• Steel and Composite Structures
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• 제16권3호
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• pp.289-303
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• 2014

In recent, development of construction and design technology gives taller, larger and heavier steel framed structures. With the tendency of increasing high-rise building, this study is strongly related to structural system, one of significant components in structural design. This study presents an innovative structural system, with high performance steel material, diagrid. Its detail, structural analysis, and structural experiments are all included for the development of new structures.

• Steel and Composite Structures
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• 제42권6호
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• pp.827-841
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• 2022

The rotation capacities of the plastic hinges located at beam-ends are significantly reduced in traditional steel framed-tube structures (SFTSs) because of the small span-to-depth ratios of the deep beams, leading to the low ductility and energy dissipation capacities of the SFTSs. High-strength steel framed-tube structures with replaceable shear links (HSSFTS-RSLs) are proposed to address this issue. A replaceable shear link is located at the mid-span of a deep spandrel beam to act as a ductile fuse to dissipate the seismic energy in HSSFTS-RSLs. A 2/3-scaled HSSFTS-RSL specimen with a shear link fabricated of high-strength low-alloy Q355 structural steel was created, and a cyclic loading test was performed to study the hysteresis behaviors of this specimen. The test results were compared to the specimens with soft steel shear links in previous studies to investigate the feasibility of using high-strength low-alloy steel for shear links in HSSFTS-RSLs. The effects of link web stiffener spaces on the cyclic performance of the HSSFTS-RSLs with Q355 steel shear links were investigated based on the nonlinear numerical analysis. The test results indicate that the specimen with a Q355 steel shear link exhibited a reliable and stable seismic performance. If the maximum interstory drift of HSSFTS-RSL is designed lower than 2% under earthquakes, the HSSFTS-RSLs with Q355 steel shear links can have similar seismic performance to the structures with soft steel shear links, even though these shear links have similar shear and flexural strength. For the Q355 steel shear links with web height-to-thickness ratios higher than 30.7 in HSSFTS-RSLs, it is suggested that the maximum intermediate web stiffener space is decreased by 15% from the allowable space for the shear link in AISC341-16 due to the analytical results.

• Steel and Composite Structures
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• 제8권5호
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• pp.343-359
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• 2008

In the present study, an efficient method for the optimum design of three-dimensional (3D) steel framed structures is proposed. In this method, in addition to choosing the best position of columns based on architectural requirements, the optimum cross-sectional dimensions of elements are determined. The preliminary design variables are considered as the number of columns in structural plan, which are determined by a direct optimization method suitable for discrete variables, without requiring the evaluation of derivatives. After forming the geometry of structure, the main variables of the cross-sectional dimensions are evaluated, which satisfy the design constraints and also achieve the least-weight of the structure. To reduce the number of finite element analyses and the overall computational time, a new third order approximate function is introduced which employs only the diagonal elements of the higher order derivatives matrices. This function produces a high quality approximation and also, a robust optimization process. The main feature of the proposed techniques that the higher order derivatives are established by the first order exact derivatives. Several examples are solved and efficiency of the new approximation method and also, the proposed method for the best position of columns in 3D steel framed structures is discussed.

• Steel and Composite Structures
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• 제35권2호
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• pp.199-213
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• 2020

This paper proposes a Global-Local Analysis Method (GLAM) to assess the progressive collapse of steel framed structures under fire-induced column failure. GLAM obtains the overall structural response by combining dynamic analysis of the heated column (local) with static analysis of the overall structure (global). Test results of two steel frames which explicitly consider the dynamic effect during fire-induced column failure were employed to validate the proposed GLAM. Results show that GLAM gives reasonable predictions to the test frames in terms of both whether to collapse and the displacement verse temperature curves. Besides, several case studies of a two-dimensional (2D) steel frame and a three-dimensional (3D) steel frame with concrete slabs were conducted by using GLAM. Results show that GLAM gives the same collapse predictions to the studied cases with nonlinear dynamic analysis of the whole structure model. Compared with nonlinear dynamic analysis of the whole structure model, GLAM saves approximately 70% and 99% CPU time for the cases of 2D and 3D steel frame, respectively. Results also show that the load level of a structure has notable effects on the restraint condition of a heated column in the structure.

