下承式系杆钢拱桥施工阶段风致响应分析

风灾是沿海地区最为频发的自然灾害,具有登陆频繁,破坏力强,影响范围广等特点,对桥梁具有较大的危害。下承式系杆钢拱桥属于较为柔性的结构体系,风荷载对其作用比较明显,以实际工程为研究背景,采用MATLAB软件模拟了施工阶段桥梁的三维风场,采用有限元软件ANSYS对下承式系杆钢拱桥在施工阶段的风致响应进行分析。结果表明,施工阶段的桥梁在脉动风荷载作用下具有较好的力学性能,能够抵抗较强的风力作用。     

大跨径异型系杆钢拱桥主桥吊装施工技术

莆田城港大道跨木兰溪大桥主桥是两跨简支的双肋下承式钢箱拱肋结合梁桥面系的异型系杆拱桥,2跨跨径均为72 m.介绍大跨径异型系杆钢拱桥吊装施工技术,对钢结构拱桥安装的主要受力杆件进行计算,可供同类吊装施工参考和借鉴.     

下承式异形系杆钢拱桥抗震性能分析

近年来,钢拱桥凭借着自身的独特优点越来越被人们所应用,随着人们对桥梁美学追求的不断提高,拱肋外倾的拱桥也就随之产生,但其结构构造比较复杂,因此地震反应也比较复杂。通过对某下承式异形系杆钢拱桥为例,利用Midas Civil程序建立有限元模型,研究其动态特性以及在横向和纵向地震作用下的抗震性能。     

大跨度钢-混叠合梁简支系杆钢拱桥施工控制分析

结合上海市松江区玉阳大道新建工程北泖泾桥主桥工程的施工过程,就下承式钢–混叠合梁简支系杆钢拱桥的施工工序和质量控制进行简要分析。     

下承式钢管混凝土系杆拱桥施工过程稳定性分析

在拱桥设计中稳定问题至关重要,随着施工技术的发展,施工过程中的稳定性是否满足要求往往成为一个控制因素。本文以一座下承式钢管混凝土系杆提篮拱桥为例,利用有限元软件ANSYS对其施工过程主要阶段及成桥运营阶段进行特征值屈曲分析,得到相应的稳定安全系数,其结果分析表明了该桥在施工过程及运营阶段均不会出现失稳现象。     

《大跨度下承式刚性系杆钢拱桥整体吊运及吊装技术研究与应用》课题通过科技成果鉴定

2013年8月1日,由中国钢结构协会在广东省中山市组织召开了《大跨度下承式刚性系杆钢拱桥整体吊运及吊装技术研究与应用》成果鉴定会。鉴定委员会由中国钢结构协会刘万忠秘书长、中山广船国际船舶公司杨茨祥总工程师等7人组成,成果主要完成单位是中机建重工有限公司、西南交通大学、广州航海高等专科学校。鉴定会上,中机建设公司技术负责人对各位专家的到来表示热烈欢迎,     

斜靠式拱桥力学性能分析

以有限元为理论基础,以数值模拟为计算手段,对斜靠式拱桥静力、屈曲、动力特性和反应谱作用等方面进行了分析。拱桥在自重和车道荷载作用下,主拱轴力符合一般拱桥力学概念,斜靠拱受到主拱作用,在拱顶轴力最大。在恒载和使用荷载作用下,拱桥纵向和横向稳定系数值都大于5,满足拱桥稳定性要求。动力特性分析表明,相对于纵向刚度,横向刚度较弱,故在设计和施工中需注意主拱与稳定拱上部连接可靠、变形协调、空间受力一致。斜靠式拱桥在空间三个方向反应谱作用下,主拱在竖向激励下轴力最大,稳定拱为在竖向和横向激励下最大。纵观不同方向作用,纵向刚度较大,而地震作用较小。综合不同方向地震作用,主拱和稳定拱轴力分布规律大致类似于静力作用效果。     

鲁南高铁洸府河特大桥1-128 m简支系杆拱施工技术

目前我国高铁桥梁建设技术处于世界领先地位,高铁建设中采用了大量的新型结构。结合鲁南高铁洸府河特大桥1-128 m简支钢管混凝土系杆拱桥工程实际,对系杆钢拱桥在施工过程中采取的技术方案、施工措施、质量控制关键环节等进行了详细论述。工程实践证明该工程所采用技术措施合理可行,效果显著,可以为同类工程积累、传递实践经验,具有一定的借鉴、推广意义。     

大跨度下承式简支系杆钢拱桥拱肋方案研究

某桥为主跨345 m下承式简支系杆钢拱桥,为特大型市政桥梁。主跨300 m以上的同类型桥梁在国内外应用较少。以该桥为研究对象,从截面形式、矢高、拱轴线形等方面对该桥进行拱肋方案研究。分析结果表明:基于研究确定的拱肋方案,该结构体系各项指标满足要求,可应用于大跨度市政桥梁。研究成果和研究方法可为同类型桥梁设计提供参考。     

系杆拱桥钢锚箱结构的优化设计及制造工艺

系杆拱桥钢钻箱,具有“承受大吨位,适应小空间”的特点,给设计和制造增加了难度。对佛陈大桥系杆钢锚箱结构进行了空间应力仿真分析,提出了结构优化设计方案,并介绍了钢锚箱的制造工艺。设计方案和制造工艺可为类似钢锚箱的设计和制造提供借鉴。     

斜梁加腋山形门式单层刚架的平面整体屈曲

在竖向荷载作用下 ,山形门式单层多跨刚架平面内可能产生两种整体分岔屈曲模式 ,一种是侧移屈曲 ,另一种是跃越屈曲。介绍了影响刚架屈曲的拱效应和为避免发生整体屈曲的准则。     

