1年持续载荷下GFRP-混凝土组合梁长期性能试验

玻璃纤维增强树脂(GFRP)-混凝土组合梁由上部混凝土板和下部GFRP型材以及连接二者的抗剪连接件组成。开展了2根GFRP-混凝土组合梁(非预应力及施加体外预应力组合梁各1根)在1年持续载荷下行为的试验研究。考虑混凝土收缩徐变及GFRP型材蠕变耦合的影响,开展了50年的24根GFRP-混凝土组合梁时随有限元参数分析。结果表明:在1年持续载荷下,非预应力与施加体外预应力组合梁长期挠度分别为其初始挠度的1.42倍及2.91倍;非预应力与预应力组合梁中连接件的长期滑移分别为0.230 mm及0.164 mm,相比初始滑移2种组合梁的最终滑移分别增加了53.3%和58.2%;50年后,非预应力组合梁长期挠度与初始挠度的比值在1.50~1.56之间;而施加体外预应力组合梁长期挠度与初始挠度的比值在3.03~6.08之间。基于以上研究提出了GFRP-混凝土组合梁长期挠度的计算建议。 

Long-term property test of GFRP-concrete composite beam under sustained load for one year

The glass fiber reinforced plastic (GFRP)-concrete composite beam consists of a concrete slab on the upper side,a GFRP profile on the lower side and shear connectors to connect these two sides.A test study was con-ducted on the behaviors of two GFRP-concrete composite beams (non-prestressed and external prestressed composite beams each had one)under sustained load for one year.A time-dependent finite element parametric analysis of 24 GFRP-concrete composite beams,taking coupling effect of the shrinkage and creep of concrete and creep of GFRP profile into account,was carried out for 50 years.The results show that long-term deflections of the non-prestressed and external prestressed composite beams are 1.42 and 2.91 times of their respective instantaneous deflections under sustained load for one year.The long-term slips of the non-prestressed and external prestressed composite beams are 0.230 mm and 0.164 mm,respectively.Compared with initial slips,the terminal slips of the two composite beams increase by 53.3% and 58.2%,respectively.The ratios of long-term deflection to the instantaneous deflection for the non-prestressed composite beam are between 1.50-1.56 while the ratios of the long-term deflection to the instan-taneous deflection for the external prestressed composite beam are between 3.03-6.08.Based on the above resear-ches,calculation proposals of long-term deflections of GFRP-concrete composite beams were proposed.