延性基材对小跨高比连梁抗震性能的影响

Influence of Matrix's Ductility on Seismic Behavior of RC Coupling Beams with Small Span-to-depth

将具有高延性的超高韧性水泥基复合材料(UHTCC)替代混凝土作为联肢剪力墙连梁构件的基体材料,进行了2个跨高比为1.5的对角斜筋连梁拟静力反复加载试验,研究了基体材料延性对连梁抗震性能包括裂缝发育、破坏模式、滞回性能、抗剪承载力及延性的影响。结果表明:2个连梁均沿对角发生斜截面剪压破坏,但UHTCC连梁较RC连梁可延缓钢筋的屈服,提高抗震受剪承载力和延性,且在高剪切变形下仍可很好握裹钢筋,避免了保护层剥落的发生。可见,采用高延性UHTCC基材能够有效改善钢筋混凝土连梁的抗震性能和耐损性能。

Low-reversed cyclic loading tests were performed on two coupling beams with span-to-depth ratio of 1.5 and with diagonal reinforcements,in which different matrix materials were used in tested specimens to investigate the influence of matrix＇s ductility on seismic behavior of RC coupling beam. Analysis were done in terms of cracks development,failure mode,hysteretic response,shear capacity and ductility. Results showed that the tested two specimens failed in shear-compression mode along the diagonal of the specimens and,however,compared to conventional RC beam specimen,UHTCC specimen may delay the yielding of steel reinforcement,present higher shear capacity and ductility. Moreover,even if subjected to high shear deformation,UHTCC still may well confine steel reinforcement to prevent from spalling of cover layer. Therefore,it is believed that to utilize ultra high toughness cementitious composites（ UHTCC） in the small span-to-depth coupling beams is effective in improving seismic performance and damage tolerance of conventional RC coupling beams.