配筋PVA-钢混杂纤维增强水泥基复合材料梁弯剪性能试验研究及数值模拟

Experimental Investigation and Numerical Simulation on Flexural and Shear Performance of PVA-Steel Hybrid Fiber Reinforced Cementitious Composites Beams with Steel Bars

为改善普通混凝土梁的破坏形态,防止脆性破坏,提高承载力,采用特定掺量的PVA-钢混杂纤维增强水泥基复合材料(HyFRCC)替代普通混凝土。共设计8根试验梁,包括6根配筋PVA-钢HyFRCC梁和2根普通钢筋混凝土梁,进行弯剪性能试验。受剪性能试验结果表明,与普通钢筋混凝土试验梁出现的剪压破坏不同,配筋PVA-钢HyFRCC试验梁均表现为弯曲破坏,这表明在同样条件下,PVA-钢HyFRCC可以改变梁的破坏模式,有效抑制剪切裂缝的形成和发展,使试验梁呈现多缝开裂的延性破坏。剪跨比对PVA-钢HyFRCC梁的承载能力和破坏模式有较大影响。箍筋间距减小到一定程度,试验梁的开裂荷载和极限荷载均有一定的提高。受弯性能试验结果表明,试验梁均发生弯曲破坏,配筋PVA-钢HyFRCC梁的承载能力和变形能力均较普通钢筋混凝土梁有明显的提高。采用有限元分析软件ABAQUS,将PVA-钢HyFRCC的应力-应变关系与混凝土损伤塑性模型结合,对配筋PVA-钢HyFRCC梁的性能进行数值模拟,数值模拟结果与试验结果吻合较好。

In order to improve the failure pattern,prevent brittle failure,and improve bearing capacity ofordinary concrete beams,hybrid fiber reinforced cementitious composites(Hy FRCC)with specific amount ofpolyvinyl alcohol(PVA)fiber and steel fiber was proposed to replace ordinary concrete. A total of 8 beamspecimens were designed,including 6 PVA-steel Hy FRCC beams with steel bars and 2 ordinary reinforcedconcrete beams. The shear and bending performance of the beam specimens were tested. The results of shearperformance tests show that the failure pattern of the PVA-steel Hy FRCC beams with steel bars is bendingfailure,while the failure pattern of ordinary reinforced concrete beam is shear compression failure. PVA-steelHy FRCC can change the failure pattern and effectively suppress the formation and development of shear cracks. The PVA-steel Hy FRCC beams show ductile failure with multiple cracks. The shear span ratio has agreat influence on the bearing capacity and failure pattern of PVA-steel Hy FRCC beams with steel bars. Andwhen the stirrup spacing decreases to a certain extent,the cracking load and the ultimate load of the testbeams increase to a certain extent. The results of the flexural performance test show that all test beams sufferbending failure,and the bearing capacity and deformation capacity of the PVA-steel Hy FRCC beams withsteel bars are significantly improved comparing with ordinary reinforced concrete beams. Furthermore,numerical simulation of test beams was carried out based on the finite element analysis software ABAQUS bycombining stress-strain relationship of PVA-steel Hy FRCC with concrete damage plastic model. The numericalsimulation results are in good agreement with the experimental results.