• Title/Summary/Keyword: Precast

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A Basic Study on the Arrangement of In-situ Production Module of the Composite PC Members (합성 PC 부재 현장생산배치에 관한 기초 연구)

  • Lee, Goon-Jae;Joo, Jin-Kyu;Lee, Sung-Ho;Kim, Sun-Kuk
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2011.11a
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    • pp.29-30
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    • 2011
  • A Green Frame is a composite Rahmen precast concrete structure that utilizes the advantages of the steel frame and the reinforced concrete. Compared to bearing wall structure, the precast concrete structure may raise construction cost If the precast concrete members are produced in plant. Thus, if the precast concrete members can be produced in site, the cost-effectiveness and quality shall be increased. Various site conditions must be considered and reviewed to ensure a space for the in-situ production. Therefore, this study focuses on the basic study on the arrangement of in-situ production module of composite precast concrete members.

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Pre-construction Simulation of Precast Bridge Piers and Quality Management using Augmented Reality (증강현실 기반의 프리캐스트 교각의 사전시공 시뮬레이션 및 시공성 정밀도 관리방안)

  • Park, Seong-Jun;Dang, Ngoc-Son;Yoon, Do-Sun;Lon, Sokanya;Shim, Chang-Su
    • Journal of KIBIM
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    • v.8 no.1
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    • pp.15-23
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    • 2018
  • Geometry control of precast members is the most important technology for modular construction. In this paper, image-based modeling and rendering (IBMR) technology was adopted for 3D modeling of precast elements. It is necessary to use match-casting method for precast post-tensioned column assembly. Preassembly using 3D models created by image processing can minimize construction error. Augmented reality devices are used to check the geometry of the segment. Laboratory-scale tests were performed. The proposed process has been applied to the real precast bridge pier segments.

Construction of Continuous Bridges in Hi8h-Speed Railway using Precast Span Method (프리캐스트 스팬 공법을 적용한 고속철도 연속교 시공)

  • 김성일;김성호;이원표;윤철수
    • Proceedings of the KSR Conference
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    • 2001.05a
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    • pp.401-407
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    • 2001
  • Out of 412km long Kyung-bu high-speed railway, 302km was designed in tile form of either bridges or tunnels. Most of bridges were designed to be prestressed concrete box girder type. The precast span method was selected because of good quality of bridge section secured by factory manufacturing, fast construction speed, low construction cost with mechanized construction and the safety fur field workers. The precast span method has been mainly utilized in bridges consisted of repeated simple spans. However, we applied the precast span method to continuous bridge for high-speed railway Since it was the first attempt to apply ate precast span method to a continuous bridge for high-speed railway, many design and construction details were studied and implemented in the construction. Design and construction processes of a continuous bridge construction using tile precast span mettled are briefly described in this paper.

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Study on Development of Steam Curing Method for In-situ production of Precast Concrete members (프리캐스트 콘크리트 부재의 현장생산용 증기 양생 방법 개발 연구)

  • Sung, Soojin;Lim, Chaeyeon;Kim, Sunkuk
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.11a
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    • pp.71-72
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    • 2014
  • Green Frame is a building frame system to construct a column-beam structure using composite precast concrete members. To reduce the cost of producing precast concrete, in-situ production of members is required. However, when the structural members are produced on site, it needs a large space for production. So, "Just-In-Time" production method should be adopted. For Just-In-Time to be realized, the early strength of members should be ensured for them to be transported. Thus, steam curing to secure the early strength is applied in Green Frame. Yet, a large-scale steam curing system is not possible for in-situ production of precast concrete. A smaller steam curing system is needed. In this regard, the study is aimed to develop a new steam curing method applicable to the in-situ production of precast concrete.

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Crack control of precast deck loop joint using high strength concrete

  • Shim, Changsu;Lee, Chi dong;Ji, Sung-woong
    • Advances in concrete construction
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    • v.6 no.5
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    • pp.527-543
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    • 2018
  • Crack control of precast members is crucial for durability. However, there is no clear provision to check the crack width of precast joints. This study presents an experimental investigation of loop joint details for use in a precast bridge deck system. High strength concrete of 130 MPa was chosen for durability and closer joint spacing. Static tests were conducted to investigate the cracking and ultimate behavior of test specimens. The experimental results indicate that current design codes provide reasonable estimation of the flexural strength and cracking load of precast elements with loop joint of high strength concrete. However, the crack width control of the loop joints with high strength concrete by the current design practices was not appropriate. Some recommendations to improve crack control of the loop joint were derived.

A Basic Study of the Calculation Model for Shear Connectors of Composite Precast Concrete Beams (합성 PC 보를 위한 전단 보강 계산 모형 기초 연구)

  • Lim, Chaeyeon;Lee, Dong Hoon;Kim, Sun Kuk
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.05a
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    • pp.19-20
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    • 2013
  • Green Frame is a column-beam system constructed by composite precast column and beam connected by embedded steel of their. From when the precast concrete beam of Green Frame is installed, until the concrete of slab and connection joint is cured, the self load of beam shall be supported by the embedded steel of it. Therefore, the concrete of beam could be separated from the embedded steel if the shear connector of beam of Green Frame is designed by the code on Structural standard. So, this study suggest an equation for the shear connection of composite precast concrete beams of Green Frame. The result of this study will be used as the main equation of the calculation model for shear connectors of composite precast concrete beams.

