• International Journal of Korean Welding Society
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• v.1 no.2
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• pp.18-22
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• 2001

The stress intensity factor has been calculated theoretically for the cracked plate subjected to remote normal stress and reinforced with a plate by symmetric seam welding. The singular integral equation was derived based on displacement compatibility condition between the cracked plate and the reinforcement plate, and solved by means of Erdogan and Gupta's method. The results from the derived equation for stress intensity factor were compared with FEM solutions and seems to be reasonable. The reinforcement effect gets better as welding line is closer to the crack and the stiffness ratio of the cracked plate and the reinforcement plate becomes larger.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.863-874
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• 2009

The engineering characteristics and the reinforcement effect of the elephant foot method were discussed with parametric study. The elephant foot method is adopted to support the loads transferred from tunnel crown and improve bearing capacity of elephant foot in poor ground condition. The evaluation of reinforcement effect, which has the mechanical relationship between ground condition, footing size and reinforcement system, was carried out through the previous research and numerical analysis. In addition, the simple design chart was proposed to estimate the applicability of the elephant foot reinforcement method. It will be practical for the engineer to determine the optimum reinforcement method for safe tunnelling in soft ground condition.

• Journal of the Korea Concrete Institute
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• v.23 no.6
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• pp.749-756
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• 2011

Most experimental studies on durability of FRP reinforcements subjected to high temperature have focused on the effect of high temperature only on tensile properties. But FRP reinforcement used in newly constructed concrete structure is first degraded by moisture and alkaline environment of concrete. When the structure is subjected to fire, the degraded FRP reinforcement is exposed to high temperature. Therefore, the effects of concrete environment and high temperature should be simultaneously considered for evaluation of FRP reinforcement damaged by fire. In this study, FRP reinforcements submerged in simulated solutions of pH 12.3 and 7 for extended period of time were subjected to temperatures of $60^{\circ}C$, $100^{\circ}C$, $150^{\circ}C$, and $300^{\circ}C$ to be examined. In order to investigate the effect of the high temperature, interlaminar shear strengths were measured and compared to those of control ones. The experimental results demonstrated that the combined effect of concrete environment and high temperature on properties of FRP reinforcement was more significant than the effect of high temperature or concrete environment solely.

• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.39-45
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• 2010

The effects of non-woven geotextiles on mechanical behavior of sand were investigated. A comprehensive series of triaxial compression tests were performed for these investigation on unreinforced and reinforced sand with geotextiles. The Joomunjin standard sand was used and non-woven geotextiles were included into sand specimen with three layers. The inclusion of non-woven geotextile reinforcement into sand increased the peak strength of sand significantly and the reinforced samples exhibited a greater axial strain at failure. Also the effect on number of reinforcement layers was studied and found as increasing the number of reinforcement layers resulting in more ductility by clogging developed in the shear band within the specimens. It was also found that the tendency of samples to dilate is restricted by non-woven geotextile inclusion. The effect of nunber of reinforcement layer increasing is just same to the effect of decreasing void ratio of sand in this case.

• Journal of Welding and Joining
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• v.16 no.1
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• pp.63-69
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• 1998

The stress intensity factor has been calculated theoretically for the cracked plate subjected to remote normal stress and reinforced with a sheet by symmetric seam welding. The singular integral equation was derived based on displacement compatibility condition between the cracked sheet and the reinforcement plate, and solved by means of Erdogran and Gupta's method. The results from the derived equation for stress intensity factor were compared with FEM solutions and seems to be reasonable. The reinforcement effect gets better as welding line is closer to the crack and the stiffness ratio of the cracked plate and the reinforcement sheet becomes larger.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.110-118
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• 2010

This research dealt with the effect of steel-fiber reinforcement on the compressive strength of ultra high performance cementitious composites (UHPCC) and compared with that in normal steel-fiber reinforced concrete(SFRC). With wide range of compressive strength of UHPCC, experiments on the fiber reinforcement effect confirmed that the compressive strength in UHPCC is also improved by adding fibers as in normal SFRC. The experimental results were compared with previous researches about reinforcement effect by adding fibers, which are limited within 100MPa compressive strength. The comparison revealed the linear relationship between $f'_{cf}-f'_c$ and RI regardless of the magnitude of compressive strength, from which a general equation to express the effect of fiber reinforcement, applicable to various SFRC's with wide range of compressive strength including UHPCC.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.04a
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• pp.85-90
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• 1994

Three high strength reinforced concrete structural walls were tested under the combined action of a constant axial and a horizontal cycle load. The aim of the tests has been to investigate the effects of the web horizontal reinforcement on hysteretic behavior of wall. The results have helped to identify the causes of wall failure and have demonstrated the web horizontal reinforcement does not appear have a significant effect on shear capacity, stiffness and energy dissipation but have a significant effect on the failure mode of the walls.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.617-620
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• 2003

This paper presents the confinement effect of transverse reinforcement and cross-tie in hollow rectangular sectional columns. 20 analytical models with different amounts of transverse reinforcement and cross-tie in a plastic hinge region were analyzed by 3D nonlinear FEM. The analytical results show that the higher ductility can be achieved by the resonable combination of transverse re-bar and cross-tie providing sufficient lateral confinement.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1181-1186
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• 2006

This study analyzed the reductive effect of lateral flow by the section and height of reinforcement of EPS. The conclusions of the study are as follows. (1) The lateral flow increased as the section of reinforcement decreased. The reinforcement section that satisfied the allowable range of the lateral flow turned out to beapproximately 80% of the standard reinforcement section. (2) As reinforcement height was decreasing, the lateral flow increased. The reinforcement heigh that satisfied the allowable range of the lateral flow turned out to be approximately 50% of the total lateral height of abutment.

• Earthquakes and Structures
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• v.22 no.1
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• pp.39-51
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• 2022

The axial compression behavior of nine self-compacting concrete columns confined with CFRP-PVC spirals was studied. Three parameters of spiral reinforcement spacing, spiral reinforcement diameter and height diameter ratio were studied. The test results show that the CFRP strip and PVC tube are destroyed first, and the spiral reinforcement and longitudinal reinforcement yield. The results show that with the increase of spiral reinforcement spacing, the peak bearing capacity decreases, but the ductility increases; with the increase of spiral reinforcement diameter, the peak bearing capacity increases, but has little effect on ductility, and the specimen with the ratio of height to diameter of 7.5 has the best mechanical properties. According to the reasonable constitutive relation of material, the finite element model of axial compression is established. Based on the verified finite element model, the stress mechanism is revealed. Finally, the composite constraint model and bearing capacity calculation method are proposed.