【作者】 刘涛；

【导师】 郭彦林；

【作者基本信息】 清华大学 ， 土木工程， 2005， 博士

【摘要】 由于良好的受力性能和方便的梁柱节点构造,箱形截面柱在钢框架结构体系中得到了广泛的应用。对于多层钢框架结构,如果能够在设计中适当放宽框架柱的壁板宽厚比限值将能够有效地减少结构用钢量,从而更有利于这种结构体系的推广。但现行的钢结构设计规范没有给出相应的设计方法。利用弹塑性三维大挠度板壳有限元方法,本文对箱形截面构件及采用箱形截面构件的多层钢框架进行了系统研究,揭示了其在发生壁板局部失稳时的受力性能。研究过程中考虑了焊接残余应力、构件初弯曲以及壁板的初始缺陷对构件稳定极限承载性能的影响。本文首先分别对承受轴心压力、纯弯曲以及同时承受轴心压力和弯矩的箱形截面短柱和长柱进行了系统的参数研究。研究了构件的壁板宽厚比(D/t)、截面边长比(B/D)以及长细比(λ)对其稳定极限承载性能的影响。在大量数值分析的基础上,彻底抛弃了“有效宽度”的概念,提出了直接以构件三个几何参数为自变量的稳定承载力计算公式。公式统一了利用壁板屈曲后强度与不考虑壁板屈曲后强度的两种设计方法,大大简化了设计程序。研究了箱形截面构件的非弹性等效弯矩系数并比较了其与弹性等效弯矩系数以及现行钢结构设计规范简化计算公式的区别。研究了使用箱形截面框架柱的钢框架静力稳定极限承载性能。分析了框架柱壁板宽厚比(D/t)对钢框架承载能力以及破坏机理的影响。对箱形截面构件在轴向拉压、常轴力循环弯矩作用下的滞回性能进行了研究。分析了构件的壁板宽厚比(D/t)、截面边长比(B/D)、长细比(λ)以及轴向荷载水平(N/Nu)对构件滞回性能的影响。在系统研究的基础上,对箱形截面构件的滞回性能进行了评估。评估结果表明,在抗震设防烈度较低或者非抗震设防地区,在严格控制框架柱轴向荷载水平的情况下,可以适当放宽框架柱的壁板宽厚比限值。本文最后通过几个典型的算例对现有的三类钢框架设计方法即计算长度系数法、二阶弹性分析方法和二阶弹塑性分析方法进行了分析、比较及评价。更多还原

【Abstract】 Box-section beam-column is used more and more widely because of its goodload-carrying capacity. The Chinese Code for Design of Steel Structures(GB50017-2003) has not proposed a detailed method in the design of box-sectionbeam-column considering plate local buckling. For a multi-storey steel frame, thedesign can save a great amount of consumed steel if local buckling of plates formingbox section is permitted. But the present specification did not propose thecorresponding design method.A 4 nodes and 24 DOFs shell element provided by ANSYS software package isemployed to investigate the influence of component plates’ local buckling on theultimate load-carrying behavior of box-section beam-column. The influence of largedisplacement and elastic-plastic material, residual stress and initial imperfection arealso incorporated into the analysis.A detailed parameter study on the box-section beam-column subject to the axialcompressive force, pure bending and both the axial compression and end moments iscarried out to review the effect of component plates’ width to thickness ratio (D/t),section aspect ratio (B/D) and member’s slenderness ratio. Based on numbers ofnumerical results, design formulas that are expressed directly as the function of widthto thickness ratio (D/t), section aspect ratio (B/D) and member’s slenderness ratio (λ)are proposed.The nonlinear effective moment factor is researched, and a comparison of theelastic effective moment factor with the results from current Chinese steel structuredesign code is made , respectively.The ultimate load-carrying capacity of steel frame is researched, and the effect ofcomponent plates’ local buckling on the frame’s load-carrying capacity and failuremode is reviewed.The hysteretic behavior of box-section beam-column subject to cyclic axial loadand a combination of the constant axial compressive force and cyclic moment isresearched. The influence of component plates’ width to thickness ratio (D/t), sectionaspect ratio (B/D), member’s slenderness ratio (λ) and the amount of axialcompressive force is studied detailedly. Based on the evaluation of members’hysteretic behavior, some design suggestions are presented.The effective length factor method, second order elastic analysis method andsecond order elastic-plastic analysis method are used in the design of six typicalframes individually. Based on the comparison of calculation results, an evaluation ismade to the precision of the above methods.更多还原