• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.3
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• pp.277-289
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• 2005

The study examines the limit strength for steel cable-stayed bridges. A case studies have been performed in order to evaluate the limit strength lot steel cable-stayed bridges using nonlinear inelastic analysis approach and bifurcation point instability analysis approach, effective tangent modulus $(E_f)$ method. To realize it, a practical nonlinear inelastic analysis condoling the initial shape is developed. In the initial shape analysis, updated structural configuration is introduced instead of initial member forces for beam-column members at every iterative step. Geometric and material nonlinearities of beam-column members are accounted by using stability function, and by using CRC tangent modulus and parabolic function, respectively Besides, geometric nonlinearity of cable members is accounted by using secant value of equivalent modulus of elasticity. The load-displacement relationships obtained by the proposed method are compared well with those given by other approaches. The limit strengths evaluated by the proposed nonlinear inelastic analysis for the proposed cable-stayed bridges with tee dimensional configuration compared with those by the inelastic bifurcation point instability analyses.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.2
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• pp.10-21
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• 2015

For the safe design of steel-concrete composite structure, usable yield strength of steels are limited in most of design standard. However, this limitation sometimes cause the uneconomical design for some kind of members such as slender columns which was affected by elastic buckling load. For the economical design for slender columns, parametric study of RCFT (Rectangular CFT) with high-strength steel is conducted, especially investigating the limitation of yield strength of high-strength steels. Using ABAQUS, finite element analysis program, the finite element model was constructed and calibrated with experimental study for RCFT with high strength steel which have yield strength up to 680MPa. Investigated design parameters are yield strength of steel, compressive strength of concrete, steel thickness and slenderness ratio. The effect of design parameters were compared with design standard, KBC-09. From the parametric study with 54 models and previous test specimens, RCFT can be safely design with higher yield strength of steels than currently limited by KBC for large range of slenderness ratio.

• Journal of Korean Society of Steel Construction
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• v.24 no.5
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• pp.559-569
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• 2012

Cross-beam in the existing temporary bridge system is usually installed to prevent the lateral-torsional buckling of girders and to promote the construction efficiency. However, most of this cross-beams are connected to the girder web by bolts, and therefore, gravitational load resisting capacity of the cross-beams are negligibly small. In recent years, new temporary bridge system, in which the cross-beams and girders are connected to resist the external loads as a unit, was developed. In this paper, we present the experimental and analytical study results pertaining to the structural behavior and load carrying capacity of new temporary bridge system. From the results of study, it was found that the continuous cross-beam increased the flexural rigidity and reduced the maximum flexural stress in the girder. In addition, it was also found that the new temporary bridge system developed is more appropriate for the application in the long-span temporary bridge.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.35-43
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• 2006

In this paper, procedures and research results involved in the development of glass reinforced composite bridge deck of hollow section were presented. Laminate design for the 3 cell deck section was performed. Structural characteristics such as serviceability, strength, failure and stability for DB24 load were analytically studied through the finite element analysis for the composite deck plate girder bridge. Composite deck tube was fabricated with pultrusion and extensive tests such as flexural test, girder-connection test, barrier-connection test, compression fatigue test and flexural fatigue test were carried out to evaluate structural behavior experimentally. Also, field load test was conducted for the demonstration plate girder bridge with composite deck and requirements for the strength and serviceability were reviewed.

• Computational Structural Engineering
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• v.26 no.2
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• pp.37-42
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• 2013

준공 후 상당한 시간이 지나 내진설계가 되지 않았거나 내진상세가 이루어지지 않은 건물의 부족한 내진성능을 보완하기 위한 방법의 하나로 좌굴이 제한된 가새형 댐퍼를 적용할 수 있다. 이 방법을 적용할 경우, 기존 내진보강법의 불확실성을 줄일 수 있었음에도 불구하고, 댐퍼의 설계과정이 복잡하여 실무에 적용하기 어려웠다. 그러나 본 원고에서는 강성과 강도개념을 적용한 댐퍼의 설계법을 적용함으로써, 실무에서 쉽게 적용할 수 있도록 하였다. 준공된 지 16년이 지난 비틀림 비정형 건물에 대한 내진성능을 평가한 후, 가새형 댐퍼로 보강한 결과는 다음과 같다. (1) 일방향해석결과 나타난 골조별 하중-지붕변위의 관계를 이용하여, 연약골조의 강성을 강한 골조의 강성과 일치시키고, 이 강성비로부터 댐퍼가 부담하는 최적의 내력비율을 정하여 내진보강을 수행한 결과, 가새를 설치한 방향으로는 가새형댐퍼가 비틀림 방지와 연성증대효과를 구조물에 부여하여 성능이 획기적으로 증가하였다. 또한, 그 가새의 직각방향 하중에 대해서도 가새를 설치함으로써 비틀림 강성이 증가하고, 가새와 코어벽체가 인장과 압축으로 횡력에 저항하여 횡저항 성능이 증가하였다. (2) 내진성능이 부족한 비틀림 비정형 건물의 내진성능을 증진시키기 위해 가새형 댐퍼를 적용함에 있어, 댐퍼의 강성을 이용하여 구조체의 비틀림 거동을 최소화하고, 연성을 증진시키는 방법을 체택할 경우, 실무자들이 보다 쉽게 적용할 수 있으면서 그 효과도 상당히 클 것으로 기대된다.

