轻型钢结构节约造价的几个途径

结合轻钢规程,提出钢结构,主要是门式钢架结构设计中减轻材料重量以节约造价重要途径。包括合理选用彩钢板,最优柱距选择,合理的截面形式,塑性设计,工形截面腹板屈曲强度利用,楔形构件和变截面构件的应用,考虑结构相互约束作用和蒙皮效应等。     

轻钢结构建筑的应用发展及优化设计

介绍了国内轻钢结构建筑的特点及应用发展，从合理选择柱网尺寸，采用变截面构件或塑性设计等，对门式刚架轻型结构的优化设计提出了技术措施。     

多层轻钢结构框架设计

对轻钢框架结构适用范围、主要优点、材料选型和设计中的注重点均作了扼要介绍和总结，对结构构件的电算结果进行了分析，解决了节点设计中粱柱连接的问题，并指出轻钢框架结构有更好的应用前景。     

轻钢结构建筑破坏原因分析和预防建议

结合轻钢结构建筑破坏实例,从设计、施工、使用维护和灾害反应几方面分析了导致轻钢结构建筑破坏的主要原因,提出预防轻钢结构破坏的建议,包括适当提高轻钢结构安全储备和荷载水平、改善分析设计水平、加强围护结构和次要受力构件、重视施工安全保证施工质量等等.     

浅谈轻钢结构设计理念

结合轻钢结构的特点，从概念设计理念、一体化设计理念和截面优化设计理念等方面，论述了轻钢结构的设计理念，以不断充实钢结构设计思维，突破传统结构约束，不断适应新形势的要求?     

门式刚架轻钢结构的应用及设计分析

门式刚架轻钢结构是目前国内应用和发展速度最快的新型结构形式，随着以冷弯薄壁型钢和彩色压型钢板为标志的新型围护结构和材料的出现．门式刚架轻钢结构“轻”的特征更加突出．主要体现有恒荷载轻：采用轻质围护结构，恒荷载及地震作用大幅度减小．基础形式简单．对地基要求低：构件截面轻．采用新的设计理论、高强钢材、新结构体系．承     

轻钢桁架混凝土楼板试验研究

轻钢桁架混凝土楼板是轻钢轻混凝土结构体系配套的一种采用免拆模板的新型单向密肋楼板,该楼板由轻钢桁架和普通混凝土组成。本文通过轻钢桁架混凝土楼板受弯承载力试验,结合型钢混凝土和钢筋混凝土受弯构件工作原理,研究了其受弯承载力、裂缝宽度及短期抗弯刚度的计算方法。结果表明该楼板各工作阶段与钢筋混凝土受弯构件类似,受弯承载力与截面高度、受拉钢材面积基本成线性关系,抗弯刚度与受拉钢材面积基本成线性关系,与截面高度成二次方关系。     

蒙皮支撑新型轻钢龙骨墙柱的屈曲性能

采用标准V型连接件连接薄壁方钢管构成墙柱的承重骨架,是一种新型的轻钢龙骨结构。墙柱外侧或内侧包覆墙板材料构成的组合墙体,是这种轻钢结构房屋中主要的竖向受力构件。由于其结构形式的特殊性,目前尚缺乏适用的设计理论和设计规范。首先根据应变能等效原则,给出这种特殊形式的轻钢龙骨墙柱的等效截面。墙板材料对于轻钢龙骨墙柱的屈曲性能有着重要影响,考虑墙板材料对于墙柱的蒙皮支撑效应,建立双侧有相同墙板材料和单侧有墙板材料时墙体的总势能方程,采用里兹法导出这两种支撑条件下轻钢龙骨墙柱的轴压弹性屈曲荷载计算公式,给出的计算公式可供工程设计和应用参考。     

轻钢屋面厂房鉴定及加固方案分析

某轻钢屋面厂房，改造过程中由于钢构件本身损伤、设计缺陷及使用条件的改变，导致钢构件应力比不满足相关规范要求。以该工程为例对改变计算图形及加大截面两种加固方案进行比选，选择最优方案并对不满足规范要求的构件进行加固。     

