• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2004년도 학술대회지
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• pp.21-26
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• 2004

This study deals with the Hydrated Ability of the Ready-Mixed Concrete's Sludge which is the recycling technology of that sludge. The experiment gathers sludge from Ready-mixed factory. shatters these into pieces in dry condition and understands the differences between current using Portland cement. And then. this examines the possibility of the recycle as a bonding agent through the Compressive Strength and considers the recovery of the hydration. This experiment concludes the same Chemical Composition with the normal Portland cement. while. under the appropriate procedure in hydration recovery. this sludge can be used as the bonding agent in cement. The chemical composition of solid Remicon sludge shows that it has 1.8 times $SiO_2$ than the normal Portland cement. meaning lots of aggregate in Remicon sludge. Also. the specific gravity of Remicon sluge increases with the rise of Baking Temperature and has no difference between 2.77 and 2.94. The mortar flow used for combining the baking material of Remicon sludge does was not changed and is the highest between $750^{\circ}C{\cdot}120min\;and\;800^{\circ}C{\cdot}180min$. Additionally. the Compressive Strength increases with the age, certifying the same Hydrated Ability like cement and the best condition for hydration is $750^{\circ}C{\cdot}120min.$

• Smart Structures and Systems
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• 제19권5호
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• pp.523-538
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• 2017

A series of field vibration tests are conducted on the Runyang Suspension Bridge during both the construction and operational stages. The purpose of this study is devoted to the analysis of the dynamic characteristics of the suspension tower. After the tower was erected, an array of accelerometers was deployed to study the evolution of its modal parameters during the construction process. Dynamic tests were first performed under the freestanding tower condition and then under the tower-cable condition after the superstructure was installed. Based on the identified modal parameters, the effect of the pile-soil-structure interaction on dynamic characteristics of the suspension tower is investigated. Moreover, the stiffness of the pile foundation is successfully identified using a probabilistic finite model updating method. Furthermore, challenges of identifying the dynamic properties of the tower from the coupled responses of the tower-cable system are discussed in detail. It's found that compared with the identified results from the freestanding tower, the longitudinal and torsional natural frequencies of the tower in the tower-cable system have changed significantly, while the lateral mode frequencies change slightly. The identified modal results from measurements by the structural health monitoring system further confirmed that the vibrations of the bridge subsystems (i.e., the tower, the suspended deck and the main cable) are strongly coupled with one another.

• 대한기계학회논문집A
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• 제26권1호
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• pp.179-187
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• 2002

Finite element analysis was performed to evaluate the integrity of the tubes in the fixed tubesheet of horizontal type heat exchanger under operating condition. For the finite element analysis of the heat exchanger, tubes and tubesheets were equivalently modeled with concentroidal hexagonal columns and solid plates having equivalent properties for the convenience of finite element modeling, respectively. Load combination of tube pressure and thermal expansion most likely to precipitate possible failure of the tubes was selected and applied to the finite element analysis. The compressive stresses of the tubes were calculated based on displacements of each tube, which were obtained from anile element analysis. Finally, the maximum tube stress was compared with the design criterion of ASME Boiler and Pressure Vessel Code Section VIII.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.246-247
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• 2017

In this study, it reviewed the effect of moisture migration in concrete with heating rate on concrete spalling. Concrete specimens with compressive strength 30MPa and 110MPa are used and its size is □100×100×h200mm. And, two kinds of heating rate are set such as IS0 834 and 1℃/min. As a result, in the concrete specimen exposed to ISO 834 standard heating condition, moisture could migrate through pore network and surface concrete pieces fall out by generating moisture clog near the surface in 110MPa concrete specimen. Meanwhile, In the case of concrete specimens exposed to 1℃/min. heating condition, it is appeared that moisture could not migrate because temperature is distributed uniformly. Therefore, surface spalling is not occurred with low heating rate. However, in the case of 110MPa concrete specimen is exploded even though it heated by low heating rate.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.149-154
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• 2008

국내 교량구조물의 대부분은 구조물, 자체에 의한 열화, 손상과 같은 물리적인 수명에 의하여 공용수명이 결정될 수 있어야 하지만, 이에 대한 연구가 미비하여 교량의 유지관리시 최적 유지관리 시나리오를 선정하는데 많은 어려움이 있다. 최적의 유지관리 시나리오를 선정하기 위해서는 부재별 열화에 의한 상태변화 및 유지관리를 위한 보수보강 효과를 고려한 상태/성능 분석이 반드시 요구되며, 본 연구에서 제안된 상태변화모델을 기반으로 기존에 구축된 DB 및 현재 운용중인 고속도로교량관리시스템(Highway Bridge Management System; HBMS)에 LCC 분석을 접목한 시스템개선의 효과 증대를 이를 수 있을 것으로 고려된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1132-1140
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• 2009

