A Method for Elastic Shear Buckling Calculation of Curved Bridge Webs

平钢腹板曲线梁桥腹板弹性剪切屈曲计算

刘素梅,丁汉山

（东南大学 土木工程学院,南京 210096）

创新点说明：

曲线组合梁桥和曲线钢桥在国内外已大量修建,但在曲线桥设计时,平钢腹板的剪切屈曲计算通常采用直桥公式,或仅在直桥公式上新增一个修正系数。本文把曲线桥中的平钢腹板等效为各向同性柱形扁壳,采用满足四边简支边界条件的双重三角级数作为位移函数,利用伽辽金法,推导了曲线桥平钢腹板的弹性剪切屈曲强度计算公式。参数分析表明：曲线桥平钢腹板弹性剪切屈曲系数随着参数 h²/(Rt) 的增大而增大,随着长高比 l/h 的增大而减小。说明曲线桥平钢腹板的弹性剪切屈曲强度高于直桥腹板。对于参数 h²/(Rt) 小于2的曲线桥,平钢腹板的弹性剪切屈曲强度较直桥腹板提高幅度不超过4.5%,此时,曲线桥平钢腹板的弹性剪切屈曲强度可偏保守地采用直桥公式。但是对于参数 h²/(Rt) 较大的曲线桥,平钢腹板弹性剪切屈曲强度采用直桥公式太过保守。本文提出的公式可更好地估算曲线桥平钢腹板的弹性剪切屈曲强度。

研究目的：

得出平钢腹板曲线梁桥腹板弹性剪切屈曲强度计算公式。

研究方法：

把曲线桥中的平钢腹板等效为各向同性柱形扁壳进行剪切屈曲分析;

1）采用满足四边简支边界条件的双重三角级数作为位移函数,利用伽辽金法,推导曲线桥平钢腹板的弹性剪切屈曲强度计算公式。

2）针对实桥,确定参数h²/(Rt)的取值范围。给定参数h²/(Rt)和长高比l/h具体数值,利用Matlab程序计算弹性剪切屈曲系数。

3）对弹性剪切屈曲系数进行拟合,得到曲线桥平钢腹板弹性剪切屈曲系数拟合公式,进而得到曲线桥平钢腹板弹性剪切屈曲强度拟合公式。

研究结果：

1）曲线桥平钢腹板弹性剪切屈曲系数随着参数 h²/(Rt) 的增大而增大,随着长高比 l/h 的增大而减小。说明曲线桥平钢腹板的弹性剪切屈曲强度高于直桥腹板。

2）对于参数 h²/(Rt) 小于2的曲线桥,平钢腹板的弹性剪切屈曲强度较直桥腹板提高幅度不超过4.5%,此时,曲线桥平钢腹板的弹性剪切屈曲强度可偏保守地采用直桥公式。但是对于参数 h²/(Rt) 较大的曲线桥,平钢腹板弹性剪切屈曲强度采用直桥公式太过保守。

结论：

本文提出的公式可更好地估算曲线桥平钢腹板的弹性剪切屈曲强度。

关键词：曲线桥;曲线腹板;剪切屈曲;各向同性壳

     

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