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| Abstract: |
| Curved composite bridges and curved steel bridges have already been constructed around the world; however, the calculation for shear buckling of curved bridge webs generally uses the equations for straight bridge webs or just introduces a modification factor for bridge design. In this paper, the curved bridge web is equivalent to an isotropic cylindrical flat shell, and the double triangular series satisfying four-edge simply supported boundaries are used as the displacement function of the shell. Then by means of the Galerkin method, the analytical formula for elastic shear buckling stress of curved bridge webs is deduced. The parameter studies show that the shear buckling coefficient kc of curved bridge webs is positively correlated with the parameter h2/(Rt), and negatively correlated with the length-height ratio l/h. This implies that the elastic shear buckling stress of a curved bridge web is larger than that of an equivalent straight bridge web. For a curved bridge with the parameter h2/(Rt) less than 2, the amount of increase is less than 4.5%. The elastic shear buckling stress of curved bridge webs can be estimated conservatively as the webs in straight bridges. While for a curved bridge with larger h2/(Rt), using the equations for straight girders to calculate the elastic shear buckling stress is too conservative. The proposed formulas provide a more accurate estimation for shear buckling stress of curved bridge webs. |
| Key words: curved bridge curved webs shear buckling isotropic shell |
| DOI：10.11916/j.issn.1005-9113.18029 |
| Clc Number:U448.213 |
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| Descriptions in Chinese: |
| 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 |