• Journal of Ocean Engineering and Technology
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• v.17 no.5 s.54
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• pp.39-47
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• 2003

A study of the structural strength evaluation on the doubler plate, considering various load cases that were subjected to in-plane and out of plane combined load, has been performed through the systematic evaluation process. In order to estimate the proper static strength of doubler plate for various load cases, elasto-plastic large deflection analysis is introduced, including the contact effect between main plate and doubler. The characteristics of stiffness and strength variation are discussed, based on the results. In order to compare the doubler structure with the original strength of main plate, without doubler, simple formulas for the evaluation of the equivalent flat plate thickness are derived for each load case, respectively, based on the additional series of analysis of flat plate structure. Using these derived equations, the thickness change of an equivalent flat plate is analyzed according to the variation of various design parameters of doubler platesome design guides are suggested in order to maintain the original strength of main plate without doubler reinforcement. Finally, correlation between derived equivalent flat plate formula and the developed buckling strength formulas are discovered, and these relations are formulated for the future development of simple strength evaluation formula of general doubler plate structure.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.6
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• pp.11-19
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• 2001

A series of test on concrete-filled composite columns was preformed to evaluate structural performance under axial compression and cyclic lateral loading. It was presented that concrete-filled composite columns had high strength, high stiffness and large energy-absorption capacity on account of mutual confinement between the steel plate and filled-in concrete. A cross section analysis procedure developed to predict the moment-curvature relation of composite columns was proven to be on accurate and effective method. The ductility factor and the response modification factor were evaluated for the seismic design of concrete-filled composite columns. It was shown that concrete-filled composite columns could be used as a very efficient earthquake-resistant structural member.

• Composites Research
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• v.22 no.4
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• pp.1-12
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• 2009

In this paper, quasi-static crushing tests of composite circular tubes under axial compression load are conducted to investigate the energy absorption characteristics. Circular tubes used for this experiment are glass/epoxy (GFRP) composite tubes which are fabricated by the filament winding method. One edge of the composite tube is chamfered to reduce the initial peak load and to prevent catastrophic failure during crushing process. Energy absorption characteristics vary significantly according to the constituent materials, fabrication conditions, tube geometry and test condition. In tube geometry, according as inner diameter increase, unstable crush mode is caused by local buckling of delamination, but control of the fiber orientation should help composite tubes get stable crush mode.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.4
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• pp.351-359
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• 2007

Multi-axial compression tests have been frequently conducted to evaluate the in situ properties of rock masses and the mechanical behaviors of rock strata through the model tests. Without the proper boundary condition for the model tests, the mechanical behavior of rock mass would deviate, as can be expected, from the in situ conditions. The boundary condition will affect the internal stress distribution of the specimens and cause some distortion on the measurement. In this study, a design process regarding the steel brush, which has been employed for multi-axial compression test to reduce the frictional restraint along the specimen/loading platen interface, is introduced. The individual brushes are regarded as a simple column and beam to calculate the cross-sectional size and length of the brushes in consideration of the buckling capacity and the allowable deflection.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.1
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• pp.95-102
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• 2023

This study investigated the structural performance of wire-integrated steel decks with varied lattice end support conditions through finite element analysis. The results indicated that the steel decks with the lattice foots positioned above the supporting structural member have the higher system stiffness compared to the cases with the lattice foots shifted away from the support. It is also observed that the contribution of the end vertical bars on both the system stiffness and the strength is negligible when the lattice foots are located on the support. It is, especially, revealed that the end vertical bars can be eliminated when the lattice foot length is not smaller than 40mm. The ultimate load-carrying capacity of the system is not significantly affected by the lattice end support condition. The failure mode of the system is the top bar buckling at the center of the deck plate, the lattice end buckling, and the combination of both depending of design intention.