单调荷载作用下高强混凝土梁受弯性能尺寸效应研究

Size effect on flexural behavior of reinforced high-strength concrete beams subjected to monotonic loading

进行了不同截面尺寸高强混凝土梁的弯曲试验,研究了梁高对其受弯性能的影响。试件采用C70高强混凝土,纵向受力钢筋采用HRB400级钢筋。试件截面尺寸不同,截面长宽比、剪跨比和配筋率等参数保持一致。分析了不同截面尺寸对高强混凝土梁的名义开裂弯矩、名义屈服弯矩、名义极限弯矩、延性以及塑性转动能力的影响。研究结果表明,高强混凝土梁的名义开裂弯矩、名义屈服弯矩和名义极限弯矩无明显尺寸效应,而试件的位移延性系数和塑性铰区的塑性转动能力则表现出明显的尺寸效应,随截面尺寸的增大梁的位移延性系数和塑性铰区塑性转动能力有所降低。

Reinforced high-strength concrete beams subjected to bending were tested to investigate the effect of depth on flexural behavior of beams.The geometry of specimens varied in cross sections with the depth-width ratios of the cross sections,the shear span ratios and longitudinal reinforcement ratios of specimens being constant.C70 concrete was used to cast the specimens and HRB 400 steel bars were used for the longitudinal reinforcement.The influence of beam depth on the nominal cracking moment,nominal yield moment,nominal ultimate flexural moment,ductility,and plastic rotation capacity of high-strength concrete beams was investigated.It is shown that there is no apparent size effect on nominal cracking moment,nominal yield moment and nominal ultimate moment of reinforced high-strength concrete beams.But the displacement ductility ratio and plastic rotation capacity show significant size effect.The displacement ductility factor and the rotational capacity of high-strength concrete beam decrease with the increasing of cross section.