圆钢管空间桁架结构的直接分析设计方法研究

王珺; 卿强; 龚景海

doi:10.13206/j.gjgS22101701

圆钢管空间桁架结构的直接分析设计方法研究

doi: 10.13206/j.gjgS22101701

王珺^1,2,
卿强^1,2,
龚景海^1,2, ,

1. 上海交通大学土木工程系, 上海 200240;
2. 上海市公共建筑和基础设施数字化运维重点实验室, 上海 200240

详细信息

作者简介:
王珺,男,1998年出生,硕士研究生,wangjun9861@sjtu.edu.cn

通讯作者:
龚景海,男,研究员,gongjh@sjtu.edu.cn。

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- 被引次数: 0
出版历程
- 收稿日期: 2022-10-17
- 网络出版日期: 2023-04-20

Study on Direct Analysis and Design Method of Space Truss Structure with Steel Pipes

WANG Jun^1,2,
QING Qiang^1,2,
GONG Jinghai^{1,2
, ,}

1. Department of Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2. Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure, Shanghai 200240, China

摘要

摘要: 目前国内外多部钢结构设计标准将直接分析法推荐为钢结构分析设计首选方法,然而对应用于圆钢管空间桁架结构这一结构形式的直接分析法中,构件初始缺陷的施加方向、施加初始缺陷后构件的模拟方法、截面纤维划分方法的实施细则并未详细说明,还存在亟需解决的问题。故采用基于位移的梁柱单元,综合考虑几何非线性、材料非线性、圆钢管空间桁架结构整体初始缺陷、圆钢管构件初始缺陷等对结构稳定和承载力有重要影响的因素,对结构进行非线性分析及满应力优化设计,提出了圆钢管空间桁架结构直接分析设计流程。以某实际工程中三心圆桁架结构的一榀主桁架为例,对比了不同的构件等分数、初始几何缺陷的施加方向和不同的圆钢管截面纤维划分数情况下的结构z向最大变形,构件的应力、轴力和弯矩结果,研究了这三个因素对圆钢管空间桁架结构直接分析结果的影响规律。通过与传统一阶弹性分析方法计算结果对比,以验证提出的圆钢管空间桁架结构直接分析设计方法在工程实际中的适用性。结果表明:在1.3D+1.5L和0.9D+1.5W组合工况下,随着引入初始缺陷后构件等分数的增加,计算的桁架变形及构件的应力均逐渐增大;随着构件初始几何缺陷施加方向绕构件二轴方向旋转角度的增加,直接分析计算得出的结构z向最大变形、构件的应力和二轴弯矩均呈现递减趋势,其中构件二轴弯矩受影响较大,其变化率超过80%;由于圆钢管壁厚相对周长而言小很多,径向等分数从2增加到4时,结构计算结果变化十分有限,变形和应力的变化率均小于0.1%;在0.9D+1.5W组合工况下,环向等分数为32时的结构z向最大变形与环向等分数为4时相差达15.9%,说明截面环向划分数对结构刚度有着不可忽略的影响;对于圆钢管空间桁架结构中构件长细比较小的构件,直接分析设计方法与传统一阶弹性分析方法两者计算得出的应力较为接近,两种工况下应力结果差异小于3%,而对于细长构件,两种计算方法的计算结果差距较明显,差异可达25.5%。
- 直接分析法 /
- 圆钢管空间桁架结构 /
- 构件等分 /
- 初始缺陷 /
- 截面纤维模型
Abstract: At present, many steel structure design standards at home and abroad recommend the direct analysis method as the preferred method for steel structure analysis and design. The simulation method of the rear member and the implementation details of the cross-section fiber division method are not described in detail. The displacement-based beam-column element is used to comprehensively consider the geometric nonlinearity, material nonlinearity, the overall initial defect of the circular steel tube space truss structure, the initial defect of the circular steel tube member and other factors that have an important influence on the structural stability and bearing capacity, and the nonlinear analysis of the structure is carried out. Based on the analysis and full stress optimization design, the direct analysis and design process of the circular steel tube space truss structure is proposed. Taking a main truss in an actual project of a three-center truss structure as an example, the structural orientations of different member equal fractions, different initial geometric defect application directions of different members, and different fiber division numbers of circular steel tube sections are compared. The maximum deformation of z-direction, the stress, the axial force and the bending moment of the member are studied. The influence of these three factors on the results of the direct analysis of the circular steel tube space truss structure is studied. By comparing the calculation results with the traditional first-order elastic analysis method, the applicability of the proposed direct analysis and design method of the circular steel tube space truss structure in engineering practice is verified. The results show that: under the combined working conditions of 1.3D+1.5L and 0.9D+1.5W, the calculated truss deformation and the stress of the members increase gradually with the increase of the equal fraction of the members; With the increase of the rotation angle of the maximum bending direction of the member around the biaxial direction of the member, the maximum z-direction deformation of the structure obtained by direct analysis and calculation, the stress of the member and the biaxial bending moment all show a decreasing trend, and the biaxial bending moment of the member is greatly affected with a change rate exceeding 80%; because the wall thickness of the round steel pipe is much smaller than the circumference, the change of the structural calculation results is very limited when the radial equal fraction increases from 2 to 4, and the change rates of deformation and stress are both less than 0.1%. Under the combined condition of 0.9D+1.5W, the maximum z-direction deformation of the structure when the hoop equal fraction is 32 is 15.9% different from that when the hoop equal fraction is 4, indicating that the number of section divisions has a nonnegligible effect on the structural stiffness; for the members with small slenderness in the circular steel tube space truss structure, the stress calculated by the direct analysis and design method and the traditional first-order elastic analysis method are relatively close, and the difference between the stress results under the two working conditions is less than 3%. For slender members, the difference between the calculation results of the two calculation methods is obvious, and the difference can reach 25.5%.
- direct analysis /
- space truss structure with steel pipe /
- equal division of member /
- initial defect /
- fiber section

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参考文献(12)

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