两端铰接楔形压弯杆平面外稳定

用有限元方法计算楔形压杆的平面外屈曲荷载 ,并按能量法推导出表达式 ,对系数进行修正 ,得到物理意义明确 ,精度较高的扭转、弯扭屈曲荷载表达式 ,该公式形式与等截面压弯杆屈曲荷载的计算公式类似。最后还给出梁柱P -M关系 ,以便于在工程中应用。     

Finite strip elastic buckling solutions for thin-walled metal columns with perforation patterns

Approximate finite strip eigen-buckling solutions are introduced for local, distortional, flexural, and flexural-torsional elastic buckling of a thin-walled metal column with perforation patterns. These methods are developed to support a calculation-based strength prediction approach for steel pallet rack columns employing the American Iron and Steel Institute׳s Direct Strength Method, however they are generally posed and could also be useful in structural studies of thin-walled thermal or acoustical members made of steel, aluminum, or other metals. The critical elastic global buckling load including perforations is calculated by reducing the finite strip buckling load of the cross-section without perforations using the weighted average of the net and gross cross-sectional moment of inertia along the length of the member for flexural (Euler) buckling, and for flexural-torsional buckling, using the weighted average of both the torsional warping and St. Venant torsional constants. For local buckling, a Rayleigh–Ritz energy solution leads to a reduced thickness stiffened element equation that simulates the influence of decreased longitudinal and transverse plate bending stiffness caused by perforation patterns. The cross-section with these reduced thicknesses is input into a finite strip analysis program to calculate the critical elastic local buckling load. Local buckling at a perforation is also treated with a net section finite strip analysis. For distortional buckling, a reduced thickness equation is derived for the web of an open cross-section to simulate the reduction in its transverse bending stiffness caused by perforation patterns. The approximate elastic buckling methods are validated with a database of 1282 thin shell finite element eigen-buckling models considering five common pallet rack cross-sections featuring web perforations that include 36 perforation dimension combinations and twelve perforation spacing combinations.     

Improved prediction of simultaneous local and overall buckling of stiffened panels

In this paper, improved expressions for elastic local plate buckling and overall panel buckling of uniaxially compressed T-stiffened panels are developed and validated with 55 ABAQUS eigenvalue buckling analyses of a wide range of typical panel geometries. These two expressions are equated to derive a new expression for the rigidity ratio (EI_x/Db)_CO that uniquely identifies “crossover” panels—those for which local and overall buckling stresses are the same. The new expression for (EI_x/Db)_CO is also validated using the 55 FE models. Earlier work by Chen (Ultimate strength analysis of stiffened panels using a beam-column method. PhD Dissertation, Department of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 2003) had produced a new step-by-step beam-column method for predicting stiffener-induced compressive collapse of stiffened panels. An alternative approach is to use orthotropic plate theory. As part of the validation of the new beam-column method, ABAQUS elasto-plastic Riks ultimate strength analyses were made for 107 stiffened panels—the 55 crossover panels and 52 others. The beam-column and orthotropic approaches were also used. A surprising result was that the orthotropic approach has a large error for crossover panels whereas the beam-column method does not. Some possible reasons for this are suggested.     

Buckling analysis of thin-walled cold-formed steel structural members using complex finite strip method

In this paper, a generalised complex finite strip method is proposed for buckling analysis of thin-walled cold-formed steel structures. The main advantage of this method over the ordinary finite strip method is that it can handle the shear effects due to the use of complex functions. In addition, distortional buckling as well as all other buckling modes of cold-formed steel sections like local and global modes can be investigated by the suggested complex finite strip method. A combination of general loading including bending, compression, shear and transverse compression forces is considered in the analytical model. For validation purposes, the results are compared with those obtained by the Generalized Beam Theory analysis. In order to illustrate the capabilities of complex finite strip method in modelling the buckling behavior of cold-formed steel structures, a number of case studies with different applications are presented. The studies are on both stiffened and unstiffened cold-formed steel members.     

不同自由端约束条件下双轴对称工字形截面悬臂梁的稳定性

对自由端侧向位移和扭转简支约束、自由端仅扭转约束和自由端仅简支扭转弹性约束条件下,双轴对称工字形截面悬臂梁的稳定性进行研究,并提出临界弯矩的计算公式。这一计算公式能够考虑悬臂梁长细比的变化,以及横向荷载作用点沿截面高度方向变化对其临界弯矩的影响。通过与有限元结果的比较可以发现,所提出的计算公式可以获得精度良好的临界弯矩值。     

冷弯薄壁梁的屈曲及优化设计综述

介绍了冷弯薄壁梁的整体-局部屈曲和优化,包括:简化分析与计算、数值分析及试验。详细阐述了薄壁梁翼缘和腹板的屈曲问题。采用质量检测方法,对不同横截面薄壁梁进行比较。     

四边简支层合板在剪切作用下的稳定分析

采用伽辽金变分法分析了四边简支的FRP复合材料层合板在纯剪作用下的屈曲荷裁,得出了四边简支层合板的剪切屈曲解析解,并使用有限元软件ANSYS对解析解进行了数值验算与对比分析。所得公式适合长宽比≤4的正交异性层合板,与数值分析结果吻合良好,所得理论公式对实际工程有一定的参考价值,并在一定程度上丰富了复合材料层合板屈曲公式的理论研究。     

两侧边开缝钢板剪力墙弹性屈曲分析

提出一种新型的两侧边开缝的钢板剪力墙,并对其两侧边有无加劲肋的两种结构形式进行有限元弹性屈曲分析,分别讨论其临界屈曲荷栽和屈曲模态。对两侧无加劲肋的钢板剪力墙,给出用于其设计的屈曲系数公式,对两侧有加劲肋的钢板剪力墙给出具有参考价值的设计建议。