• Title, Summary, Keyword: Slab joint

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The Effects of Slab Size on Pavement Life Cycle Cost

  • Parsons, Timothy A.;Hall, Jim W.Jr
    • International Journal of Highway Engineering
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    • v.8 no.2
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    • pp.49-54
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    • 2006
  • The purpose of this study was to determine the effect of expansion joint spacing (slab size) on the life cycle costs of owning Portland Cement Concrete (PCC) airfield pavements. Previous research has shown that slab size has a statistically significant impact on pavement performance. A probabilistic life cycle cost analysis was performed to determine if the effect of slab size on pavement performance would affect the total cost of ownership of PCC pavements. Data from 48 Pavement Condition Index (PCI) inspections of military and civilian airfields were used to develop probability-of-distress-by-condition curves, which were then used to develop probabilistic cost-of-repair-by-condition curves. A present worth life cycle cost analysis was then performed for various slab sizes, using construction costs, rehabilitation costs, and maintenance costs. Maintenance costs were determined by assuming a condition deterioration rate appropriate for each slab size and applying the cost-by-condition curves. The probabilistic cost-of-repair-by-condition curves indicated that smaller slabs are more expensive to repair on a unit cost basis. Life cycle cost analysis showed that larger slabs have a higher total cost of ownership than smaller slabs due to a faster rate of deterioration.

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Load Transfer Capacity for the Planar Joints between Existing Slab Retrofitted with Carbon Fiber Plate and New Slab (탄소판으로 보강된 기존 슬래브와 신규 슬래브 접합부의 횡방향 하중전달 능력)

  • Kim, Seung Hun;You, Young Chan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.2
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    • pp.117-124
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    • 2007
  • An experimental research has been performed to evaluate the load transfer capacity for the planar joints between existing and new slab in an apartment remodelling constructions expecially for enlarging the interior space. Post-installed dowel bars were used as a joint connector. The existing slabs were obtained from the existing apartment housing which will be demolished, and were retrofitted with carbon fiber plate. Test results showed that the planar joints with post-installed dowel bars behaved in full composite modes until ultimate capacity of test specimens, so sufficient ultimate and serviceability performance are confirmed.

Propriety Examination of Expansion Joint Spacing of Airport Concrete Pavement by Weather and Material Characteristics (기상과 재료 특성에 의한 공항 콘크리트 포장 팽창줄눈 간격의 적정성 검토)

  • Park, Hae Won;Jeong, Jin Hoon
    • International Journal of Highway Engineering
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    • v.20 no.3
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    • pp.65-73
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    • 2018
  • PURPOSES : In this study, the propriety of expansion joint spacing of airport concrete pavement was examined by using weather and material characteristics. METHODS : A finite element model for simulating airport concrete pavement was developed and blowup occurrence due to temperature increase was analyzed. The critical temperature causing the expansion of concrete slab and blow up at the expansion joint was calculated according to the initial vertical displacement at the joint. The amount of expansion that can occur in the concrete slab for 20 years of design life was calculated by summing the expansion and contraction by temperature, alkali-silica reaction, and drying shrinkage. The effective expansion of pavement section between adjacent expansion joints was calculated by subtracting the effective width of expansion joint from the summation of the expansion of the pavement section. The temperature change causing the effective expansion of pavement section was also calculated. The effective expansion equivalent temperature change was compared to the critical temperature, which causes the blowup, according to expansion joint spacing to verify the propriety of expansion joint applied to the airport concrete pavement. RESULTS : When an initial vertical displacement of the expansion joint was 3mm or less, the blowup never occurred for 300m of joint spacing which is used in Korean airports currently. But, there was a risk of blow-up when an initial vertical displacement of the expansion joint was 5mm or more due to the weather or material characteristics. CONCLUSIONS : It was confirmed that the intial vertical displacement at the expansion joint could be managed below 3mm from the previous research results. Accordingly it was concluded that the 300m of current expansion joint spacing of Korean airports could be used without blowup by controling the alkali-silica reaction below its allowable limit.

Evaluation of the Joint Design in Composite Truss Bridges (복부 트러스 복합교량 접합구조의 실험적 연구)

  • Shim, Chang-Su;Park, Jae-Sik;Kim, Kwang-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.325-328
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    • 2006
  • Joint structures of composite truss bridges can have the same details for the connection between diagonal members and upper concrete slab as the connection between diagonal members and lower concrete slab. Adequate connection details should be decided according to design codes, constructibility, and economical evaluation. It is necessary to clarify the design check items and load transferring mechanism because combined external loads on composite truss bridges are concentrated at the joints. Joints with gusset plates and stud connectors are applied and complicated joint details may arise some problems in construction. This paper deals with experimental evaluation of the joints in composite truss bridges and proper design provisions were investigated to enhance the details. Push-out test specimens with group studs were fabricated and the effects of grouping and bent studs were studied.

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The Study of joint structure of composite slabs with the tensile grip connection (고력볼트 인장접을 갖는 합성상판의 이음구조에 관한 연구)

  • Seo, Seung-Tag
    • Journal of the Korean Society of Industry Convergence
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    • v.9 no.3
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    • pp.215-220
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    • 2006
  • Recently, steel-concrete composite slab decks have been widely used as highway bridge decks. In the construction of the composite slab decks, it is necessary to join two adjacent blocked bottom plates to form one unite in the longitudinal direction. In this paper, several types of longitudinal direction joints for Robinson type composite slab decks ared proposed herein and static bending test are carried out by using slab specimens. And the stress and deformation of the tensile grip connection with high strength bolts are discussed by using three-dimensional elastic-plastic FEM.

