小受压区高度RC梁正截面的破坏状态

Normal Section Failure State of RC Beam with Short Compression Zone

采用条带积分法,应用计算机编程,对相对受压区高度为0.15左右的钢筋混凝土梁的弯矩—曲率关系进行全过程分析,得出弯矩—曲率关系曲线,并给出弯矩与混凝土应变、钢筋应变及梁的相对受压区高度的对应关系。结果表明钢筋屈服后,受压和受拉合力大小不变,内力臂略有减小,截面抗弯承载力略有降低。纵向受拉钢筋应变为4500×10-6时,梁达到正截面承载能力极限状态。

The whole process of moment-curvature relationship for RC beam was analyzed with the relative depth of compressive zone of the beam about 0.15 using the strip integral method and computer programme. The relationships between moment and strain of concrete, strain of steel, depth of compressive zone were got. Results showed that, after the longitudinal tensile steel bar yielded, the flexural carrying capacity of the beam and the ann of the internal force decreased a little, and the force of tensile steel bar and the force of compressive concrete keep unchanged. When the beam reached the flexural limit state, the strain of longitudinal tensile steel bar was about 4 500×10^-6.