• Title, Summary, Keyword: Slab joint

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Seismic behavior and strength of L-shaped steel reinforced concrete column-concrete beam planar and spatial joints

  • Chen, Zongping;Xu, Deyi;Xu, Jinjun;Wang, Ni
    • Steel and Composite Structures
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    • v.39 no.3
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    • pp.337-352
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    • 2021
  • The study presented experimental and numerical investigation on the seismic performance of steel reinforced concrete (SRC) L-shaped column- reinforced concrete (RC) beam joints. Various parameters described as steel configuration form, axial compressive ratio, loading angle, and the existence of slab were examined through 4 planar joints and 7 spatial joints. The characteristics of the load-displacement response included the bearing capacity, ductility, story drift ratio, energy-dissipating capacity, and stiffness degradation were analyzed. The results showed that shear failure and flexural failure in the beam tip were observed for planar joints and spatial joint, respectively. And RC joint with slab failed with the plastic hinge in the slab and bottom of the beam. The results indicated that hysteretic curves of spatial joints with solid-web steel were plumper than those with hollow-web specimens. The capacity of planar joints was higher than that of space joints, while the opposite was true for energy-dissipation capacity and ductility. The high compression ratio contributed to the increase in capacity and initial stiffness of the joint. The elastic and elastic-plastic story deformation capacity of L-shaped column frame joints satisfied the code requirement. A design formula of joint shear resistance based on the superposition theory and equilibrium plasticity truss model was proposed for engineering application.

Experimental Study of High Strength Concrete Beam-Column-Slab Connections subjected to cyclic loading (고강도 콘크리트 보-기둥-슬래브 접합부의 반복하중 실험)

  • 오영훈;오정근;장극관;김윤일
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.339-344
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    • 1995
  • In the design of ductile moment-resisting frames (DMRFs) following the strong column-weak beam dsign philosophy, it is desirable that the joint and column remain essentially elastic in order to insure proper energy dissipation and lateral stability of the structure. The joint has been identified as the "weak link" in DMRFs because any stiffness or strength deterioration in this region can lead to substantial drifts and the possibility of collapse due to P-delta effects. Moreover, the engineer is faced with the difficult task of detailing an element whose size is determined by the framing members, but which must resist a set of loads very different from those used in the design of the beams and columns. Four 2/3-scale beam-column-slab joint assemblies were designed according to existing code requirements of ACI 318-89, representing interior joints of DMRFs with reinforced high strength concrete. The influence on aseismic behavior of beam-column joints due to monolithic slab, has been investigated.estigated.

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Structural Behavior of Cement Concrete Pavement at Transverse Joint Using Model Test

  • Ko, Young-Zoo;Kim, Kyung-Soo;Bae, Ju-Seong
    • KCI Concrete Journal
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    • v.12 no.2
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    • pp.23-30
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    • 2000
  • This paper presents behavior of concrete pavement at transverse joint subject to static test load. The test was conducted on 1/10 scale model in the laboratory. Load transfer across the crack is developed either by the interlocking action of the aggregate particles at the faces of the joint or by a combination of aggregate interlock and mechanical devices such as dowel bars. In this study, significant three variables considered to the performance of joints were selected. : (a)diameter of dowel bars(2.5mm, 3.0mm, 4.0mm), (b)presence or absence of dowel bars, (c)aggregate types(crushed stone, round stone). Experimental results were analyzed to find relationships among displacement of discontinuous plane at jointed slab, load transfer efficiency and joint opening, etc. Displacement of discontinuous plane at joint was decreased according to the increase of dowel bar diameter. In addition, it is found that model slabs made using crushed stone had better load transfer characteristics by aggregate interlock than model slabs made using similarly graded round stone. Displacement of discontinuous plane was increased according to the increase of loading. In addition, it was decreased as dowel diameter(2.5mm, 3.0mm, 4.0mm) was increased. In the case of slab without dowel bars, displacement of discontinuous plane was greatly increased and load transfer effciency of slab applied crushed stone was shown 30 percent greater than round stone. In addition, load transfer efficiency of slabs, which were made using crushed and round stone without dowel bars, was decreased to 20 percent and 30 percent, respectively as it was compared with slabs made us-ing dowel bars.

