混凝土梁底面与侧面裂缝宽度相关性研究

STUDY OF THE RELATIONSHIP OF CRACK WIDTH BETWEEN BOTTOM AND SIDE OF RC BEAMS

通过对14根钢筋混凝土梁的反向加载试验,量测了开裂后各级荷载下梁受拉顶面和侧面的裂缝宽度,统计分析正裂缝出现及扩展的规律,对比验证裂缝平均间距、宽度的计算值与试验值的吻合程度,进而对梁侧面与顶面裂缝宽度间的相关性进行数理统计分析。结果表明:梁横向受力裂缝主要在正常使用极限状态内出现,纯弯段内裂缝出齐时的荷载大小约为极限承载力的1/3;正常使用极限状态内纯弯段梁顶与梁侧裂缝宽度存在线性关系,回归系数平均值为1.35。基于试验数据进一步理论分析,建立了正常使用极限状态内梁受拉区正面横向受力裂缝最大宽度的计算式。

The reverse loading experiment on 14 RC beams was carried out,both top surface crack width and side suface crack width of beam were measured at all load levels after cracking. The statistical analysis for propagation of the rules of appearance and normal section crack was conducted. The calculation values of average crack spacing and average crack width were compared with measured values to vertify the degree of agreement. Then relationship of crack width between the top and side of beam was analyzed by mathematical statistic method. The results showed that the lateral stressed cracks mainly appeared in serviceability limit state,and that cracks in pure bending section did not appear beyond approximately 1/3 of ultimate bearing capacity. The crack width of top and side in pure bending section had linear relationship within serviceability limit state,namely the mean regression coefficient was 1. 35. Based on the test data and further theoretical analysis,the maximum width formula of lateral stressed crack in normal section of tensile zone was established within serviceability limit state.