• Structural Engineering and Mechanics
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• 제45권3호
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• pp.277-309
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• 2013

Beam-to-column connections behaviour plays an important role in the analysis and design of steel and precast concrete structures. The paper presents a computer-based method for geometrically nonlinear frames with semi-rigid beam-to-column connections. The analytical procedure employs modified stability functions to model the effect of axial force on the stiffness of members. The member modified stiffness matrix, and the modified fixed end forces for various loads were found. The linear and nonlinear analyses were applied for two planar steel structures. The method is readily implemented on a computer using matrix structural analysis techniques and is applicable for the efficient nonlinear analysis of frameworks.

• Structural Engineering and Mechanics
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• 제56권2호
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• pp.169-188
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• 2015

There are two types of nonlinear analysis methods for building frameworks depending on the method of modeling the plastification of members including lumped plasticity and distributed plasticity. The lumped plasticity method assumes that plasticity is concentrated at a zero-length plastic hinge section at the ends of the elements. The distributed plasticity method discretizes the structural members into many line segments, and further subdivides the cross-section of each segment into a number of finite elements. When a reinforced concrete member experiences inelastic deformations, cracks tend to spread form the joint interface resulting in a curvature distribution. The program IDARC includes a spread plasticity formulation to capture the variation of the section flexibility, and combine them to determine the element stiffness matrix. In this formulation, the flexibility distribution in the structural elements is assumed to be the linear. The main objective of this study is to evaluate the accuracy of linear flexibility distribution assumed in the spread inelasticity model. For this purpose, nonlinear analysis of two reinforced concrete frames is carried out and the linear flexibility models used in the elements are compared with the real ones. It is shown that the linear flexibility distribution is incorrect assumption in cases of significant gravity load effects and can be lead to incorrect nonlinear responses in some situations.

• Structural Engineering and Mechanics
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• 제24권4호
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• pp.463-478
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• 2006

The design of structural frameworks for buildings is constantly evolving and is dependent on regional issues such as loading and constructability. One of the most promising recent developments for low to medium rise construction in terms of efficiency of construction, robustness and aesthetic appearance utilises concrete-filled steel tubular sections as the columns in a moment-resisting frame. These are coupled to rigid or semi-rigid connections to composite steel-concrete beams. This paper includes the results of a pilot experimental programme leading towards the development of economical, reliable connections that are easily constructed for this type of frame. The connections must provide the requisite strength, stiffness and ductility to suit gravity loading conditions as well as gravity combined with the governing lateral wind or earthquake loading. The aim is to develop connections that are stiffer, less expensive and easier to construct than those in current use. A proposed fabricated T-stub connection is to be used to connect the beam flanges and the column. These T-stubs are connected to the column using "blind bolts" with extensions, allowing installation from the outside of the tube. In general, the use of the extensions results in a dramatic increase in the strength and stiffness of the T-stub to column connection in tension, since the load is shared between membrane action in the tube wall and the anchorage of the bolts through the extensions into the concrete.

• Structural Engineering and Mechanics
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• 제82권5호
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• pp.595-609
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• 2022

Prestressed composite steel-concrete beams are still a technology restricted to repair sites of large-scale structures and spans. One of the reasons for that is the absence of standard frameworks and publications regarding their design and implementation. In addition, the primary normative codes do not address this subject directly, which might be related to a scarcity of papers indicating methods of design that would align the two technics, composite beams and external prestressing. In this context, this paper proposes methods to analyze the sizing of prestressed composite beams submitted to pre-tension and post-tension with a straight or polynomial layout cable. This inquiry inspected a hundred and twenty models of prestressed composite beams according to its prestressing technology and the eccentricity and value of the prestressing force. The evaluation also included the ratio between span and height of the steel profile, thickness and typology of the concrete slab, and layout of the prestressing cables. As for the results, it was observed that the eccentricity of the prestressing force doesn't significantly influence the bending resistance. In prestressed composite beams subjected to a sagging moment, the ratio L/d can reach 35 and 30 for steel-concrete composite slabs and solid concrete slabs, respectively. Considering the negative bending moment resistance, the value of the L/d ratio must be less than or equal to 25, regardless of the type of slab. When it comes to the value of the prestressing force, a variation greater than 10% causes a 2.6% increase in the positive bending moment resistance and a 4% decrease in the negative bending moment resistance. The pre-tensioned composite beams showed a superior response to flexural-compression and excessive compression limit states than the post-tensioned ones.

