超宽波形钢腹板箱梁内衬混凝土合理设计参数和构造研究

Research on rational design parameters and structural measures for lining concrete of extra wide composite box girder bridges with corrugated steel webs

某跨河特大桥采用波形钢腹板预应力混凝土连续箱梁桥结构,采用超宽尺寸的单箱三室结构。目前国内主要对机动车道宽度不超过四车道的单箱单室箱梁做过部分研究,同时该类桥梁设计中对内衬混凝土长度、厚度等主要参数设置尚未有精细的方法。本文依托该桥建立了超宽波形钢腹板箱梁的精细空间有限元仿真分析模型,从结构变形、轴向性能、弯曲性能以及剪切性能等方面系统地分析内衬混凝土对波形钢腹板组合桥梁力学性能的影响。根据研究成果,选取合适的力学指标,对内衬混凝土长度、厚度进行参数化分析,归纳提取出内衬混凝土的合理设计参数。在确保结构安全的前提下,显著提高了特大跨度超宽尺寸的波形钢腹板连续梁桥整体经济性,较大程度上降低了超宽箱梁内衬构造现浇的施工难度,同时节约了宝贵的施工工期。该项研究成果可为今后同类型桥梁的设计提供参考,对充分发挥这种组合结构桥梁的优点和拓宽使用范围具有重要的参考意义。

An extra wide composite PC box girder bridge with corrugated steel webs was constructed for a long-span river-crossing bridge.In China,only limited studies have been carried out for single-box single-cell box girder bridges with a width smaller than four traffic lanes.Meanwhile,detailed methods to determine the design parameters such as length and thickness of lining concrete is still to be developed.This paper developed a refined finite element model for this extra wide composite PC box girder bridge with corrugated steel webs,and systematically investigate the influence of lining concrete on the mechanical performance of this kind of bridge considering deformation,axial behavior,flexural behavior and shear behavior.Based on numerical simulation results,parametric study was carried out for the length and thickness of lining concrete with proper mechanical indices,and the rational design parameters of lining concrete were proposed.This research greatly enhances the global economy of this kind of bridge with the structural safely guaranteed.The difficulty of in-situ casting of lining concrete and the construction period of this kind of bridge are efficiently reduced.The results of this research provide reference for the design of this kind of bridges in the future,which is of great significance for fully making use of the advantages widening the range of use of this kind of bridge.