对预应力混凝土箱梁桥应力设计方法的探讨

Approach to Stress Design Method for PC Box Girder Bridges

在调查既有预应力混凝土连续箱梁桥开裂状况和裂缝形态的基础上,较全面地分析了引起箱梁受力开裂的原因。指出现阶段桥梁设计中采用的平面杆系程序,对箱梁局部应力估算的不准确是导致箱梁受力开裂的主要原因。根据箱梁结构的受力特点,提出采用应力设计方法解决预应力混凝土箱梁的受力开裂问题。通过实桥算例分析,论证了箱梁空间应力状态分析对保证箱梁桥结构安全的必要性。

A survey of the cracks conformation and distribution rules in the PC box girders is presented. The causes and the influence factors of the box girder cracking are analyzed. The undetermined local stress that calculated by the plane bar elements is the primary reason in present design methods. On the basis of the mechanical behavior of box girders, the stress design method is brought forward against the PC box girder bridge cracking. According to the results of a actual bridge, it is demonstrated that the spatial stress analysis is indispensable to the box girder bridge safety.