• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.397-400
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• 2004

This research aims to estimate the shear strength of the composition of prestressed hollow-core slab and steel beam. The shear strength of prestressed hollow-core slab combined with the steel beam decreases, as the beam deflection increases to a considerable extent. Existing studies on the shear strength of prestressed hollow-core slab are mostly limited to 265mrn- and larger thickness slab on concrete beam. This study investigates the slab of 100mm-thickness combined with steel beam instead of concrete beam. Five shear connector methods are proposed and the shear strength is estimated with or without the beam deflection for each composition method, respectively. Finally the reduction coefficient $(\beta)$ for the transverse shear stress$(\tau_{zx})$, which is critical for the failure of prestressed hollow-core slab, is proposed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.311-314
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• 2005

This research aims to analyze of prestressed composite hollow-core slab and box type steel beam. The smeared crack model used in abaqus for the modeling of hollow core reinforced concrete, including cracking of the concrete, rebar and concrete interaction using the tension stiffening concept, and rebar yield. The structure modeled is a simply supported hollow core spancrete slab subjected spa-h beams and prestressed in one direction. The hollow core spancrete slab is subjected to four-point bending. The concrete-rebar interaction that occur as the concrete begins to crack are of major importance in determining the spancrete slab's response between its initial, deformation and its collapse. This smeared crack model used in analysis involved non-liner concrete analysis concept.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.167-172
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• 2001

Hollow core slabs generally have not been used for a bridge slab or a parking in Korea. In this study, high performance hollow core slabs, which has been the most thick one in domestic are re-designed and examined for practical use. Flexural tests were performed on four 315mm deep hollow core slabs to investigate adaptability for high vehicle live loadings and composite action with topping concrete. The precast slabs were reinforced with 10-l/2 inch dia-strands at the lower of slab and 4-l/2 inch dia-strands at tile upper of slab, and cast with 80mm deep topping concrete. Those tested hollow core slabs showed ductile failure behaviors which were conform to the current Ultimate Strength Design Method for a span of l0m up to the live load of 1, 000 kg/$m^2$.

• 한국공간구조학회논문집
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• 제23권2호
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• pp.61-68
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• 2023

A two-hour fire-resistance PC hollow slab for residential use was developed to secure structural and fire-resistance performance and to be applied to the general building and apartment housing markets. Compared to the existing hollow slab, in order to secure the same or better structural performance and economic feasibility by reducing the quantity, it was attempted to secure the fire resistance performance by reducing the concrete filling rate in the cross section and adjusting the thickness of the upper and lower flanges by optimizing the hollow shape in the cross section of the slab. For structural performance evaluation, experiments were performed on PC hollow slabs by varying the member thickness and the presence or absence of overlaid concrete, and all of the experimental results showed that the design strength was sufficiently exhibited and that stability during construction was possible. The developed synthetic PC hollow slab has secured fire resistance and residential performance so that it can be applied to all buildings, and it is intended to be immediately applied to the field.

• Computers and Concrete
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• 제19권5호
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• pp.567-577
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• 2017

This study presents investigation of the behavior of moderately thick reinforced concrete slabs having hollow cores with different parameters. The experimental part of this investigation includes testing eight specimens of solid and hollow-core slab models having (2.05 m) length, (0.6 m) width and (25 cm) thickness under two monotonic line loads. Load versus deflection was recorded during test at mid span and under load. Numerically, the finite element method is used to study the behavior of these reinforced concrete slabs by using ANSYS computer program. The specimens of slab models are modeled by using (SOLID65) element to represent concrete slabs and (LINK180) element to represent the steel bars as discrete axial members between concrete nodes. The finite element analysis has showed good agreement with the experimental results with difference of (4.71%-8.68%) in ultimate loads. A parametric study have been carried out by using ANSYS program to investigate the effects of concrete compressive strength, size and shape of core, type of applied load and effect of removing top steel reinforcement.

• Computers and Concrete
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• 제21권2호
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• pp.117-126
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• 2018

This research investigate the behavior of reinforced normal and lightweight aggregate concrete hollow core slabs with different core shapes, shear span to effective depth (a/d). The experimental work includes testing seven reinforced concrete slabs under two vertical line loads. The dimensions of slab specimens were (1.1 m) length, (0.6 m) width and (0.12 m) thickness. The maximum reduction in weight due to aggregate type was (19.28%) and due to cross section (square and circular) cores was (17.37 and 13.64%) respectively. The test results showed that the decrease of shear span to effective depth ratio from 2.9 to 1.9 for lightweight aggregate solid slab cause an increase in ultimate load by (29.06%) and increase in the deflection value at ultimate load or the ultimate deflection by (17.79%). The use of lightweight aggregate concrete in casting solid slabs give a reduction in weight by (19.28%) and in the first cracking and ultimate loads by (16.37%) and (5%) respectively for constant (a/d=2.9).The use of lightweight aggregate concrete in casting hollow circular core slabs with constant (a/d=2.9) (reduction in weight 32.92%) decrease the cracking and ultimate loads by (12%) and (5.18%) respectively with respect to the solid slab. These slab specimens were analyzed numerically by using the finite element computer program ANSYS. Good agreements in terms of behavior, cracking load (load at first visible crack) and ultimate load (maximum value of testing load) was obtained between finite element analysis and experimental test results.

