• Title/Summary/Keyword: bearing walls

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A Study on the Properties and Mix Design of Eco-friendly Concrete Bricks Using Recycled Fine Aggregates (순환잔골재를 활용한 친환경 콘크리트 벽돌의 물성 및 배합설계 연구)

  • Choi, Hyungkook;Yang, Sungchul;Son, Jaeho;Lee, Seunghyun
    • Korean Journal of Construction Engineering and Management
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    • v.25 no.5
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    • pp.32-40
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    • 2024
  • In the construction industry, lack of reliability in the quality of recycled aggregates, harmful substance problems, and negative consumer perceptions limit the expansion of the use of recycled aggregates. In this respect, existing studies mainly focus on the use of recycled coarse aggregates in concrete in consideration of durability. On the other hand, in the case of recycled fine aggregates, not only are there insufficient cases applied to major structures, but the scope of application is very limited due to lack of awareness. Therefore, the main purpose of this study is to present the possibility of their application in bearing and non-bearing wall structures through physical characteristics experiments of concrete bricks for masonry according to various mixing ratios of recycled fine aggregates and cement amounts. To this end, the compressive strength and absorption rate of concrete bricks were measured focusing on the mixing ratio of the recycled fine aggregate and the crushed fine aggregate and the amount of cement. As a result, it is found that it is possible to use 100% of recycled fine aggregate for 200kg/m3 of cement or 25% of crushed fine aggregate mixed with 75% of recycled fine aggregate for the same amount of cement to achieve the compressive strength of 13MPa, witch is one of the quality requirements for concrete bricks for bearing walls. In addition, it is found that to meet the strength of 8MPa, one of the quality requirements for non-bearing walls, it is sufficient to use 100% of the recycled fine aggregate for 100kg/m3 of cement. Through the absorption rate tests, it is also confirmed that the absorption rate of the concrete brick is 13% or less by meeting the required performance criteria. This means that even if recycled fine aggregate is used in the manufacture of concrete bricks, the quality standards required by KS F 4004 (concrete bricks) can be sufficiently met.

Static Characteristics of Micro Gas-Lubricated proceeding Bearings with a Slip Flow (미끄럼 유동을 고려한 초소형 공기 베어링의 정특성)

  • Kwak, Hyun-Duck;Lee, Yong-Bok;Kim, Chang-Ho;Lee, Nam-Soo;Choi, Dong-Hoon
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.05a
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    • pp.137-142
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    • 2002
  • The fluid mechanics and operating conditions of gas-lubricated proceeding bearings in micro rotating machinery such as micro polarization modulator and micro gas turbine are different from their larger size ones. Due to non-continuum effects, there is a slip of gas at the walls. Thus in this paper, the slip flow effect is considered to estimate the pressure distribution and load-carrying capacity of micro gas-lubricated proceeding bearings as the local Knudsen number at the minimum film thickness is greater than 0.01. Based on the compressible Reynolds equation with slip flow, the static characteristics of micro gas-lubricated proceeding bearings are obtained. Numerical predictions compare the pressure distribution and load capacity considering slip flow with the performance of micro proceeding bearings without slip f]ow for a range of bearing numbers and eccentricities. The results clearly show that the slip flow effect on the static characteristics is considerable and becomes more significant as temperature increases.

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A Study on the Spatial Composition Characteristic in Rural Residential Area: A case of Hanbam Village (한밤마을을 통해본 농촌주거지의 공간구성 특성에 관한 연구)

  • 심근정;정응호
    • Journal of the Korean housing association
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    • v.13 no.3
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    • pp.61-69
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    • 2002
  • This research is to analyze the spatial organization of a traditional rural community and its characteristics, the case of Hanbam village located in the north of Daegu city. The conclusions of this study are as follows; 1. The difference between private space and public space in the residential area of Hanbam village is obvious, and these two spaces are organically related each other by means of road. These spaces have some spatial characteristics of organization, such as center, hierarchy and sequence. 2. The private space consists of a residence module and a farming area in the settlement, and it is clearly farmed by the firm fence of rocks and by surrounding roads. Fruit-bearing trees such as Pyrus pyrifolia, Cornus officinalis, Diospyros kaki, Juglans sinensis are planted at the boundary. And most of residences are composed of a building, a inner court and farming fields. 3. The public space for the community mainly functions as ‘a meeting place’for residents, and consists of recreational spaces, ceremonial spaces, community facilities, and social facilities. Among these, Jeong-ja(pavilion), Seong-an Soop(forest) and Dae-chong(building for common use) are of great cultural value as important traditional spaces. 4. Two kinds of road are commonly fecund in the village; spontaneously generated one and planned one. This is straight inner streets and access paths to the village, and that is curvilinear alleys which are connected to Dae-chong, the core of village. Also stone walls and climbing plants on them are major elements of village landscape.

