纤维增强材料复材筋混凝土界面随机疲劳黏结性能试验研究

EXPERIMENTAL RESEARCH ON THE RANDOM FATIGUE BONDING PERFORMANCE OF INTERFACE BETWEEN FRP BARS AND CONCRETE

针对(FRP)筋材与混凝土之间的界面脱黏问题,研究随机疲劳荷载作用下的FRP筋混凝土疲劳黏结性能对FRP筋在实际工程中的应用与推广具有重要的意义。在前期FRP筋与超高性能活性粉末混凝土(RPC)在等幅疲劳荷载作用下的黏结性能试验研究基础上,结合矮寨大桥的随机荷载谱研究,开展了对FRP筋疲劳前后承载能力研究和疲劳荷载循环次数、锚固长度对荷载-滑移曲线影响的试验研究,并计算分析得到经历200万次疲劳荷载后FRP筋的损伤量。结果表明:与等幅疲劳荷载作用相比,即使随机荷载对FRP筋的疲劳损伤程度略大,但在随机荷载作用下FRP筋与RPC仍能保持良好的黏结性能,且其疲劳寿命大于200万次,疲劳后FRP筋黏结试件极限承载能力在20%以内变化。

For the interface debonding between Fiber Reinforced Plastic（FRP） bars and concrete,the study of the bonding performance between FRP bars and concrete under random fatigue loads was of great significance to the application and promotion of FRP bars in practical engineering.Based on the previous experimental results of the bonding performance between FRP bars and Reactive Powder Concrete（RPC） under the equal amplitude fatigue load,combining the random load spectrum of Aizhai Bridge,the bearing capacity of FRP bars before and after fatigue test,the influence of fatigue load cycles and anchorage length on the load-slip curves was studied.And the damage amount of FRP bars was calculated and analyzed after 2 million fatigue loads.The results showed that,the fatigue damage of FRP bars was slightly larger than that of random loads,which compared with equal amplitude fatigue loading.However,the excellent bonding performance between FRP bars and RPC could still be maintained under random loads,and fatigue life was more than 2 million times.In addition,after the random fatigue test,the ultimate bearing capacity of FRP bars was improved in less than 20%.