• Advances in concrete construction
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• 제11권4호
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• pp.271-284
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• 2021

This study aims to trace the response of twelve one-way sustainable concrete hollow-core slabs made by reducing cement content and using replacement of coarse aggregate by plastic aggregate. The trial mixes comprise the 25, 50, 75, and 100% replacement of natural coarse aggregate. The compressive strength of the resulting lightweight concrete with full replacement of coarse aggregate by plastic aggregate was 28 MPa. These slabs are considered to have a reduced dead weight due to using lightweight aggregate and due to reducing cross-section through using voids. The samples are tested under two verticals line loads. Several parameters are varied in this study such as; nature of coarse aggregate (natural or recycled), slab line load location, the shape of the core, core diameter, flexural reinforcement ratio, and thickness of the slab. Strain gauges are used in the present study to measure the strain of steel in each slab. The test samples were fourteen one-way reinforced concrete slabs. The slab's dimensions are (1000 mm), (600 mm), (200 mm), (length, width, and thickness). The change in the shape of the core from circular to square and the use of (100 mm) side length led to reducing the weight by about (46%). The cracking and ultimate strength is reduced by about (5%-6%) respectively. With similar values of deflection. The mode of failure will remain flexural. It is recognized that when the thickness of the slab changed from (200 mm to 175 mm) the result shows a reduction in cracking and ultimate strength by about (6% and 7%) respectively.

• Structural Monitoring and Maintenance
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• 제6권4호
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• pp.269-289
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• 2019

This study investigated experimentally the response of thick reinforced concrete specimens having hollow cores with critical parameters. The investigation includes testing of twelve specimens that are solid and hollow-core slab models. Each specimen consists of two pieces, the piece dimensions are (1.2 m) length, (0.3 m) width and (20 cm) thickness tested under both monotonic and repeated loading. The test program is carried out to study the effects of load type, core diameters, core shape, number of cores, and steel fiber existence. Load versus deflection at mid span, failure modes, and crack patterns were obtained during the test. The test results showed that core shape and core number has remarkable influenced on cracking pattern, ultimate load, and failure mode. Also, when considering repeated loading protocol, the ultimate load capacity, load at yielding, and ductility is reduced.

• 한국재난정보학회 논문집
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• 제14권3호
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• pp.343-351
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• 2018

연구목적: 최근 기반시설물이 대형화 됨에 따라 콘크리트 구조물의 경우는 중량감소를 위하여 중공 슬래브가 대안의 하나로 제시되고 있다. 연구방법: 중공부재의 시공 시 부력으로 인하여 시공이 어려운 점과 콘크리트 단면적이 줄어 전단성능이 부족하게 되는 구조적인 단점이 있으므로, PVC관과 같은 중공체를 이용하여 일방향 슬래브를 제작하고 시공성과 구조성능을 검토하는 실험을 실시하였다. 연구결과: PVC관을 이용한 일방향 중공슬래브의 경우 부력방지장치를 이용하면 타설 시 발생하는 중공체의 부상 및 침강을 예방하여 시공성능이 크게 개선되었으며, 휨 및 전단성능도 적합한 성능을 가진 것으로 확인되었다. 결론: 중공율과 휨성능은 큰 관계가 없지만 중공율이 큰 경우는 항복 후 2차 강성이 낮으므로 이에 대한 고려가 필요하며, 중공율의 증가에 따른 전단성능의 감소는 전단철근을 배근하면 보완될 수 있을 것으로 사료된다.

• 한국건축시공학회지
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• 제21권4호
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• pp.293-303
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• 2021

국내 PC공장은 PC 유공 슬래브를 생산하기 위해 자동화 설비를 도입하거나 매입물 삽입을 통해 중공 단면을 구현하지만 PC공장의 과다한 초기투자비용이 생산원가의 증가라는 주요 원인으로 작용하기에 다른 대안이 필요한 상황이다. 따라서 본 연구에서는 PC 유공 슬래브 부재 생산시 고무 튜브를 내부 속빈 공간을 형성하는 거푸집으로 사용함으로써 다양한 중공 형상의 성형 및 대단면화, 초경량화, 신속생산 대응 가능을 통한 생산성 확보에 기여하고자 한다.