Investigation of the effect of weak-story on earthquake behavior and rough construction costs of RC buildings

  • Gursoy, Senol;Oz, Ramazan;Bas, Selcuk
    • Computers and Concrete
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    • v.16 no.1
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    • pp.141-161
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    • 2015
  • A significant portion of residential areas of Turkey is located in active earthquake zones. In Turkey occurred major earthquakes in last twenty years, such as Erzincan (1992), Kocaeli and $D{\ddot{u}}zce$ (1999), $Bing{\ddot{o}}l$ (2003), Van (2011). These earthquakes have demonstrated that reinforced concrete (RC) buildings having horizontal and vertical irregularities are significantly damaged, which in turn most of them are collapsed. Architectural design and arrangement of load-bearing system have important effect on RC building since architectural design criteria in design process provide opportunity to make this type of buildings safer and economical under earthquake loads. This study aims to investigate comparatively the effects of weak story irregularity on earthquake behavior and rough construction costs of RC buildings by considering different soil-conditions given in the Turkish Earthquake Code. With this aim, Sta4-CAD program based on matrix displacement method is utilized. Considering that different story height and compressive strength of concrete, and infill walls or their locations are the variables, a set of structural models are developed to determine the effect of them on earthquake behavior and rough construction costs of RC buildings. In conclusion, some recommendations and results related to making RC buildings safer and more economical are presented by comparing results obtained from structural analyses.

Strength and behaviour of reinforced SCC wall panels in one-way action

  • Ganesan, N.;Indiraa, P.V.;Prasad, S. Rajendra
    • Structural Engineering and Mechanics
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    • v.36 no.1
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    • pp.1-18
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    • 2010
  • A total of 28 wall panels were cast and tested under uniformly distributed axial load in one-way in-plane action to study the effect of slenderness ratio (SR) and aspect ratio (AR) on the ultimate load. Two concrete formulations, normal concrete (NC) and self compacting concrete (SCC), were used for the casting of wall panels. Out of 28 wall panels, 12 were made of NC and the remaining 16 panels were of SCC. All the 12 NC panels and 12 out of 16 SCC panels were used to study the influence of SR and the remaining 4 SCC panels were tested to study the effect of AR on the ultimate load. A brief review of studies available in literature on the strength and behaviour of reinforced concrete (RC) wall panels is presented. Load-deformation response was recorded and analyzed. The ultimate load of SCC wall panels decreases non-linearly with the increase in SR and decreases linearly with increasing values of AR. Based on this study a method is proposed to predict the ultimate load of reinforced SCC wall panels. The modified method includes the effect of SR, AR and concrete strength.

Improvement Plan for Connecting Form of PC Member -Focused on Apartment Buildings- (PC부재의 접합부 거푸집의 개선방안 연구 -공동주택을 중심으로-)

  • Kim, Seon-Hyung;Choi, Jae-Hwi;Kim, Sun-Kuk;Lee, Dong-Hoon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2010.05a
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    • pp.9-12
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    • 2010
  • Conventional apartment building projects have favored wall slab structure for the ease of construction and economic viability. However, wall slab structure, consisting of bearing walls, makes remodeling a difficult challenge. In addition, as the amendment to the Building Act in November, 2005 incentivized easy-to-remodel Rahmen structure design for apartment building in terms of floor area ratio and the number of stories, were are seeing more use of PC construct method in apartment building projects gradually. However, PC construction method requires complex connections between beams and columns, making it difficult to install and remove formwork. Furthermore, it is not possible to reuse forms after removal, generating lots of construction wastes, and it is necessary to install new forms again when the size of connection changes in line with modification of column cross-section. Researchers in Korea and elsewhere in the world have focused on structural performance of connection in PC construction method, with little attention to alternative approaches to improving connection forms for PC construction method. Accordingly, this research aims to study an approach to improving connection forms for PC construction method.

