GFRP筋地下连续墙混凝土板受弯性能试验研究及有限元分析

Experimental study and finite element analysis on flexural behavior of diaphragm wall reinforced with GFRP bars

为了解GFRP筋地下连续墙的受弯性能,通过GFRP筋混凝土板和钢筋混凝土板的对比受弯试验,分析了两者的受力-变形过程和破坏形态,对比了两者的挠度、开裂荷载、极限荷载以及混凝土应变。结果表明:GFRP筋混凝土板的受力-变形曲线大致可划分为开裂前和开裂后两个阶段,其破坏表现为脆性;混凝土开裂前两种板的截面应变变化规律均基本符合平截面假定,但开裂后GFRP筋混凝土板的挠度增长速率远大于钢筋混凝土板,且该速率基本不变;两种板的开裂荷载较为接近,而GFRP筋混凝土板的极限荷载为钢筋混凝土板的1.2倍。在试验基础上,建立了GFRP筋混凝土板的有限元模型,通过参数分析表明,GFRP筋混凝土板的抗弯刚度在开裂后随配筋率的增大而增大。

In order to understand the flexural behavior of diaphragm wall reinforced with GFRP bars,flexural tests were carried out on concrete slabs reinforced with GFRP bars and steel bars,respectively.The deformation process and failure mode of specimens were examined.Through comparison and analysis of deflection,cracking load,ultimate load and strain of concrete between two types of concrete slabs,it is found that the force-deformation curve of concrete slab reinforced with GFRP bars can be divided into two stages.The strain distributions of both types of slabs essentially complied with the plane section assumption before concrete cracks.However,the deflection of concrete slab reinforced with GFRP bars increases much faster after cracking than that of concrete slab reinforced with steel bars,and the increment speed changes very little.The cracking loads of both types of slabs are very close,while the ultimate load of concrete slab reinforced with GFRP bars is 1.2 times of that of concrete slab reinforced with steel bars.Based on the test results,finite element models are established for concrete slabs with different GFRP reinforcement ratios.Parameter analysis shows that the flexural rigidity of concrete slab reinforced with GFRP bars increases with the reinforcement ratio after cracking.