• Title, Summary, Keyword: Slab joint

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Prediction of the Effective Concrete Strength for Column-Slab Connections

  • Lee, Joo-Ha;Lee, Seung-Hoon;Sohn, Yu-Shin;Yoon, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.577-578
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    • 2009
  • For cases where the column concrete strength exceeds 1.4 times the slab concrete strength, the KCI Code requires that either: puddled high-strength concrete(HSC) be used in the slab, or the use of vertical dowels and spirals through the joint, or the use of an effective concrete strength in the joint. This paper studies on the third strategy. A prediction model of the effective concrete strength for interior columns was proposed using an analogy of brick and mortar in brick masonry. The proposed prediction model is verified by comparison with experimental results and various design equations.

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Tests of Slab-Column Connections with Partially Debonded Reinforcement under Cyclic Lateral Loading (부분적인 비 부착 철근을 갖는 슬래브-기둥 접합부의 반복 횡하중 실험)

  • Choi, Jung-Wook;Song, Jin-Kyu
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.13-16
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    • 2006
  • This article summarizes tests conducted on two full-scale interior slab-column connections with and without partially debonded reinforcement subjected to cyclic loading. Each test specimen consisted of a 4.2m square slab with a 355mm square column protruding 1.5m above and below the slab. The slab thickness was 152mm. The specimen with partially debonded reinforcement exhibited more lateral drift capacity than did the specimen with fully bonded reinforcement. With partial debonding of the flexural reinforcement, cyclic load appeared to produce less damage to the connection in the vicinity of the slab-column joint region.

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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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Behavior and Strength of Wall-Slab Connection in SC Structure (SC구조 벽-바닥 접합부의 내력 및 거동 특성)

  • Kim, Hyeong Gook;Kim, Woo Bum;Kim, Won Ki
    • Journal of Korean Society of Steel Construction
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    • v.20 no.2
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    • pp.347-354
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    • 2008
  • Steel plate-concrete (SC) structure has recently been used in nuclear power structure because of its construction efficiency. In this study, experimental and analytical study to investigate the behavior of the SC structure's wall slab connection was carried out. Experiments were performed for typical SC and RC connections in order to examine the basic difference between each structure. Finite element analysis was performed and the result of the analysis was found to closely reflect the experimental result. By varying the thickness of the shear plate and friction coefficients and the distance of applied load from the wall, the influence of the parameters on the joint strength and failure modes were examined. Finally, it was confirmed that the joint strength formula proposed in th this research gives conservative results.

Behavior of composite CFST beam-concrete column joints

  • Kim, Seung-Eock;Choi, Ji-Hun;Pham, Thai-Hoan;Truong, Viet-Hung;Kong, Zhengyi;Duong, Nguyen-The;Vu, Quang-Viet
    • Steel and Composite Structures
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    • v.37 no.1
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    • pp.75-90
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    • 2020
  • This paper introduces a new composite joint, which is the composite CFST beam- concrete column joint, and it is more convenient for transportation and erection than conventionally welded joints. The main components of this joint include steel H-beams welded with CFST beams, reinforced concrete columns, and reinforced concrete slabs. The steel H-beams and CFST beams are connected with a concrete slab using shear connectors to ensure composite action between them. An experimental investigation was conducted to evaluate the proposed composite joint performance. A three-dimensional (3D) finite element (FE) model was developed and analyzed for this joint using the ABAQUS/explicit. The FE model accuracy was validated by comparing its results with the relevant test results. Additionally, the parameters that consisted of the steel box beam thickness, concrete compressive strength, steel yield strength, and reinforcement ratio in the concrete slab were considered to investigate their influence on the proposed joint performance.

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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