玻璃纤维筋与钢筋复合配筋预应力混凝土管桩承载性能试验研究

针对预应力钢筋混凝土管桩（普通管桩）水平承载力不足的问题，开发研制了采用玻璃纤维筋与钢筋复合配筋预应力混凝土管桩（复合配筋管桩），进行了复合配筋管桩与普通管桩受弯和受剪性能的对比试验。受弯试验结果表明：GFRP筋的配置较大幅度改善了普通管桩的承载性能；与普通管桩相比，复合配筋管桩的开裂弯矩和极限弯矩均有显著的提高，且其裂缝分布范围小、数量少且长度略短于普通管桩；两种类型桩裂缝出现前跨中截面应变符合平截面假定，破坏时复合配筋管桩受压区混凝土破碎而管桩的预应力筋被拉断。受剪试验结果显示：配置GFRP筋较大幅地改善了普通管桩的受剪性能，其开裂剪力有显著的提高；两种类型桩破坏过程相似，均是支座处先出现裂缝，并沿与桩长方向大致30°夹角方向开展延伸，当延伸至加载点垂直面时，以平行于桩长方向继续扩展，最后形成贯通面。对比试验结果表明，采用玻璃纤维筋与钢筋复合配筋预应力混凝土管桩在受弯和受剪性能方面均有不同程度的提高，可有效解决普通管桩水平承载力不足的问题。

Experimental study on bearing capacity of compositely reinforced with GFRP prestressed concrete pipe pile

Aiming at the technical problem of insufficient horizontal bearing capacity of pipe pile, compositely reinforced with GFRP prestressed concrete pipe pile (hereinafter referred to as PRC-G pile) was developed . The flexural properties of innovatively developed compositely reinforced with GFRP prestressed concrete pipe pile were studied through a comprehensive field test program. The results show that GFRP can evidently improve the flexural properties. The cracking bending moment and the ultimate bending moment of PRC-G piles are all increased to different extent. Cracking is of shorter distribution, less number and short in length. Furthermore, the strain of mid-span cross section is in accordance with the hypothesis of planar section until the concrete cracks. Concrete compression zone is broken in PRC-G piles and tendons of PRC piles are pulled off at failure. The shearing test results show that GFRP can improve the shear properties and the cracking shear force can be improved significantly. Two types of pipe piles failure process are similar, cracking from bearing and extending to the loading point of vertical surface in approximately 30 degrees direction, finally forming through surface of pipe piles. The experimental results show that glass fiber reinforced bar and PRC-G can improve the flexural and shear properties in different degrees, and it can effectively solve the technical problem of ordinary pipe pile's horizontal bearing capacity shortage.