预应力混凝土桥梁弯曲孔道摩阻预应力损失分析

Analysis of Prestress Loss Due to Friction in Curved Ducts of Prestressed Concrete Bridge

混凝土桥梁预应力设计直接影响到桥梁结构的可靠性与耐久性。针对预应力损失中占比较大的弯曲孔道摩阻预应力损失部分,基于弹性体接触理论,通过对预应力筋与孔道内壁接触应力的分析,假设接触应力为:二次曲线、余弦函数、指数函数这3种非均匀分布的形式,导出了相应的弯曲孔道摩阻计算公式。进而通过模拟计算指出了现行桥梁设计规范中弯曲孔道摩阻预应力损失计算公式的弊端;在此基础上对原有的摩阻预应力损失计算公式进行了适当的修正,并通过实桥摩阻试验验证了修正公式的合理性。研究结果可为预应力混凝土桥梁的设计与现有结构设计理论的修正提供参考依据。

The prestress design of concrete bridges directly affects the reliability and durability of the bridge structure.Based on the elastic body contact theory and the analysis of the contact stress between the prestressed tendons and the inner wall of the tunnel,this paper aims at the part of the prestress loss due to the frictional resistance of the curved tunnel,which accounts for the larger prestress loss.It is assumed that the contact stress is conic,cosine function,the exponential function has three non-uniform distribution forms,and the corresponding formulas for calculating the frictional resistance of curved channels are derived.Furthermore,the shortcomings of the calculation formula for the frictional prestress loss of curved ducts in the current bridge design code are pointed out through simulation calculation;on this basis,the original frictional prestress loss calculation formula is appropriately revised,and the actual bridge friction is passed.The experiment verified the rationality of the revised formula.The research results can provide reference for the design of prestressed concrete bridges and the revision of existing structural design theories.