基于弹性扭转约束边界的波形钢板整体剪切屈曲分析

GLOBAL SHEAR BUCKLING OF CORRUGATED STEEL PLATES WITH EDGES ELASTICALLY RESTRAINED AGAINST ROTATION

波形钢板的整体剪切屈曲对波形钢腹板PC组合箱梁桥的竖向抗剪设计有重要意义。该文在正交各向异性薄板理论的基础上,利用势能驻值原理和瑞利-里兹法,推导了基于弹性扭转约束边界的波形钢板弹性整体剪切屈曲荷载的分析方法,并给出了几种特殊边界条件下的简化计算公式。计算结果表明:对于四边简支板和四边嵌固板,该方法与现有公式计算结果一致;波形钢板强抗弯刚度方向上的约束条件是影响其整体剪切屈曲的决定性因素,随着该方向上约束的增强,屈曲模式将从四边简支情况向四边嵌固情况过渡;弱抗弯刚度方向上约束条件的影响很小,可以忽略。最后给出了将波形钢板在实际梁结构中受到的边界约束等效为弹性扭转弹簧的方法。

The global shear buckling of corrugated steel plates plays a vital role in the vertical shear design of prestressed concrete box girders with corrugated steel webs. Thusly, an estimation of the global shear buckling capacity of corrugated plates with edges elastically restrained against rotation is presented. The corrugated plate was modeled as an orthotropic thin plate and elastically rotational restraint on boundary edges was taken into account in the form of rotational springs. The implementation was carried out by utilizing the principle of resident potential energy and Rayleigh-Ritz method. The results show that the prediction of buckling capacities of corrugated plates is consistent with those predicted by existing formulas for the limiting cases of simply-supported and clamped edges. And the restraints in the direction with larger flexural stiffness determine buckling capacities of corrugated plates, while the effect of the restraints in the direction with smaller flexural stiffness can be neglected. Finally, the equivalent rotational spring constants are proposed to evaluate the actual boundary conditions of corrugated web in a real girder.