• Title/Summary/Keyword: 양중공법

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Decision Support Model for Selecting of Lifting Methods for Large Spatial Roof Construction (대공간 지붕철골공사 양중공법 선정을 위한 의사결정지원모델)

  • Cha, Min-Su;Lee, Myung-Do
    • Journal of the Korea Institute of Building Construction
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    • v.18 no.5
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    • pp.489-498
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    • 2018
  • The purpose of this study was to propose a decision support model for selecting a lifting method of large spatial roof construction. First, we deducted influential factors consist of 6 factors and 19 sub-factors through literature reviews and expert's advices. Second, the relative importance of each factor was calculated by Analytic Hierarchy Process. As a result, 'site condition(0.237)' among 6 factors and 'available space of the site(0.118)' among 19 sub-factors were identified as the most important factor for selecting lifting method. In addition, methods and procedures were established for evaluating alternatives of lifting methods for each influential factor. A decision support model was completed by providing the Site Suitability Index(SSI) of each lifting method. Finally, we got advices form experts who were actually in charge of the works for large spatial construction project to validate the model. The model proposed in this study was analyzed to be useful in selecting the lifting method. The findings of this study are expected to support the decision making of on-site managers when they select the lifting method on the beginning of the project.

A Study on the Lifting Progress for Composite Precast Concrete Members of Green Frame (그린 프레임 합성 PC부재의 양중공정 분석 연구)

  • Joo, Jin-Kyu;Kim, Shin-Eun;Lee, Gun-Jea;Kim, Sun-Kuk;Lee, Sung-Ho
    • Korean Journal of Construction Engineering and Management
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    • v.13 no.3
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    • pp.34-42
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    • 2012
  • Green frame technology intended to facilitate the remodeling of apartment housing complexes in Korea and extend their service life has been developed. Green frame design is a Rahmen structure using composite precast concrete members and, unlike a bearing-wall structure, lifting and installing structural members accounts for major steps of structural construction. Therefore, if green frame structure construction is to be scheduled appropriately, systematic lifting plan needs to be developed in advance. Development of lifting plan also requires unit lifting process of composite PC members (columns and beams) that consist of green frame to be analyzed first. Therefore, this study attempts to analyze the lifting process of composite PC members used in green frame structure. To that end, lifting procedure and time of composite PC column and beam are estimated and applied to a project case to analyze the lifting cycle of reference floor. Outcomes produced herein will be used as key data for development of lifting plan in subsequent green frame structure construction.

Construction of Super-block Unit Curtain Wall for High-rise Buildings Utilizing a Specialized Installing Equipment (전용 양중틀을 활용한 초고층 건물의 슈퍼블럭 유닛 커튼월 시공)

  • Chung, Sam-Yong;Lee, Sang-Heon;Ohk, Young-Mu
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2004.11a
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    • pp.174-181
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    • 2004
  • We will introduce a method of construction of super-block curtain wall applied to Tower Palace III which is the highest high-rise complex building in Korea. Up-up method is utilized on Tower Palace III to shorten the term of works and it is that the curtain walls for the belt wall part are installed after the rests. The belt wall structure increases the horizontal structural stiffness of the building. The method of construction of super-block curtain wall is developed and used to raise and install the curtain wails of the belt wall floor. It is that the large block of curtain walls corresponding to three stories is fabricated on the ground in advance and the block is installed at a time by a tower crane. Specialized installing equipment :,s newly developed and applied to install the super-block. curtain wail. The curtain wall of the upper floor of the belt wall part is installed after the super-block. The installing equipment for this floor is developed utilizing a mini excavator and vacuum suctions. The application of this method had made it possible to omit the setting up the scaffold and financial profits such as the shortening of the terms of works was realized. The safety of works was secured and the productivity was also improved.