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A Study on the Prescriptions of American Codes for Straw Bale Structures and the Legislation Direction of Korean Straw Bale Code (미국 짚단벽구조 법규 분석 및 국내의 법제화 방향 연구)

  • Kim, Jeong-Gyu
    • KIEAE Journal
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    • v.9 no.2
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    • pp.91-98
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    • 2009
  • The purpose of this study is analyzing the prescriptions of American codes for straw bale structures and proposing the legislation direction of Korean building code. The process of this study is as follows: (1) To set up the legislation direction of straw bale code of Korea, this study investigated the current state and features of straw bale houses in Korea, and looked into the worldwide status of straw bale codes and permitting. (2) To provide basic data for the legislation of Korean straw bale code or guideline, this study analyzed American codes for straw bale structures like the Tucson/Pima County Arizona Building Code Appendix Chapter 72 - Straw-Bale Structures, California State Guidelines for Straw-Bale Structures, New Mexico Standards for Non-load Bearing Baled Straw Construction, Oregon State Residential Code Appendix M - Straw-Bale Structures and so on. The analysis items are the scope of rule application, material specifications, requirements for straw bale walls/foundations and construction requirements. (3) On the base of analysis of American straw bale codes, this study proposed the legislation process and direction of Korean straw bale code and guideline.

Numerical study of the cyclic behavior of steel plate shear wall systems (SPSWs) with differently shaped openings

  • Ali, Mustafa M.;Osman, S.A.;Husam, O.A.;Al-Zand, Ahmed W.
    • Steel and Composite Structures
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    • v.26 no.3
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    • pp.361-373
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    • 2018
  • This paper presents the development of finite element (FE) models to simulate the behavior of diagonally stiffened steel plate shear wall systems (SPSWs) with differently shaped openings subjected to a cyclic load. This walling system has the potential to be used for shear elements that resist lateral loads in steel-framed buildings. A number of $\text\tiny{^1/_2}$-scale one-story buildings that were un-stiffened, stiffened and stiffened with opening SPSWs are modeled and simulated using the finite element method based on experimental data from previous research. After validating the finite element (FE) models, the effects of infill plate thickness on the cyclic behavior of steel shear walls are investigated. Furthermore, triple diagonal stiffeners are added to the steel infill plates of the SPSWs, and the effects are studied. Moreover, the effects of a number of differently shaped openings applied to the infill plate are studied. The results indicate that the bearing capacity and shear resistance are affected positively by increasing the infill plate thickness and by adding triple diagonal stiffeners. In addition, the cyclic behavior of SPSWs is improved, even with an opening in the SPSWs.

The Characteristic and Improvement of Flexibility Performance Item evaluated by "Housing Performance Grading System" (주택성능등급 가변성 세부성능 항목의 특성 및 개선방안)

  • Lee, Sung-Ok
    • KIEAE Journal
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    • v.11 no.6
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    • pp.29-35
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    • 2011
  • This study aims to suggest improvement plans and explain about the current situation for facilitating Long-life housing, based on the results on flexibility items among 27 items consisting the "Housing Performance Grading System". From the 9th of January, 2006 to the month of July in 2011, study has analyzed evaluation results on 216 different types for each grade and reviewed evaluation criteria and methods. Current evaluation criteria applies quantitative analysis, by calculating in percentage how much bearing walls and columns, which hinder flexibility, take up space in the household. The evaluation rate for each household was assessed in relation to its structural system, and a higher grade was given to column-typed structures. In addition, to facilitate long-life housing, this study extracted harmful factors, expanding the range of evaluation. The first step was to evaluate structure, which is the basic element. The second step can to evaluate the probability of applying resources in response to the changes of structural systems. As The third step, Flexibility item will evaluate the probability of moving the water-using area, suggesting gradual approach. Thus, through evaluations of flexibility items, the study aims to improve the quality of life in household, by avoiding uniform structures and acquiring more freedom for space designs.

Benefit/Cost Analysis of Form Work Methods for Composite Basement Wall in Building Constructions (건축물의 합성 지하옹벽 거푸집에 대한 편익·비용 분석 연구)

  • Kim, Jae Yeob;Kim, Gwang-Hee;Ahn, Sung-Hoon;Lee, Ji-Young
    • KIEAE Journal
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    • v.8 no.1
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    • pp.99-104
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    • 2008
  • This study surveys the types of form works used for constructing composite basement walls found in domestic construction sites. Based on expert surveys, the research provides criteria for selecting a form work type and cost-benefit analysis for different types of form works. In selecting a form work type, safety was considered the most important factor. It is induced from the survey that a successful construction requires a form work type that could solidly bear the lateral pressure of concrete rather than other types that cut back the cost and shorten the construction period. In the cost-benefit analysis, the benefit was the highest in 'euro-form+soldier system', and the cost was most competent in 'rib-lath+soldier system'. In considering benefit and cost together, 'euro-form+soldier system' was judged to be the best option. This is likely to be attributed to the following reasons: site workers are familiar with euro-forms because it is the most widely used; and, soldier system is more reliable in bearing lateral pressure compared to steel pipes.