• Computers and Concrete
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• 제17권5호
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• pp.597-612
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• 2016

The present work focuses on the use of coconut fiber in self compacting concrete. Self-Compacting Concrete (SCC) is a highly flowable, stable concrete which flows readily into place, filling formwork without any consolidation and without undergoing any significant segregation. Use of fibers in SCC bridge the cracks and enhance the performance of concrete by not allowing cracks to propagate. They contribute to an increased energy absorption compared to plain concrete. Coconut fiber has the highest toughness among all natural fibers. It is known that structures in the seismic prone areas are always under the influence of cyclic loading. To justify the importance of strengthening SCC beams with coir fiber, the present work has been undertaken. A comparison is made between cyclic and static loading of coconut fiber reinforced self compacting concrete (FRSCC) members. Using the test data obtained from the experiment, hysteresis loops were drawn and comparison of envelope curve, energy dissipation, stiffness degradation were made and important conclusions were draw to justify the use of coconut fiber in SCC.

• Structural Engineering and Mechanics
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• 제61권3호
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• pp.397-406
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• 2017

The use of fiber reinforced polymer (FRP) for torsional strengthening of reinforced concrete (RC) single cell box beams has been analyzed considerably by researchers worldwide. However, little attention has been paid to torsional strengthening of multicell box girders in terms of both experimental and numerical research. This paper reports the experimental work in an overall investigation for torsional strengthening of multicell box section RC girders with externally-bonded Carbon Fiber Reinforced Polymer CFRP strips. Numerical work was carried out using non-linear finite element modeling (FEM). Good agreement in terms of torque-twist behavior, steel and CFRP reinforcement responses, and crack patterns was achieved. The unique failure modes of all the specimens were modeled correctly as well.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.727-730
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• 2003

The objective of this work is to understand the deterioration mode of ordinary portland cement pastes and mortars immersed in 5% sodium sulfate solution for 510 days. In order to achieve the goal, x-ray diffraction (XRD) and scanning electron microscopy (SEM) are presented in this experimental work. Strength deterioration (SDF) and length change of the mortars were also measured to evaluate resistances to the attacking solution. The mortars were prepared by using water-cement ratio of 35%, 45% and 55%, respectively, and the water-cement ratio of pastes was fixed at 45%. Conclusively, the deterioration by sodium sulfate attack was primarily due to the formation of ettringite and thaumasite. This process of deterioration may submit the reasonable understanding on the sulfate attack mechanism of hardened cement pastes, mortars, and concretes.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.419-422
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• 2010

In this study, I executed civil engineering design and compared it with the existing method in order to analyze the expected effect of civil engineering design by using three dimensional space information and its advantages. Through a series of processes, it is possible to enhance the usability of three-dimensional space information, expected more accurate calculation of earth work and proceed with more reasonable construction in soil conversion and civil engineering work. Also, it enables improvement of productivity by establishing efficient construction plan.

• Structural Engineering and Mechanics
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• 제63권5호
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• pp.683-689
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• 2017

In this paper, a hyperbolic shear deformation theory is presented for bending analysis of functionally graded beams. This theory used in displacement field in terms of thickness co-ordinate to represent the shear deformation effects and does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. The governing equations are derived by employing the virtual work principle and the physical neutral surface concept. A simply supported functionally graded beam subjected to uniformly distributed loads and sinusoidal loads are consider for detail numerical study. The accuracy of the present solutions is verified by comparing the obtained results with available published ones.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.509-512
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• 2013

An inappropriate space zoning plan causes the unnecessary transportation of construction material and equipment among work areas and increases the disorder of work space. Space zoning is an essential operation management technique which contributes to reduce the process and/or operation idle-time. This paper introduces a method that computes the idle-times between construction operations (or processes) by using Web-CYCLONE. It allows computing with idle-times that affect the construction productivity. Using the idle time between operations and between processes, it computes the optimal number of zones and finds the optimal combination of zones that minimize the idle times. The method contributes to minimize the idle times relative to the operation schedule using complete enumeration. This paper presents the system prototype in detail. A case study is presented to demonstrate the system and verifies the validity of the model. It allows a project manager to establish space zoning plan that effectively segregates a project into optimal number of construction zones and to assign the constrained resources (e.g., laborer, equipment).

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.513-516
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• 2013

Earthmoving equipment's haul-route has a great influence on the productivity of the earth work operation. Haul-route grade is a critical factor in selecting the haul-route. The route that has low grade resistance contributes to increase machine travel speed and production. This study presents a mathematical model called "Hauling-Unit Optimal Routes Selecting system" (HUORS). The system identifies optimal path that maximize the earth-work productivity. It consists of 3 modules, i.e., (1) Module 1 which inputs site characteristic data and computes site location and elevation using GIS(Geographical Information System); (2) Module 2 which calculates haul time; (3) Module 3 which displays an optimum haul-route by considering the haul-route's gradient resistances (i.e., from the departure to the destination) and hauling time. This paper presents the system prototype in detail. A case study is presented to demonstrate the system and verifies the validity of the model.

• 대한토목학회논문집
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• 제33권6호
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• pp.2519-2528
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• 2013

표준품셈은 공공기관 및 민간기관의 공사비를 책정하는 기본적인 자료로 이용되고 있다. 본 논문은 하천공사에서 선정된 대표공종을 대상으로 새로운 형식의 표준품셈 및 장비의 작업량 산출방식을 제안하고자 한다. 품셈에서 작업조 구성의 정보 및 1일 생산성 정보의 제공이 가능하도록 함으로써 공정계획 단계에서 품셈의 적용성을 향상시키고 장비의 작업량 산출과정을 간소화하여 사용자의 편의성을 증대할 수 있기를 기대한다. 하천공사의 경우 작업조건이라는 변수가 매우 크게 작용하기 때문에 생산성 정보 및 기계의 작업량을 일반화 하는 것은 많은 어려움이 존재하지만 지속적인 생산성 정보와 기계의 작업량 정보를 개선하여 정확도를 향상할 수 있다면 품셈을 통한 공정계획 수립 및 적산과정의 간소화가 가능할 것이다.

• 한국지리정보학회지
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• 제6권3호
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• pp.73-82
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• 2003

본 연구는 대축척 수치지도 ver. 2.0(1/5,000)을 이용하여 소축척 수치지도 ver. 2.0(1/25,000)으로 제작하기 위한 처리공정을 개발하였다. 기존 수치지도와 달리 수치지도 ver. 2.0은 속성정보 및 면처리 등 많은 정보들을 포함하고 있기 때문에 이를 효율적으로 처리하기 위하여 소축척 수치지도의 지형 지물코드에 포함되지 않는 레이어를 삭제하고, 자료처리를 8대 지형 지물별로 분류하여 처리한 후, 자료를 병합하는 과정으로 작업공정을 도출하였다. 따라서 본 연구에서 개발한 작업공정은 향후 최적 자동일반화시스템 개발시 기초자료로 이용할 수 있을 것이고, 소축척 수치지도 및 각종 주제도 제작에 기여할 수 있을 것이다.

• 대한토목학회논문집
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• 제13권5호
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• pp.53-65
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• 1993

본 연구에서는 강성기초의 동적응답을 얻기 위해서 비완화 경계조건(non-relaxed boundary condition)을 적용한 3차원 경계요소를 사용하였다. 경계요소는 장래의 비선형문제의 확장을 위해서 시간영역에서 형식화되었으며 기본해는 무한영역의 Stokes 해를 사용하였다. 본 연구는 검증되었으며 지반기초 및 임의 형상의 지하구조물외 동적응답을 얻는데 이용할 수 있다.