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A Study on the Economic and the Field Application Feasibility of Unit Curtain Wall Mullion Rail Lift System (유니트 커튼월 멀리온 레일 양중 시스템의 경제성 및 현장 적용 가능성에 관한 연구)

  • Jung, Ui-In;Kim, Hea-Na;Kim, Bong-Joo
    • Journal of the Korea Institute of Building Construction
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    • v.21 no.1
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    • pp.41-49
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    • 2021
  • This study was to solve the lift problem of the existing unit curtain wall type by using the vertical material mullion as a rail in curtain wall, which is recently used as an external finishing material for high-rise buildings. It has been shown that the application of the curtain wall mullion's rail can be quantified even at 20m/sec wind speed through the Mock-Up test. Based on the sites selected for comparison of construction methods, it was analyzed that the construction period could be shortened by 48 days, or about 20 percent. It was analyzed that the number of construction workers could be reduced by about 33 percent from the previous nine to six. Based on these results, assuming the installation of curtain wall units of 10,000㎡, it is judged that construction cost can be reduced by 80% or more.

Alternative Evaluation Model for Tower Crane Operation Plan in Modular Construction - Focusing on Modular Unit Installation and Finishing works - (모듈러 건축 타워크레인 운용 계획의 대안 평가 모델 - 유닛 설치 및 마감공사를 중심으로 -)

  • Kim, Joo Ho;Park, Moonseo;Lee, Hyun-Soo;Hyun, Hosang
    • Korean Journal of Construction Engineering and Management
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    • v.19 no.2
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    • pp.50-60
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    • 2018
  • Recently, modular construction method has been widely applied to projects with repetitive processes including dormitory, the residential facility, and the hotel construction due to reduced labor input and shortened construction schedule. Generally, about 40% of total on-site construction cost excluding unit installation cost, is put on exterior finishing work, and thus management of finishing work is deemed important in maintaining the targeted schedule and cost. Since limited equipment is shared so that subsequent activities are not affected while carrying out on-site installation and finishing work, lifting plan becomes more important for modular projects with greater portion of finishing work load. In this regard, tower crane operation plan may take the form of a single cycle or multiple cycles in which equipment efficiency can be affected. However, difficulties exist in evaluating alternatives to tower crane operation plans supporting unit installation and finishing work. Therefore, this study aims to evaluate the alternative of tower crane operation method according to the cyclic period setting in modular building site to determine the effect on T/C uptime and process by parameterizing lifting time for unit and exterior finishing material, lift cycle for unit and exterior finishing material and time required for finishing work. Accordingly, this study develops a simulation model that can increase the tower crane efficiency by controlling the work speed. An academic contribution of this study is to suggest a resource leveling method applying the concept of lifting cycle, and further is expected to be managerially used as a basis for an alternative evaluation of equipment plan.

Economic Alternative for Volumetric Module Lifting/Offloading (볼류메트릭 모듈 양중 및 인양 대안에 관한 연구)

  • Song, Seung-Ho;Kwon, Woo-Bin;Choi, Jin-Ouk;Cho, Hun-Hee
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.05a
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    • pp.75-76
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    • 2023
  • The construction industry's lack of experience and expertise makes it difficult for projects to realize the full benefits of implementing modular construction. Such project performance-hindering elements are often labeled as modular challenges. The added requirement for the transportation of the finished volumetric module is one aspect of the 'module transportation logistics,' the under-researched modular challenge that can prevent projects from incurring maximum cost and productivity benefits. The typical module transportation phases include lifting, transporting, and offloading. From conducting a literature review, this paper aims to investigate the equipment commonly adopted to lift and offload the module and validate its economic efficiency by comparing it with the alternative lifting/offloading equipment used in the two case projects. The results showed that hydraulic jacks are an economic alternative to the crane for lifting/offloading the module. The increase in single-module projects with smaller budgets made crane usage economically undesirable, and this study suggested a viable option for a more economical alternative.

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Development of PC Double Wall for Staircase Construction (계단실 공사를 위한 PC Double Wall 공법 개발)

  • Suh, Jung-Il;Park, Hong-Gun;Hwang, Hyeon-Jong;Im, Ju-Hyuk;Kim, Yong-Nam
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.6
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    • pp.571-581
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    • 2014
  • In the present study, hollow precast concrete wall (PC Double Wall) for staircase construction was developed. Comparing the conventional walls, the PC Double Wall can be reduced the lift weight using hollow core and improves the integrity between the PC members. The cross-section and re-bar details of the PC Double Wall were developed considering precast concrete manufacturing, constructability, and the structural safety. Particularly, a form system was developed to manufacture thin and hollow core PC wall efficiently. A mock-up test for a staircase using the PC Double wall was performed to verify the constructability and integrity of the PC walls. The test result verified that joint deformation and cracking did not occur as showing good constructability.

