• Journal of the Korean Geotechnical Society
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• v.15 no.1
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• pp.15-29
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• 1999

This study presents an analytical method of estimating the developed horizontal active thrusts against GRS-RW( Geosynthetic Reinforced Soil Retaining Wall) system adapted to the case of distanced surcharge. In addition, the design charts that could be used for preliminary design of GRS-RW system are presented. The proposed method of analysis uses two body translation mechanism as well as force polygon concept. taking into account the effect of facing's rigidity. Besides. the effect of tension cracks in c-\Phi$ soils, seismic effects and horizontal distance from the back face of wall to uniformly distributed surcharge loadings are also included. The results of horizontal active thrusts obtained from the developed method of analysis are compared with those from Jarquio's modified Boussinesq equation.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.225-228
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• 2008

This paper presents out-of-plane shear strength models for composite wall with steel plates based on limit theorem in the framework of the plasticity theory. The formulas proposed by JEAG 4618 need to be reconsidered with a couple of limitations; ignoring the effect of bond stress generated by studs in the process of calculating arch action, illogically discriminating between concrete shear cracking strength and arch strength by algebraic relation in short shear span ratio(0-2.0). In most cases, reinforcement ratio is not sufficient to yield, as a result, arch strength is determined by accounting equilibrium including both bond strength and concrete compressive strength. We conducted experimental research assuming that SC wall is a continuous beam under the simplified loading patterns, changing main valuables involving the number of studs, stirrups. The results show good agreements with the formula and we quoted the test results of JEAG.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.9-17
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• 2020

The purpose of this study was to evaluate lateral load resistance of a wall structure composed of precast concrete wall and H-Pile. This type of structure can be used for noise barrier foundation or retaining wall. Mock-up specimens having actual size were designed and fabricated. The lateral design load is 54.6kN. The H-pile length for the test specimen is 1.5m for simulating behavior of actual wall structure has 6.5m H-pile in the field, which is determined from theoretical study. Lateral displacements and strains of wall and H-pile were monitored and cracking in precast concrete wall inspected during the test. Load and deformation capacity of test specimens was compared with design capacity. The comparisons demonstrated that this type of structures, precast concrete wall and H-pile, can resist enough to lateral design load.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.23-28
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• 2002

This paper reports the performance results of hydration heat control of mass concrete walls with pipe cooling system. The thickness of walls ranged from 0.9 to 2.2m. In order to investigate the effect of pipe cooling on the thermal and thermal crack characteristics, the pipe cooling was conducted for 42 walls, and the investigation of thermal cracks was conducted for 14 walls. Based on the investigation, the pipe cooling method decreased the peak temperature of about 13-2$0^{\circ}C$ and the thermal crack width of about 30% for mass concrete walls.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.06a
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• pp.209-214
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• 2000

토류벽체는 배면토의 과도한 변형을 막기 위한 구조물이다. 일반적인 형식의 옹벽에는 중력식 옹벽, 철근 콘크리트 옹벽, 보강토 옹벽, 그리고 타이백(tie-back) 옹벽 등이 있다. 그러나 실용적인 관점에서는 실제로 많이 사용되고 있는 이들 형식의 옹벽들은 배수구의 막힘 현상과 보강재의 부식 및 정착공간의 부족, 온도차 신축균열, 미관상 자연 환경에 친화적이지 못한 문제점 등을 갖고 있다. 이에 따라 최근에는 콘크리트 블록으로 만든 새로운 형태의 옹벽이 개발되었다. (중략)

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.5-6
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• 2010

In this study, assuming that there is a diagonal uniaxial compression field in combination with triangular homogeneous stress fields in the cracked concrete wall and a tensile stress of a steel plate occurs in the perpendicular to the direction of the diagonal compression field, an ultimate shear strength of a slender composite shear wall is estimated.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.293-308
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• 1999

