基于模型试验的体外预应力加固梁应力增量分析  

Analysis of Stress Increment in Externally Prestressed Reinforced Beams Based on Model Experiments

作　　者：杨永恒 原淼淼 刘喆 雷浪 YANG Yongheng;YUAN Miaomiao;LIU Zhe;LEI Lang(Shaanxi Transportation Holding Group Co.,Ltd.,Xi′an,Shaanxi 710065,China;Inner Mongolia University of Science and Technology,Baotou,Inner Mongolia 014010,China;Xi′an Highway Research Institute Co.,Ltd.,Xi′an,Shaanxi 710065,China)

机构地区：[1]陕西交通控股集团有限公司,陕西西安710065 [2]内蒙古科技大学,内蒙古包头014010 [3]西安公路研究院有限公司,陕西西安710065

出　　处：《水利与建筑工程学报》2024年第2期94-101,共8页Journal of Water Resources and Architectural Engineering

基　　金：陕西省交通科技项目(20-10K)。

摘　　要：为研究不同体外预应力加固方式对预应力混凝土(PC)梁受力性能的影响,对三根T形简支梁进行静载试验,观察PC梁的裂缝开展以及破坏情况,分析荷载、挠度、应变等的变化趋势,并提出预应力筋的极限应力计算公式,探讨体外加固预应力筋的有效高度、面积以及有效应力对体内外预应力筋应力增量的影响。结果表明:与未加固梁A1梁相比,A2梁的承载力提高了57.5%,A3梁的承载力提高了52.7%,可见不同的体外预应力加固方式对PC梁的承载力均有不同程度的提高;体外加固T梁的荷载-挠度曲线基本呈三折线,且预应力筋应力增量与跨中挠度基本呈线性关系;通过对比发现,体外筋有效高度增加时,体内外筋的应力增量分别随之减小、增加,而在其他因素影响下,体内外筋的应力增量均逐渐减小。In order to analyze the influence of different external prestressing reinforcement methods on the mechanical properties of prestressed concrete(PC)beams,load tests were carried out on three T-shaped beams.The crack development and failure of PC beams were observed,and the variation trends of load,deflection,and strain were analyzed.Subsequently,the formula for calculating the ultimate stress of prestressed tendons was proposed.Furthermore,the influence of effective height,area,and effective stress of external prestressing tendons on the stress increment of internal and external prestressing tendons was discussed.The results showed that different external prestressing reinforcement methods have different degrees of improvement in the bearing capacity of PC beams,the bearing capacity of the A2 and A3 beams was increased by 57.5%and 52.7%compared with the unreinforced beam A1 beam,respectively.The load-deflection curve of PC beams was trilinear,and the stress increment of prestressed tendons was linear with the mid-span deflection.Through comparison,it can be found that the stress increment of internal and external tendons decreases and increases respectively when the effective height of the external tendon increases,but the stress increment of internal and external tendons decreases gradually under the influence of other factors.

关 键 词：体外预应力 加固 预应力混凝土梁 极限应力 应力增量 

分 类 号：U441[建筑科学—桥梁与隧道工程]