高强钢筋混凝土梁裂缝宽度的试验研究和分析

Research on Crack-width of Concrete Beam Reinforced with High-strength Bars

为了研究配置高强钢筋混凝土梁开裂后的使用性能,对14根配置500MPa钢筋的混凝土梁进行了受弯性能试验.给出了梁侧面裂缝宽度沿裂缝高度的分布规律;梁底面裂缝宽度沿梁宽变化规律;典型位置处平均裂缝宽度与弯矩关系等,并对裂缝宽度值进行了统计分析.由本次试验和其他相关试验的数据分析表明:在钢筋应力较高时产生的次生裂缝会明显抑制主裂缝的扩展速度;我国现行规范的裂缝宽度公式的计算值明显大于试验值,不适用于配置高强钢筋混凝土梁的情况.对钢筋高应力下的裂缝宽度主要影响因素进行了分析,并提出了配置高强钢筋混凝土梁裂缝宽度的2种计算模式.建议公式与试验结果吻合较好.

A test of 14 flexural members reinforced with 500 MPa bars was carried out to investigate the cracking behavior of reinforced concrete beam with high-strength bars.The crack distribution along the beam height and width and the relationship between crack width and moment were explored.This experiment and other relevant experiments results show that the sub cracks between cracks limit the width of crack when the steel bars stress is high.Crack width calculated according to GB 50010—2002 was larger than the experimental value,which means that the crack width formula could not apply to the member with high-strength bars.A comparative study of the major factor of crack-width of this experiment and other relevant experiments data,a new crack width formula was put forward.The results of the proposed formulas were in good agreement with the experiment results.