• 설비공학논문집
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• 제22권1호
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• pp.20-25
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• 2010

In this study, As a basic research for improving indoor thermal environment at tower type apartment houses, specifications of heat storage and heat emission in the structures of apartment houses were investigated, and the ratio of indoor and outdoor air velocity at tower type apartment house was examined, too. Indoor temperature at night time was higher than outdoor air temperature because heat emission from the structure of wall, ceiling and floor those are constructed by use of reinforced concrete which has large heat capacity. The ratio of indoor and outdoor air velocity was lower than 0.1 and this was caused by the plan of tower type apartment house. PMV was in the range of 0.3~1.9, and was about 1.0 (it means slightly warm) at 10 : 00 p.m.. To improve indoor thermal environment in summer season at tower type apartment houses, it needs more investigation on specifications of heat storage and heat emission in the structure including winter season, and on the improvement of the ratio of indoor and outdoor air velocity.

• 콘크리트학회논문집
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• 제17권5호
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• pp.835-842
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• 2005

This paper presents an experimental investigation of bond-strengthening hooks as a new method to increase bond strength along flexural reinforcing bars in reinforced concrete (RC) beams and columns. The RC members, which consisted of 1,300 MPa-class spirals as shear reinforcement, often suffered from bond splitting failure. The proposed method attempts to increase confining stiffness around the flexural bars by placing U-shaped hooks and to prevent premature bond splitting failure. Twelve specimens with varied amounts and sizes of the hooks were prepared to verify the strengthening effectiveness under monotonic and cyclic loading conditions. The test result indicated that the hooks increased the bond strength along the flexural bars although the strengthening effectiveness was limited by effective reinforcement ratio $P_{be}$. This limit is determined by size of stress-transmitting zones of concrete around anchors of the hooks. Anchors of the hooks are recommended to be longer than twelve times the hook diameter and inserted deeper than a quarter of the member depth (D/4). Proposed design equations provide modest estimates of the shear strengths.

• International Journal of Concrete Structures and Materials
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• 제5권2호
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• pp.77-85
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• 2011

The use of headed bars as opposed to standard 90- or 180-degree hooked bars in beam ends, beam-column joints or other steel congested areas for anchorage and bond has become more favorable due to the fact that steel congestion is often created by large bend diameters or crossties. This research mainly focuses on evaluating the code provisions regarding the use of headed bars. Nine simply supported rectangular concrete beams with headed longitudinal reinforcement were tested under a four-point monotonic loading system. The design clear spacing, which varies from 1.5 to 4.25 times the bar diameter, was the only parameter for the experimental investigation. The test results showed that the closely-spaced headed bars were capable of developing to full yield strength without any severe brittle concrete breakout cone or pullout failure. Bond along the bar was not sufficient due to the early loss of concrete integrity. However, the headed bars were effective for anchorage with no excessive moment capacity reduction. This implies that the clear spacing of about 2 times the bar diameter for headed bars may be reasonable to ensure the development of specified yield strength of headed bars and corresponding member design strength.

• 한국농촌건축학회논문집
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• 제13권4호
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• pp.125-132
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• 2011

End of all living subjects which are a dead the low of meaning is word. Also is a funeral and in compliance with from the customary family formality of the Chu Hsi generally at in the ceremonial occasions and alias that calls says. The human being went without question a all ages and countries and many and in order to extend the time endeavored came. Received with the fact which is not the possibility the dead avoiding finally came to admit, that was afraid and comfort the methods for appeared. This annular lifestyle rises prays the peace of future life with the method for the shop custom in even modern age to make the funeral culture be located which is general, becomes and there is a possibility of seeing with the cause which is biggest. Our country ceremonial occasions from past undergoes the influence of China on a large scale in here and comes but there is a possibility seeing with the one kind cause that to Korea time the Confucianism ideology overflows specially in the national whole.

• 한국실내디자인학회논문집
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• 제17권6호
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• pp.3-10
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• 2008

The basestone is a kind of foundation part of the building and can be said to deliver the loads from the upper part to ground. It is the explanation of structural role for the basestone. But the basestone has been used as the decorative element in a building. So this study is on design of the basestone. First the type division can be studied as form of the basestones. Also the investigation of development aspect of them needs to as times and the spatial characteristics. Another goal of this study is on the design characteristics of the basestone from the comparison to the basestone in ancient Japan was initiated in the architectural technology from Korea. The results are as follows. In Baekje rectangular basestones were used in static space for ceremony and circular ones were used in dynamic space for life. Also the basestones with joojwa(smoothing surface for sitting on column) were used for accessory buildings rather than main. In Silla the same type of basestone was made in a temple but according to hierarchy of buildings the sizes of them seem to have been different. The other side in Japan carved basestones were for the main buildings and for the accessory natural stones were used to. According to the hierarchy of the buildings the kinds of stones were different.

