• Title/Summary/Keyword: PC slab

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Performance of connection of Waffle Shape Precast Prestressed Concrete Slab Panels (와플(Waffle) 형상을 가지는 PC 패널의 접합 성능)

  • Heo, Seok-Jae;Kim, Hyeon-Jin;Ryu, Han-Gook;Choi, Kyoung-Kyu;Cho, Seung-Ho;Chung, Lan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.305-308
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    • 2008
  • This paper presents the results of an experimental study carried out Prestressed Concrete Slab System of WAffle Shape(WAS), was perfomed in order to inverstigate it connection shear behavior according to primary paramaters: connection interval, filling matarial. Specimen is produced in Precast Concrete factories and it comprised one WAS panel and two half WAS panels and then it is filled with packing. Within the ranges of the parameters of the connection details used in this test, connections can develop greater shear strength than the nominal shear strength and the design service load for parking structures.

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An experimental evaluation of hardened property of concrete using early-strength-binder with curing temperature (조강형 결합재를 사용한 콘크리트의 양생온도에 따른 경화특성 실험적 평가)

  • Kim, Kwang-Ki;Kim, Young-sun;Lee, Joo-ho
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.05a
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    • pp.88-89
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    • 2015
  • In cold weather, the speed of concrete strength development is slow. As a result, construction speed becomes slow and it is problem for all construction site to solve this. So in this study, to shorten removing frame time after placing concrete, mix proportion using early-strength-binder(ESB) and curing method such as using heat line in concrete was considered. At first, concrete mix proportion was examined at -5℃ temperature between ordinary portland cement(OPC) and ESB. And second step, concrete, using mix proportion with OPC, was examined according to curing method(: 1) heat line used and 2) no heat line) and kinds of form (: 1) Deck slab, 2) Half PC slab and 3) SOG slab). All cases are same condition: slab thickness is 1,500mm, double-bubble sheet is used as a curing sheet after placing concrete. After the test, OPC is enough to get strength compared to ESB in special condition and 48~60 hours is needed according to form condition.

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A Evaluation of Fire Behavior According to Member Thickness of Precast Prestressed Hollow Core Slab of Fire Resistance Section (프리캐스트 프리스트레스트 내화단면 중공슬래브의 부재두께에 따른 화재거동평가 )

  • Yoon-Seob Boo;Kyu-Woong Bae;Sang-Min Shin
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.1
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    • pp.1-8
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    • 2023
  • At construction sites, interest in the production of precast materials is increasing due to off-site conditions due to changes in construction site conditions due to increased labor costs and the Act on the Punishment of Serious Accidents. In particular, the precast prestressed hollow slab has a hollow shape in the cross section, so structural performance is secured by reducing weight and controlling deflection through stranded wires. With the application of structural standards, the urgency of securing fire resistance performance is emerging. In this study, a fire-resistance cross section was developed by reducing the concrete filling rate in the cross section and improving the upper and lower flange shapes by optimizing the hollow shape in the cross section of the slab to have the same or better structural performance and economic efficiency compared to the existing hollow slab. The PC hollow slab to which this was applied was subjected to a two-hour fire resistance test using the cross-sectional thickness as a variable, and as a result of the test, fire resistance performance (load bearing capacity, heat shielding property, flame retardance property) was secured. Based on the experimental results, it is determined that fire resistance modeling can be established through numerical analysis simulation, and prediction of fire resistance analysis is possible according to the change of the cross-sectional shape in the future.

Experimental Study on the Fire Performance of PC Slab by the Bearing Length (걸침길이에 따른 PC 슬래브의 화재성능에 관한 실험적 연구)

  • Park, Siyoung;Kang, Thomas H.K.;Lee, Ho-Wook;Gwak, Si-Young;Park, Jun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.6
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    • pp.14-22
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    • 2022
  • In this study, a fire test was conducted to evaluate the fire performance of precast concrete (PC) slabs in an outdoor environment in response to the increase in fire incidents caused by the growth of warehouses. Prior to the field fire test, the tensile yield strength of the tendon at elevated temperatures was tested to analyze the mechanical properties. Also, by referring to previous studies, the thermal properties of tendon and the mechanical and thermal properties of concrete were investigated. A field fire test was conducted to analyze the structural and fire performance of two identical slabs with 50 and 150 mm bearing length. As the bearing length increased, deflection and horizontal displacement decreased. The fire test lasted for 200 minutes without the collapse of slabs, validating current codes. Based on the structural performance which maintained even with concrete spalling and rupture of some tendons, the bonded method is assumed to be practical in pre-tensioned PC slabs. The results of fire test are expected to be utilized in evaluating the fire performance of PC slabs in warehouses.

