GFRP筋混凝土梁正截面受弯性能试验研究

摘要

To deeply research the bending properties and design method of glass fiber reinforce plastic (CFRP) reinforced concrete beams, the flexural capacities of 36 concrete beams was investigated under the loading mode of four-point bending moment, including 21 GFRP reinforced concrete beams and 15 steel reinforced concrete beams. The deflection and flexural capacity were analyzed comparatively between the CFRP and steel reinforced concrete beams with the same parameters, such as reinforcement ratio, geometry size and concrete strength. The calculation formulas for the flexural capacities of the GFRP reinforced concrete beams and the critical relative depths of their compression zones were derived. The correctnesses of the formulas were proved with the test data. The research result shows that the ratio of the ultimate deflections of the two types of concrete beams is 1.5 to 2.5, the ratio of initial cracking load is 0. 53 to 0. 69, and the ratio of ultimate load is 0. 75 to 1. 02. In addition, the critical relative depth of the compression zone is from 0.17 to 0.20. It is suggested that reinforcement ratio should be equal to 1. 4 times of balanced reinforcement ratio to improve safety storage.%为深入研究GFRP筋混凝土梁弯曲性能及设计方法,通过36根混凝土梁(其中GFRP筋混凝土梁21根,钢筋混凝土梁15根)的四点弯曲试验,对GFRP筋混凝土梁正截面的受弯性能进行了研究.在配筋率、几何尺寸、混凝土强度相同的条件下,对比分析了GFRP筋混凝土梁与钢筋混凝土梁的挠度及承载力特性；推导了GFRP筋混凝土梁受弯承载力、界限受压区高度的计算公式,并用试验数据验证了公式的正确性.结果表明:GFRP筋混凝土梁与钢筋混凝土梁的最大挠度之比为1.5 ～2.5；初裂承载力之比为0.53 ～0.69,极限承载力较接近,比值为0.75～1.02;GFRP筋混凝土梁界限相对受压区高度为0.17 ～0.20.建议取配筋率为1.4倍平衡配筋率,以使构件具有足够的承载力储备.