• Geomechanics and Engineering
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• 제22권6호
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• pp.497-507
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• 2020

This paper presents the results of a three-dimensional numerical investigation into the effect of new tunnel construction on structural performance of existing tunnel lining. A three-dimensional finite difference model, capable of modelling the tunnel construction process, was adopted to perform a parametric study on the spatial variation of new tunnel location with respect to the existing tunnel with emphasis on the plan crossing angle of the new tunnel with respect to the existing tunnel and the vertical elevation of the new tunnel with respect to the existing one. The results of the analyses were arranged so that the effect of new tunnel construction on the lining member forces and stresses of the existing tunnel can be identified. The results indicate that when a new tunnel underpasses an existing tunnel, the new tunnel construction imposes greater impact on the existing tunnel lining when the two tunnels cross at an acute angle. Also shown are that the critical plan crossing angle of the new tunnel that would impose greater impact on the existing tunnel depends on the relative vertical location of the new tunnel with respect to the existing one, and that the overpassing new tunnel construction scenario is more critical than the underpassing scenario in view of the existing tunnel lining stability. Practical implications of the findings are discussed.

• Steel and Composite Structures
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• 제8권3호
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• pp.217-230
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• 2008

The increasing use of performance-based approaches in structural fire engineering design of multi-storey composite buildings has prompted the development of various tools to help quantify the influence of tensile membrane action in composite slabs at elevated temperatures. One simplified method which has emerged is the Bailey-BRE membrane action method. This method predicts slab capacities in fire by analysing rectangular slab panels supported on edges which resist vertical deflection. The task of providing the necessary vertical support, in practice, requires protecting a panel's perimeter beams to achieve temperatures of no more than $620^{\circ}C$ at the required fire resistance time. Hence, the integrity of this support becomes critical as the slab and the attached beams deflect, and large deflections of the perimeter beams may lead to a catastrophic failure of the structure. This paper presents a finite element investigation into the effects of vertical support along slab panel boundaries on the slab behaviour in fire. It examines the development of the membrane mechanism for various degrees of edge-beam protection, and makes comparisons with predictions of the membrane action design method and various acceptance criteria.

• 한국안전학회지
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• 제23권4호
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• pp.53-58
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• 2008

This paper presents the findings obtained from the investigation of fatal disasters occurred by small-sized construction firms which have been accepted as to provide lower safety performance other than large-sized construction enterprises and cause more than half of the safety accidents in average. The study identifies the current status of safety performance provided by the small-sized construction contractors in details, find the issues involved with lack of safety performance, and suggest the improvement measures derived from the findings. A survey questionnaire was administered to the construction contractors, which are listed in the database of Construction Association of Korea as to fall into rank between 501st and 1000th in construction capacity. Safety issues such as the performance of safety management system, safety control structure, safety cost relative to safety control, education devoted to safety improvement, usage of safety garments or individual protective tools, and activities to maintain safety performance on site, etc were investigated from the study.

• 설비공학논문집
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• 제13권4호
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• pp.279-288
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• 2001

This paper is to derive energy retrofit strategies through energy audit and analysis for a selected small-to-medium office building located in Seoul, Korea,. To activate ESCO business in Korea, our final goal is to develope a simple and adequate energy retrofit procedure through computer simulation. Calibration process was fairly successful eve without the aid of tough field measurement. In terms of annual energy consumption, the percent difference between the predicted and the monitored values were within a reasonable tolerance of $\pm10$%. Based on the calibrated baseline model and the systematic investigation of target building, retrofit measures were suggested with two categories such as architectural side and equipment side. Both selected parametric and interactive retrofit measure simulations resulted in various energy saving quantities and cost, thus the priority among the measures were made. If we were to select the more realistic and reasonable retrofit measure in future, economic estimate were should be practiced with the life cycle cost analysis.

• Computers and Concrete
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• 제9권6호
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• pp.439-455
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• 2012

The interaction of plan geometry and structural configuration, a determinative factor in the earthquake behavior of buildings, has become a serious issue in the building industry in Turkey due to the poor seismic performance of R/C buildings during the latest earthquake. Consequently, designing new buildings without structural irregularities against earthquake loads is proving to be more significant. This study focuses on the effects of plan geometries on earthquake performances of buildings. In that respect, structural irregularities in the plan are investigated in detail based on the Turkish Earthquake Code (TEC 2007). The study is based on five main parametric models and a total of 40 sub-models that are grouped according to their plan geometries with excessive projections such as L-shaped, H-shaped, T-shaped and U-shaped models. In addition to these, a square model without any projections is also generated. All models are designed to have the same storey gross area but with different number of storeys. Changes in the earthquake behavior of buildings were evaluated according to the number of storeys, the projection ratios and the symmetry conditions of each model. The analysis of each structural irregularity resulted in many findings, which were then assessed. The study demonstrates that the square model delivers the best earthquake performance owing to its regular plan geometry.