• 한국강구조학회 논문집
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• 제15권4호통권65호
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• pp.389-401
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• 2003

본 연구의 목적은 H형강 단면과 콘크리트의 합성단면으로 구성된 보와 기둥의 합성 뼈대구조물에 대해 신뢰성지수를 고려한 최적 단면을 설계할 수 있는 알고리즘을 개발하는데 있다. 합성 뼈대구조물의 최적화 문제는 단면 치수를 설계변수로 취하고 목적함수와 제약조건을 형성한다. 목적함수는 구조물의 총 경비로 형성하고, 제약조건식은 단면응력과 허용응력의 신뢰성지수를 고려하여 유도한다. 합성 뼈대구조물의 단문을 최적화하는 알고리즘은 수정 Newton-Raphson 탐사법을 사용하는 SUMT기법을 사용한다. 본 연구에서 개발된 최적화 알고리즘은 1층 1경간 합성 뼈대구조물과 5층 1경간 합성 뼈대구조물의 수치예에 신뢰성지수(${\beta}=3.0$, ${\beta}=0.0$)를 고려한 합성 뼈대구조물 설계의 실용화를 위하여 적용된다. 제안된 알고리즘의 최적화 가능성과 적용성 그리고 수렴성 등을 살펴보기 위하여 수치결과들을 비교 분석한다.

• Structural Engineering and Mechanics
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• 제8권4호
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• pp.361-382
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• 1999

This paper reviews aspects of current design procedures for seismic design of structures, and specifically examines their relevance to the design of light framed residential buildings under earthquake loading. The significance of the various structural contributions made by the components of cold formed steel framed residential structures subjected to earthquake induced loadings has been investigated. This is a common form of residential construction worldwide. Particular attention is given to aspects related to ductility and overstrength, the latter arising principally from the contributions of the designated "non-structural" components. Based on both analytical and experimental data obtained from research investigations on steel framed residential structures, typical ranges of the ductility reduction factor and overstrength ratios are determined. It is concluded that the latter parameter has a very significant influence on the seismic design of such structures. Although the numerical ranges for the inelastic seismic parameters given in this paper were obtained for Australian houses, the concepts and the highlighted aspects of seismic design methodology are more widely applicable.

• Structural Engineering and Mechanics
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• 제48권5호
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• pp.587-613
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• 2013

A 3-node 3D co-rotational beam element using vectorial rotational variables is employed to consider the geometric nonlinearity in 3D space. To account for shape versatility and reinforced concrete cross-sections, fibre model has been derived and conducted. Numerical integration over the cross-section is performed, considering both normal and shear stresses. In addition, the derivations associated with material nonlinearity are given in terms of elasto-plastic incremental stress-strain relationship for both steel and concrete. Steel reinforcement is treated as elasto-plastic material with Von Mises yield criterion. Compressive concrete behaviour is described by Modified Kent and Park model, while tensile stiffening effect is taken into account as well. Through several numerical examples, it is shown that the proposed 3D co-rotational beam element with fibre model can be used to simulate steel and reinforced concrete framed structures with satisfactory accuracy and efficiency.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1991년도 가을 학술발표회 논문집
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• pp.127-132
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• 1991

The purpose of this study is to integrate a structural design Process of framed steel structures. It is composed of analysis, design, drafting and construction management. However each step of these works involved with a large amount of data and man hour resources. The aim of this study is to alleviate time consuming efforts mentioned above by integrating the different stage of works. Very successful results have been achieved by setting up a common database in whole process and applying the techniques of knowledge base system.

• Steel and Composite Structures
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• 제37권3호
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• pp.323-339
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• 2020

In steel framed-tube structures (SFTSs), the plastic hinges at beam-ends cannot be adequately improved because of the large cross sections of spandrel beams, which results in the lower ductility and energy dissipation capacities of traditional SFTSs. To address this drawback, high-strength steel fabricated SFTSs with bolted web-connected replaceable shear links (HSFTS-SLs) have been proposed. In this system, shear links use conventional steel and are placed in the middle of the deep spandrel beams to act as energy dissipative components. In this study, 2/3-scaled HSFTS-SL specimens were fabricated, and cyclic loading tests were carried out to study the seismic performance of both specimens. The finite element models (FEMs) of the two specimens were established and the numerical results were compared with the test results. The results showed that the specimens had good ductility and energy dissipation capacities due to the reliable deformation capacities. The specimens presented the expected failure modes. Using a shorter shear link can provide a higher load-carrying capacity and initial elastic lateral stiffness but induces lower ductility and energy dissipation capacity in HSFTS-SLs. The performance of the specimens was comparable to that of the original sub-structure specimens after replacing shear links. Additionally, the expected post-earthquake recoverability and resilience of the structures could be achieved by replacing shear links. The acceptable residual interstory drift that allows for easy replacement of the bolted web-connected shear link was 0.23%. The bolted web-connected shear links had reliable hysteretic responses and deformation capacities. The connection rotation had a notable contribution to total link rotation. The results of the numerical analysis run for the proposed FEMs were consistent with the test results. It showed that the proposed FEMs could be used to investigate the seismic performance of the HSFTS-SL.

• 한국공간구조학회지
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• 제2권2호
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• pp.16-20
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• 2002