Applications of Construction Sequence Analyses to Prototype Models of Twisted Tall Buildings (비틀림 초고층 프로토타입 모델에 대한 시공단계해석의 적용)

  • Choe, Mi-Mi;Kim, Jae-Yo;Eom, Tae-Sung;Jang, Dong-Woon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.1
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    • pp.89-97
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    • 2013
  • With regard to complex-shaped tall buildings whose plans and constructions have been gradually on the increase, this study was aimed to analyze their structural behaviors during construction by applications of construction sequences analyses to prototype models. For twisted tall buildings, total 18 models of with three conditions of a lateral load-resisting system, a twisting angle, and a construction method were selected. A diagrid system and a braced tube system were applied as a lateral load-resisting system. For each lateral load-resisting system, three types of plan with $0^{\circ}$, $1^{\circ}$, and $2^{\circ}$ twisting angles and three construction methods with construction sequences of exterior tube and interior frame were assumed. The structural performances of tall buildings under constructions were analyzed with results of lateral displacements from construction sequence analyses. Also, construction performances of the construction period and the maximum lift weight were compared.

Soil Washing and Effluent Treatment for Contaminated Soil with Toxic Metals (유해원소로 오염된 토양 세척 및 세척수의 처리)

  • Yang, Jung-Seok;Hwang, Jin-Min;Baek, Kitae;Kwon, Man Jae
    • Korean Chemical Engineering Research
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    • v.51 no.6
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    • pp.745-754
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    • 2013
  • This study evaluated the optimal soil washing conditions for toxic metals considering the removal efficiency of toxic metals from contaminated soils as well as from soil washing effluents. In the contaminated soils, As was the major contaminant and extracted by sodium hydroxide solution better than by sulfuric acid. However, in the case of the treatment of soil washing effluents, sodium hydroxide was less effective extractant because soil organic matter extracted by sodium hydroxide prevented the solid-liquid phase separation and toxic metal removal. In the treatment of soil washing effluents with sulfuric acid, toxic metals in the effluents were mostly precipitated at the pH above 6.5. In addition, granular ferric oxide (GFO) as an adsorbent enhanced the removal of As and Pb indicating that toxic metals in the washing effluents can be removed almost completely by the use of combined adsorption-neutralization process. This study suggests that soil washing techniques for toxic metals should be optimized based on the physical and chemical properties of the contaminated soils, the nature of chemical extractant, and the removal efficiency and effectiveness of toxic metals from the soils as well as soil washing effluents.

Effect of Soil Micro-environments on the Remediation Efficiency of Contaminated Soil and Groundwater: Review and Case Study (토양지하수 미세환경과 오염정화효율과의 상관성 고찰)

  • Shim, Moo Joon;Yang, Jung-Seok;Lee, Mi Jung;Lee, Giehyeon;Park, Jae Seon;Kim, Guk Jin;Min, Sang Yoon;Kim, Joo Young;Choi, Min Joo;Kim, Min Chan;Lim, Jong Hwan;Kwon, Man Jae
    • Journal of Soil and Groundwater Environment
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    • v.19 no.1
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    • pp.34-45
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    • 2014
  • A variety of physical, chemical, and microbiological techniques have been developed to deal with soil and groundwater contamination. However, in the presence of the large portion of soil micro-environments, contaminant rebound and/or tailing have been frequently reported. Case study of total petroleum hydrocarbons (TPH) removal by full-scale land farming showed that contaminant rebound and/or tailing occurred in 9 out of total 21 cases and subsequently resulted in problems of a long term operation to satisfy TPH guidelines of contaminated soil and groundwater. The main cause of contaminant rebound and tailing is considered to be the strong interactions between contaminants and micro-environments including micro-particles, micro-pores, and organic matter. Thus, this study reviewed the effects of soil micro-environments of soil and groundwater on the removal efficiency for both heavy metals and petroleum contaminants. In addition, the various methods of sampling, analysis, and assessment of soil micro-environments were evaluated. Thorough understanding of the effects of soil micro-environments on contaminant removal will be essential to achieve a cost-effective and efficient solution to contaminated sites.