薄壁空心高墩局部及整体稳定性分析

LOCAL AND GLOBAL STABILITY ANALYSIS OF HOLLOW THIN-WALLED HIGH PIERS

薄壁空心高墩的稳定问题一直受到国内外工程界的广泛关注,因此采用杆系有限元MIDAS Civil对某一联四跨连续梁桥高墩进行内力分析。首先提取承载能力组合下某一高墩的顶部作用力作用于ANSYS实体单元模型;其次通过对不同壁厚桥墩的一阶屈曲模态与特征值的分析,给出局部失稳与整体失稳的临界条件;然后基于四边简支薄板弹性屈曲理论推导薄壁矩形截面空心墩的局部失稳临界应力计算,给出避免矩形截面空心墩发生局部失稳的截面宽厚比限值;最后考虑材料和几何非线性对空心高墩的整体稳定进行研究。

The stability of the hollow thin-walled high pier has been widely concerned by the engineering circles at home and abroad,so the finite element software MIDAS was used to analyze the internal forces of the high piers for a bridge with four spans. Firstly,the force at the top of the piers,which was under the combination of bearing capacity,was imposed on solid element model based on ANSYS. Secondly,the critical condition of the integral and local instability was given by the research on the first-order buckling mode and the eigenvalues of the piers with different thickness; Then,based on the elastic buckle theory of the thin plate with simply supported at all edges,the buckling stress formula of the local instability was dedued,and the limit value of section width-thickness ratio was given to prevent local buckling in the hollow thin-walled high piers. Finally,considering geometric and material nonlinear factors,the integral stability analysis of the high piers was carried out.