GFRP抗浮锚杆螺母托盘锚具外锚固性能试验

摘要

In order to solve the external anchorage problem of GFRP (glass fiber reinforced plastics) anti-floating anchors, a new anchorage system–nut-pallet anchorage was proposed. Based on counter-pulled test of self-designed two large components, external anchorage bearing behavior of nut-pallet anchorage of GFRP anti-floating anchors was studied. The external anchorage deformation (slippage) and the ultimate capacity were also monitored during the test. The results show that the failure modes of the GFRP anti-floating anchors are pulled out. Under the conditions of C25 concrete and the GFRP anti-floating anchors diameter with 28 mm, and with other conditions remain unchanged, the anchorage length is only changed, the limit supporting capacity of the external anchorage length with 30d is 384 kN, the maximum slippage is 8.98 mm, the generalized efficiency coefficient of external anchorage is 0.890, and the generalized average bond strength is 5.20 MPa; the limit supporting capacity of the external anchorage length with 15d is 267 kN, the maximum slippage is 5.13 mm, the generalized efficiency coefficient of external anchorage is 0.619, and the generalized average bond strength is 7.24 MPa. The average bond strength between the GFRP anti-floating anchors and the concrete reduces along with the increase of external anchorage length. Under the counter-pulled loads of each level, the generalized average bond strength between the GFRP anti-floating anchors and the concrete reduces along with the increase of test sample both sides slippage quantity. Finally, the generalized average bond strength increasing rate decreases along with the increase of slippage quantity unceasing.%为了解决玻璃纤维增强聚合物(GFRP)抗浮锚杆外锚固问题，提出一种新型的锚固系统—螺母托盘锚具。通过自行设计的2组大型构件对拉试验，测定外锚固段变形(滑移)及外锚固极限承载力，研究GFRP抗浮锚杆螺母托盘锚具外锚固承载性能。研究结果表明：增设螺母托盘的GFRP抗浮锚杆结构的破坏形式为锚杆拔出破坏；直径d为28 mm的GFRP抗浮锚杆，在标号为C25的混凝土条件下，外锚固长度为30d的极限承载力为384 kN，最大滑移为8.98 mm，外锚固段广义效率系数为0.890，广义平均黏结强度为5.20 MPa；外锚固长度为15d的极限承载力为267 kN，最大滑移为5.13 mm，外锚固段广义效率系数为0.619，广义平均黏结强度为7.24 MPa。GFRP抗浮锚杆与混凝土之间的广义平均黏结强度随着外锚固长度的增加而降低；在每级对拉荷载作用下，GFRP 抗浮锚杆与混凝土广义平均黏结强度随试件两端的滑移增加而降低，随着滑移增加，广义平均黏结强度的增大速率变小。