轻钢建筑结构方案及构件设计研究

本文结合一幢二层轻钢结构住宅设计实例,分析研究了轻钢结构框架构件的强度及稳定验算、计算分析要点和常见的设计过程较难解决的屋盖支撑、拉条构件、拉条连接及其概念上的差异问题。     

门式刚架轻型房屋钢结构设计的几点问题

比较了梁柱轴线取法不同对内力分析结果的影响,对门式刚架稳定性计算的各有关问题进行了详细的计算分析,提出了简化计算公式,可供设计人员参考.对内力分析采用一阶和二阶方法产生的差别也进行了讨论.     

Elastic buckling load of multi-story frames consisting of Timoshenko members

The objective of this paper is to propose a method for the evaluation of the elastic critical buckling load of columns in frames consisting of members susceptible to non-negligible shear deformations, such as built-up members in steel frames, based on Engesser's approach. To that effect, a stability matrix is proposed and three general stability equations are derived for the cases of unbraced, partially braced and braced frames. Indicative graphic interpretation of the solutions for the stability equations of the braced and unbraced cases is shown. Slope-deflection equations for shear-weak members with semi-rigid connections are also derived and used for the presentation of a complete set of rotational stiffness coefficients, which are then used for the replacement of members converging at the bottom and top ends of the column in question by equivalent springs. All possible rotational and translational boundary conditions at the far end of these members, as well as the eventual presence of axial force, are considered. Five examples are presented, dealing with braced, unbraced and partially braced frames, with rigid and semi-rigid beam to column connections, loaded with concentrated or uniformly distributed loads, in a symmetrical or non-symmetrical pattern. In all cases the proposed approach is in excellent agreement with finite element results.     

Effect of sequence of construction in the analysis of multistoreyed building frame

Multistoreyed building frames are analysed in a single step on the assumption that the frame is subjected to design load once the whole frame is constructed completely. In fact the dead load due to the various members and finishing items are imposed in stages as the frame is constructed storey by storey.In this paper, a model of the sequence of construction has been assumed and two multistoreyed frames of different configurations have been analysed. The results of analyses along with a comparison with conventional one step analysis have been presented. The effect of sequence of construction due to the self-weight of members has been studied and its effect on the overall design forces has also been highlighted.     

Optimum design of cold-formed steel portal frame buildings including joint effects and secondary members

In steel portal frames, cold-formed steel channel sections are increasingly used as the primary framing components, in addition to the secondary members e.g. purlins and side rails. For such framing systems, the stiffness of the joints at the eaves and apex affects the bending moment distribution, as well as the frame deflections. This paper investigates the influence of two joint configurations having full rigidity and semi-rigidity, respectively, on the optimum design of cold-formed steel portal frames. A real-coded genetic algorithm is used to search for the most cost-effective design. It is shown that through incorporating joint effects explicitly into the design process, a more appropriate balance between the joints and the member properties can be obtained, thus optimizing material use. The study then investigates the effect of secondary members on the optimum design. It is shown that incorporating the secondary members is important for portal frames having spans shorter than 12 m. For example, for a frame spacing less than 6 m, the material cost of the primary members can be reduced by up to 15%.     

门式钢框架轻型化的技术措施

论述门式钢框架轻型化的技术措施,包括变化构件截面、减小腹板厚度、把中柱设计为摇摆柱、利用底板式简单柱脚的转动约束和屋面板的蒙皮效应等.给出了相应的计算方法和计算原则.     