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Verification of diaphragm seismic design factors for precast concrete parking structures

  • Zhang, Dichuan;Fleischman, Robert
    • Structural Engineering and Mechanics
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    • v.71 no.6
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    • pp.643-656
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    • 2019
  • A new seismic design methodology was proposed for precast concrete diaphragms. This methodology adopts seismic design factors applied on top of current diaphragm design forces. These factors are aimed to produce diaphragm design strengths aligned with different seismic performance targets. These factors were established through extensive parametric studies. These studies used a simple evaluation structure with a single-bay rectangular diaphragm. The simple evaluation structure is suitable for establishment of the design factors over comprehensive structural geometry and design parameters. However, the application of the design factors to prototype structures with realistic layouts requires further verification and investigation. This paper presents diaphragm design of several precast concrete parking structures using the new design methodology and verification of the design factor through nonlinear dynamic time history analyses. The seismic behavior and performance of the diaphragm were investigated for the precast concrete parking structures. It was found that the design factor established for the new design methodology is applicable to the realistic precast concrete parking structures.

Verification of diaphragm seismic design factors for precast concrete office buildings

  • Zhang, Dichuan;Fleischman, Robert B.;Lee, Deuckhang
    • Earthquakes and Structures
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    • v.20 no.1
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    • pp.13-27
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    • 2021
  • A new seismic design methodology has been developed for precast concrete diaphragms. Seismic design factors were used to be applied on top of diaphragm seismic design forces in the current code. These factors, established through extensive parametric studies, align diaphragm design strengths with different seismic performance targets. A simplified evaluation structure with a single-bay plan was used in the parametric studies. This simplified evaluation structure is reasonable and cost-effective as it can comprehensively cover structural geometries and design parameters. However, further verification and investigation are required to apply these design factors to prototype structures with realistic layouts. This paper presents diaphragm design of several precast concrete office buildings using the new design methodology. The applicability of the design factor to the office building was evaluated and verified through nonlinear time history analyses. The seismic behavior and performance of the diaphragm were investigated for the precast concrete office buildings. It was found that the design factor established for the new design methodology is applicable to the realistic precast concrete office buildings.

Mechanical Behavior of Rib-reinforced Precast Cut-and-cover Tunnels by Large-sized Experiments

  • Gyuphil Lee
    • Journal of the Korean GEO-environmental Society
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    • v.24 no.10
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    • pp.25-31
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    • 2023
  • Wide tunnels,such as those with high filling, can suffer limited applicability and also reduced structural stability. Therefore, to improve these limitations of precast cut-and-cover tunnel segments, this study proposes rib reinforcement of the vaults of the precast segments. Large-sized experiments assess the effectiveness of the various rib-reinforced precast arch cut-and-cover tunnel structures, and compare them against otherwise similar non-rib-reinforced specimens. The results show that the rib-reinforced precast cut-and-cover segments are suitable for building wide tunnels with high filling.

Experimental and numerical studies of precast connection under progressive collapse scenario

  • Joshi, Digesh D.;Patel, Paresh V.;Rangwala, Husain M.;Patoliya, Bhautik G.
    • Advances in concrete construction
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    • v.9 no.3
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    • pp.235-248
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    • 2020
  • Progressive collapse in a structure occurs when load bearing members are failed and the adjoining structural elements cannot resist the redistributed forces and fails subsequently, that leads to complete collapse of structure. Recently, construction using precast concrete technology is adopted increasingly because it offers many advantages like faster construction, less requirement of skilled labours at site, reduced formwork and scaffolding, massive production with reduced amount of construction waste, better quality and better surface finishing as compared to conventional reinforced concrete construction. Connections are the critical elements for any precast structure, because in past, major collapse of precast structure took place because of connection failure. In this study, behavior of four different precast wet connections with U shaped reinforcement bars provided at different locations is evaluated. Reduced 1/3rd scale precast beam column assemblies having two span beam and three columns with removed middle column are constructed and examined by performing experiments. The response of precast connections is compared with monolithic connection, under column removal scenario. The connection region of test specimens are filled by cast-in-place micro concrete with and without polypropylene fibers. Performance of specimen is evaluated on the basis of ultimate load carrying capacity, maximum deflection at the location of removed middle column, crack formation and failure propagation. Further, Finite element (FE) analysis is carried out for validation of experimental studies and understanding the performance of structural components. Monolithic and precast beam column assemblies are modeled using non-linear Finite Element (FE) analysis based software ABAQUS. Actual experimental conditions are simulated using appropriate boundary and loading conditions. Finite Element simulation results in terms of load versus deflection are compared with that of experimental study. The nonlinear FE analysis results shows good agreement with experimental results.