高速铁路连续刚构-拱组合桥梁墩-梁-拱结合部受力行为分析

Stress behavior analysis on pier-girder-arch conjunction of continuous rigid frame-arch composite bridge on high-speed railway

为分析高速铁路连续刚构-拱组合桥梁墩-梁-拱结合部位在施工与运营过程中的应力状态,采用建立施工全过程杆系有限元模型,计算施工及运营阶段内力与位移,同时考虑钢管与管内核心混凝土、管外拱脚混凝土接触面双重滑移效应,建立墩-梁-拱结合部位实体有限元模型并通过现场实测应力验证模型准确性的方法,探究结合部位的钢-混凝土界面滑移规律与空间应力分布状态。研究结果表明:拱肋钢管与拱脚混凝土、核心混凝土间最大相对位移值分别为1.1,1.2 mm,在设计时宜增加隔板或剪力钉以改善钢与混凝土协同受力;结合部位应力基本处于规范限值内,在过人洞处出现应力集中,倒角处最大拉应力达3.81 MPa,可设置必要的构造钢筋抑制斜向裂缝的发展;拱脚顶面混凝土出现应力集中,且远超规范限值,建议将拱脚混凝土替换为钢纤维混凝土。研究结果可为连续刚构-拱组合桥施工安全提供参考。

In order to analyze the stress state of the pier-girder-arch conjunction of the continuous rigid frame-arch composite bridge on high-speed railway in the process of construction and operation,a finite element model of the whole construction process was established to calculate the internal force and displacement in the construction and operation stages.At the same time,considering the double slip effect of the contact surface between the steel pipe and the core concrete in the pipe and the concrete at the arch foot outside the pipe,the solid finite element model of the pier-girder-arch conjunction was established,and the accuracy of the model was verified by the measured stress in the field.The slip law and spatial stress distribution of the steel-concrete interface at the conjunction were explored.The results show that the maximum relative displacement between the arch rib steel pipe and the arch foot concrete and the core concrete is 1.1 mm and 1.2 mm,respectively.In the design,the clapboard or shear stud should be added to improve the synergistic force between steel and concrete.The stress of conjunction is basically within the standard limit,and the stress concentration occurs at the human hole.The maximum tensile stress at the chamfer is 3.81 MPa,and the necessary structural reinforcement can be set to suppress the development of oblique cracks.The stress concentration occurs on the concrete at the top surface of arch foot,which is far beyond the specification limit.It is recommended to replace the arch foot concrete with steel fiber reinforced concrete.The research results can provide reference for the construction safety of continuous rigid frame-arch composite bridge.