• Steel and Composite Structures
• /
• v.37 no.3
• /
• pp.307-321
• /
• 2020

The slim-floor solution provides an efficient alternative to the classic slab-over-beam configuration due to architectural and structural benefits. Two deficiencies can be identified in the current state-of-art: (i) the technique is limited to nonseismic applications and (ii) the lack of information on moment-resisting slim-floor beam-to-column joints. In the seismic design of framed structures, continuous beam-to-column joints are required for plastic hinges to form at the ends of the beams. The present paper proposes a slim-floor technical solution capable of expanding the current application of slim-floor joints to seismic-resistant composite construction. The proposed solution relies on a moment-resisting connection with a thick end-plate and large-diameter bolts, which are used to fulfill the required strength and stiffness characteristics of continuous connections, while maintaining a reduced height of the configuration. Considering the proposed novel solution and the variety of parameters that could affect the behavior of the joint, experimental and numerical validations are compulsory. Consequently, the current paper presents the experimental and numerical investigation of two slim-floor beam-to-column joint assemblies. The results are discussed in terms of moment-rotation curves, available rotational capacity and failure modes. The study focuses on developing reliable slim-floor beam joints that are applicable to steel building frame structures located in seismic regions.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.3
• /
• pp.24-33
• /
• 2009

Stream data, gathered from ubiquitous sensor networks, change continuously over time. Because they have quite different characteristics from traditional databases, we need new techniques for storing and querying/analyzing these stream data, which are research issues recently emerging. In this research, we implemented a storage manager gathering stream data and storing them into databases, which are sampled continuously from sensor networks. The storage manager cleans faulty data occurred in mobile sensors and it also reduces the size of stream data by merging repeatedly-sampled values into one and by employing the tilted time frame which stores stream data with several different sampling rates. In this research furthermore, we measured the performance of the storage manager in the context of a sensor network monitoring fires of a building. The experimental results reveal that the storage manager reduces significantly the size of storage spaces and it is effective to manage the data stream for real applications monitoring buildings and their fires.

• Earthquakes and Structures
• /
• v.14 no.1
• /
• pp.1-10
• /
• 2018

Seismic retrofitting of existing buildings and design of earth-quake resistant buildings are important issues associated with earthquake-prone zones. Use of metallic-yielding dampers as an energy dissipation system is an acceptable method for controlling damages in structures and improving their seismic performance. In this study, the optimal distribution of dampers for reducing the seismic response of steel frames with multi-degrees freedom is presented utilizing the uniform distribution of deformations. This has been done in a way that, the final configuration of dampers in the frames lead to minimum weight while satisfying the performance criteria. It is shown that such a structure has an optimum seismic performance, in which the maximum structure capacity is used. Then the genetic algorithm which is an evolutionary optimization method is used for optimal arrangement of the steel dampers in the structure. In continuation for specifying the optimal accurate response, the local search algorithm based on the gradient concept has been selected. In this research the introduced optimization methods are used for optimal retrofitting in the moment-resisting frame with inelastic behavior and initial weakness in design. Ultimately the optimal configuration of dampers over the height of building specified and by comparing the results of the uniform deformation method with those of the genetic algorithm, the validity of the uniform deformation method in terms of accuracy, Time Speed Optimization and the simplicity of the theory have been proven.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.2
• /
• pp.52-59
• /
• 2015

In this paper, the vibration control effect of the isotropic damping devices (so-called Kagome dampers) was investigated by applying the Kagome dampers to a 20-story frame structure apartment. A new Kagome Damper System (KGDS) composed of the dampers and supporting column was proposed and numerical analyses were performed to investigate the effects of stiffness ratio between controlled structure and supporting column, the damper size and the number of the dampers. The numerical analysis results of a structure with KGDS up to the third story showed that the stiffness ratio should be higher than 6.4 and the damper size be at least $700{\times}700mm$ to effectively reduce the base shear and the maximum drift of the uppermost story. When the KGDS was installed up to the fifth story, the stiffness ratio should be higher than 7.0 and damper size needs to be at least $500{\times}500mm$ for obtaining the target performance.

• Journal of Biosystems Engineering
• /
• v.36 no.6
• /
• pp.407-415
• /
• 2011

Damage to agricultural production caused by insects and diseases affects farming yields. The orchard sprayer is mainly used in the country to protect the fruit in a large area, with less effort and at minimum cost. The excellent performance of the air blast spray increases the fruit protection. Chemical application in orchards has been accomplished by the orchard sprayers with air assist nozzles and a axial fan in Korea. However, the orchard sprayers without ROPS resulted in severe injury or death when operators drive the sprayers improperly on hilly orchard or farming road. This study was to develop a ROPS for the orchard sprayers improving farmer's safety. In this study, the accident case was used in analysing the design and building TOP structure of the orchard sprayer. The maximum impact, body torsion frame structures including the driver's protection are also analysed for adherence to safety regulations. The ROPS safety regulations according to the strength test results were established.

