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  • Title/Summary/Keyword: reinforced joints

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Effect of Specimen Geometries on the Pin Bearing Strength of Unidirectional CFRP Composites (일방향 CFRP 복합재료의 핀 베어링강도에 관한 시험편 치수의 영향)

  • Jeon, Jin-Tak;Kim, Jae-Dong;Koh, Sung-Wi
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.33 no.4
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    • pp.346-351
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    • 1997
  • The pin bearing strength is one of the most important design parameters for mechanical joints composed of fiber reinforced composites. Thus the effect of the edge distance and the width of specimen on the pin-bearing strength of unidirectional CFRP composites were experimentally investigated in this paper. As results, the failure modes and the pin bearing strength of mechanical joints turned out to depend on the edge distance and also the width of specimen. The failure of specimen with low ratio of width to hole diameter was caused by the net tension from the hole boundary, on the other hand, the failure of specimen with low ratio of edge distance to hole diameter was caused by the shear-out. The bearing strength in case of the failure by shear-out was quite lower than that in case of failure by net tension.

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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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    • 2005.05a
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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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Estimation of the Anisotropic Material Properties of Rock Masses with Permeation Grouting (그라우팅 강화터널의 설계 특성치 산정에 관한 연구)

  • Lee, Jun Seok;Bang, Chun Seok;Choe, Il Yun;Eom, Ju Hwan
    • Magazine of korean Tunnelling and Underground Space Association
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    • v.1 no.1
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    • pp.67-80
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    • 1999
  • The Grout-reinforcement technique which is widely used during the excavation of a shallow or an endangered tunnel can be classified into a couple of groups according to the properties and injection methods of the grout. The reinforcement design will, therefore, take a different approach based on the grouting method under consideration. However, the injection procedure is mainly performed by the experience of the foreman rather than engineering judgement , specifically the permeation grouting through the rock joints and its reinforcement effect Is not fully under-stood during the design stage, In this study, the anisotropic material properties of the grout-reinforced rock masses are derived from the concept of composite materials and the effect of intact rock, vertical grouting and permeation grouting is, therefore, fully accounted for. Through the parametric studies on the characteristics of rock joints, intact rock and grouting materials, various case studies have been considered. The results, illustrated via the design charts, can be directly used during the reinforcement design.

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The Torque Transmission Capacities of the Adhesive Tubular Lap Joint (접착제로 접착된 원형 겹치기이음의 토크 전달특성 연구)

  • 최진호;이대길
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.1
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    • pp.85-92
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    • 1994
  • With the wide application of fiber-reinforced composite meterial in aircraft space structures and robot arms, the design and manufacture of composite joints have become a very important research area because they are often the weakest areas in composite structure. In this paper, the torque transmission capacities of the adhesive tubular single lap joint and double lap joint were studied. The stress and torque transmission capacity of the adhesive joints were analyzed by the finite element method and compared to the experimental results. The torque capacity of the double lap joint was increased 2.7 times over that of the single lap joint. Also, the fatigue limit of the double lap joint was increased 16 times over that of the single lap joint.

A Structural Flexible Behavior T-type Joint for RCS Composite System (철근콘크리트기둥과 철골보 접합부의 휨성능(1))

  • Kim, Young-Soo;Kim, Young-Ho;Jeong, Jae-Hun;Kim, Jin-Mu;Won, Young-SuI;Joo, Kyung-Jai
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.4
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    • pp.139-146
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    • 2001
  • Res system, with Reinforced Concrete columns and Steel beams, is defined as system in which both steel and concrete materials are efficiently combined to maximize the structural and economic advantages of each material. Tested in this study were 4 exterior beam-to-column joint specimens with variables that influence joint rigidity of RCS structure. The purpose of this study is to compare and analyze the structural behavior of exterior joints through the existing studies and tests, and offer basic data for practical use of RCS structure by studying flexible behavior(semi-rigid effect) of joints according to joint details.

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Study on the Crack Shape of Concrete Exterior Beam-Column Joints Confined by Carbon Sheet Tube (카본 시트 튜브로 구속된 콘크리트 외부 보-기둥 접합부의 균열 양상에 대한 연구)

  • 문영균;박진영;이경훈;홍원기;김희철
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2003.09a
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    • pp.199-204
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    • 2003
  • The purpose of this study is to experimentally investigate the structural performance of concrete exterior beam-column joints confined by carbon sheet tube. Four specimens were produced with different numbers of carbon sheet and the other specimen was produced with reinforced concrete. A hydraulic dynamic actuator with 30tonf capacity was used to cyclic lateral loading test. The experimental results represent that the numbers of carbon sheet have an influence the load and displacement capacity. However, the bond length of carbon sheets for connecting beam and column has to be considered to improve the capacity of joint.

