纤维网格端锚自锁增强机制

Mechanism of fiber grid reinforced with end self-locking anchorage

为解决织物增强混凝土(TRC)加固混凝土梁结构界面端部剥离问题,拟采用端部自锁技术将TRC板锚固在梁底。得益于该技术提供的端部锚固作用,即使发生界面剥离,TRC板仍能继续承载。但与纤维布相比,纤维网格由于各纤维束之间间隙大得多,协同受力性能较差,在不作处理的情况下能否实现自锁尚存疑问。为了提高纤维网格强度利用率,本文通过端部自锁锚固的纤维网格拉伸试验对其端锚自锁增强效应进行了研究。对纤维网格采取增大物理摩擦或增加化学粘结等措施,进而拉伸至破坏,分析比较了各试件的破坏模式、荷载-应变曲线,提出了纤维网格增强后承载力计算公式。试验结果表明:纤维网格端部自锁锚固时的强度利用率最大提升了60.66%,通过与端部锚板的有效结合,3层网格的抗拉承载力能够达到与单层纤维布相近的水平,应用自锁锚固技术有望在TRC加固混凝土梁中解决端部界面剥离问题,提升材料利用率,改善加固效果。所提出的纤维网格增强后承载力计算公式可为相关工程实践提供有益参考。

In order to solve the problem of interface end peeling of textile reinforced concrete(TRC)reinforced concrete beam structures,an end self-locking technique was proposed to anchor the TRC slabs at the bottom of the beams.Owing to the end anchorage provided by this technique,the TRC slab can continue to carry the load even if interfacial debonding occurs.However,compared with the fiber sheet,the fiber mesh has poor synergistic stress performance due to much larger gaps between the fiber bundles,and it is doubtful whether self-locking can be achieved without treatment.In order to improve the utilization of fiber mesh strength,this paper investigates the end-anchor self-locking enhancement effect through the end self-locking anchored fiber mesh tensile test.Measures such as increasing physical friction or adding chemical bonding to the fiber grid are taken to stretch it to failure.The failure modes and load-strain curves of each specimen are analyzed and compared,and a formula for calculating the bearing capacity of the fiber grid after enhancement is proposed.The results show that even if the size of the fiber grid is limited,the strength utilization rate of the fiber grid under end anchoring is increased by 60.66% by reinforcement measures,and the tensile bearing capacity of the three-layer grid can be similar to that of the fiber sheet.The application of the self-locking anchorage technology is expected to solve the problem of end-interface debonding in TRC-reinforced concrete beams,enhance the material utilization,and improve the strengthening effect.The proposed formula for calculating the bearing capacity after fiber mesh reinforcement can provide a useful reference for related engineering practice.