• Journal of Korean Society of Steel Construction
• /
• v.18 no.5
• /
• pp.607-614
• /
• 2006

The composite metal deck plate system has been widely used of late for office structures. However, composite floor decks are bored imprudently for installation in building equipment. In this study, experimental investigations of bored composite steel deck slabs were performed to evaluate the flexural capacity of each specimen. The variables set were the shapes and positions of the openings in the composite slabs. The results were analyzed in the form of load-displacement graphs and with respect to the ductility and energy dissipation capacity ofeach specimen to evaluate its structural capacity.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2002.10a
• /
• pp.227-236
• /
• 2002

The purpose of this study makes a retrofit and rehabilitation practice trough the analysis and the improvement for the underlying problem of current retrofit and rehabilitation methods. Therefore, the deterioration process, the damage cause, the condition classification, the fatigue mechanism and the applied quantity of strengthening methods for RC deck slabs were analyzed. Artificial neural networks are efficient computing techniques that are widely used to solve complex problems in many fields. In this study, a back-propagation neural network model for estimating a management on existing reinforced concrete bridge decks from damage cause, damage type, and integrity assessment at the initial stage is need. The training and testing of the network were based on a database of 36. Four different network models were used to study the ability of the neural network to predict the desirable output of increasing degree of accuracy. The neural networks is trained by modifying the weights of the neurons in response to the errors between the actual output values and the target output value. Training was done iteratively until the average sum squared errors over all the training patterns were minimized. This generally occurred after about 5,000 cycles of training.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.2 no.3
• /
• pp.30-35
• /
• 2011

This study investigates the optimum section properties of newly developed steel-concrete composite beam. For that purpose we developed computer program calculating section properties. The suggested new beam section highly contribute to save inter-story height and reduce construction duration and cost compared with conventional steel works such as H-beam and column + RC slab system. But the section shape have different section modulus with upper and lower fiber because of the unsymmetric cross section. Therefore the parametric study on thickness-ratio of top and bottom flange plate is needed. In this paper the change of neutral axis and section modulus for thickness-ratio of up and down flage plate is analysed and discussed.

• Journal of Korean Association for Spatial Structures
• /
• v.17 no.2
• /
• pp.33-41
• /
• 2017

Composite Floor system infilled with PCM(Phase Change Material) between upper and lower steel plates was developed to apply the steel frame. When steel frames were applied this system, it can absolutely reduce the duration of construction due to dry construction method. However to apply this system as a structural floor member without fire resistance covering, it must have 2 hours fire resistance performance. Because PCM consisted of three quarters of section with thermal insulation performance, fire resistance performance of this floor system was expected to easily have 2 hours fire resistance performance. This paper was to investigate behavior characteristics of PCM infilled floor system at elevated temperature using FEM analysis to develop the fire resistance performance of it.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.6 no.1
• /
• pp.233-239
• /
• 2002

Reinforced concrete deck slabs are directly affected by traffic loads and they are also susceptible to weather-related problems, such as cracking, reinforcement corrosion, spatting, scaling, delamination, leakage, efflorescence and so on. Some of these defects are caused by water which seeps through pavements and trapped between pavements and deck slabs. For durability of reinforced concrete deck slabs and pavements, it is very important to protect deck slabs and drain the trapped water out. To develop the trapped water drainage system, the following studies have been performed in Korea Highway Cooperation: related researches a re reviewed; for six bridges, deck slabs are thoroughly investigated; new system to effectively drain the trapped water out is proposed; the proposed system is installed and evaluated. The proposed system is proved to be effective to drain the trapped water out and is expected to increase the durability of reinforced concrete deck slabs.

• Journal of Korean Society of Steel Construction
• /
• v.22 no.6
• /
• pp.533-541
• /
• 2010

H-shaped beams, which are constructed between columns, are used widely as slaves in steel structures. The bending moments that occur on both ends of an H-shaped beam, however, are about twice the bending moment that occurs at the center of the H-shaped beam. Because such beam is designed with maximum bending moment, it is deeper and has smaller spaces. To improve these features, if both ends of an H-shaped beam that have maximum bending moments are merely reinforced, the beams could be designed by the bending moment at the center of the H-shaped beam. To analyze the structural performance of the proposed end-reinforced beams (eco-girders). Four specimens were prepared with the following parameters: end-reinforced steel plate, reinforced bars, and reinforced studs and experimental tests of the specimens were performed.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2008.04a
• /
• pp.46-49
• /
• 2008

