CFRP筋粘结式锚具锚固性能试验

Experiment on Anchorage Performance of Bond-type Anchorage for CFRP Tendon

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。

Aimed at anchorage problems that carbon fiber reinforced polymer/plastics（CFRP） was used as prestress tendon and cable reactive powder concrete（RPC） was regarded as bond medium and based on it,a new bond-type anchorage was developed.The calculated formulas of average bond strength and its corresponding slip,critical anchorage length,and bond-slip constitutive model were proposed.Influences of surface shape,bond length,number and space of CFRP tendons,slope angle of inner wall of steel sleeve and pretensioning load on anchorage performance were studied by static test.Test results show that the surface shape of CFRP tendon is significant to the anchorage performance of the bond-type anchorage.When the tensile strength of the indented surface CFRP tendon is less than 3 000 MPa and compressive strength of RPC is more than 130 MPa,the critical anchorage length is 20 diameters of general CFRP tendon for common bond specimen,the shortest critical anchorage length in anchorage system is 13 diameters of pretensioning CFRP tendon with ratio of 56% of pretensioning load.The appropriate rod space is not less than rod diameter for the anchorage system with multiple CFRP tendons.