• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.53-56
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• 2005

This paper investigates the effect of ductile deformation behavior of high performance hybrid fiber-reinforced cement composites (HPHFRCCs) on the shear behavior of coupling beams to lateral load reversals. The matrix ductility and the reinforcement layout were the main variables of the tests. Three short coupling beams with two different reinforcement arrangements and matrixes were tested. They were subjected to cyclic loading by a suitable experimental setup. All specimens were characterized by a shear span-depth ratio of 1.0. The reinforcement layouts consisted of a classical scheme and diagonal scheme without confining ties. The effects of matrix ductility on deflections, strains, crack widths, crack patterns, failure modes, and ultimate shear load of coupling beams have been examined. The combination of a ductile cementitious matrix and steel reinforcement is found to result in improved energy dissipation capacity, simplification of reinforcement details, and damage-tolerant inelastic deformation behavior. Test results showed that the HPFRCC coupling beams behaved better than normal reinforced concrete control beams. These results were produced by HPHFRCC's tensile deformation capacity, damage tolerance and tensile strength.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.173-178
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• 1993

In order to quantify the effect of transverse reinforcement on the bond splitting behavior of reinforcement monotonic loading tests of 8 slmply beams were carried out. The reinforcing details and material properties were so determined that the bond splitting failure proceded the shear and flexural failure. A bond splitting strength derived from the experimental data and it accounts for following parameters: 1) Concrete Strength 2) Transverse reinforcement ratio and shape 3) Thickness of concrete cover 4)Deformation of reinforcement

• Earthquakes and Structures
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• v.9 no.6
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• pp.1233-1250
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• 2015

The behavior of reinforced concrete (RC) columns made from high strength materials was investigated experimentally. Six high-strength concrete specimen columns (1:4 scale), which included three with high-strength transverse reinforcing bars and three with normal-strength transverse reinforcement, were tested under double curvature bending load. The effects of yielding strength and ratio of transverse reinforcement on the cracking patterns, hysteretic response, shear strength, ductility, strength reduction, energy dissipation and strain of reinforcement were studied. The test results indicated that all specimens failed in splitting failure, and specimens with high-strength transverse reinforcement exhibited better seismic performance than those with normal-strength transverse reinforcement. It also demonstrated that the strength of high-strength lateral reinforcing bars was fully utilized at the ultimate displacements. Shear strength formula of short concrete columns, which experienced a splitting failure, was proposed based on the Chinese concrete code. To enhance the applicability of the model, it was corroborated with 47 short concrete columns selected from the literature available. The results indicated that, the proposed method can give better predictions of shear strength for short columns that experienced a splitting failure than other shear strength models of ACI 318 and Chinese concrete codes.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.2
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• pp.77-86
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• 2024

In this study, authors attempted to determine the bond behavior characteristics to utilize Grid typed CFRP reinforcement as an alternative to steel rebar used as concrete reinforcement. Since it is difficult to understand the influence of the transverse grid length of the Grid typed CFRP reinforcement in the existing numerical analysis proposal for bond behavior, a nonlinear 3D model was created and finite element analysis was performed. To perform the analysis, the analysis was conducted by inputting a nonlinear material model and modeling the bond interface characteristics between the Grid typed CFRP reinforcement and concrete and comparing them with the actual direct pull-out test results. The bond behavior characteristics of the Grid typed CFRP reinforcement were found to be very dominated by the factors of the transverse grid, and showed a tendency to continuously increase load.

• Journal of the Korean Society of Hazard Mitigation
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• v.2 no.1 s.4
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• pp.119-126
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• 2002

This paper presents the appropriateness for using high strength reinforcement according to the use of high strength concrete. Nine flexural tests were conducted on full-scale beam specimens according to the concrete strength, reinforcement strength and reinforcement ratio as main variable. The structural behavior was analyzed due to the flexural strength, stress-strain curve, deflections at yielding and fracture point, crack appearance and ductility factor. The member with high-strength reinforcements showed large deflection at yielding point and this was analyzed as a main cause to decrease the ductility factor. Structural behavior after yielding point, however, showed similarity to behavior of members with normal strength reinforcements of same stiffness. It was found that in the case of using reinforcements of $5500kgf/cm^2$ strength, the combination with concrete of $800kgf/cm^2$ strength demonstrated the great appropriateness which can increase the flexural capacity without any reduction of maximum reinforcement ratio.

• International Journal of Concrete Structures and Materials
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• v.18 no.2E
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• pp.79-87
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• 2006

The main objective of this research is to examine the behavior of high-strength concrete(HSC) columns. Eight test columns in one-third scale were tested under the conditions of cyclic lateral force and a constant axial load equal to 30% of the column axial load capacity. The $200{\times}200mm$ square columns were reinforced with eight DB bars constituting a longitudinal steel ratio of 2.54% of the column cross-sectional area. The main experimental parameters were volumetric ratio of transverse reinforcement(${\rho}_s$=1.58, 2.25 percent), tie configuration(Type H, Type C, Type D) and tie yield strength($f_{yh}$=548.8 and 779.1 MPa). It was found that the hysteretic behaviour and ultimate deformability of HSC columns were influenced by the amount and details of transverse reinforcement in the potential plastic hinge regions. Columns of transverse reinforcement in the amount 42 percent higher than that required by seismic provisions of ACI 318-02 showed ductile behavior. At 30% of the axial load capacity, it is recommended that the yield strength of transverse reinforcement be held equal to or below 548.8 MPa. Correlations between the calculated damage index and the damage progress are proposed.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.8 no.1
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• pp.51-68
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• 2001