본 논문은 이동 로봇의 이동 및 거리 센싱의 불확실성을 고려한 시뮬레이터 개발에 대해 소개한다. 이동 로봇은 구동기, 바닥의 불안정성, 바퀴 및 구동 기구의 불확실성, 그리고 기타 구조적으로 어려운 다양한 원인으로 동작 명령과 차이가 있게 이동한다. 또한 이동 로봇에 장착된 각종 센서는 센서 자체의 불안정성, 주변 환경의 불안정성등에 의하여 정확한 측정값을 출력하지 못한다. 이러한 이동 및 센서의 불안정성은 로봇의 자율 주행 알고리즘의 구현이 가장 큰 장애물이 되고 있다. 예측하기 어려운 불안정성을 고려하지 않은 알고리즘은 실제 환경에서 필연적으로 동작에 실패하여 크고 작은 사고를 일으킨다. 따라서 알고리즘의 검증을 위해 시뮬레이터가 각종 불확실성을 포함하여 로봇 동작이 실제에 유사하도록 하여야 한다. 본 연구에서는 이동 로봇의 이동과 센싱에 불확실성을 포함하도록한 시뮬레이터를 개발하였다. 다양한 센서들 중 이동 로봇의 위치 추정, 장애물 인식, 지도 작성등에 가장 기본적으로 사용되는 영역 센서를 대상으로 불확실성을 구현하였다. 개발된 시뮬레이터를 사용하여 알고리즘을 검증하는 경우와 불확실성을 고려하지 않은 시뮬레이터를 사용하여 알고리즘을 검증하는 경우를 비교하여, 제안된 시뮬레이터의 성능을 검증하였다.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.2
• /
• pp.75-85
• /
• 2004

Various geosynthetics are widely installed as a liner or a protective layer of waste landfills. The interface shear strength between the layers of geosynthetics in waste landfills is an important parameter to ensure the safety of bottom and cover system design. In this study, estimations of interface shear strength between geomembrane and geotextile or Geosynthetic Clay Liners (GCL) are performed by large direct shear tests. Especially, this research is focused on the effect of moisture within the interface shear strength between geosynthetics, because most interfaces are vulnerable to rain, leachate and groundwater beneath the liners.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2004.11a
• /
• pp.271-278
• /
• 2004

컨테이너 터미널에서 적하 작업을 수행할 때에는 선박의 안정성을 위하여 무거운 컨테이너들을 선박의 바닥쪽에 우선하여 배치한다. 그러므로 장치장(yard)에서 동일한 선박 베이(bay)에 선적할 컨테이너들을 무게가 무거운 순서로 효율적으로 반출할 수 있다면, 적하 계획의 수립과 수행일 수월해진다. 만일 장치장에서 적하를 위하여 지금 반출하여야 하는 컨테이너의 상단에 다른 컨테이너들이 장치되어 있다면, 부득이하게 위에 놓여 있는 컨테이너들을 임시로 옮겨야 하는데, 이러한 부가 작업을 재취급(rehandling)이라 한다. 채취급이 빈번히 발생하게 되면 적하 작업의 흐름은 차질을 빚게 되므로 재취급의 최소화는 작업 효율 측면에서 매우 중요하다. 본 논문에서는 컨테이너가 장치장에 반입되는 시점에 해당 컨테이너의 무게를 알 수 있다는 가정하에, 적하 작업을 위한 반출시 재취급이 적게 발생하도록 신규 반입된 컨테이너의 장치 위치를 결정하는 휴리스틱을 제안한다. 제안하는 휴리스틱은 각 스택(stack)별로 장치되어 있는 컨테이너들 중에서 자장 먼저 반출될 가장 무거운 컨테이너의 무게를 해당 스택의 대표 무게로 설정하고, 이를 신규 반입 컨테이너의 무게와 비교하여 장치 위치를 결정한다. 장치장 베이 하나로 시뮬레이션한 실험 결과 4단 6열 및 6단 9열의 장치장 베이 구조에서 임의의 위치에 신규 반입 컨테이너를 장치하는 방식에 비해 재취급 횟수를 1/5이하로 줄일 수 있음을 확인하였다

• Journal of the Korea Concrete Institute
• /
• v.28 no.1
• /
• pp.3-11
• /
• 2016

The concern about hollow core PC slab has been increased to improve the workability during a construction of building by reducing self weight of structural members. In this manner, recently, TRS (Tripple Ribs Slab) was developed as a new type of half PC slab system. TRS member consists of the triple webs and the bottom flange prestressed by strands. The slab system is completed by casting of topping concrete on the TRS after filling styrofoam between the webs. This paper, presents a flexural experiment to investigate the flexural capacity of the TRS. Five full scale TRS members were made and tested under simple support condition to be failed by flexure and their strength was evaluated by code equations; the variables in the test are the depth and the presence of topping or raised spot formed when slip-forming. In addition, a nonlinear sectional analysis was performed for the specimens and the result was compared with the test results. From the study, it was found that the TRS has enough flexural strength and ductility to resist the design loads and its strength can be suitably predicted by using code equations. The raised spot did not affect the strength so that the spot need not to be removed by doing additional work. For the more accurate prediction of TRS's flexural behavior by using nonlinear sectional analysis, it is recommended to consider the concrete's brittle property due to slip-forming process in the modeling.