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Static Load Tests on Flexural Strength and Crack Serviceability of a Longitudinal Joint for the Slab-Type Precast Modular Bridges (슬래브 형식 프리캐스트 모듈러교량 종방향 연결부의 휨강도 및 균열 사용성에 관한 정적재하실험)

  • Lee, Jung-Mi;Lee, Sang-Yoon;Song, Jae-Joon;Park, Kyung-Hoon
    • Journal of the Korea Concrete Institute
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    • v.27 no.2
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    • pp.137-145
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    • 2015
  • The slab-type precast modular bridge consists of the precast slab bridge modules which are connected in the transverse direction. The longitudinal joints between the precast slab bridge modules are filled with cast-in-place mortar. The construction of the slab-type precast modular bridge is completed by applying the prestressing force on the longitudinal joints. In this study, 4-points bending tests and 3-points bending tests were conducted to examine the effects of the prestressing force and the shape of joint on the flexural strength and crack serviceability of longitudinal joint. The results of 4-points bending tests showed that the flexural strength is affected by the prestressing force but not by the shape of join. From the results of 3-points bending tests by which the bending moment and the shear force are simultaneously applied on the joints of the specimens, it is observed that the shape of joint affects on the flexural strength and the crack behavior. The results of two types of bending tests confirmed that the prestressing force according to the design code is appropriate and the joint with two shear keys gives the better performances against the crack of joint.

Improved Transmission of UHSC Column Loads by Puddling of Fiber Reinforced UHSC (강섬유 보강 초고강도 콘크리트의 확대 타설을 통한 기둥 하중 전달 성능 향상)

  • Lee, Joo-Ha;Yang, Jun-Mo;Lee, Seung-Hoon;Yoon, Young-Soo
    • Journal of the Korea Concrete Institute
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    • v.19 no.2
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    • pp.209-216
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    • 2007
  • This study reports on the structural characteristics of slab-column connections using fiber-reinforced ultra-high-strength concrete (UHSC). Compression tests were performed on two slab-column and four isolated column specimens. In the column load tests, slab loads were also applied on the slab-column specimens so that the actual confinement condition at the slab-column joint was considered. The main parameter investigated was the "puddling" of fiber-reinforced UHSC. This paper also investigates the effects of some parameters, such as confinement of slab concrete, steel fibers, and concrete strength of the joint, related to the ability of the slab-column specimens and isolated column specimens without the surrounding slab to transmit axial loads from the UHSC columns through slab-column connections. Furthermore, the ACI Code (2005) and the CSA Standard (2004) are compared to the experimental results. The beneficial effects of the puddling of fiber-reinforced UHSC on the transmission of column loads through slab-column connections are demonstrated.

Effection of The Existing Reinforcement on The Strength of Reinforced Concrete Slabs Connected by Hinged Jointeds (활절점으로 연결된 철근콘크리트 슬래브 내력에 기존 슬래브 철근이 미치는 영향)

  • Sim Kyu-Kwan;Kim Sang-Sik;Choi Kwang-Ho;Im Juhyeuk;Lee Jung-Yoon
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.271-274
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    • 2005
  • In this research, 13 RC slabs connected by hinged joints were tested. the new slab was connected to the existing slab by hinge joint injecting dowel bars between two slabs. Main parameters of the slabs were the spacing of the dowel bars (150mm, 300mm, and 450mm) and the locations of the longitudinal reinforcement of the old slab. The test results indicated that the joint strength of the RC test slabs having various types of dowel bars was about twice that calculated by the ACI 318-02 code. The locations of the longitudinal reinforcement of the old slab slightly increased the strength of the slabs connected by hinged joints.

