• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.125-128
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• 2008

오늘날 많은 연구기관에서 구조물 설계에 관한 연구가 수행되고 있는 가운데 내진분야에서 처음으로 구조물에 대한 성능기반설계에 대한 기본개념이 제시되었다. 이후 여러 연구기관에서 성능기반설계를 수행하기 위해 사용자와 설계자 간의 의사소통을 원활히 이루어지게 하기 위해 요구성능에 대한 기준을 정립를 하였다. 성능기반설계는 구조물이 위치하게 될 지역적 특성이나 구조물의 특성에 따라 구조물에 발생될 수 있는 위험에 대한 정확한 분석과 구조물에 대한 사회적 경제적 환경적 영향에 대한 분석을 통하여 구조물에 요구되는 요구성능에 맞추어 구조물을 설계하여 공용기간동안 구조물에 대한 안전을 보장하는 설계방법이다. 구조물에 대한 정확한 요구성능을 파악하기 위해 성능수준 및 성능목표에 대한 정의가 필요하여 본 연구에서 성능기반설계를 수행하기 위해 ATC-40(2002), FEMA-273(1997), Eurocode(1998)에서의 요구성능기준에 관한 기초자료를 조사하였다.

• 한국해양공학회지
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• 제29권3호
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• pp.207-216
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• 2015

Amanifold is one of the essential subsea oil and gas production components to simplify the subsea production layout. It collects the production fluid from a couple of wellheads, transfers it to onshore or offshore storage platforms, and even accommodates water and gas injection flowlines. This paper presents the basic design procedure for a manifold frame structure with novel structural verification using in-house unity check codes. Loads and load cases for the design of an SIL 3 class-manifold are established from a survey of relevant industrial codes. The basic design of the manifold frame is developed based on simple load considerations such as the self weights of the manifold frame and pipeline system. In-house software with Eurocode 3 embedded, called INHA-SOLVER, makes it possible to carry out code checks on the yield and buckling unities. This paper finally proves that the new design of the manifold frame structure is effective to resist a permanent and environment load, and the in-house code is also adaptively combined with the commercial finite element code Nastran.

• Structural Engineering and Mechanics
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• 제42권1호
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• pp.121-129
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• 2012

All contemporary seismic Codes have adopted smooth design acceleration response spectra, which have derived by statistical analysis of many elastic response spectra of natural accelerograms. The above smooth design spectra are characterized by two main branches, an horizontal branch that is 2.5 times higher than the peak ground acceleration, and a declining parabolic branch. According to Eurocode EN/1998, the period range of the horizontal, flat branch is extended from 0.1 s, for rock soils, up to 0.8 s for softer ones. However, from many natural recorded accelerograms of important earthquakes, the real spectral amplification factor appears to be much higher than 2.5 and this means that the spectrum leads to an unsafe seismic design of the structures. This point is an issue open to question and it is the object of the present study. In the present paper, the spectral amplification factor of the smooth design acceleration spectra is re-calculated on the grounds of a known "reliability index" for a desired probability of exceedance. As a pilot scheme, the seismic area of Greece is chosen, as it is the most seismically hazardous area in Europe. The accelerograms of the 82 most important earthquakes, which have occurred in Greece during the last 38 years, are used. The soil categories are taken into account according to EN/1998. The results that have been concluded from these data are compared with the results obtained from other strong earthquakes reported in the World literature.

• Structural Engineering and Mechanics
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• 제32권6호
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• pp.705-724
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• 2009

The two major widely used building design code documents of reinforced concrete structures are the ACI 318-05 and Eurocode for the Design of Concrete Structures EC2. Therefore, a thorough comparative analysis of the provisions of these codes is required to confirm their validity and identify discrepancies in either code. In this context, provisions of flexural computations would be particularly attractive for detailed comparison. The provisions of safety concepts, design assumptions, cross-sectional moment capacity, ductility, minimum and maximum reinforcement ratios, and load safety factors of both the ACI 318-05 and EC2 is conducted with parametric analysis. In order to conduct the comparison successfully, the parameters and procedures of EC2 were reformatted and defined in terms of those of ACI 318-05. This paper concluded that although the adopted rationale and methodology of computing the design strength is significantly different between the two codes, the overall EC2 flexural provisions are slightly more conservative with a little of practical difference than those of ACI 318-05. In addition, for the limit of maximum reinforcement ratio, EC2 assures higher sectional ductility than ACI 318-05. Overall, EC2 provisions provide a higher safety factor than those of ACI 318-05 for low values of Live/Dead load ratios. As the ratio increases the difference between the two codes decreases and becomes almost negligible for ratios higher than 4.

• Steel and Composite Structures
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• 제13권3호
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• pp.295-308
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• 2012

This paper experimentally investigated the buckling capacity of built-up steel columns mainly, Cruciform Columns (CC) and Side-to-Side (SS) columns fabricated from two Universal Beam (UB) sections. A series of nine experimental tests comprised of three UB sections, three CC sections and three SS sections with different lengths were tested to failure to measure the ultimate axial capacity of each column section. The lengths used for each category of columns were 1.8, 2.0, and 2.2 m with slenderness ratios ranging from 39-105. The measured buckling loads of the tested specimens were compared with the predicted ultimate axial capacity using Eurocode 3, AISC LRFD, and BS 5959-1. It was observed that the failure modes of the specimens included flexural buckling, local buckling and flexural-torsional buckling. The results showed that the ultimate axial capacity of the tested cruciform and side-by-side columns were higher than the code predicted design values by up to 20%, with AISC LRFD design values being the least conservative and the Eurocode 3 design values being the most conservative. This study has concluded that cruciform column and side-to-side welded flange columns using universal beam sections are efficient built-up sections that have larger ultimate axial load capacity, larger stiffness with saving in the weight of steel used compared to its equivalent universal beam counterpart.

