• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.6
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• pp.34-48
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• 2004

In this paper an optimization algorithm is suggested to reduce the huge computation time in the optimum design of large structures, especially in spacecraft structures. It combines the coupled load analysis model using a constrained mode of component mode synthesis and the modal transient analysis. The computer simulation code is developed and evaluated in optimizing spacecraft platforms. The developed algorithm can alleviate the computational load with adequate accuracy. From the optimization of a spacecraft structural member, the characteristics of each structural member can be understood.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.143-149
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• 2019

In this study, a U-shape composite beam was developed to be effectively used for a steel parking lot which is 8m or lower in height. When the U-shape composite beam was applied to a steel parking lot, essential considerations were story-height and long-span. In addition, due to the mixed structural system with reinforced concrete and steel material, the U-shape composite beam needed to have a structural integrity and reliable performance over demand capacity. The main objective of this study was to investigate the performance of the structure consisting of the reinforced concrete (RC) slab and U-shape beam. A U-shape composite beam generally used at a parking lot served as a control specimen. Four specimens were tested under four-point bending. To calculate theoretical values, strain gauges were attached to rebar, steel plate, and concrete surface in the middle of the specimens. As the results, initial yielding strength of the control specimen occurred at the bottom of the U-shaped steel. After yielding, the specimen reached the maximum strength and the RC slab concrete was finally failed by concrete crush due to compressive stress. The structural performance such as flexural strength and ductility of the specimen with the increased beam depth was significantly improved in comparison with the control specimen. Furthermore, the design of the U-shape composite beam with the consideration of flexural strength and ductility was effective since the structural performance by a negative loading was relatively decreased but the ductile behavior was evidently improved.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.3 s.43
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• pp.59-68
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• 2005

The energy-based seismic design method Is more rational in comparison with current seismic design code in that it can directly account for the effects of cumulative damage by earthquake and hysteretic behavior of the structure. However there are research results that don't reach a consensus depending on the ground motion characteristic and structural properties. For that reason in this study the influences of ground motion characteristics and structural properties on energy demands were evaluated using 100 earthquake ground motions recorded in different soil conditions, and the results obtained were compared with those of previous works. Results show that ductility ratios and sue conditions have significant influence on input energy. The results show that the ratio of hysteretic to input energy is considerably influenced by the ductility ratio, damping ratio, and strong motion duration, while the effect of site condition is insignificant.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.2
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• pp.1-9
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• 2015

In this paper, the RC column-based joint connection part carry out loading test by reinforced hollow or extended Base Plate in order to confirm that RC joint punching shear reinforcement effect of applying the Base Plate. Base Plate thickness, extension length, size, and type as the variable, Base Plate suitable for the stress distribution and shape and dimensions confirmed through experiment and then reinforcing effect was analyzed. Experimentally, vertical load transmitted to the Base Plate from column to foundation is effective to stress distribution and then, type of hollow reinforcement more efficient than a closed. Through experiment, improve performance and ductility due to reinforcement and relative to the thickness of the existing foundation reduced even showed better performance than the existing. The behavior of the reinforced specimens be able to induce from brittle to ductile. Experiment on loading to destroy performed the pattern of cracks, destruction aspect before and after reinforcement.

• Journal of Korean Association for Spatial Structures
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• v.6 no.1 s.19
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• pp.117-127
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• 2006

Membrane structures, a kind of lightweight soft structural system, are used for spatial structures. The design procedure of membrane structures are needed to do shape finding, stress-deformation analysis and cutting pattern generation, because the material property has strong axial stiffness, but little bending stiffness. The problem of cooing pattern is highly varied in their size, curvature and material stiffness. So, the approximation inherent in cutting pattern generation methods is quite different. Therefore the ordinary computer software of structural analysis & design is not suitable for membrane structures. In this study, we develop the program for cooing pattern generation using geodesic line, and investigate the result of example's cooing pattern in detail.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.56-66
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• 2017

In this study, seismic strengthening performance of RC circular columns reinforced with high ductile PET and hybridized fibers(HF, PET + aramid) strand was experimentally compared and investigated. As a result, the maximum flexural strength and ductility capacity of all reinforced columns were improved than control column and fiber rupture did not occur at the ultimate stage. In addition, the resistive strength and displacement of the PET sheet 25 layers reinforcing column and the HF strand 1 layer reinforcing column were almost similar, so that 1 layer of HF strand showed the same lateral confinement effect as the PET sheet 25 layers. As a result of this experimental study, PET is considered to be suitable as seismic reinforcement material for RC structures in terms of flexural strength and ductility. However, in order to increase the possibility of application in the field, it is necessary to use a prefabricated PET sheet such as HF used in this study. The durability of PET needs investigation in the future.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.35-43
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• 2017

The minimum reinforcement ratio is an important design factor to prevent a brittle failure in RC flexural members. A minimum reinforcement ratio is presented by assuming an effective depth of cross-section and moment arm lever in CDC and KHBDC. In this study, it suggests that a rational method for minimum reinforcement ratio is calculated by material model and force equilibrium. As results, a minimum reinforcement ratio using a p-r curve in KHBDC is evaluated about 52~80% of recent design code's value and it induces an economical design. And also, a ductility capacity in case of placing this minimum reinforcement amount is evaluated about 89% of recent design code's value, but ductility in a member is 7 or more, so it has a sufficient ductility capacity. Therefore, it is judged that a minimum reinforcement ratio using p-r curve has a theoretical rationality, safety and economy in a flexural member design.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.90-97
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• 2024

In this study, we employed Highly Ductile Cement Composite (HDCC) to evaluate the flexural performance of a RC slab that simulates the laminating structure of a seashell. To evaluate flexural performance, we produced conventional RC slab specimens, HDCC slab specimens, and HDCC-M slab specimens which biomimics a seashell's layered structure by inserting PE mesh inside the slab made of HDCC. A series of 4-point bending tests were conducted. Experimental results shows the flexural strength of the HDCC-M slab specimen was 1.7 times and 1.2 times higher than that of the RC and HDCC slab specimens, respectively. Furthermore, the ductility was evaluated using the ratio of yield deflection to maximum deflection, and it was confirmed that the HDCC slab test specimen exhibited the best ductility. This is most likely due to the fact that the inserted PE mesh separates the layers and increases ductility, while the HDCC passing through the mesh prevents the loss of load carrying capacity due to layer separation.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.255-258
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• 2010

최근 초고층 구조물은 다양한 형태에 따른 건축 계획 및 설계에 대한 요구되어지며 이를 충족시키기 위해 다양한 구조시스템이 개발되어지고 있다. 특히 경사기둥은 구조물의 높이가 증가할수록 구조물의 면적이 점차적으로 감소하는 Tapered 형태의 비정형 초고층 구조물의 중요한 설계 및 구조요소이다. 본 논문에서는 경사기둥의 축하중에 의해 발생하는 수평력으로 인한 접합부의 영향 및 보 플랜지의 취성파괴에 대한 저항성능을 평가하기 위하여 강구조물 경사기둥 접합부에 대한 유한요소해석을 수행하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.917-918
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• 2012