• Journal of Preventive Medicine and Public Health
• /
• v.46 no.3
• /
• pp.134-138
• /
• 2013

This road map aims to establish a stable and integrated healthcare system for the Korean Peninsula by improving health conditions and building a foundation for healthcare in North Korea through a series of effective healthcare programs. With a basic time frame extending from the present in stages towards unification, the roadmap is composed of four successive phases. The first and second phases, each expected to last five years, respectively, focus on disease treatment and nutritional treatment. These phases would thereby safeguard the health of the most vulnerable populations in North Korea, while fulfilling the basic health needs of other groups by modernizing existing medical facilities. Based on the gains of the first two phases, the third phase, for ten years, would prepare for unification of the Koreas by promoting the health of all the North Korean people and improving basic infrastructural elements such as health workforce capacity and medical institutions. The fourth phase, assuming that unification will take place, provides fundamental principles and directions for establishing an integrated healthcare system across the Korean Peninsula. We are hoping to increase the consistency of the program and overcome several existing concerns of the current program with this roadmap.

• Journal of Korean Society of Steel Construction
• /
• v.18 no.3
• /
• pp.385-393
• /
• 2006

In Korea, the effective utilization of wod structure is encour aged to preserve natural resources and the global environment.ote demand for wod. The efective combination of structural la minated timber and other materials is expected to extend the potential of building structures. This research examines the moment resis tance-type jointing method using structural laminated timber and H-section stel aiming at development of the two-direction frame for lar ge 9 mm and 12 mm) of the H section. Therefore, we conducted the experiment with bending test of the joints to investigate the s tifnes, strength, strain distributions of laminated timber an d of the flange of the H section, and failure paterns. As shown in the results, t he joints with a flange thicknes of 9 mm and 12 m have superi or strength with a flange thicknes of 9 mm and 12 mm were very large, whic h confirmed the high level of energy absorption of such structure s.

• Journal of Korean Society of Steel Construction
• /
• v.25 no.3
• /
• pp.279-287
• /
• 2013

The steel members are applied to high rise building since they have high strength compare to the concrete member. On the other hand, the elastic buckling is likely to occur in steel member because of their small section. When the elastic buckling occur, the steel structure lose a load carrying capacity. The steel frame would be unstable due to a rapid decline in strength by buckling. The purpose of this study is the development of FLD(Force Limiting Device) to prevent a elastic buckling for a slender member. Further, the behavior of steel structures with FLD would be stable by high energy absorption capacity. The proposed type of FLD is the type of out-of-plane resistance. In this study, member test and FEM analysis for proposed type were performed. The test parameters are thickness and gradient angle of out-of-plane plate. The proposed type may be effective method for FLD.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.9
• /
• pp.5854-5860
• /
• 2014

The on-site performance of a vision-based displacement measurement system (VDMS) was evaluated through a field test on a bridge. The VDMS used in this study is composed of a camera, a marker, a frame grabber, and a laptop. The system measures the displacement by attaching a marker at the location to be measured on the structure, by capturing images of that marker with a fixed rate, and by processing a series of images using a planar homography technique. The developed system was first validated from a laboratory test using a small-scale building structure. The VDMS was then employed in a field test on a railroad bridge with a KTX train running under various conditions. The on-site performance was evaluated by comparing the obtained displacement using the VDMS with the displacement measured from a laser Doppler vibrometer (LDV), which is an expensive and accurate displacement measurement device.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.11
• /
• pp.6915-6921
• /
• 2014

This study examined the composition and spatial characteristics of the Illinois Institute of Technology (1939-1959) campus by Mies van der Rohe. Studies of the Mies' architecture has been focused mostly on "universal space", structural rationality for a single building. Therefore, it is interesting to study an IIT campus through which Mies composed public space dealing with several buildings together. To determine the relationships with his previous works and the design intentions for IIT campus, this paper studied his preliminary sketches, perspective drawings etc.. By doing so, the paper presents the following conclusions. First, Mies composed the IIT campus with simple linear buildings as walls to create the "flowing space" through the campus. Secondly, the IIT campus could become the "neutral frame" integrating the campus with urban space. Third, Mies also created an open, continuous public space in the center of the campus that allows protective, quiet seclusion for the students.