• 한국공간구조학회논문집
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• 제17권1호
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• pp.69-75
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• 2017

In fire design for floors, the three criteria of stability, integrity and insulation are required for the specified fire resistance duration. Among these, stability is not easy to confirm. For solid prestressed concrete slabs of uniform thickness, Eurocode 2 provides tabulated data and specifies an axis distance to the centroid of strands to achieve particular fire resistance ratings, but it is not clear if this data can be used for a wide range of different prestressed slab profiles. In order to verify the current code-fire ratings for precast prestressed slabs, both simple and advanced calculation methods are investigated. This paper examines the use of calculation methods, accounting for the real behaviour of unprotected simply supported prestressed concrete slabs exposed to the standard ISO 834 fire. The calculated fire resistance of each prestressed concrete slab is compared with tabulated data in Eurocode part 1.2, with detailed discussion.

• Structural Engineering and Mechanics
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• 제29권1호
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• pp.17-35
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• 2008

Neglecting the real joint behaviour in frame analysis may result in unrealistic predictions of the response and reliability of steel frames. The reliability of the prediction of main joint properties according to the component method (Eurocode 3-Part 1.8) still remains open to further investigation. The first step toward the solution is to compare the theoretical expressions given in EN 1993-1-8 and the experimental results. With that goal in mind six nominally the same, but really different specimens of welded beam-to-column joints subjected to static load were tested. The specimens present a combination of nominally identical structural elements produced in different European mills. This paper provides these tests, as well as their detailed evaulation and interpretation. All three joint structural properties (rotational stiffness, moment resistance and rotation capacity) have been considered. Four models for determining the plastic resistance out of experimental Mj-${\phi}$ curves have been applied. The results that have been discussed in detail, point to the fact that EN 1993-1-8 underestimates the real structural properties of the tested type of joint, as well as to the conclusion that detailed research of this problem needs to be conducted using the probabilistic reliability methods.

• 한국산학기술학회논문지
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• 제17권1호
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• pp.298-303
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• 2016

수직 및 수평의 원형단면 강관으로 구성된 공간프레임 타워는 강재량을 줄이면서도 풍하중의 영향을 완화시킬 수 있는 장점으로 다양한 목적으로 널리 적용되고 있다. 이러한 공간프레임 타워를 하나의 타워구조로 거동하게 하기 위해서는 수직 강관과 수평 강관의 연결부인 강관조인트의 강도 확보가 중요하다. 본 연구에서는 압축과 휨이 동시에 작용하는 강관 T조인트의 강도평가를 수행하였다. AISC, Eurocode3, ISO 19902의 3가지 강관조인트 설계기준을 검토하고, 주강관과 지강관의 세장비를 주요 매개변수로 한 비선형 유한요소해석을 통하여 축력과 모멘트에 대한 극한강도 상호작용을 설계식으로 제안하였다.

• 한국강구조학회 논문집
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• 제17권4호통권77호
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• pp.491-498
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• 2005

본 연구는 온도상승에 따른 압축을 받는 I-형강 보의 플랜지와 웨브의 국부좌굴응력해석을 위한 컴퓨터프로그램과 항복파괴전에 I-형강 보의 플랜지와 웨브에 국부좌굴이 일어나지 않을 최적 폭-두께비를 구할 수 있는 최적알고리즘의 개발이다. 본 연구에서 사용한 고온에 있어서 강재의 응력-변형도 관계식은 EC3(Eurocode3) Part1.2(2000b)를 근거하였다. 본 연구에서 국부좌굴응력과 최적 폭-두께비는 항복응력, 플랜지와 웨브의 국부좌굴계수와 폭-두께비 영향을 고려하여 해석하였다. 그리고 본 연구의 컴퓨터 프로그램을 적용한 설계 예를 들었다.

• Computers and Concrete
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• 제16권2호
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• pp.223-243
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• 2015

Self-compacting concrete (SCC) can be placed and compacted under its own weight with little or no compaction. It is cohesive enough to be handled without segregation or bleeding. Modifications in the mix design of SCC may significantly influence the material's mechanical properties. Therefore, it is vital to investigate whether all the assumed hypotheses about conventional concrete (CC) are also valid for SCC structures. The aim in this paper is to develop analytical models for flexural cracking that describe in appropriate detail the observed cracking behaviour of the reinforced concrete flexural one way slabs tested. The crack width and crack spacing calculation procedures outlined in five international codes, namely Eurocode 2 (1991), CEB-FIP (1990), ACI318-99 (1999), Eurocode 2 (2004), and fib-Model Code (2010), are presented and crack widths and crack spacing are accordingly calculated. Then, the results are compared with the proposed analytical models and the measured experimental values, and discussed in detail.