CFRP预应力筋粘结式锚固系统的抗疲劳性能

Fatigue Behavior of Bond-type Anchorage with CFRP Tendon

CFRP预应力筋锚固系统的系统研究成果尤其是疲劳性能研究仍较少,采用疲劳试验机对以高性能活性粉末混凝土RPC作为新型粘结介质的CFRP预应力筋粘结式锚具的疲劳性能进行试验研究,CFRP预应力筋锚固系统疲劳试验采取对组装件交替施加静荷载和疲劳荷载,即用静载试验来检验组装件在经历一定次数重复荷载后的静力性能变化。试验结果表明该类锚具具有良好的抗疲劳性能,随着循环加载次数的增加,组装件之间的相对位置将趋于更加稳定的状态;循环加载过程中CFRP筋抗拉刚度略有降低,疲劳136万次与疲劳前组装件CFRP筋的抗拉刚度比值为93.7%。循环荷载作用下对粘结式锚具组装件有损伤,但当所施加的荷载未超过其极限破断力的40%时,CFRP筋与RPC之间的相对位置将保持比较稳定的状态,此时存在一定损伤的粘结式锚具组装件仍具有较好的承载能力。

The research on the anchorage system for CFRP tendons, especially about the fatigue behavior, is weak. A series of fatigue tests were conducted for the developing a bond-type anchorage system for CFRP tendon characterized with RPC as bond medium by fatigue machine under static load and fatigue load alternatively. Then the static behavior of the anchorage system, which experienced certain cycling loading, was inspected by static load test. The test result shows that （ 1 ） the new type of anchorage system has good fatigue behavior, with the increasing of cycling load times, the relative position of the parts of anchorage system at more stable status; （2） the tensile stiffness of CFRP tendons be slightly lower in loading process, after 136 million fatigue tests, it is 93.7% of that before fatigue test; （3） harm of anchorage system will occur under cyclic loading, however the relative slip is smaller between CFRP tendon and RPC under less than 40% of ultimate load, and the higher bearing capacity of harmed anchorage system for CFRP tendon exists to some extent.