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Nonlinear Finite Element Analysis on the Transmission of Column Loads through Slab-Column Connections

  • Lee, Joo-Ha;Yoon, Young-Soo;Sohn, Yu-Shin;Lee, Seung-Hoon
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.466-469
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    • 2006
  • This paper presents the structural characteristics of slab-column connections by using nonlinear finite element analysis. FEA considering material non-linearity was performed to investigate average column strain, failure mode, principal stress distribution, and steel yielding conditions for various slab-column members. In addition, to investigate alternative methods for improving the strength of interior column-slab joints, some specimens were provided with different reinforcing types of high-strength concrete puddling, high-strength column longitudinal steels, dowel bars, and high-strength concrete core. To make certain of the reliability of the analytical program, analysis results for concrete material model developed and two specimens with and without puddling were compared with experimental results. It was found that providing the alternative reinforcing methods in the slab-column joint results in a significant improvement in performance. This includes an increase in the axial compressive strength, greater loading stiffness, and ductility.

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SFRHPC interior beam-column-slab joints under reverse cyclic loading

  • Ganesan, N.;Nidhi, M.;Indira, P.V.
    • Advances in concrete construction
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    • v.3 no.3
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    • pp.237-250
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    • 2015
  • Beam-column joints are highly vulnerable locations which are to be designed for high ductility in order to take care of unexpected lateral forces such as wind and earthquake. Previous investigations reveal that the addition of steel fibres to concrete improves its ductility significantly. Also, due to presence of slab the strength and ductility of the beam increases considerably and ignoring the effect of slab can lead to underestimation of beam capacity and defiance of strong column weak beam concept. The influence of addition of steel fibres on the strength and behaviour of steel fibre reinforced high performance concrete (SFRHPC) interior beam-column-slab joints was investigated experimentally. The specimens were subjected to reverse cyclic loading. The variable considered was the volume fraction of crimped steel fibres i.e., 0%, 0.5% and 1.0%. The results show that the addition of steel fibres improves the first crack load, strength, ductility, energy absorption capacity and initial stiffness of the beam.

A Study on the Cause and Reduction of Cracks in the Wall Connecting the Underground Parking Lot and the Apartment (지하주차장과 아파트 연결 벽체의 균열 원인 분석 및 저감방안 연구)

  • Shim, Hak-Bo;Park, Soon-Jeon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.161-162
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    • 2020
  • Cracks are caused by drying shrinkage between the upper part of the underground parking lot and the apartment wall. As a result of the investigation, the distance between the apartment and the apartment is more than 45m, and the top slab of the underground parking lot is usually flat when there is not with steps. Therefore, the crack occurs more when the underground parking lot is a PC slab than a RC slab. In this study, the reduction of cracks was conducted by extending the slab, expanding the beam size, increasing the wall thickness, and installing a delay joint on slab. In each case, a finite element analysis was performed to examine the crack reduction method.

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An Experimental Study on Structural Capacity of Joint Between Composite PHC Wall Pile and Bottom Slab with CT Shear Connector (CT형강 전단연결재가 적용된 합성형 PHC벽체파일-하부슬래브 연결부 성능에 관한 실험적 연구)

  • Mha, Ho Seong;Won, Jeong Hun;Lee, Jong Ku
    • Journal of Korean Society of Steel Construction
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    • v.25 no.5
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    • pp.531-541
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    • 2013
  • This paper investigated the structural capacity of the CT shear connectors, which is a kind of the perfobond rib and functions as an anchor transferring the tension force in the joint between a composite PHC wall pile and a bottom slab. The direct pull-out test was performed for various specimens. From failure modes and load-displacement curves, it was found that transverse rebars should be placed to holes in a web to restrict pull-out failure of CT shear connectors. The results of additional tests for specimens with transverse rebars and various support lengths indicated that all specimens were failed by the tension failure of PHC pile before pull-out failure of CT shear connector and concrete pull-out failure. Thus, the CT shear connector could endure the tension force between the PHC wall pile and the bottom slab.

Comparative Analysis of Track-Bridge Interaction of Sliding Slab Track and Rail Expansion Joint for Long-Span Railway Bridge (장경간 철도 교량에 적용된 슬라이딩 궤도와 레일신축이음장치의 궤도-교량 상호작용 비교)

  • Lee, Kyoung Chan;Jang, Seung Yup;Lee, Jungwhee;Choi, Hyun Sung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.2
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    • pp.169-177
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    • 2016
  • Sliding slab track system, which consists of low friction sliding layer between track slab and bridge deck, is recently devised to reduce track-bridge interaction effect of continuously welded rail(CWR) without applying special devices such as rail expansion joint(REJ). In this study, a series of track-bridge interaction analyses of a long-span bridge with sliding slab track and REJ are performed respectively and the results are compared. The bridge model includes PSC box girder bridge with 9 continuous spans, and steel-concrete composite girder bridge with 2 continuous spans. The total length of the bridge model is 1,205m, and the maximum spacing between the two fixed supports is 825m. Analyses results showed that the sliding slab track system is highly effective on interaction reduction since lower rail additional axial stress is resulted than REJ application. Additionally, horizontal reaction forces in fixed supports were also reduced compared to the results of REJ application. However, higher slab axial forces were developed in the sliding slab track due to the temperature load. Therefore, track slab section of the sliding slab track system should be carefully designed against slab axial forces.