预制UHPC组合梁槽口式连接界面抗剪性能研究

相比现浇混凝土桥面板,全预制混凝土桥面板有诸多优势,能够提高桥梁工程质量、加快桥梁施工速度和降低成本.预制超高性能混凝土(Ultra-high Performance Concrete,UHPC)梁和预制UHPC桥面板通过槽口连接形成组合梁是一种新的结构形式,这种槽口式连接的界面抗剪性能会影响全梁整体承载力.通过16个...

Study on the Interface Shear Behavior of Precast UHPC Composite Beam with Shear Pocket

Compared with cast-in-place concrete bridge decks,full-depth precast concrete bridge decks have numerous advantages,which can improve the quality of precast concrete slabs,accelerate bridge construction,and reduce costs.In this study,the interface shear behavior of a novel shear pocket was evaluated,which connected a precast ultra-high performance concrete(UHPC)beam and a precast UHPC bridge deck.The interface shear behavior of shear pocket effects the overall load-bearing capacity of the composite beam.Sixteen push-out specimens with different reinforcement ratios,concrete types of precast beam,concrete types of precast deck,and grouted concrete types were tested to estimate the effect on the interface shear behavior.The propagation of cracks were observed during the test,and the vertical slip,horizontal slip,reinforcement strain,ultimate load,and residual load were recorded.The test results showed that the reinforcement ratio plays a significant role in the ultimate Vuand residual Vrloads.The ultimate load with a reinforcement ratio of 3.7%is 1.06times and 1.20times the reinforcement ratio of 2.8%and 2.0%,respectively.Second,Vuand Vrare dominated together by the grouted concrete types and precast beam concrete types.Third,the precast bridge deck concrete type has a slight effect on the shear behavior.Simultaneously,it is deduced that the dowel action of the reinforcement is mainly affected by the diameter and concrete strength grade.Compared with AASHTO LRFD 2015and ACI 318,it is inferred that the two codes are conservative in estimating the shear capacity of UHPC composite beams by shear pocket connection.Finally,a formula for predicting the precast UHPC composite beam is proposed in this paper,which is in good agreement with experimental value.