The purpose of this study was to explain the relationship between smoking status, smoking behavior and hardiness in university students in Gangnung City. The subjects were a convenience sample of 315 students. The data were collected by a questionnaire given to the students between May 22 to June 2, 2000. An instrument developed by Akers & Gang(1996) and translated by Sohn, Jung-Nam(1999) was used in this study to measure definition of smoking, differential reinforcement of smoking and smoking behavior. The differential peer association scale developed Krohn et al.(1982) and translated by Sohn, Jung-Nam(1999), and the hardiness scale developed by Pollock(1984) and translated by Suh, Mun-Sa(1988) were also used. The data were analyzed using the SAS/PC+ Program and included descriptive statistics, t-test, ANOVA, and Spearman correlation coefficients. The results of this study are as follows : 1. The smoking rate for university students was 50.5% of which 44.7% started smoking in high school. 2. The mean score for level of hardiness was $3.14{\pm}0.43$ 3. The mean score for smoking behavior was as follows : 1) The mean score for the neutralizing definition was $2.16{\pm}0.57$ 2) The mean score for the negative definition was $2.37{\pm}0.71$ 3) The mean score for the positive differential reinforcement was $1.89{\pm}0.63$ 4) The mean score for the negative differential reinforcement was $2.96{\pm}0.64$ 5) The mean score for the differential peer association was $2.67{\pm}1.05$ 4. The data showed positive correlations between hardiness and the neutralizing definition(r=.1951, P<.001), between hardiness and the positive differential reinforcement(r=.1128, P<.05), between hardiness and the amount of smoking per day(r=.1452, P<.05) between the neutralizing definition and positive differential reinforcement(r=.4212, P<.0001), between the neutralizing definition and differential peer association(r=.1856, P<.001), between the neutralizing definition and age at smoking initiation(r=.1582, P<.05), between the negative definition and negative differential reinforcement(r=.2985, P<.0001), between the positive differential reinforcement and differential peer association(r=.3451, P<.0001), between positive differential reinforcement and the amount of smoking per day(r=.4431, P<.0001), between differential peer association and the duration of smoking(r=.2789, P<.0001), between differential peer association and the amount of smoking per day(r=.5410, P<.0001), between the duration of smoking and the amount of smoking per day(r=.4245, P<.0001). The data showed negative correlations between the neutralizing definition and the negative definition(r=-.2065, P<.001) between the neutralizing definition and negative differential reinforcement(r=-.3943, P<.0001) between the neutralizing definition and duration of smoking(r=-.1957, P<.05), between the negative definition and positive differential reinforcement(r=-.2093, P<.001), between the negative definition and the amount of smoking per day(r=-.2282, P<.001), between positive differential reinforcement and negative differential reinforcement(r=-.5555, P<.0001) between negative differential reinforcement and differential peer association(r=-.3653, P<.0001), between negative differential reinforcement and the amount of smoking per day(r=-.4570, P<.0001), between the age at smoking initiation and the duration of smoking(r=-.4594, P<.0001).

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.493-498
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• 1998

An experimental investigation was conducted to examine the behavior of high-strength concrete R/C columns subjected to moment, shear and axial load. The test parameters of specimens were the compressive strength of concrete(f'c=250, 516, 600kg/ ㎠), space of lateral reinforcement (20, 30, 37cm) and lateral reinforcement ratio(ρs=2.1, 3.15%). Test results indicated that compressive strength of concrete and lateral reinforcement can significantly affect and alter the behavior of column under inelastic cyclic loadings. Despite of the defaults of high-strength concrete, with increased amount of lateral reinforcement ratio to core concrete and added sub-lateral reinforcement, ductility and strength of RC columns used high-strength concrete can secured.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.419-426
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• 2002

In this study, the steel strip reinforcement bolted with braced angles is displayed skin friction resistance as well as passive resistance through existing the steel strip reinforcement. To understand pullout behavior characteristics, friction effects between soil and reinforcement are evaluated with the width of reinforcement, magnitude of surcharge, and existence of passive resistance member through laboratory pullout test. To analyze interference effects for passive resistance member, various tests are carried on case that the number, the location, and the spacing of braced angles are different. Using this test result, pullout resistance factor is calculated to consider location of braced angles and degree of interference for spacing ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.3-4
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• 2009

This study predicts the structural behavior of RC beams using high strength shear reinforcement and evaluates current design codes restricting the strength of shear reinforcement steel. Under the present design codes, the yield strength of shear reinforcement steel is restricted to 400MPa. In case that use high yield strength reinforcement steel, could incure heavily crack and deflection at the members of structure, and have not verified ductility capacity, fatigue resisting capacity, shear and torsion resisting capacity, anchoring capacity and seismic capacity. To this end, we evaluate structural behavior of reinforced concrete beams using high strength shear reinforcement.