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An Experimental Study III on the Bolted Connection between H-Beam and Precast-Concrete Column (PC 기둥-H형강보의 볼트접합부에관한 실험적 연구III)

  • Yeo, In-Seok;Park, Soon-Kyu
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.307-310
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    • 2005
  • The PCS system, which consists of precast concrete column and steel beam, has been under development. Experimental test has been carried out to investigate the structural performance of the system under earthquake. Two types of test specimens of beam-column joints are designed in order to compare the performances. One is the system with reinforced concrete slab and the other is without slab. It is found that the system with slab could satisfy all of the requirements from ACI Criteria such as strength, stiffness degradation and energy dissipation capacity except initial stiffness. It is also investigated that the stiffness of the joint is belong to rigid joint type according to Bjorhovde criterion. And it is observed that the partial-composite system between beam and slab is more effective than full-composite system in the respect of the energy dissipation capacity of the system.

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Design Program of Deck Plate Slab System with Non-welding Truss Type Reinforced Bar (철근트러스 압접 데크플레이트 바닥 구조의 설계 프로그램)

  • Yoon, Myung-Ho;Oh, Sang-Hoon
    • Journal of The Korean Digital Architecture Interior Association
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    • v.8 no.1
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    • pp.57-64
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    • 2008
  • There are many problems in present truss-deck slab system for example welding defect, segregation, water leakage, rust and tarnish etc. These problems may be caused by spot welding thin galvanized steel plate and lattice bar. The TOX Joining Systems is to join metal sheets of different material and thickness with and without coating or painting without adding heat or a joining part. Newly developed TOX-deck slab system using non-welding joint is free from above mentioned problems. The objects of this study are suggestion of design strength of TOX joint by experimental and statistical analyses and development of window based program to design the TOX-deck slab system.

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Application possibility of dowel bar in low floating slab system (다우얼 바의 저진동 슬래브 궤도 시스템 적용 가능성)

  • Park, Sung-Jae;Kim, Yong-Jae;Park, Myoung-Gyun;Jeon, Jong-Su;Lee, Du-Hwa;Park, Man-Ho
    • Proceedings of the KSR Conference
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    • pp.665-670
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    • 2009
  • From the result of preceding study, there is no reinforcement such as dowel bar or etc. in Joint system of floating slab. Length of floating slab in preceding study is short than one of this study. If there is no reinforcement in the joint of long slab span, fracture of slab is predicted by difference between two slabs. Therefore using of dowel bar is demanded. In this study, General characteristic and preceding technology of dowel bar is researched for data of analysis study. And it is considered application of dowel bar in floating slab system.

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Investigation of Composite Action on Seismic Performance of Weak-axis Column-tree Moment Connections

  • Xu, Yinglu;Lu, Linfeng;Zheng, Hong
    • International journal of steel structures
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    • v.17 no.3
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    • pp.1199-1209
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    • 2017
  • This paper presents an experimental study on a developed weak-axis column-tree moment connection subjected to horizontal cyclic loading. In order to study possible positive or negative effect of a composite slab on the seismic performance of the proposed connection, six cruciform specimens were designed and constructed in pairs, where one specimen was bare steel joint and the other involved a composite slab. The standard, cover-plate, and material-changed connection details were considered. The test program is described in detail, and then the structural behavior of test specimens is discussed based on the test data. The tests revealed that although designed with 50% degree of shear connection, the concrete slab still caused obvious upward shift of the neutral axis and increase the strain demand on the bottom flange. But it is clear from the comparison of results that the composite joint specimens performed slightly better than the bare steel counterparts in terms of load-displacement hysteretic curves and energy dissipation capacity, as the concrete slab could effectively enhance the stability of the steel beam and delay the deterioration of the strength and stiffness. The cover-plate connection appears to be one of the more promising moment connection schemes which are able to deliver a much higher level of stability and energy dissipation capacity. The maximum magnitude of slab-steel beam interface slip was less than 0.5 mm, indicating that the concrete floor slab and steel beam could work well together under 50% partial shear connection.