Recently soil improvement methods are using in many ways such as costal and soft ground of inland. Among them, sand compaction pile be widely used because of quiet few advantages. There are two ways for quality evaluation method of sand compaction pile. Especially standard penetration test is used the most general method. However, Current method have problems in that it is not consider the condition of construction site. Therefore this study is propose new quality evaluation method. Relation of N-$\Phi$ is always not fixed but changing by condition of construction site. By through the Laboratory test we can know relationship between relative density and internal friction. Also this study propose revision for effective stress. From these study, we can acquire more accurate and reasonable result than current method.

• 한국정보통신학회논문지
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• 제8권7호
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• pp.1501-1505
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• 2004

IP기반 초고속인터넷의 인증체계가 전송방식에 따라 인증ㆍ무인증 접속체계로 이원화되어 이용자의 적법성 확인, 네트워크의 접속 권환 및 자원 할당에 대한 이용자의 체계적인 인증정보의 관리가 미약했다. 또한 무인증 접속으로 시스템 및 네트워크의 부하 가중과 전송속도 저하로 이용자들의 욕구 충족이 어려운 실정이다. 따라서 본 논문에서는 인증-무인증 접속체계를 단일 인증시스템으로 통합하여 최적의 네트워크 환경을 구축할 수 있는 SPAM 서버를 이용한 인증 시스템 구축 방안을 제시하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.95-98
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• 2007

This study investigates the mechanical properties of the high strength concrete in the region of 80MPa corresponding to the temperature and fiber content change. For the properties of the fresh, slump flow is $600{\pm}100mm$, and air content is $3.0{\pm}1.0%$. They satisfy each targets, and there was no difference for the each fiber types. As the propertied of the hardened concrete, the compressive strength at 28 days is indicated over 80MPa, and they are similar to the change of the fiber types. The residual compressive strength in response to the temperature change of the NY, PP, and NY+PP fiber at $200^{\circ}C$ are increased by 115, 114, and 110% on the standard condition, and it is suddenly decreased at $400^{\circ}C$. They are decreased by 33, 19, and 16% on the standard condition at $800^{\circ}C$.

• Computers and Concrete
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• 제7권3호
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• pp.249-269
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• 2010

Managing and reusing knowledge in engineering and construction sectors can lead to greater competitive advantage, improved designs, and more effective management of constructed facilities. The use of Information Technology (IT) in design and construction can exploit strategic opportunities for new ways of integration, sharing and facilitating information and knowledge in any field of engineering. The integrating of separate areas of IT can be used to bring a group of experts and specialists in any field of engineering closer together by allowing them to communicate and exchange information and expertise that facilitate knowledge capture, sharing, and reuse. A lack of an advisory management system and a need to marshal all available data in a common format has indicated the need for an integrated engineering computing environment to investigate concrete repair problems. The research described in this paper is based upon an evaluation management system (EMS) which comprising a database management system (REPCON) alongside visualisation technologies and evaluation system (ECON) is developed to produce an innovative platform which will facilitate and encourage the development of knowledge in educational, evolution and evaluation modes of concrete repair. This allows us to create assessment procedures that will allow the current condition of the concrete structure and its components to be expressed numerically using a confidence level (CL) so as to take the best course of action in the repair and maintenance management. The explained rating system, which is related to structural integrity and serviceability of the structure, allows the confidence level to be determined by visual inspection and the descriptive information and pictures taken from an available REPair of CONcrete (REPCON) database.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.799-804
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• 2005

In this work, the characteristics of train performance of Korean rubber-tired AGT system(K-AGT) are evaluated by using TPS(Train Performance Simulation) and these results are compared to those of other LRT(Light Rail Transit) systems. The performance characteristics of K-AGT was analyzed by comparing the scheduled speed and the energy consumption in case of station interval change and rail track condition change in, the scheduled construction line. In the scheduled construction line, scheduled speed of K-AGT was no difference with other systems and energy consumption was less than other LRT's. In case station intervals are increased, scheduled speed of K-AGT shows similar increasing rate and in curved and graded track conditions K-AGT has no difference in scheduled speed with other systems. As a simulation result by track condition change, when the track which is smaller than curved line of 250m dominates more than $50\%$ in whole track, K-AGT is similar to other systems to the point of scheduled speed and there is advantage in energy consumption.