考虑轴力与底板约束的埋入式钢柱脚刚度模型  

Stiffness model for embedded steel column bases considering the effects of axial force and constraint of base plate

作　　者：赵宪忠[1,2] 许晓旭 闫伸[1,2] ZHAO Xianzhong;XU Xiaoxu;YAN Shen(State Key Laboratory of Disaster Reduction in Civil Engineering(Tongji University),Shanghai 200092,China;College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]土木工程防灾国家重点实验室(同济大学),上海200092 [2]同济大学土木工程学院,上海200092

出　　处：《哈尔滨工业大学学报》2024年第2期18-27,共10页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金(52178152)。

摘　　要：为准确预测埋入式(特别是浅埋)钢柱脚节点的初始转动刚度,将柱脚的埋入段简化为地基梁,基于初参数法完善考虑轴力影响的Winkler地基上的Timoshenko梁理论,提出受锚栓和混凝土约束的柱脚底板转动刚度的计算方法,进而建立可以综合反映柱脚埋深、埋入段剪切变形、钢柱轴力、底板约束影响的埋入式钢柱脚转动刚度模型。基于已验证的有限元模型进行参数分析,研究埋深比、轴力和锚栓布置对柱脚转动刚度的影响。与有限元结果的对比表明,提出的刚度模型较过往文献中理论模型具有更高的精度和更好的适用性,尤其是对于埋深比为0.5~1.5的浅埋柱脚节点。理论与有限元结果表明:埋深比较小时,柱脚转动刚度随埋深比的增加快速增大,而埋深比增加到一定程度后,其对转动刚度几乎无影响;柱脚转动刚度随钢柱轴压力增加呈增大的趋势;对于浅埋柱脚节点,底板约束对其转动刚度的影响较大,而随着埋深的增大,其影响逐渐减小;底板转动约束对埋深比小于1.5的节点刚度具有显著影响,当埋深比增大至2.5,其影响可以忽略。In order to accurately predict the rotational stiffness of embedded steel column bases,shallowly embedded,in particular,this paper proposes a stiffness model that collectively allows for the effects of the embedded depth,shear deformation of the embedded column,axial force applied to the column and restraint from the base plate.For developing the model,the embedded segment of the column is simplified as a beam on the Winkler foundation,and its deformation is computed using the Timoshenko beam theory on Winkler foundation,considering the influence of axial force applied to the column and solved by initial parameter method.To investigate the influence of the above-mentioned factors and verify the proposed model,finite element(FE)models are developed and validated against existing experimental results.Comparisons between the FE results and model predictions show that the proposed model exhibits higher accuracy than the theoretical models reported,especially for shallowly embedded column bases.The model prediction and FE results indicate that the rotational stiffness of the column base depends on the embedded depth in a nonlinear fashion-the stiffness increases rapidly for small embedded depth but remains almost constant when embedded depth is larger than a certain value;the axial compression load applied to the steel column is a beneficial factor to the stiffness;the restraint from the base plate shows a significant effect on the rotational stiffness of embedded column bases with the embedded depth ratio less than 1.5,being negligible when the embedded depth ratio increases up to 2.5.

关 键 词：埋入式柱脚 转动刚度 埋深 轴力 底板约束 TIMOSHENKO梁 WINKLER地基 

分 类 号：TU391[建筑科学—结构工程]