摘要
结合48 m跨桁架栈桥项目,先对上下弦杆承担弯矩、腹杆承担剪力的简支梁简化计算模型进行桁架截面预设计,简化计算结果与有限元分析结果接近,可用于估算桁架栈桥的强度承载能力。通过增设上下弦层的斜撑和竖向平面支撑,提出两种增强桁架侧向稳定的不同优化方案,分别进行线性屈曲分析和整体稳定性分析。结果表明,上下弦杆增设斜撑后,第一阶线性屈曲荷载可增加3.57倍,若横向间隔设置K形支撑则可增加4.61倍,考虑初始缺陷的几何非线性分析得到的稳定承载力分别提高了11%和21%,而增设支撑导致的用钢量增加不多。钢桁架暴露于室外,温度作用较大,考虑温度效应时必须释放纵向和横向约束,从而有效减小杆件的应力。
With the background of the 48 m-span truss trestle project, the strength bearing capacity of the truss was analyzed according to the simplified calculation model, which the simply supported beams with the upper and lower chords bearing the bending moment and the web members bearing the shearing force. The simplified calculation results were close to the finite element analysis results, and it could be used to estimate the truss trestle. Through diagonal bracing and vertical plane bracing on the upper and lower chord layers, two different optimization structure schemes for enhancing the lateral stability of the truss were proposed, and the linear buckling analysis and the overall stability analysis were carried out respectively. The results show that the first-order linear buckling load of the second scheme is increased by 3.57 times, and that of the third scheme is increased by 4.61 times, which can effectively improve the lateral stability of the truss. The stable bearing capacity of the second and third options is increased by 11% and 21% respectively, while the amount of steel used is not increased much. When the steel truss is exposed to the outside, the temperature effect is so great that the longitudinal and transverse restraints must be released when considering the temperature effect, so the stress of the member can be reduced effectively.
作者
沈意
SHEN Yi(Zhejiang College of Construction,311231,Hangzhou,China)
出处
《建筑技术》
2024年第5期525-528,共4页
Architecture Technology
基金
浙江省住房和城乡建设厅建设科研项目(2021K201)。
关键词
桁架栈桥
侧向稳定
简化计算模型
线性屈曲分析
整体稳定性分析
温度效应
释放约束
truss trestle
lateral stability
simplified calculation model
linear buckling analysis
overall stability analysis
temperature effect
release restraint