이 논문에서는 패널, 깊은 보 그리고 전단벽과 같이 평면응력상태하에 있는 철근콘크리트 구조물의 비선형 유한요소해석에 있어서의 직교이방성 콘크리트 구성 모델의 적용성을 보여준다. 등가의 일축 변형을 개념을 토대로 콘크리트의 구성 관계가 주변형률 축과 일치하고 하중이력에 따라 회전하는 직교하는 축에 대해 제시된다. 제안된 모델은 이축 압축응력상태와 인장-압축 응력상태에서 각각 압축강도의 증가와 인장 저항력의 감소효과를 보여주는 이축 파괴영역의 정의를 포함한다. 인장균열이 발생한 후, 콘크리트의 압축강도의 감소효과가 제시되고, 인장강화효과로 알려진 철근에 의해 지지되는 콘크리트의 인장응력이 고려된다. 평균응력과 평균변형률 개념을 사용하여 힘의 평형, 적합조건 그리고 철근과 철근을 둘러싼 콘크리트 사이의 부착응력-슬림 관계를 토대로 인장강화효과를 모사하기 위한 모델이 제안된다. 유한요소 모델에 의한 예측은 유용한 실험자료와의 비교에 의해 입증된다. 이 논문에서는 해석결과와 이상화한 전단 패널실험으로부터 얻어진 실험값의 비교연구가 수행되고, 제안된 모델의 타당성을 보여주기 위해 서로 다른 응력상태하의 전단 패널 보와 벽체의 힘-변위 관계를 평가하였다.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1437-1443
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• 2010

Thermal stresses due to the heat of hydration can cause extensive cracking in subway structures. In order to reduce heat cracks, construction methods (e.g. sequential or skipping construction methods) need to be changed. However, to our knowledge, the existing literature contains little information on the correlation between heat cracks and construction methods. Thus, in this study, the temperature crack index table was suggested based on construction lengths (6 m, 9 m and 18 m), concrete mixtures (Type I cement with FA of 20 % in cement weight, Type IV cement with FA of 10 % in cement weight, and mixture of three different cements), construction seasons (spring or autumn, summer and winter) and construction method (sequential or skipping construction methods). The index table can be easily used corresponding to changes in concrete placing method at the construction site. Also, the correlation of cracking due to sequential or skipping construction methods was derived based on the statistical approaches.

• Journal of the Korea Institute of Building Construction
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• v.23 no.2
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• pp.197-207
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• 2023

Concrete is a widely used material due to its excellent compressive strength and durability. However, depending on the surrounding environment and the characteristics of the materials used in the construction, various defects may occur, such as cracks on the surface and subsidence of the structure. The detects on the surface of the concrete structure occur after completion or over time. Neglecting these cracks may lead to severe structural damage, necessitating regular safety inspections. Traditional visual inspections of concrete walls are labor-intensive and expensive. This research presents a deep learning-based semantic segmentation model designed to detect cracks in concrete walls. The model addresses surface defects that arise from aging, and an image augmentation technique is employed to enhance feature extraction and generalization performance. A dataset for semantic segmentation was created by combining publicly available and self-generated datasets, and notable semantic segmentation models were evaluated and tested. The model, specifically trained for concrete wall fracture detection, achieved an extraction performance of 81.4%. Moreover, a 3% performance improvement was observed when applying the developed augmentation technique.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.3
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• pp.21-32
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• 1999

A ground motion resulting from the destructive earthquakes can subject reinforced concrete members to very large forces. The reinforced concrete shear walls are designed as earthquake-resistant members of building structure in order to prevent severe damage due to the ground motions. The current research activities on seismic behavior of reinforced concrete member under ground motions have been limited to the shaking table test or equivalent static cyclic test and the obtained results have been summarized and proposed for the seismic design retrofit of structural columns or shear walls. The present study predicted the seismic response and failure behavior of reinforced concrete shear wall subjected to base acceleration using the finite element method. A decrease in strength and stiffness, yielding of reinforcing bar, and repetition of crack closing and opening due to seismic load with cyclic nature are accompanied by the crack which is necessarily expected to take place in concrete member. In this study the nonlinear material models for concrete and reinforcing bar based on biaxial stress field and algorithm of dynamic analysis were combined to construct the analytical program using the finite element method. The analytical seismic response and failure behaviors of reinforced concrete shear wall subjected to several base accelerations were compared with reliable experimental result.