• 콘크리트학회지
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• 제5권1호
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• pp.68-72
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• 1993

• Wind and Structures
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• 제13권6호
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• pp.487-498
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• 2010

When designing structures to the wind action, the variation of the mean wind velocity and turbulence parameters with the height above the ground must be taken into account. This paper presents the numerical simulation results of atmospheric boundary layer (ABL) airflows, in a numerical domain with no obstacles and with a cubic building. The results of the flow characterization, obtained with the FLUENT CFD code were performed using the ${\kappa}-{\varepsilon}$ turbulence model with the MMK modification. The mean velocity and turbulence intensity profiles in the inflow boundary were defined in accordance with the Eurocode 1.4, for different conditions of aerodynamic roughness. The maintenance of the velocity and turbulence characteristics along the domain were evaluated in an empty domain for uniform incident flow and the ABL Eurocode velocity profiles. The pressure coefficients on a cubic building were calculated using these inflow conditions.

• Steel and Composite Structures
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• 제8권1호
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• pp.53-83
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• 2008

A rational and efficient seismic design methodology for irregular space steel frames using advanced methods of analysis in the framework of Eurocodes 8 and 3 is presented. This design methodology employs an advanced static or dynamic finite element method of analysis that takes into account geometrical and material non-linearities and member and frame imperfections. The inelastic static analysis (pushover) is employed with multimodal load along the height of the building combining the first few modes. The inelastic dynamic method in the time domain is employed with accelerograms taken from real earthquakes scaled so as to be compatible with the elastic design spectrum of Eurocode 8. The design procedure starts with assumed member sections, continues with the checking of the damage and ultimate limit states requirements, the serviceability requirements and ends with the adjustment of member sizes. Thus it can sufficiently capture the limit states of displacements, rotations, strength, stability and damage of the structure and its individual members so that separate member capacity checks through the interaction equations of Eurocode 3 or the usage of the conservative and crude q-factor suggested in Eurocode 8 are not required. Two numerical examples dealing with the seismic design of irregular space steel moment resisting frames are presented to illustrate the proposed method and demonstrate its advantages. The first considers a seven storey geometrically regular frame with in-plan eccentricities, while the second a six storey frame with a setback.

• 한국구조물진단유지관리공학회 논문집
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• 제24권1호
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• pp.97-107
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• 2020

본 연구에서는 화재시 매입형 합성기둥의 높은 축력비에 따른 내화성능을 알아보기 위해 유한요소해석 프로그램(ANSYS)을 통한 해석을 실시하였다. 온도에 따른 응력-변형률 곡선을 적용하여 ASTM E 119 가열곡선과 축력비 0.7, 0.6, 0.5에 따른 과도상태 열전달해석 및 정적구조해석을 실시하였으며, 해석조건과 동일한 조건에서의 재하가열실험을 실시하였다. 또한, 기준식(Eurocode 4)에 따라 가열시간에 따른 합성기둥의 공칭압축강도를 산정하고, 축력비로 나타내어 해석값 및 실험값과 비교하였다. 해석 및 실험과 기준(Eurocode 4)을 통해 가열시간에 따른 단면별 온도분포를 확인하고, 이에 따른 내화성능을 측정해 비교분석하였다. 유한요소해석 결과 축력비 0.5에서는 내화시간 180분으로 실험값과 유사한 값이 도출된 반면, 축력비 0.6, 0.7에서 내화시간 150분과 60분이 도출되어 실험결과에 비해 다소 높은 결과가 도출된 것을 알 수 있었다. 그리고 기준식(Eurocode 4)에 따라 산정한 축력비에 따른 내화시간이 실제 실험값에 비해 다소 낮게 평가하고 있다는 것을 확인하였다. 그러나 축력비 0.7에서는 기준(Eurocode 4)이 실험값에 비해 다소 높게 평가하는 것을 확인하였다. 이에 따라 고축력에서의 매입형 합성기둥의 내화특성(시간-축력비 관계)을 확인하고, 도출된 매입형 합성기둥의 실험 및 해석데이터를 Eurocode기준의 검증의 자료로 활용할 수 있을 것으로 보인다.

• Steel and Composite Structures
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• 제3권6호
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• pp.383-401
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• 2003

Two new formulae for the design of beam-columns at room temperature have been proposed into Eurocode 3, prEN 1993-1-1 (2002), and are the result of great efforts made by two working groups that followed different approaches, a French-Belgian team and an Austrian-German one. Under fire conditions the prEN 1993-1-2 (structural fire design) presents formulae, for the design of beam-columns based on the prENV 1993-1-1 (1992). In order to study the possibility of having, in part 1-1 and part 1-2 of the Eurocode 3, the same approach, a numerical research was made using the finite element program SAFIR, developed at the University of Liege for the study of structures subjected to fire.

