• Computational Structural Engineering
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• v.6 no.1
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• pp.91-98
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• 1993

Minimum weight design of the boom of an excavator with stress and displacement constraints was performed. The procedure of analysis consists of the following steps. The finite element model of the boom was built up by using 227 triangular plate elements each of which has three nodes. And then the finite element program was implemented and its accuracy was verified by comparing its results with those of the commercial structural analysis package-ANSYS 4.4A. For the constraints of stresses and displacements, the design sensitivities of those were computed using direct differentiation method. To verify the reliability of them the results were compared with those of the finite difference method. The optimum design value was obtained by using PLBA(Pshenichny-Lim-Belegundu-Arora)non-linear optimization program which adopts the active set strategy. Using the above results, minimum weight design of an excavator boom showed an effect of 27% reduction in weight.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.335-342
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• 1999

It is well known that l-girders are weak in torsion and it might be more economical to use a box girder, which has great torsional rigidity. The use of box beams does, however, present a potential problem in that cross-sectional distortions can induce large warping normal stresses and transverse bending stress. Accordingly a sufficient number of diaphragms are provided to make the distortional effects minimal. In engineering practice, diaphragms are spaced in 5m intervals without reasonable basis. It is considered to be noneconomical design to the almost design engineers, and it may produce the unsafe structural systems in special cases such as curved bridges with large initial curvature. These problems have not been solved for the lack of adequate tools of structural analysis. In this study, on the basis of the parametric studies, the design formulas for the distortional warping stress and the reasonable diaphragm spacing of box girder were presented.

• Journal of the Korean Institute of Educational Facilities
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• v.26 no.5
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• pp.25-36
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• 2019

School gymnasium is a multi-purpose large space building for various events and physical education activities, and is a facility that requires an approach to the desirable structural design, besides mechanical problems of structure against loads. For the integrated structure design concerning the architectural features, the major considerations of gymnasium planning that are the internal and external shape of the gymnasium, the space scale with structure members, the structural efficiency by members weight reduction and openness of the gymnasium space will have to take into account in the structural planning. From this point of view, the several cases of the school gymnasium were investigated and the parametric analyses were performed to the models using the various structural system. The parameters were the composition elements of structure system that are profile of structure, rigidity of member, connection and anchorage and stability. At the result, It was presented that the profile of structure member was the most influential factor to structural efficiency and the effect of the form and space of gymnasium. Also the design informations of structure design having the various feature of form and space were presented for the initial gymnasium planning.

• Journal of KSNVE
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• v.10 no.3
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• pp.493-499
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• 2000

Structural vibration analysis of the stationary power plant system employing a large two-stroke low speed diesel engine is performed to verify that the vibration characteristics of the system meet design requirements, The system consists of the diesel engine generator and concrete foundation including pile and soil. The system is modeled in the form of a mass-elastic system of 5 degrees of freedom for vibration analysis. Excitation moments and dynamic parameters including engine body stiffness soil stiffness and damping are identified for the analysis, Results of structural vibration analysis of the system are presented and compared with measurements in this paper.

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.148-157
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• 1999

Dynamic structural behavior in long span bridges, especially cable structures, is very sophisticated due to their flexibility and structural members are sequentially erected in each construction step. In this study, the consistent mass matrix for dynamic analysis is formulated and computational program considering construction sequences is developed where structural members can be builded or removed by command language and automatically reanalyzed in the moment when structural system is changed. The dynamic analysis, i.e. eigenvalue and time series analysis and the geometrically nonlinear analysis considering construction sequence are conducted to the Namhae Bridge. The analytical results are satisfactory compared with measuring values and the developed computational program can successfully be applied to design and safety check.

• Structural Engineering and Mechanics
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• v.71 no.6
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• pp.643-656
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• 2019

A new seismic design methodology was proposed for precast concrete diaphragms. This methodology adopts seismic design factors applied on top of current diaphragm design forces. These factors are aimed to produce diaphragm design strengths aligned with different seismic performance targets. These factors were established through extensive parametric studies. These studies used a simple evaluation structure with a single-bay rectangular diaphragm. The simple evaluation structure is suitable for establishment of the design factors over comprehensive structural geometry and design parameters. However, the application of the design factors to prototype structures with realistic layouts requires further verification and investigation. This paper presents diaphragm design of several precast concrete parking structures using the new design methodology and verification of the design factor through nonlinear dynamic time history analyses. The seismic behavior and performance of the diaphragm were investigated for the precast concrete parking structures. It was found that the design factor established for the new design methodology is applicable to the realistic precast concrete parking structures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.163-164
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• 2009

• Structural Engineering and Mechanics
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• v.45 no.3
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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.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.233-240
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• 1999

A general procedure is presented here to develope seismic design and analysis method for cable-supported bridges like suspension bridges subjected to ground motion. For representing a numerical model of suspension bridges. a new approach which satisfy design conditions for the initial equilibrium state of suspension bridges. without any nonlinear iterations. is proposed. The dynamic behavior of that model is verified by free vibration analysis. This study uses the response spectrum analysis to determine the Peak response of a suspension bridge to earthquake-induced ground motion. The SRSS(Square Root of Sum of Square). modal combination rule, is adopted for each direction, longitudinal and transverse. To illustrate the potential applicability for the seismic design of suspension bridges, a numerical example is presented in which the dynamic response of the Nam-hae suspension bridge subjected to earthquake

• Composites Research
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• v.25 no.2
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• pp.54-61
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• 2012

In this study, a specific structural design procedure for 2 MW class glass/epoxy composite wind turbine system towers is newly proposed through load case study, trade-off study, optimal structural design and structural analysis. Optimal tower design is very important because its cost is about 20% of the wind turbine system's cost. In the structural design of the tower, three kinds of loads such as wind load, blades, nacelle and tower weight and blade aerodynamic drag load should be considered. Initial structural design is carried out using the netting rule and the rule of mixture. Then the structural safety and stability are confirmed using a commercial finite element code, MSC NASTRAN/PATRAN. The finally proposed tower configuration meets the tower design requirements.