• International Journal of Highway Engineering
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• v.13 no.4
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• pp.81-91
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• 2011

This study was conducted to evaluate the necessity of the anchor lug system in continuously reinforced concrete pavement(CRCP) by comparing longitudinal displacements of CRCPs with and without anchor lugs, and to investigate the effect of horizontal cracking on CRCP performance by measuring the vertical displacements. The measurements before and after the anchor lug section was separated were conducted for 12 days in June, and for 14 days in August after the abrupt displacements according to cutting disappeared, respectively. This short term measurement results showed that when anchor lugs were installed, a daily displacement variation at any location was less than 0.1mm; therefore, longitudinal movements were negligibly small. When there were no anchor lugs, longitudinal displacements mainly occurred near the free end and the displacement variation was small; therefore, an expansion joint system seems to be employed at a CRCP terminus without installing anchor lugs. However, further studies are needed to verify the terminus behavior due to annual temperature changes. The horizontal crack width variation was ignorable and did not affect the vertical displacement of the slab. Therefore, the horizontal crack did not delaminate the slab and did not seem to reduce the structural capacity and performance of CRCP.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.237-237
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• 2022

우리나라 하천 내에 설치된 횡단구조물은 보 35,000개소 이상으로 전국 하천의 0.6 km마다 수공구조물이 위치해 있으며 이로 인해 종적(longitudinal) 연결성에 영향을 미치는 것으로 나타났다. 농어촌연구원의 조사에 따르면 하천 횡단구조물이 설치된 구간에 어도 설치율은 14.9%로 나타났으며 이는 수생태 관점에서 연속성이 매우 열악한 상태임을 확인 할 수 있다. 이에 우리나라 각 부처 국토교통부, 환경부 등에서는 수생태 연속성을 확보하고자하는 노력이 지속되고 있으며 대표적으로 어류의 이동통로인 어도를 설치하거나 기존 어도의 효율을 향상시키기 위하여 개보수 작업을 지속적으로 실시하고 있다. 어도의 기능을 평가하기 위해서는 어도 내의 수리특성을 정확히 파악하는 것이 중요한데 연속적인 구조물로 구성된 어도 내 흐름은 매우 복잡하다. 특히 어도 내 구조물간 상호작용에 의하여 비정상 흐름이 발생하며 구조물 뒤에서는 사수역(dead zone)이 형성된다. 사수역에서 나타나는 와류의 거동은 구조물의 기하학적 특성에 따라 변화한다. 본 연구에서는 2차원 수심적분 수치모형을 활용하였으며 벽면 근처 점성저층의 유속분포을 재현하기 위하여와 점성항에 감쇠함수(damping function)를 고려하였다. 수치모형의 검증을 위해 실내 실험수로의 직선 개수로에서 PIV(particle image velocimetry)를 활용하여 연속적으로 배치된 구조물에 의한 유속자료를 활용하였다. 이 결과는 향후 새로운 어도설계 혹은 기 설치된 어도의 수리학적 기능을 평가하는데 활용이 가능할 것으로 보인다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.235-240
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• 2011

A flexible hose attached to a mother ship experiences various motions that depend on the movement of the mother ship and that of underwater vehicle. Although the motion of the hose is a very important factor that determines how a mother ship should be steered in a real situation, it is difficult to experimentally obtain information about the hose motion. Therefore, we study the motion of the hose analytically. The ANCF(absolute nodal coordinate formulation) was used to model the hose, because this formulation can relax the Euler-Bernoulli theory and the Timoshenko beam theory and allow the deformation of the cross section. The mother ship is assumed to be a rigid body with 6 degrees of freedom. The motion of the hose is predominantly affected by the behavior of the mother ship and by the fluid flow.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.263-272
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• 2003

