论体外预应力筋加固混凝土梁正截面承载能力计算的合理性  

Calculation Rationality of the Normal Section Bearing Capacity of Concrete Beams Strengthened with External Prestressed Tendons

作　　者：单成林[1] 郑小红[1] SHAN Chenglin;ZHENG Xiaohong(School of Civil Engineering and Transportation,South China University of Technology,Guangdong 510640,China)

机构地区：[1]华南理工大学土木与交通学院,广州510640

出　　处：《结构工程师》2021年第3期27-30,共4页Structural Engineers

基　　金：国家自然科学基金项目(51508202);广东省自然科学基金项目(2019A1515012222)。

摘　　要：按照惯例,在计算体外预应力筋加固混凝土梁正截面承载能力时,体外筋的作用是按有黏结受拉钢筋对待的,即作为构件承载力的一部分。通过计算理论及计算示例来论证这一做法的不合理性,说明目前计算方法的力学概念不清、平截面假定有更多的不符,同时在正截面承载力、斜截面承载力计算和正截面应力计算的许多方面,体外筋作为有黏结受拉钢筋处理是前后相互矛盾的。应该将体外预应力筋的作用作为作用效应的一部分考虑,将其视为计算截面作用效应组合中的卸载作用效应,从而消除当前计算方法中的不合理性。In convention,when the normal section bearing capacity of the concrete beams strengthened with external prestressing tendons is evaluated,the effect of external prestressing tendons is treated as bonded tensile reinforcement,which was a part of the bearing capacity of the members.The irrationality of this approach was discussed through theoretic analysis and examples,and it was demonstrated that mechanics concept of the current calculation method was unclear,and there were discrepancies in the plane section assumption,meanwhile the calculation of the normal section bearing capacity,the oblique section bearing capacity and the calculation of the normal section stress were contradictory in many ways before and after the treatment of the external tendons as bonded tensile reinforcement.The effect of external prestressing tendons should be considered as part of the action effect,and treated as an unloading action in the combination for action effects of the calculated cross section,and therefore the irrationality in the current method would be erased.

关 键 词：桥涵工程 混凝土梁 体外筋加固 正截面承载力 计算合理性 

分 类 号：U441[建筑科学—桥梁与隧道工程]