部分波形钢腹板箱梁桥受力特性分析

Mechanical behavior of box girder bridge with partial corrugated steel webs

为了分析部分波形钢腹板预应力混凝土箱梁桥结构的空间力学特性,以24 m+40 m+24 m连续梁桥设计方案为对象,用三维有限元方法分析了在竖向荷载以及预应力作用下的结构应力和变形特性,并与波形钢腹板扩展梁理论进行比较,讨论了扩展梁理论的适用性.在此基础上进一步分析了部分波形钢腹板箱梁桥的力学行为,以及两种腹板过渡区域的传力机理.结果表明,按扩展梁理论设计虽然能够得到精度较好的纵向应力结果,但挠度和剪切应力计算精度有待提高;按腹板承担截面全部竖向剪力的设计方法偏于安全;波形钢腹板箱梁和预应力混凝土腹板箱梁过渡区域的结构传力机理十分复杂,设计时应予慎重分析.

To analyze the mechanical behavior of the prestressed concrete continuous box girder bridge with partial corrugated steel webs, taking the scheme of 24 m＋40 m＋24 m continuous bridge design as object, 3-D finite element method （FEM） was applied to investigate the structure＇s stress and deformation under vertical load and prestress. Results between 3-D FEM and the expanded beam theory considering the effect of corrugated steel webs were compared, and the applicability of the expanded beam theory was discussed. The mechanical behavior of the box girder bridge with partial corrugated steel webs and the load transferring mechanism in the connecting region between two different kinds of webs were also analyzed with 3-D FEM. Results showed that the longitudinal stress obtained from the expanded beam theory was satisfied, but the precision for deflection and shear stress calculation should be improved. The assumption that the webs bear all the vertical shear force in section is too conservative for design. The load transferring mechanism in the connecting region between corrugated steel webs and prestressed concrete webs is very complicated, thus should be studied with more consideration in design.