钢筋混凝土柱正截面承载力尺寸效应研究

通过对6根截面边长分别为300、500和700 mm的钢筋混凝土柱开展正截面承载力尺寸效应试验研究,分析正截面承载力、钢筋应变、混凝土压应变、中和轴高度和强度系数随截面尺寸的变化规律。结果表明:试件受压区混凝土的极限变形能力随截面边长的增大而减小;对于大尺寸试件,对混凝土的极限压应变的取值偏大;正截面承载力随截面尺寸的增大而减小,且随水平位移的增加,正截面承载力尺寸效应越明显。在试验的基础上,利用混凝土材料尺寸效应得到修正的正截面承载力计算结果,使大小尺寸试件的安全储备系数趋于一致。

SIZE EFFECT OF NORMAL SECTION BEARING CAPACITY OF REINFORCED CONCRETE COLUMNS

In order to investigate the size effect of normal section bearing capacity of reinforced concrete columns,three different section size,including 300,500 and 700 mm,six reinforced concrete columns were tested. The change rule of normal section size bearing capacity,reinforcement strain,concrete strain,neutral axis height and strength coefficient with the section size was analyzed. The results indicate the deformation capacity of concrete under compression zone is decreased as section size increased. For large size specimen,the code value of concrete ultimate compressive strain is larger. Normal section bearing capacity is decreased as section size increased,the more large level deformation increase,the more obvious the size effect of normal section bearing capacity becoming. Then on the basis of experiment,a practical model of normal bearing capacity of reinforced concrete column considering size effect on concrete was proposed,the safety coefficient of large size specimen is consistent with results of small size specimen.