• Structural Engineering and Mechanics
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• 제58권1호
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• pp.1-19
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• 2016

Recently, the high-strength concrete is increasingly used in the construction of reinforced concrete structures due to its benefits, but this use is influenced negatively on the local ductility of structural elements. The objective of this study is the prediction of a new approach to evaluate the curvature ductility factor of high strength concrete beams according to Eurocode 2. After the presentation of the Constitutive laws of materials and the evaluation method of curvature ductility according to the Eurocode 2, we conduct a parametric study on the factors influencing the curvature ductility of inflected sections. The calibrating of the obtained results allows predicting a very simple approach for estimating the curvature ductility factor. The proposed formula allows to calculate the curvature ductility factor of high strength concrete beams directly according to the concrete strength $f_{ck}$, the yield strength of steel $f_{yk}$ and the ratio of tension and compression reinforcements ${\rho}$ and ${\rho}^{\prime}$ respectively, this proposed formula is validated by theoretical and experimental results of different researchers.

• Advances in Computational Design
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• 제1권4호
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• pp.297-313
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• 2016

The flexural strength of circular concrete-filled tubes (CCFT) can be estimated by several codes such as ACI, AISC, and Eurocode 4. In AISC and Eurocode, two methods are recommended, which are the strain compatibility method (SCM) and the plastic stress distribution method (PSDM). The SCM of AISC is almost the same as the SCM of the ACI method, while the SCM of Eurocode is similar to the ACI method. Only the assumption of the compressive stress of concrete is different. The PSDM of Eurocode approach is also similar to the PSDM of AISC, but they have different definitions of material strength. The PSDM of AISC is relatively easier to use, because AISC provides closed-form equations for calculating the flexural strength. However, due to the complexity of calculation of circular shapes, it is quite difficult to determine the flexural strength of CCFT following other methods. Furthermore, all these methods give different estimations. In this study, an effort is made to review and compare the codes to identify their differences. The study also develops a computing program for the flexural strength of circular concrete filled tubes under pure bending that is in accordance with the codes. Finally, the developed computing algorithm, which is programmed in MATLAB, is used to generate design aid graphs for various steel grades and a variety of strengths of steel and concrete. These design aid graphs for CCFT beams can be used as a preliminary design tool.

• Steel and Composite Structures
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• 제19권4호
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• pp.811-827
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• 2015

This paper presents a probabilistic investigation of American and European specifications (i.e., AISC and Eurocode 4) for square concrete-filled steel tubular (CFT) stub columns. The study is based on experimental results of 100 axially loaded square CFT stub columns from the literature. By comparing experimental results for ultimate loads with code-predicted column resistances, the uncertainty of resistance models is analyzed and it is found that the modeling uncertainty parameter can be described using random variables of lognormal distribution. Reliability analyses were then performed with/without considering the modeling uncertainty parameter and the safety level of the specifications is evaluated in terms of sufficient and uniform reliability criteria. Results show that: (1) The AISC design code provided slightly conservative results of square CFT stub columns with reliability indices larger than 3.25 and the uniformness of reliability indices is no better because of the quality of the resistance model; (2) The uniformness of reliability indices for the Eurocode 4 was better than that of AISC, but the reliability indices of columns designed following the Eurocode 4 were found to be quite below the target reliability level of Eurocode 4.

• Steel and Composite Structures
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• 제8권3호
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• pp.201-216
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• 2008

The Eurocode system provides limited information regarding the structural fire design of external steel structures. Eurocode 1 provides thermal action for external member but only in steady-state conditions. On the other hand, Eurocode 3 provides a methodology to determine heat transfer to external steelwork, but there is no distinction in cross section shapes and, in addition, the calculated temperature distribution is assumed to be uniform in the cross section. This paper presents the results of a research carried out to develop a new transient heat transfer model for external steel elements to improve the current approach of the Eurocodes. This research was carried out as part of the project EXFIRE "Development of design rules for the fire behaviour of external steel structures", funded by the European Research Programme of the Research Fund for Coal and Steel (RFCS).

• 한국강구조학회 논문집
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• 제16권4호통권71호
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• pp.433-442
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• 2004

본 연구는 Eurogode 3 Part 1.3을 근거하여 온도증가에 따른 압축을 받는 냉간성형 C-형강 기둥의 플랜지와 웨브의 탄성국부좌굴 응력 해석 프로그램을 개발하였다. 고온에서 응력-변형률 관계식은 Eurocode 3 Part 1.2를 근거하였다. 온도증가에 따른 압축을 받는 냉간성형 C-형강의 임계온도와 탄성국부좌굴 응력은 본 연구에서 개발한 컴퓨터 프로그램에 의해 해석하였고, 해석 예에 대한 비교 고찰을 하였다.