珊瑚海砂海水混凝土中CFRP-钢复合筋搭接性能
Lap-spliced behavior of CFRP-steel composite bars in coral sea-sand seawater concrete
周济 1陈宗平 2徐炜圣 1覃伟恒 1刘丁瑗1
作者信息
- 1. 广西大学 土木建筑工程学院,南宁 530004
- 2. 广西大学 土木建筑工程学院,南宁 530004;南宁学院 土木与建筑工程学院,南宁 530200;广西大学工程防灾与结构安全教育部重点实验室,南宁 530004
- 折叠
摘要
为研究珊瑚海砂海水混凝土(CSSC)中碳纤维增强复合材料(CFRP)-钢复合筋(简称"复合筋")搭接连接受力性能,合理确定CSSC中复合筋的搭接长度,以复合筋直径、搭接长度、保护层厚度、混凝土强度、搭接净距、配箍率、混凝土及筋材种类为试验参数,对 27组共 81个搭接连接试件进行了对拉试验,获得了各试验参数对CSSC中复合筋搭接连接性能的影响规律.结果表明:当搭接长度小于17倍复合筋直径(dc)时,试件发生拔出-劈裂破坏,反之则发生拉断破坏.发生拔出-劈裂破坏时,复合筋表面出现严重的剪切损伤;当搭接长度小于 14dc时,试件的搭接强度约为 7.2 MPa,当搭接长度大于 14dc时,试件的搭接强度随搭接长度的增大逐渐减小;保护层厚度大于 4dc或CSSC轴心抗压强度大于 30 MPa后,试件搭接强度的变化基本上可以忽略;增大配箍率,搭接强度逐渐增大,且劈裂裂缝的宽度显著减小;与钢筋试件相比,复合筋试件搭接强度的降幅超过 25%.基于试验结果,建立了CSSC中复合筋搭接强度及搭接长度计算公式,计算结果与试验结果相符,并参考《混凝土结构设计规范》简化了搭接长度的计算公式.
Abstract
In order to study the mechanical behavior of lap-spliced carbon fiber reinforced polymer(CFRP)-steel composite bars(referred to as"composite bars")in coral sea-sand seawater concrete(CSSC)and determine the splice length of composite bars reasonably,tensile tests were conducted on 27 sets of 81 lap-spliced specimens and test variables included the composite bar diameter,splice length,cover thickness,concrete strength,clear space between the lap-spliced bars,stirrup ratio,concrete type,and reinforcement type.The influence of various test vari-ables on the behavior of lap-spliced composite bars in CSSC was obtained.The results indicate that pull-out failure accompanied by concrete splitting is found for specimens with a splice length less than 17 times the diameter of the composite bar(dc),while tensile fracture failure is found for specimens with a splice length greater than 17dc.After the specimen undergoing pull-out failure,severe shear damage is formed on the surface of the composite bars.When the splice length is less than 14dc,the splice strength of the specimen is about 7.2 MPa.When the splice length is greater than 14dc,the splice strength of the specimen gradually decreases with the increase of the splice length.After the cover thickness is greater than 4dc or the axial compressive strength of CSSC is greater than 30 MPa,the change in the splice strength of the specimen can be basically ignored.Increasing the stirrup ratio gradually in-creases the splice strength and significantly reduces the width of the splitting crack.Compared with the lap-spliced specimens of steel bars,the decrease in splice strength of the lap-spliced specimens of composite bars exceeds 25%.Based on the experimental results,the equations for calculating the splice strength and splice length of composite bars in CSSC were established,and the calculation results are consistent with the experimental results.Then,refer-ring to the"Code for Design of Concrete Structures",the equation for calculating the splice length was simplified.
关键词
珊瑚海砂海水混凝土/CFRP-钢复合筋/搭接强度/临界搭接长度/简化公式Key words
coral sea-sand seawater concrete/CFRP-steel composite bar/splicing strength/critical splice length/simplified equation引用本文复制引用
基金项目
国家自然科学基金(51578163)
中央引导地方科技发展资金项目(桂科ZY21195010)
八桂学者专项([2019]79号)
广西科技基地与人才专项(桂科AD21075031)
出版年
2024
NETL
NSTL
万方数据