基于板单元的钢-混凝土组合斜拉桥桥面板配筋优化设计

Optimization Design of Steel Concrete Composite Cable-Stayed Bridge Deck Reinforcement Based on Plate Elements

单索面钢-混凝土组合箱形截面斜拉桥由于存在索力传递效应、箱形截面扭转畸变、剪力滞效应等使其空间受力特征显著,所以如采用“传统1D杆系模型+横向框架模型”的设计理论,将会忽略桥面板面内水平剪应力,导致工程实践中桥面板斜向开裂病害发生。JTG 3362—2018《公路钢筋混凝土及预应力混凝土桥梁设计规范》提出设计应关注箱形截面的空间应力体系。基于新规范提出的基于平面应力的板单元结构设计方法,并将其应用于上海市昆阳路闵浦三桥斜拉桥混凝土桥面板的承载力配筋设计中。结果表明,基于平面应力的板单元结构设计方法与完整空间效应下的混凝土桥面板受力特征相吻合,能够准确识别结构重点关注的桥面板位置,并有效防止桥面板斜向开裂等病害的发生,从而可以指导钢-混凝土组合断面桥梁的混凝土桥面板配筋设计。

The single cable plane steel-concrete composite box section cable-stayed bridge has significant spatial stress characteristics due to the existence of cable force transfer effects,box section torsional distortion,shear lag effects,etc.Therefore,if the design theory of traditional 1D rod model+transverse frame model is adopted,the horizontal shear stress in the bridge deck will be ignored,leading to the occurrence of diagonal cracking disease in the bridge deck in engineering practice.JTG 3362-2018 Design Specification for Highway Reinforced Concrete&Prestressed Concrete Bridges proposes that design should focus on the spatial stress system of box sections.The design method of plate element structure based on plane stress proposed by the new standard is applied to the bearing capacity reinforcement design of the concrete bridge deck of the Minpu Third Bridge on Kunyang Road in Shanghai.The results show that the design method of plate element structure based on plane stress is consistent with the stress characteristics of concrete bridge decks under complete spatial effects,and can accurately identify the position of bridge decks which are of great concern to the structure,and effectively prevent the occurrence of diseases such as diagonal cracking of bridge decks.It can guide the reinforcement design of concrete bridge decks for steel-concrete composite section bridges.