悬臂梁抗裂非线性分析

Nonlinear analysis for cantilever beam’s anti-cracking

应用非线性分析方法,研究了钢筋混凝土悬臂结构在弹性工作阶段、受拉钢筋屈服阶段、受压混凝土强度下降阶段的受力特性。基于平截面假定,推导出钢筋混凝土悬臂结构在不同工作阶段的应力、内力和抗裂性计算公式。通过实桥测试,当裂缝宽度小于桥涵设计规范规定的允许值[δ]时,采用规范公式计算和非线性分析法计算裂缝宽度均与实际相吻合;当裂缝宽度接近或超过桥涵设计规范规定的允许值[δ]时,沿用规范公式计算与实际裂缝宽度出入较大,采用非线性分析法计算与实际较吻合。分析结果表明,用非线性分析法计算钢筋混凝土悬臂结构的抗裂性能够更好地反映裂缝的实际开裂宽度和规律。

The mechanics characteristic of RC cantilever structure during the elastic and the yield stage as well as the strength decline stage of compression concrete was studied with nonlinear analysis method. Based on plane section supposition, the formulas for calculating the stress, force and anti-cracking were derived during the structure’s different working period. From the field test, it was found that when the crack width is less than the allowable one in the specification, the presented method is accordance with the specification’s, if the crack width is close to or more than the allowable one, the presented results using nonlinear analysis method have a considerable accuracy compared to the real one, which was unmatched with the specification’s. The results showed that nonlinear analysis method is effective to calculate crack width and it can reflect the real structure’s working performance.