“上”形截面钢梁弯扭联合作用下整体稳定性分析

发布时间：2018-01-26 07:10

本文关键词： 桥梁工程 “上”形截面钢梁整体稳定性整体稳定系数偏跨比　出处：《建筑科学与工程学报》2017年05期 　论文类型：期刊论文

【摘要】：为对"上"形截面钢梁弯扭联合作用下的整体稳定性进行分析,采用有限元数值计算方法,通过失稳模态考虑构件L/1 000(L为跨径)的几何初始缺陷,对比已有文献试验结果,验证了模拟方法的正确性,在此基础上,对跨中集中荷载和满跨均布荷载作用下的简支"上"形截面钢梁整体稳定性进行分析,通过曲线拟合给出了"上"形截面钢梁整体稳定系数计算公式,分析了荷载偏心距和跨径对稳定承载力及弯扭效应分配的影响。研究结果表明:通过失稳模态考虑构件L/1 000几何缺陷可以准确地计算稳定承载力;"上"形截面钢梁整体稳定系数的取值较国标规范工字梁小,且均布荷载较集中荷载小;"上"形截面钢梁的稳定承载力随着偏心距和跨径的增加逐渐降低,且影响程度也逐渐变小;偏跨比较大时,失稳破坏主要由扭转效应引起,偏跨比较小时,则主要由弯曲效应引起;集中荷载较均布荷载更容易使"上"形截面钢梁失稳;使用《冷弯薄壁型钢结构技术规范》(GB50018—2002)进行"上"形截面钢梁的整体稳定性验算会偏于不安全。
[Abstract]:In order to analyze the overall stability of steel beam with "upper" section under the combined action of bending and torsion, the finite element numerical method is used. The geometric initial defects of the component L / 1 000 L are considered by the instability mode. The correctness of the simulation method is verified by comparing the experimental results. The overall stability of simply supported "upper" section steel beam under concentrated load and full span uniform load is analyzed, and the formula of overall stability coefficient of "upper" section steel beam is given by curve fitting. The effects of load eccentricity and span on the stability bearing capacity and the distribution of bending and torsion effect are analyzed. The results show that the stability bearing capacity can be accurately calculated by considering the geometric defects of the member L / 1 000 by considering the instability mode. The overall stability coefficient of steel beam with "upper" section is smaller than that of I-beam of GB standard, and the uniform load is smaller than that of concentrated load. With the increase of eccentricity and span, the stable bearing capacity of "upper" section steel beam decreases gradually, and the influence degree becomes smaller. When the span is large, the instability is mainly caused by torsional effect, but when the span is small, it is mainly caused by the bending effect. The concentrated load is more likely to make the steel beam with "upper" section unstable than the uniformly distributed load. Using the Technical Specification for Cold-Formed Thin-walled Steel structures (GB50018-2002) to check the overall stability of steel beams with "upper" section will be considered unsafe.
【作者单位】：长安大学公路学院;青海省交通科学研究院青藏高原公路建设与养护重点实验室;中交第二公路勘察设计研究院有限公司;
【基金】：交通运输部建设科技项目(2014 318 363 230) 陕西省交通运输厅科研项目(15-24K,16-29K)
【分类号】：U441
【正文快照】： 0引言在桥梁钢结构中,钢梁是最基本的受力构件,往往在主轴平面内承担由横向荷载所产生的弯矩、剪力以及荷载偏心时产生的扭矩作用,如果没有设置足够的平面外支撑,钢梁的上翼缘在压应力作用下发生侧向失稳进而带动整个截面发生侧向弯曲和扭转,使构件在未到达强度破坏之前就丧失

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