A Study on Early Strength Estimation of Precast Concrete joint Mortar with Microwave (마이크로파에 의한 PC접합모르타르의 조기강도추정에 관한 연구)

  • 원준연;박일용;백민수;이종균;안형준;정상진
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.217-222
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    • 2000
  • A large Pc structure building is system that consisted of bearing wall and slab joint. It has general structure stability from unity thar each members tied at joint. The strength of mortar that packing in joint among panels is important to internal force in entire building system. Do, if we could get early strength estimation with microwave. It would bring good construction planning, reduce construction time, and judge building stability and so on. The purpose of this study is to develop early estimation method for making better quality control and constructing good PC panel structure. The results of this study were as follows :1) With sealed molds, reduced moisture volatilization to more than 60% and enlarged 30% accelerated compressive strength than before one. 2) To get more accelerated strength, we should control maximum temperature difference to $30^{\circ}C$ downward 3)Interrelation with 7-day and 28-day strength were 0.831,0.902, and it is above than before one

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Effects of Reinforcing Method Influnced to the Shear Strength of Vertical and Horizontal Joints in Precast Concrete Large Panel Structures -Focused on the Vertical Joints and Slab-Slab Type Horizontal Joints- (대형판조립식 구조 수직.수평접합부의 전단강도에 미치는 보강방법의 영향-수직접합부 및 슬래브-슬래브 수평접합부를 중심으로-)

  • Chung, Lan;Park, Hyun-Soo;Cho, Seung-Ho
    • Magazine of the Korea Concrete Institute
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    • v.8 no.4
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    • pp.171-179
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    • 1996
  • A proposal of the basic fbrm on the design of joint parts that can increase the shear strength by the useful joint shapes of each member is intended. The vertical joint parameters are the number of' shear key and a variety of' reinfbrcement details and the horizontal joint paramctcrs arc t,hc number of shear key and the direction of' shear f'orcc. 10 PC panel vortical joint arid 12 PC panel horizontal joint specimens were tested to investigate the effects of these parameters. Test results show that : 1. The ductility of the test specimen that has the horizontal reinforcing steels is larger than that does not have. 2. The maximum resisting force of round bar specimen is similar to that of strand wire specimen under the condition of fixed horizontal displacement.

A Study on the Development of Precast Concrete Modular and its Application Onsite (프리캐스트 콘크리트 모듈러 개발 및 현장적용에 관한 연구)

  • Bae, Kyu-Woong;Boo, Yoon-Seob;Shin, Sang-Min
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.05a
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    • pp.27-28
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    • 2023
  • Currently, the Off-Site Construction (OSC) construction method, which emphasizes the minimization of field work, is being emphasized at construction sites due to the lack of construction skilled manpower, extreme weather, and the Severe Disaster Punishment Act. In this study, we developed a stacked PC modular, which is a method of stacking PC modules, and solved the lifting problem by reducing the weight of the unit module, which is emerging as the biggest disadvantage of PC modules, to around 20 tons. For the connection between modules, structural safety was secured through repeated history tests of the wall and slab connection. Walls and slabs satisfied all statutory fire resistance times through fire resistance tests, and residential performance was evaluated to be satisfactory through mock-up demonstration. The developed PC modular has been applied to the construction of commercial houses, detached houses, shopping malls, churches, etc., and has design results for many buildings such as dormitories, detached houses with 4 floors or more, and resorts, so it is expected that an atmosphere of revitalization of construction methods will be created.

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Crack Control of the Upside of Double Tee Slab and Inversed Tee Beam Joint (더블티 슬래브-역티형 보 접합부 상부의 균열억제를 위한 실험연구)

  • Nam, Sang-Uk;Song, Han-Beom;Yi, Waon-Ho;Yang, Won-Jik;Baik, Young-Soo;Tae, Kyung-Hoon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.345-348
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    • 2008
  • Recently, demand is caused that new building environment of value added rising demand on the lines of becoming bigger, manhattanize of structure and becoming high standard of structure in a construction site and influx of advanced foreign nation technique. To satisfy these requirements for alternative, structures applied to the PSC, PC is increasing. Double Tee Slab is possible for long length structure and applied to the method of construction. When assembling Double Tee Slab produced by the factory in the field, becamed carry-out topping concrete in upper, but occurred crack to slab line. There is no structural problem to crack occurred in upper, waterproof in maintenance and repair of structure due to a conservative cause several problems.

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Prediction of Drying Shrinkage behavior of Half PC Slab (주차장 무근콘크리트 컬링에 관한 실험적 연구)

  • Seo, Tae-Seok;Choi, Hoon-Jae;Gong, Min-Ho
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.11a
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    • pp.88-89
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    • 2017
  • Curling is caused by the shrinkage difference between surface and bottom side of concrete, and the cracks can be occurred by vehicle load after curling. It is important to investigate and predict the curling behavior to minimize the quality defect of concrete due to the curling. Therefore, the experimental and analytical investigation was carried out.

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