摘要
首次提出了界面剪切疲劳试验的新方法,借此研究了疲劳荷载作用下的碳纤维与混凝土粘结界面间的抗疲劳性能。并基于弹性理论,得出剪切变形条件下与弯曲变形条件下的碳纤维与混凝土界面间粘结剪应力的计算公式是相同的结论。因此用界面剪切疲劳试验代替弯曲疲劳试验去考察碳纤维与混凝土界面间粘结强度的疲劳性具有更高的精度和效率。同时试验结果表明:在应力比R=0.2条件下,碳纤维布与混凝土界面间的极限粘结疲劳强度约是其静粘结强度的64%,可见在疲劳荷载的作用下,碳纤维布与混凝土界面间的粘结强度将下降,因此在碳纤维加固的混凝土梁的设计中,应重视疲劳荷载导致的界面粘结强度降低的问题,并且设计时应对粘结剪切强度赋予一定的安全系数。
The method of the torsional low cycle fatigue experiment is first put forward in this paper, and the fatigue properties of the bonding at the interface of CFRP and concrete are studied using the proposed method. According to elasticity theory, it is fotmd that the formula to calculate the bonding stress at flexion state is identical to that at shearing state. Therefore, the torsional low cycle fatigue experiment is more efficient and precise than the flexural fatigue experiment to study the fatigue properties of the bonding. Experiment results show that the fatigue bonding strength at the interface of CFRP and concrete is 64% of the static bonding strength in the condition of R=0.2. This reduction need to be paid more attention in the design of concrete structures strengthened with CFRP sheets. A safety factor of the fatigue strength at the interface of CFRP and concrete should be applied in design,
出处
《工程力学》
EI
CSCD
北大核心
2008年第8期200-204,共5页
Engineering Mechanics
基金
交通部联合攻关项目(2003353322100)
吉林省科技厅资助项目(20040511)
关键词
桥梁结构
碳纤维布
混凝土梁
剪切疲劳试验
粘结剪应力
疲劳粘结强度
bridge structure
CFRP sheets
RC beam
torsional low cycle fatigue experiment
bonding shear stress
fatigue bonding strength
