复合材料腰梁受弯性能的试验研究

Experimental Study on the Mechanical Properties of Composite Middle Beam in Foundation Pit Support

为在基坑支护中采用玻璃纤维复合材料(GFRP)腰梁取代传统材料腰梁,进行了材料性能试验和工字形、双背槽形两种截面形式梁的受弯试验,对GFRP梁的受力性能和破坏形态进行了研究。试验结果表明,材料性能、构件的稳定性以及腹板和翼缘连接处的局部受压应是GFRP构件设计分析的主要内容。复合材料腰梁截面形式的优化选取既要考虑满足稳定性要求,又要充分发挥材料的强度特性,整合后的双腹工字形是比较适宜的截面形式。腰梁和锚杆连接处需采取局部加强措施。

This paper discusses application of glass-fiber-reinforced plastic（GFRP） in a foundation pit support instead of conventional material.The laboratory studies on the mechanical properties of the GFRP beams with different sections were carried out.Their mechanical behavior and the failure features are described and analyzed.The test results indicate that the material properties and the stability of the GFRP middle beam and the local strength at the joint between web and flange are the main factors in the composite middle beam designing.The optimal selection of the GFRP middle beam section should satisfy the requirements of both globe and local stabilities simultaneously,the material strengths of the middle beam should fully be utilized.The composite material of I-section with double webs is the best section type for the middle beam.Local strengthening should be adopted in the middle beam-bolt joint.