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针对碳纤维增强塑料(CFRP)作为预应力筋或拉索时出现的锚固问题,开发了一种以活性粉末混凝土(RPC)作为粘结介质的粘结式锚具。建立了平均粘结强度及其对应的滑移量、临界锚固长度以及粘结滑移本构模型等计算公式。通过静载试验研究了筋材表面形状、锚固长度、根数、间距、套筒内壁倾角以及筋材预张拉等对锚固性能的影响。结果表明:CFRP筋的表面形状对以RPC作为粘结介质的粘结式锚具的锚固性能有着决定性影响;当表面压纹CFRP筋的抗拉强度不大于3 000 MPa,RPC抗压强度不小于130 MPa时,对于普通粘结试件,临界锚固长度为20倍筋材直径;对于预张拉粘结试件,当预张比为56%时,锚固系统具有最短的临界锚固长度为13倍筋材直径;多筋同时锚固时,其间距不宜小于1倍筋材直径。
Aiming at the anchoring problem of carbon fiber reinforced plastic (CFRP) as prestressing tendons or cables, a bonded anchor with activated powder concrete (RPC) as the bonding medium was developed. The formulas of average bond strength, corresponding slippage, critical anchorage length and bond-slip constitutive model were established. The effects of surface shape, anchorage length, root number, spacing, inner wall inclination of the sleeve and pre-tension of the tendons on the anchoring performance were studied by static load test. The results show that the surface shape of the CFRP tendons has a decisive influence on the anchoring performance of the bonded anchor with RPC as the bonding medium. When the tensile strength of the surface embossed CFRP bars is not more than 3 000 MPa, the RPC compressive strength is not less than 130 MPa, the critical anchorage length is 20 times the diameter of the reinforcement for ordinary bonded specimens. For the prestressed specimens, when the pre-stretch ratio is 56%, the anchorage system has the shortest critical anchoring length of 13 times Reinforced material diameter; multiple anchors at the same time, the spacing should not be less than 1 times the diameter of the reinforcement.