Scaled model tests were carried out to investigate a seismic behavior of reinforced concrete piers with hollow-rectangular section that were not detailed for seismic load. Additional lateral reinforcing bars were not provided that might be required for confinement against earthquake load. Two kinds of reinforcement details were considered for the longitudinal reinforcing bars: lap-spliced and continuous. In the lap-spliced model all longitudinal bars were lapped at the same height in a bottom plastic hinge zone. In the other model all longitudinal bars extended continuously throughout the height. The constructed models were subjected to quasi-static cyclic lateral loading in the presence of the constant vertical load. Limited ductile behavior was observed in the test of lap-spliced model and more ductile behavior was observed in the test of a continuous longitudinal reinforcement model.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.137-149
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• 2023

In order to intuitively grasp the earth pressure direction acting on the structure and displacement state, displacement data in the horizontal and vertical directions were processed using the sigmoid function. A displacement coordinate system was set up for each axis. The system can intuitively check the current displacement and assess the management stage of each point. A displacement path can be compiled from continuously recorded points, allowing trends in the displacement's history and stress direction to be known. Analysis of data measured for excavated ground, found that displacement occurred in the direction of destressing at all points, and that the points' management state steady. Similar behavior trends were found among measurement points with high spatial correlation, whereas differing behavior trends occurred among measurement points with low spatial correlation. If the correlation analysis of the precursor and behavior area is performed using the continuously distributed surface settlement data and displacement coordinate system, it will be possible to predict the failure time and area.

• Journal of the Korean GEO-environmental Society
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• v.2 no.3
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• pp.81-88
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• 2001

The behavior of porous medium is modeled by linear thermoporoelastic behavior, linear poroviscoelastic behavior, poroplastic behavior, and poroviscoplastic behavior, etc. The behavior has, in general, a complicated aspect which makes a mechanical description of the problem with time. Constitutive modeling for deformation behavior of porous medium with coupling effects is needed since there is interaction between the constituents in pores with a relative velocity to each other. In this work, it is explained 3-dimensional behavior depending on degree of saturation for porous medium composed of homogeneous, isotropic materials. It is obtained the governing equations based on continuum porous mechanics. In addition, it is developed constitutive model which can be understood of behavior for porous medium which can be understood, analysed behavior of porous medium. It can be accomplished exact analysis and prediction of behavior in porous medium. The behavior for porous medium is analysed exactly, and the prediction of deformation behavior is accomplished. Consequently, it will be basis to analyze 3-dimensional behavior in municipal solid waste landfill, and the practical using of porous medium ground which are composed of nonhomogeneous, anisotropic materials can be done widely.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.555-564
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• 2013

An effective method was proposed in this study which can improve the strengthening effect of continuous girder bridges by external tendons. The improvement of the proposed strengthening method in comparison with conventional methods was analyzed by applying equivalent load concept. In order to verify the strengthening effect, the enhancement of load-carrying capacity achieved by external prestressing was investigated through the test of continuous beams that were or were not strengthened by the external prestressing. The continuous beams were fabricated by making the deck slab continuous according to general construction practice of an actual concrete girder bridge. The test results showed that the deflections and strains of the strengthened beam were significantly reduced when comparing with those of the non-strengthened beam for the same level of external loads, and the stiffness of the member increased by strengthening. In particular, it was verified that the proposed method can effectively reduce the tensile stresses of the deck caused by negative moment at the intermediate supports of a continuous bridge.

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• v.19 no.3
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• pp.43-49
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• 2015

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.84.2-84.2
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• 2000

• Tunnel and Underground Space
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• v.10 no.3
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• pp.278-290
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• 2000

불연속면이 발달한 암반 내에서 터널을 굴착하는 경우 불연속면을 고려한 터널의 역학적 안정성을 검토하는 것이 중요하다. 불연속 암반 내에 터널을 굴착하게 되면 대부분의 거동은 불연속면에서 발생하게 된다. 이는 암반블록보다 암반 내 불연속면의 강성이 현저하게 작기 때문이다. 불연속면을 고려한 터널의 안정성 해석은 암반을 연속체로 가정할 때 필요한 입력변수 외에 여러 종류의 입력변수가 추가로 필요하다.(중략)