• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.2 s.72
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• pp.115-124
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• 2006

The 1st and 2nd tension forces of the PSSC(Prestressed Steel and Concrete) grider constructed with commercial rolling beams and concrete are optimally designed. The design variables are the 1st and 2nd tension forces due to multi-step prestressing and live load. The objective function is set to the maximum live load. Design conditions are allowable stresses at the top and bottom of slab, beam and infilled concrete due at the several construction stages. A Matlab based optimization program is developed. The results show that the tendon position as well as concrete compression strength have significant influence on the beam strength.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.743-746
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• 1998

Pine bark waste was delignified with various sulfite liquors in order to use its spent liquor as concrete additives. The bark was easily deliginfied in alkaline sulfite-anthraquinone(ASAQ) cooking, resulting in more than 90% delignification. The dispersing ability of the ASAQ spent liquor was almost equivalent to or better than that of the commercial wood lignosufonate(CSL), Sanflo R.

• Corrosion Science and Technology
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• v.3 no.6
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• pp.262-264
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• 2004

Ground Penetrating Radar (GPR) has been used to image inside concrete specimens embedded with steel bars and delamination. An imaging algorithm has been developed to improve measurement output generated from a commercial radar system. For the experiments, laboratory size concrete specimens are made with the dimensions of $1,000mm(W){\times}1,000mm(L){\times}250mm(D)$. The results have shown improved output of the radar measurements compared to commercially available processing methods.

• Computers and Concrete
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• v.9 no.5
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• pp.341-355
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• 2012

Numerical studies are performed to predict the stress-strain behavior of rectangular RC columns confined by multi-spiral hoops under axial and eccentric compressions. Using the commercial finite element package ABAQUS, the Drucker-Prager criterion and the yield surface are adopted for damaged plasticity concrete. The proposed finite element models are compared with the published experimental data. Parametric studies on concrete grades, confinement arrangement, diameter and spacing of hoops and eccentricity of load are followed. Numerical results have shown good agreements with experimental values, and indicated a proper constitutive law and model for concrete. Cross-sectional areas and spacing of the hoops have significant effect on the bearing capacity. It can be concluded that rectangular RC columns confined by multi-spiral hoops show better performance than the conventional ones.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.195-200
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• 1995

This paper presents the practical use of high strength concrete on 28-story Samsung Shin-dacbang Housing-Commercial Combined Building with 8-story basements located in Seoul. 700 Kg/$\textrm{cm}^2$ compressive Strength concrete was placed for basement core-walls and 500 kg/$\textrm{cm}^2$ concrete was used for structural frames up to 10th floor. The thermal sensors were installed prior to concrete casting into the core walls to measure the heat of hydration during hardening process. The correlation of core strength to the standard cylinder test strength was also discussed. The successful utilization of 500 and 700 kg/$\textrm{cm}^2$ concrete shows that the practical application of high strength concrete has a great potential to the high-rise R.C building construction.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.325-330
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• 1995

Three types of model concrete with different mix ratios for 1/10 scale reinforced concrete model were made and tested to find the best solution for the simulation of mechanical characteristics of prototype concrete. Scaled reinforcing materials in diameter(D1.8) having similar con-figuration and mechanical properties with commercial deformed bars(D19) were prepared for 1/10 scale model tests of reinforced concrete structures. Two types of model test using D1.8 model reinforcing bars and model concrete, monotonic simple beam test and cyclic cantilever beam test, were performed to ensure and check the similitude of bond behavior between 1/10 scale model and prototype. The test results showed that the flexural behavior of 1/10 scale models can be simulated with accuracy enough for practical use in monotonic and cyclic loading test.

• Journal of Environmental Science International
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• v.18 no.9
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• pp.993-1000
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• 2009

The development of a new type of soil-cement concrete pavement using volcaniclastic is the main purpose of this study. Various mixture ratios, specimens' penetration resistance, time of setting, slump flow of fleshly mixed concrete, compressive strength and color characteristics of hardened concrete were studied. It was concluded that the optimum weight ratio of cement:volcaniclastic to produce good properties of soil-cement concrete is 1:3 and the use of volcaniclastic as main aggregate can improve the concrete surface color that is warm earth-tone road color. Therefore, commercial development for soil-cement concrete pavement using volcaniclastic is highly promising.

• Computers and Concrete
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• v.12 no.1
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• pp.37-51
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• 2013

The responses of reinforced concrete slabs subject to an impact loading near the ultimate load range are explored. The analysis is carried out on a simply supported rectangular reinforced concrete slab using a nonlinear explicit dynamic procedure and considering three material models: Drucker-Prager, modified Drucker-Prager, and concrete damaged plasticity, available in the commercial finite element software, ABAQUS/Explicit. For comparison purposes, the impact force-time response, steel reinforcement failure, and concrete perforation pattern are verified against the existing experimental results. Also, the effectiveness of mesh density and damage wave propagation are studied independently. It is shown that the presently adopted finite element procedure is able to simulate and predict fairly accurate the behavior of reinforced concrete slab under impact load. More detailed investigations are however demanded for the justification of effects coming from an imperfect projectile orientation as well as the load and structural surface conditions, including the impulsive contacted state, which are inevitable in an actual impact environment.

• Computational Structural Engineering
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• v.28 no.4
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• pp.49-65
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• 2015

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.575-580
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• 1997

This study presents the techniques to manufacture the model concrete and model reinforcement for the 1/5-scale 3-story reinforced concrete frame. The used model concrete has sufficient workability but shows a little lower strength than expected model steel was made of commercial $\phi$3.2mm and $\phi$2.0mm wire by using deforming device and vacuum tube electric furnace. The yield strength can be simulated but it was difficult to simulate the other properties. The load cell was specially manufactured to measure the shear force in the columns of the first story. The carrying frame and the hinge adapter of artificial mass are explained. The special problems in the process of construction of model are also dressed.