预制混凝土桥墩墩-台组合连接构造受力机理分析

Mechanism Analysis of the Connection Between the Pier and Footing of Precast Concrete Bridge Piers

为了实现桥梁下部结构快速施工和改善施工环境的目的,在现有墩-台连接构造的基础上,提出一种在预制桥墩底部预埋一个钢-混凝土组合连接装置,与承台内部预埋钢板用预应力锚杆连接的新型构造,从而将混凝土桥墩与混凝土承台的连接转换为钢与钢的连接。建立了以预应力锚杆截面面积为变化参数的非线性有限元模型,研究了连接构造中构件的作用力变化,探讨了锚杆承载作用的可取代性,分析了连接装置的承载位置并且描述了荷载的传递路径。研究结果表明:减小锚杆面积产生的多余荷载先由连接钢筋承担,然后由焊钉承担,锚杆面积减小使更多的焊钉承担了较大的荷载;可继续减小锚杆面积使其仅起到锚固作用;墩-台结合部的荷载先传递到受拉侧加劲肋底部和受压侧加劲肋顶部,然后由焊钉连接件、连接钢筋和锚杆传递至承台。

To realize the rapid construction of the bridge structure and improve the construction site environment,based on the existing pier-footing connection structure,a new type of connection is proposed which is pre-buried at the bottom of the precast pier and connected with the pre-buried steel plate inside the footing with prestressing anchors,thus converting the connection of concrete pier and concrete footing into a steel-to-steel connection.A nonlinear finite element model with the variation parameter of prestressing anchor cross-sectional area was established to research the action force variation of component in the connection structure,to explore the replaceability of the anchor load-bearing action,to analyze the load-bearing position in the connection device and to describe the load transfer path.The results show that the excess load generated by the reduction of anchor area is first borne by the connection reinforcement and then by the stud connector,and the reduction of the anchor area makes more stud bear a larger load;the prestressing anchor can be used only for anchoring;the load at the pier-footing joint is first transferred to the bottom of the stiffener on the tensile side and the top of the stiffener on the compressive side,and then transferred to the footing by stud,connecting reinforcement and prestressing anchor.