复合配筋增强工程水泥基复合材料梁受弯性能试验研究

Experimental study on flexural behaviors of engineered cementitious composites beams reinforced with hybrid bars

为了研究不同筋材增强工程水泥基复合材料(ECC)受弯构件的力学性能,设计并制作6个几何尺寸相同的试验梁,包括形状记忆合金(SMA)增强ECC(SMA-ECC)梁、GFRP增强ECC(GFRP-ECC)梁、钢绞线增强ECC(SS-ECC)梁、SMA/GFRP增强ECC(SMA/GFRP-ECC)梁、钢筋增强ECC(R-ECC)梁和普通钢筋混凝土(RC)对比梁。通过低周单向循环加载试验,研究相同加载条件下相同配筋率的各试验梁的破坏过程、承载能力、耗能能力、位移延性、残余变形和自复位性能,考察SMA/GFRP-ECC梁的力学性能。结果表明:与普通钢筋混凝土梁相比,复合配筋增强ECC梁在加载过程中呈现出明显的多缝开裂特征,具有更好的延性;与采用其他筋材的复合配筋增强ECC梁相比,SMA/GFRP可以使梁兼具大承载力、高耗能以及自复位能力;SMA/GFRP-ECC梁具有较高承载力、延性以及损伤自修复、位移自复位能力。

In order to investigate the flexural behaviors of engineered cementitious composites(ECC)beams strengthened with different hybrid reinforcement materials,six beams with the same size were designed and fabricated,including a shape memory alloys(SMA)and glass fibre reinforced polymer(GFRP)reinforced ECC(SMA/GFRP-ECC)beam,an SMA reinforced ECC(SMA-ECC)beam,a GFRP reinforced ECC(GFRP-ECC)beam,a steel strands(SS)reinforced ECC(SS-ECC)beam,a reinforced ECC(R-ECC)beam and a common reinforced concrete(RC)beam.One-way cyclic tests in low frequency was conducted to study the failure process,bearing capacity,energy dissipation capacity,displacement ductility,residual deformation,and self-reset performance of each test beam under the same loading schedule and reinforcement ratio.At the same time,the mechanical properties of ECC and GFRP reinforced ECC beams were investigated.The results show that using SMA/GFRP instead of tensile reinforcement can improve the recovery performance of components.The utilizing of ECC instead of ordinary concrete can significantly increase the ductility of the composite beam.It shows significant cracking during the loading process and improves the energy dissipation capacity of the specimen.Therefore,SMA/GFRP reinforced ECC beams can improve the self-reposition,crack control ability,and ductility of composite beams.