摘要
现行混凝土结构加固设计规范对增大截面法加固受弯构件刚度计算未作明确规定,若将加固梁作为一次性整体浇筑构件计算刚度,则未考虑新增材料的应力滞后效应,与实际构件情况存在差异。针对增大截面加固受弯构件,本文基于刚度解析法,建立了考虑应力滞后效应的短期刚度理论模型,计算了不同初始弯矩水平下的加固梁的短期刚度。典型工况计算结果显示:在正常使用阶段,应力滞后效应对增大截面加固受弯构件的短期刚度产生了不利影响,当初始弯矩M1达未加固梁承载力M1u的70%时,加固构件刚度相较于未考虑应力滞后效应平均降低34.7%;按混凝土结构规范将加固梁视为一次性整体浇筑构件计算刚度结果偏大,且初始弯矩水平越高,与本文模型计算刚度偏离程度越显著。因此,考虑应力滞后效应计算的增大截面法加固梁短期刚度更加符合实际情况,建议在实际工程中进行加固梁正常使用阶段变形验算及加固规范修订时考虑应力滞后效应。
The current design code for concrete structure reinforcement does not provide clear regulations on the stiffness calculation of reinforced flexural members by the increasing section method.If the reinforced beam is treated as a monolithic cast-in-place component for stiffness calculation,the stress lag effect of the newly added materials is not considered,which is inconsistent with the actual situation of the component.For flexural members reinforced by section enlargement,this paper establishes a theoretical correction model for short-term stiffness considering the stress lag effect based on the stiffness analytical method,and calculates the short-term stiffness of the reinforced beam under different initial moment levels.The calculation results of typical working conditions show that in the normal service stage,the stress lag effect has an adverse impact on the short-term stiffness of flexural members reinforced by section enlargement.When the initial moment M1 reaches 70%of the bearing capacity M1u of the unreinforced beam,the stiffness of the reinforced component is reduced by an average of 34.7%compared with that without considering the stress lag effect.The stiffness calculation results of the reinforced beam as a monolithic cast-in-place component according to the concrete structure code are larger,and the deviation from the stiffness calculated by the model in this paper is more significant with the increase of the initial moment level.Therefore,the short-term stiffness of the reinforced beam calculated by considering the stress lag effect is more consistent with the actual situation.It is recommended to consider the stress lag effect in the deformation verification of the reinforced beam in the normal service stage and the revision of the reinforcement code in actual engineering.
作者
董增丽
杜秀丽
冀承蕾
张冰旖
Dong Zengi;Du Xiui;Ji Chengei;Zhang Bingyi(Qingdao Huanghai University,Qingdao,China)
出处
《科学技术创新》
2025年第17期157-161,共5页
Scientific and Technological Innovation
基金
青岛黄海学院校级课题科技计划项目(2023KJ22)。
关键词
增大截面法
应力滞后效应
短期刚度
钢筋混凝土梁
increasing section method
stress lagging effect
short-term stiffness
reinforced concrete beam
