摘要
该文进行了6根简支梁的单调加载试验,试验梁的增强筋分别为普通钢筋、GFRP(Glass Fiber Reinforced Polymer)筋和BFRP(Basalt Fiber Reinforced Polymer)筋,每组2根梁。分析比较了FRP筋混凝土梁的抗弯刚度、裂缝分布形式等与普通钢筋梁的区别。对依据国内外规范给定的短期抗弯刚度计算公式计算得出的荷载-挠度曲线与试验曲线进行了比较。基于试验研究和机理分析,借助收集的国内外开展的31根FRP筋混凝土梁的试验数据,对现行GB 50608—2010中FRP筋混凝土梁的短期刚度计算公式Bs进行了修正,并对修正公式的适用性进行了校核。试验结果表明:在相近截面配筋率情况下,由于自身较低的弹性模量,FRP筋混凝土梁在开裂后的抗弯刚度要明显低于普通钢筋梁;FRP筋混凝土梁的裂缝间距要大于普通钢筋梁,裂缝显得疏而宽;现有规范大都高估了FPR筋梁的短期抗弯刚度;修正后的短期抗弯刚度计算公式具有很好的适用性,可作为后续规范修订的参考。
The monotonic loading tests were firstly conducted on six simply supported concrete beams. The investigated reinforcing bars for the test beams were ordinary steel bars,GFRP（ Glass Fiber Reinforced Polymer） bars and BFRP（ Basalt Fiber Reinforced Polymer） bars,respectively,and there were two identical beams in each group. A comparison between FRP reinforced beams and ordinary steel bar reinforced beams was carried out for their differences in flexural stiffness and crack pattern. In addition,the load-deflection curves calculated according to the codes of FRP reinforced concrete structures in China and aboard were compared with the tested curves. Based on the code GB 50608—2010 and the data collected from 31 FRP reinforced beams in literature,the calculation formula for the short-term flexural stiffness Bsof FRP reinforced beams was modified,and then,the applicability of the modified formula was examined. Tests results show that with the identical cross-sectional reinforcing ratio,the post-cracking flexural stiffness of FRP reinforced beam due to its lower elastic modulus is significantly lower than that of ordinary steel bar reinforced beam. Compared to the ordinary steel bar reinforced beams,the spacing and distribution of cracks in FRP reinforced beams appear to be larger and sparser,respectively. It is found that the short-term flexural stiffness of FRP reinforced beams is often overestimated by the present codes,while the modified formula for the short-term flexural stiffness has good applicability,which can be reflected in the future revisions of codes.
出处
《土木工程学报》
EI
CSCD
北大核心
2015年第11期44-53,共10页
China Civil Engineering Journal
基金
国家"863"计划(2012AA03A204)
国家自然科学基金(51478106)
教育部科学技术研究项目(113029A)