• 마케팅과학연구
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• 제20권1호
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• pp.35-48
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• 2010

今天, 受到成熟零售市场挑战的时装市场需要新的 "品牌发展" 典范来提高他们的竞争优势. 时装市场的一个重要议题是为满足消费者由于生活方式的变化而产生的特别需求所进行的生活方式品牌扩张. 时装品牌扩张到生活方式产品类别, Y世代和婴儿潮可以说是新兴的 "前景"(婴儿潮的消费者正在改变他们的生活方式. Y世代正经历着他们生命阶段的变化). 他们有购买新产品的需求. 因此, 服装公司为品牌扩张注重消费群从而在新的产品类别中建立和管理他们的品牌资产是乐观的. 本文的研究目的是(a)评估母品牌和子品牌的品牌资产. (b)鉴定消费者对品牌扩张的感知营销因素. (c)评估两个选择的群体(Y世代和婴儿潮)的营销因素和扩张到生活方式的产品类别(包括家居时尚产品)品牌的品牌资产之间因果关系的结构方程模型. 关于理论框架, 本文关注传统的营销4P组合来鉴定哪个营销因素在品牌扩张资产方面更重要. 比较营销可以建立 "品牌扩张资产", 从而成功的进入新类别. 借鉴相关的文献, 通过关注选择的消费者(Y世代, 婴儿潮), 本研究发展的研究假设结合了品牌资产因子和营销因素. 在品牌扩张至生活方式产品的背景下, 品牌资产的构念包括品牌认知/联合, 品牌感知(例如感知质量, 情感价值)和从CBBE因子(Keller, 2001)中而来的品牌共鸣. 据推测, 通过品牌扩张至生活方式产品, 市场营销要素在品牌认知/联合, 品牌感知方面创建品牌扩张资产, 进而影响品牌的共鸣. 为了收集数据, 样本由韩国Y世代的女性消费者和在婴儿潮中出生的消费者. 这些在婴儿潮中出生的消费者由于生活周期的改变而对生活方式产品有较高的需求. 在韩国Y世代(n=326)和婴儿潮(n=325)的女性消费者中共有651份有用的问卷被使用. 我们用LISREL8.8测试了使用相关矩阵的结构和测量模型. 结果显示品牌扩张的感知营销因素包括三个因子: 价格/店铺形象, 产品和广告. 在Y世代的模型中, 价格/店铺形象对品牌资产因素有积极的影响(例如品牌认知/联合, 感知质量). 同时, 在品牌扩张中产品对情感价值有积极的影响. 品牌认知/联合有可能提高感知质量和情感价值, 从而对扩张至生活方式产积极的品牌产生品牌共鸣. 在婴儿潮消费者模型中, 价格/店铺形象对感知质量有积极的影响, 感知质量可以创造品牌扩张的品牌共鸣. 产品对质量感知和情感价值有正的影响, 这些都会消费者产生对扩张至生活方式产品的品牌的品牌共鸣. 但是, 在这两个群体中广告和品牌资产都是负相关. 本研究为时装营销者提供了发展成功的品牌扩张战略以及可持续的竞争优势的见解. 本研究补充和扩展了先前的有关通过营销努力的因素促使品牌扩张成功的研究. 研究结果支持为进入新的产品类别, 时装品牌扩张(Aaker and Keller, 1990; Tauber, 1998; Shine et al., 2007; Pitta and Katsanis, 1995)和营销行动的增效作用. 因此, 我们推荐营销者同时针对Y世代和婴儿潮一代通过标准化的营销推广进入新产品类别(例如家具)可以降低营销成本. 时装营销者可以(a)提供高价的产品线. (b)在韩国通过零售渠道(例如专门百货商店)强调高档特征的商店形象定位. (c)结合服装与生活方式产品包括新颖的款式和设计师的限量版. 对品牌资产,成功品牌延伸的关键是消费者的品牌认知度和品牌联合,确保新产品类别的品牌特征. 对于营销者来说, 在进入新产品类别的时候知道什么有助于更具体的联合是必要的. 对时装品牌而言, 品牌扩张的第二个关键是进入 "奢侈" 生活方式新产品类别的途径. 更高的价格或店铺形象都对质量感知有影响. 而质量感知可以引起品牌共鸣. 更重要的是, 本研究提高了对品牌扩张的理论理解并对营销者提出了在制定针对Y世代和婴儿潮一代消费者的行销项目时的方向.