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Eustachian tube calcification as an unusual finding on a panoramic radiograph

  • Galal Omami
    • Imaging Science in Dentistry
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    • v.54 no.1
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    • pp.105-107
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    • 2024
  • The author herein presents an unusual case of eustachian tube calcification masquerading as loose radiopacities in the temporomandibular joints on a panoramic image, creating a diagnostic challenge. The patient, a 72-year-old woman, presented to the dental service for implant treatment to improve her masticatory function. A cone-beam computed tomography scan was performed and reviewed by a board-certified oral and maxillofacial radiologist. The scan showed no evidence of calcifications in the temporomandibular joints; however, it revealed nodular calcifications within the cartilaginous portion of the eustachian tube bilaterally. Additionally, this report briefly reviews the differential diagnosis of calcified loose bodies in the temporomandibular joint and provides information that needs to be reinforced periodically.

Tensile Test for Lap Welded Joints of Rebars(SD400) (일반철근(SD400) 용접 겹침이음 인장실험)

  • Park, Won-Tae;Chun, Kyoung-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.570-576
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    • 2018
  • In reinforced concrete structures, the joints of ordinary rebars are usually lap joints, which are bound by binding wires with rebars, and mechanical joints by couplers. In domestic design standards (concrete design code), welded lap joints are restricted for ordinary rebars, but overseas standards allow welded lap joints of ordinary rebars through pre-heating. This study investigated the domestic and international standards/criteria and evaluated the fracture strength by performing the tensile test on the lap welded joint of SD400 grade rebars, which is used the most in the construction sites. The weld length of the specimen for weld lap joints is based on the minimum weld length (8d) given in the KS standard (KS B ISO 17660-1). According to AWS D1.4, the preheating temperature was set to 150C for D19 and below, and 260C for D22 and above. In the test results, the tensile strength of rebars with welded lap joints exceeded the required strength (125% of the yield strength) according to the concrete design code. To analyze the effect of preheating, the tensile strength of the welded rebars after preheating was not significantly different from that of the welded rebars without preheating. The carbon equivalent content (Ceq) of the rebars used in the test was 0.45% or less. Under AWS D1.4, no preheating is required if the carbon equivalent is less than 0.45%. All specimens with a welded lap length of 8d failed by a bar fracture. The effect of preheating was confirmed to be insignificant due to the low carbon equivalent of the rebar.

Behavior of Reinforced Concrete Inclined Column-Beam Joints (철근콘크리트 경사기둥-보 접합부의 거동)

  • Kwon, Goo-Jung;Park, Jong-Wook;Yoon, Seok-Gwang;Kim, Tae-Jin;Lee, Jung-Yoon
    • Journal of the Korea Concrete Institute
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    • v.24 no.2
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    • pp.147-156
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    • 2012
  • In recent years, many high-rise buildings have been constructed in irregular structural system with inclined columns, which may have effect on the structural behavior of beam-column joints. Since the external load leads to shear and flexural forces on the inclined columns in different way from those on the conventional vertical columns, failure mode, resistant strength, and ductility capacity of the inclined column-beam joints may be different than those of the perpendicular beam-column joints. In this study, six RC inclined beam-column joint specimens were tested. The main parameter of the specimens was the angle between axes of the column and beam (90, 67.5, and 45 degree). Test results indicated that the structural behavior of conventional perpendicular beam-column joint was different to that of the inclined beam-column joints, due to different loading conditions between inclined and perpendicular beam-column joints. Both upper and lower columns of perpendicular beam-column joints were subjected to compressive force, while the upper and lower columns of the inclined beam-column joints were subjected to tensile and compressive forces, respectively.

Seismic Performance Evaluation of Non-Seismic Reinforced Concrete Buildings Strengthened by Perimeter Steel Moment Frame (철골 모멘트골조로 보강된 철근콘크리트 건물의 내진성능 평가)

  • Kim, Seonwoong
    • Journal of the Earthquake Engineering Society of Korea
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    • v.24 no.5
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    • pp.233-241
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    • 2020
  • This paper is to investigate the retrofitting effect for a non-seismic reinforced concrete frame strengthened by perimeter steel moment frames with indirect integrity, which ameliorates the problems of the direct integrity method. To achieve this, first, full-scale tests were conducted to address the structural behavior of a two-story non-seismic reinforced concrete frame and a strengthened frame. The non-seismic frame showed a maximum strength of 185 kN because the flexural-shear failure at the bottom end of columns on the first floor was governed, and shear cracks were concentrated at the beam-column joints on the second floor. The strengthened frame possessed a maximum strength of 338 kN, which is more than 1.8 times that of the non-seismic specimen. A considerable decrease in the quantity of cracks for the strengthened frame was observed compared with the non-seismic frame, while there was the obvious appearance of the failure pattern due to the shear crack. The lateral-resisting capacity for the non-seismic bare frame and the strengthened frame may be determined per the specified shear strength of the reinforced columns in accordance with the distance to a critical section. The effective depth of the column may be referred to as the longitudinal length from the border between the column and the foundation. The lateral-resisting capacity for the non-seismic bare frame and the strengthened frame may be reasonably determined per the specified shear strength of the reinforced columns in accordance with the distance to a critical section. The effective depth of the column may be referred to as the longitudinal length from the border between the column and the foundation. The proposed method had an error of about 2.2% for the non-seismic details and about 4.4% for the strengthened frame based on the closed results versus the experimental results.