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- 2016
1年持续载荷下GFRP-混凝土组合梁长期性能试验
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Abstract:
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。 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 conducted 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 instantaneous deflection for the external prestressed composite beam are between 3.03-6.08. Based on the above researches, calculation proposals of long-term deflections of GFRP-concrete composite beams were proposed. 国家"973"计划(2012CB026200)
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