钢丝网砂浆层和附加肋提升嵌入式复材筋锚固性能试验研究

Experimental study on enhancement of the anchorage properties of NSM FRP bars using the wire mesh mortar layer and additional ribs

为提高嵌入式加固法中复材筋的锚固性能,避免嵌筋处剥离破坏的过早发生,提出了对结构构件端部锚固区联合运用外覆钢丝网砂浆防护层和设置复材筋附加肋的增强锚固方法.通过20个构件的直接拉拔试验,分析了钢丝网砂浆防护层厚度、复材筋附加肋数量、槽道黏结剂材料类型和复材筋种类等主要参数对嵌入式复材筋锚固性能的影响.试验结果表明,附加肋与钢丝网砂浆防护层联合增强锚固的方法可显著提升嵌入式复材筋的锚固性能,且对表面刚度和横向抗剪强度较高的CFRP筋试件的提升效果较BFRP筋试件更显著,对原有黏结性能较弱的砂浆槽道黏结剂试件的提升幅度较树脂黏结剂试件更大.钢丝网砂浆防护层的锚固方法对锚固承载力的贡献较附加肋锚固方法更大,该方法可改变试件的破坏形态,有效地避免复材筋剥离破坏的发生.

To improve the anchorage performance of near-surface mounted(NSM)fiber reinforced polymer(FRP)bars to avoid the detachment failure of the concrete cover in NSM FRP,a novel anchorage system was proposed.The system was a combined anchoring including both additional ribs on the FRP bars and a mesh-mortar protection layer constructed outside the anchorage zone.The pull-out tests were carried out on a total of 20 specimens.The effects of the thickness of the wire mesh-mortar protection layer,the number of additional ribs,and the type of the adhesive and the FRP bars on the anchorage properties of NSM FRP bars were discussed.The results show that the combined anchoring can significantly improve the anchorage performance of NSM FRP bars.Besides,the anchorage property of specimens using CFRP bars is improved more than that using BFRP bars due to their higher stiffness and transverse shear strength.And with the combined anchoring,the enhancement in anchorage properties of specimens using mortar with weaker bonding performance is much greater than that of the epoxy resin.The protection layer can provide a greater contribution to anchorage capacity than additional ribs.Also,it can change the failure mode,and thus effectively avoid the detachment failure of the concrete cover.