预制桥面板方台形剪力键湿接缝受力性能分析

Analysis of the mechanical behavior of precast deck slab with square platform shear key wet joint

为提高预制桥面板接缝界面的抗剪性能,提出一种方台形剪力键湿接缝结构型式,并研究该结构的受力性能。设计制作包含湿接缝在内的2种试件,即方台剪力键与传统平截面单元板试件,进行静力剪切加载试验。利用ABAQUS软件中摩擦-内聚力模型模拟接缝的界面特征,在对比验证试验结果的基础上,进行参数化分析,以探讨湿接缝处不同配筋率、方台剪力键特征尺寸(角度、底边长度、高度)及同等接缝界面面积内剪力键大小和数量(排数)对抗剪性能的影响。试验结果表明:含有方台形剪力键的湿接缝结构,其极限抗剪承载力比传统平截面结构提升65.5%。有限元数值模拟界面抗剪结果与试验结果吻合良好。参数分析结果表明:剪切作用下,方台剪力键湿接缝的最优配筋率约为1.2%。随着方台角度与底边长度的增加,湿接缝结构的抗剪刚度明显提高。方台尺寸对极限抗剪承载力的影响程度依次为底边长、角度、高度,当方台角度为45°,板宽与方台长度、高度之比为1︰0.8︰0.2时,接缝界面极限抗剪承载力最高。方台排数对抗剪刚度和承载力的影响较小,方台排数的增加,可有效提高湿接缝界面的抗裂能力。方台形剪力键桥面板施工简单,能大幅提高板在接缝处的抗剪性能。

In order to improve the shear capacity of wet joints in precast deck slabs,this paper proposed and studied the mechanical behavior of a wet joint structure with square shear keys.Two types of specimens(a unit plate specimen with square platform shear key and a traditional unit plate specimen with plane section)with wet joints were designed and prepared for static shear experiment.The friction cohesion model in ABAQUS software was used to simulate the interface of after-pouring joints.With experimental validation,reinforcement ratio and shear key dimensions(angle,base length,and height)were the parameters considered in the shear simulation of the finite element model.In the same joint area,the effect of the number of shear keys(rows)on shear capacity was studied.The experimental results indicate that the ultimate shear capacity of the specimen with a square platform shear key is 65.5%higher than that of the traditional specimen.The results of parametric analysis indicate that when the reinforcement ratio is 1.2%,the shear resistance effect of the wet joint of the square shear key is the best.As the angle and the base length of the shear keyincrease,the shear stiffness of the bridge deck with square platform shear keys augments accordingly.The base length of the shear key has the greatest effect on the shear capacity,followed by the angle and height of the shear key.When the ratio of slab width to the length and height of the square abutment is 1:0.8:0.2,the ultimate shear capacity of the joint interface is the highest.Increasing the number of shear keys can improve the crack resistance of the wet joint interface,and the number of shear keys has little effect on the shear stiffness and capacity.The bridge panel is simple to manufacture and can substantially enhance the shear capacity of the wet joint.