UHPC中栓钉连接件疲劳荷载后力学性能研究

Study on the Mechanical Properties of Stud Connectors in UHPC after Fatigue

为研究钢-UHPC组合结构中栓钉连接件在疲劳荷载作用后的剩余力学性能,设计制作了2组共4个推出试件进行试验研究,一组为静载破坏试验,一组在进行200万次疲劳循环荷载后开展静载破坏试验。试验结果表明:1)钢-UHPC推出试件在静载试验和疲劳后的静载试验中栓钉破坏模式均为剪断破坏;2)在经历200万次疲劳循环加载后,钢-UHPC试件抗剪刚度退化30%~40%,极限承载力与静载试验相比下降幅度约为6%,普通混凝土中栓钉承载力下降约23%,表明疲劳荷载抗剪刚度影响显著,但对钢-UHPC推出试件承载力影响较小,且远小于普通混凝土中栓钉承载力退化水平。

In order to study the residual mechanical properties of bolted connectors in steel-UHPC composite structures after fatigue loading,two groups of four push-out specimens were designed and fabricated for experimental study,one group of which is static load damage test,and the other one of which is static load damage test after 2 million fatigue cyclic loading.The test results show that steel-UHPC push-out specimens in the static load test and fatigue after the static load test in the stud damage mode are shear damage.After 2 million times of fatigue cyclic loading,steel-UHPC specimen shear stiffness degrades by 30%to 40%,the ultimate bearing capacity and static load test declines by about 6%,the stud bearing capacity of ordinary concrete decreases by about 23%.It can be seen that the fatigue loading has a significant effect on the shear stiffness,and its effect on the bearing capacity of steel-UHPC specimens is small,and is much smaller than the degradation level of the stud bearing capacity in ordinary concrete.