预应力CFRP布加固混凝土方柱时的预应力损失  

Study on prestress loss of prestressed CFRP cloth encapsulated concrete square column

作　　者：王强[1,2,3] 李柏林 卢春玲 张哲铭[1] Wang Qiang;Li Bolin;Lu Chunling;Zhang Zheming(College of Civil and Architecture Engineering,Guilin University of Technology.Guilin 541004,China;Guangxi Key Laboratory of Rock-Soil Mechanics and Engineering,Guilin 541004,China;Guilin University of Technology,Collaborative Innovation Center for Exploration of Hidden Nonferrous Metal Deposits and Development of New Materials in Guangxi,Guilin 541004,China)

机构地区：[1]桂林理工大学土木与建筑工程学院,广西桂林541004 [2]广西岩土力学与工程重点实验室,广西桂林541004 [3]桂林理工大学广西有色金属隐伏矿床勘查及材料开发协同创新中心,广西桂林541004

出　　处：《建筑科学》2020年第3期57-64,共8页Building Science

基　　金：广西创新驱动发展专项资金项目(桂科AA18118008);广西岩土力学与工程重点实验室基金项目(2015-B-03,2015-B-08).

摘　　要：为了研究预应力CFRP布加固混凝土方柱时的应力损失情况,在恒温恒湿条件下进行了为期7d的预应力CFRP布加固混凝土方柱的预应力损失试验。考虑了摩擦损失、锚具缺陷造成的损失以及CFRP布自身应力松弛损失三个主要因素。试验测得摩擦损失量以及摩擦损失率随预应力度的变化情况;锚具缺陷造成的应力损失随预应力度以及时间的变化情况;CFRP布自身应力松弛随时间的变化情况。进行了机理分析,同时提出了相应减少预应力损失的措施。结果表明:随着的预应力增大,摩擦损失量增大,摩擦损失率降低,适当提高预应力度可以提高CFRP布利用效率。采用超张拉和二次张拉的处理方式,可以显著降低锚具缺陷造成的这方面应力损失。0.3预应力度下,超张拉至0.32、0.35初始预应力度的损失率分别降低至14.62%、8.63%;二次张拉将预应力损失降低至9.66%。试验结果可以为实际工程的设计与施工提供一定的指导。In order to study the stress loss of concrete square columns strengthened with prestressing CFRP sheets,prestress loss test of reinforced concrete square columns is carried out under constant temperature and humidity for seven days. Three main factors are considered: friction loss,loss caused by anchor defects and stress relaxation loss of CFRP cloth. The variation of friction loss and friction loss rate with prestressing degree is measured. The stress loss caused by anchorage defects varies with the degree of prestress and time. The stress relaxation of CFRP cloth changes with time. The mechanism is analyzed,and corresponding measures to reduce prestress loss are proposed. The results show that with the increase of prestressing force,the amount of friction loss increases and the friction loss rate decreases. The utilization efficiency of CFRP cloth can be improved by increasing prestres degree appropriatly. The stress loss caused by anchorage defects can be significantly reduced by using the methods of overtensioning and secondary loading. Under 0. 3 degree of prestressing,the loss rates of over-tensioned to 0. 32 and 0. 35 degree of initial prestressing can be decreased to 14. 62% and 8. 63% respectively. Secondary loading reduces the prestress loss to 9. 66%. The test results can provide some guidances for the design and construction of practical projects.

关 键 词：CFRP布加固 预应力损失 混凝土方柱 

分 类 号：TU378.8[建筑科学—结构工程]