基于可靠度的简支梁体外预应力加固设计与优化方法  

Reliability-Based Design and Optimization Method for External Prestressing Reinforcement of Simply-Supported Beams

作　　者：马士宾 刘月钊 汲港升 徐梓菲 刘子龙 MA Shibin;LIU Yuezhao;JI Gangsheng;XU Zifei;LIU Zilong(School of Civil and Transportation Engineering,Hebei University of Technology,Tianjin 300401,China)

机构地区：[1]河北工业大学土木与交通学院,天津300401

出　　处：《工业建筑》2022年第10期168-175,145,共9页Industrial Construction

基　　金：国家自然科学基金项目(51978236);天津市交通运输科技发展项目(2022-01)。

摘　　要：为了更加科学合理地进行体外预应力加固RC简支T梁设计优化,充分考虑了体外预应力布筋过程中几何设计值的不确定性和变异性,提出了一种基于目标可靠度的体外预应力加固设计优化方法。利用有限元分析软件,基于六西格玛理论实现体外预应力加固后梁体结构可靠度的计算,采用响应面法分析各随机设计变量(钢束等效直径、钢束夹角、钢束圆角半径、钢束折线长度、钢绞线抗拉强度设计值)对体外预应力加固后简支T梁可靠度的影响规律。结果表明:体外预应力加固后,简支T梁的可靠性对体外预应力钢束等效直径的敏感程度最高。考虑在役混凝土桥梁一级安全等级目标可靠指标,给出了体外预应加固各随机变量的设计建议值,并以现场加固桥梁工程为例验证,通过2次成桥静载试验,发现跨中挠度及应变都得到了较好的控制,最小校验系数分别为0.72和0.73。In order to scientifically and reasonably study the design optimization of RC simply-supported T-beams with external prestressing reinforcement, a design optimization method for external prestressing reinforcement based on the target reliability was proposed, which fully considered the uncertainty and variability of the geometric design values during the external prestressing deployment. In addition, finite element analysis software was used to calculate the structural reliability of the beams with external prestressing reinforcement based on the six sigma theory, and a response surface method was adopted to analyze the influence of random design variables(equivalent diameter of steel tendon, included angle of steel tendon, fillet radius of steel tendon, bend length of steel tendon, and tensile strength design value of steel strand) on the reliability of the simply-supported T-beams with external prestressing reinforcement. The results show that the reliability of the simply-supported T-beams with external prestressing reinforcement is highly related to the equivalent diameter of the steel tendon with external prestressing reinforcement. In addition, recommended design values for random variables with external prestressing reinforcement were given, which took into account the target reliability indicators for the first level of safety of concrete bridges in use and were verified by an on-site bridge reinforcement project. Furthermore, the span deflection and strain were well controlled in two static load tests, with minimum calibration factors of 0.72 and 0.73, respectively.

关 键 词：简支T梁 桥梁加固 体外预应力 目标可靠度 设计优化 

分 类 号：U445.72[建筑科学—桥梁与隧道工程]