薄柔截面构件屈曲铰及钢框架破坏机构分析

对H形薄柔截面构件组成的钢框架结构的极限承载性能及变形性能进行研究。首先对H形薄柔截面钢构件的破坏机制、承载能力、变形及耗能能力等特性进行总结,表明薄柔截面构件延性虽弱,在抗震设计中仍可以被用于耗散能量。针对薄柔截面构件的承载和变形特性,阐述屈曲铰的特征和实现条件。通过引入屈曲铰,对薄柔截面构件钢框架的非线性发展过程进行数值分析。分析结果表明,由“弱延性”构件组成的超静定框架可以实现非线性变形发展条件下的内力重分布,并使框架结构表现出一定的延性。基于结构的最终破坏机构模型,对薄柔构件利用屈曲铰模型,采用极限状态分析法预测框架结构的极限承载能力,并通过2个框架试验验证该方法的可行性。     

循环荷载作用下钢筋混凝土框格单元结构受力机理试验研究

为研究密肋复合墙板内钢筋混凝土框格单元结构的力学性能退化机理,对3个不同相对刚度比的框格单元及3个空框格结构进行了1/2比例模型循环加载试验。分析钢筋混凝土框格单元结构的破坏发展过程,探讨了外围框格构件对结构承载能力与变形能力的影响。研究结果表明框格单元结构的破坏顺序与结构相对刚度有关。随着结构相对强度的变化,框内填充砌体表现出不同的破坏模式。压缩变形越大,框格单元结构变形滞后现象越明显。界面缝隙对框格单元结构的初始刚度影响显著,但对峰值承载能力影响较小。经多次加卸载循环后,框格单元结构的峰值承载能力仍远高于对应的空框格结构。当外围框格构件与填充砌体在刚度与强度两方面均匹配时,填充砌体刚度退化较慢。     

半刚接刚架内力性能分析

在节点半刚性连接的线性化模型基础上,对工程中常用的4种类型半刚接刚架进行了内力分析,推导了刚架杆端弯矩的计算公式。对传统刚接刚架计算弯矩值用乘以弯矩系数的方法进行修正,得到半刚接刚架弯矩值,可应用于工程设计。分析结果表明,随着刚度比增大,节点约束程度减弱,刚架横梁跨中弯矩增大,梁端弯矩减小,节点半刚性对刚架受力性能有明显影响,在刚架分析和设计中应加以考虑。     

Experimental investigation of behavior of steel frames with y-shaped concentric bracing

Concentric bracings composed of three members arranged in y-shaped geometry have been traditionally used to provide openings in braced bays. However, using common single gusset plates in y-braced frames leads to single curvature flexure and out of plane buckling of braces accompanied by low hysteretic energy dissipation. In order to explore and improve the behavior of y-braced frames, a research program including experimental tests was conducted at BHRC¹ structural engineering laboratory. Specimens presented in this paper include four full-scale frames with y-bracings of different geometries and cross sections. Quasi-static cyclic loading was increasingly applied until yielding and failure occurred in the specimens. The results show that out-of-plane buckling with single curvature in braces can be replaced by in-plane, double curvature buckling through appropriate detailing of cross sections and connections. These sections have larger radius of gyration for out of plane buckling of bracing members. Hysteretic energy dissipation and damping of y-bracing are increased due to inelastic flexural deformation of brace members. Energy dissipation capacity of y-braced frames with new details is comparable with the traditional X bracing. Based on these findings, two-bay y-braced frames were designed to carry the same lateral load as X-braced frames. The seismic performance of these frames was compared using nonlinear static procedures and found to be similar.     

An efficient method for computation of effective length factor of columns in a steel gabled frame with tapered members

The concept of effective length is the only available common method for column design without non-linear structural analysis. Researches conducted for determination of effective length of members are mainly related to a constant moment of inertia. In many investigations related to members with variable moment of inertia, finite element and approximation methods are used. In this article, a method for quick calculation of the effective length factor of columns in steel gabled frames with tapered members is proposed. The method is based on two-dimensionless design-oriented charts relating the critical load of columns to frame characteristics and boundary conditions. Since I-sections are usually used for gabled frames members, the variation of moment of inertia along the length of members (beams or columns) is approximated as a parabolic function. As is demonstrated in the Numerical studies, these calculations can yield, in a very efficient way, accurate results for gabled frames consisting of tapered elements.