弱对力学性能的影响。

Abstract:

In order to explore the influence of different layouts of welding stud on the shrinkage of steel-ultra-high performance concrete （UHPC） composite bridge slabs， a full-scale segmental composite bridge slab shrinkage monitoring test with a welding stud spacing of 200 mm and 300 mm under normal temperature curing conditions was conducted. Finite element analysis software was used to simulate the shrinkage of the test model. based on which， the parametric analysis of the shrinkage of the composite bridge deck at different welding stud spacing was performed. The test monitoring results show that the initial setting time of UHPC in the test is about 17 hours. The UHPC shrinkage in the edge area of the steel-UHPC composite bridge deck is larger than that in the central area. The maximum shrinkage in the first 72 hours is about 450×10^－6. When the stud spacing increases from 200 mm to 300 mm， the UHPC is weakened by the overall restraint， the restraint effect of the steel plate decreases， and the maximum compressive strain is reduced by about 51.6 %. The restraint effect of the reinforcing steel is strengthened， and the maximum compressive strain value increases by about 42.9 %. The finite element analysis shows that the strain difference at the interface between UHPC and the end of the steel plate increases by 20.9 %， and the shear stress of the welding stud at the maximum slippage increases by 64.7 %. The parametric analysis shows that when the stud spacing increases from 100 mm to 400 mm， the UHPC tensile stress in the mid-span decreases by 3.7 %. The compressive stress of the steel plate in the mid-span decreases by 17.8 %， and the compressive stress of the steel bar increases by 86.3 %. The above results show that the increase of the welding stud spacing weakens the combined effect between steel and UHPC， and at the same time causes the distribution of the secondary internal force of the structure. The secondary internal force between UHPC and the steel structure decreases， the restraining effect of the steel bars increases， and the compressive stress increases. Properly increasing the stud spacing can reduce the UHPC tensile stress and the secondary internal force of the steel structure caused by shrinkage， but it is necessary to pay attention to the weakening of the combined effect on the mechanical properties.