GFRP抗浮锚杆与混凝土底板黏结特性现场试验

Field test on bond strength between Glass Fiber Reinforcement Polymer anti-floating anchor and concrete floor

采用倒置的混凝土底板开展GFRP抗浮锚杆与其黏结性能的现场试验,探究实际工程中GFRP抗浮锚杆在混凝土底板中的受力特性,并测量GFRP抗浮锚杆与混凝土底板的相对滑移.结果表明:GFRP抗浮锚杆主要发生剪切滑移与拔断两种破坏形态,GFRP抗浮锚杆的弯折长度越大,其破坏荷载和极限抗拔承载力越小;直径28 mm的GFRP抗浮锚杆的弯折影响系数为0.56~0.89,弯折处理后GFRP抗浮锚杆的滑移量比未经弯折的滑移量小;未弯折与弯折处理后的GFRP抗浮锚杆相比,锚杆与混凝土的平均黏结强度提高1.6倍,锚杆杆体与混凝土底板的平均黏结强度随弯折长度的增加呈线性减小的趋势;通过将锚杆弯折或增加锚杆弯折长度的方法来提高GFRP抗浮锚杆与混凝土底板的抗拔承载力不可行,建议采取增大锚杆直径、增加混凝土底板厚度和增设应力扩散托盘等措施.

The field tests on bond strength between concrete floor and GFRP anti-floating anchor were conducted using inverted concrete floor,which are able to present force characteristics of GFRP anti-floating anchor in real concrete floor and measure relative slippages between GFRP anchor and concrete floor.The results show that there are two failure modes of GFRP anti-floating anchors including shear-slippage failure and pull-out failure.The longer of the bending length,the less of the failure load and ultimate uplift bearing capacity.The bend impact factor of GFRP anti-floating anchor in 28-diameter ranged from 0.56 to 0.89,and the slippage of the bent GFRP anchor was less than that of the original one.Compared with the bent GFRP anchor,the unbent anchor’s average bond strength between anchor and concrete increased by 1.6 times,and the average bond strength linearly decreased as the bend length got longer.Bending the anchor or increasing the bend length is unable to increase the uplift bearing capacity between GFRP anti-floating anchor and concrete floor.On the contrary,increasing the diameter of the anchor,the thickness of the concrete floor and adding stress diffusion tray are recommended.