• Title/Summary/Keyword: maximum shear reinforcement

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An Ezperimental Study on the Behavior of Girder Ledge of Precast Girder-Beam Connection (피리캐스트 Girder-Beam 접합부에서 Girder Ledge의 거동에 관한 실험적 연구)

  • 김기범;박성무
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.04a
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    • pp.483-491
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    • 1997
  • The purpose of this study id to define the behavior of the girder ledge of precast girder-beam joint in Frame Type Precast Concrete Construction Method. And in behavior, girder ledge is different with bracket, because of longitudinal effective width and longitudinal bending. specif c objectives of this study are followed: $\circled1$ To investigate the effects of concrete compressive strength on the maximum shear strength of girder ledge, $\circled2$ To investigate the effects of the shear-span ratio and effective area on behavior of girder ledge, $\circled3$ To investigate the effects of the types of reinforcement on behavior and maximum shear strength of girder ledge, $\circled4$ To study the applicable possibility of the suggested shear friction formulas to estimating the shear strength of girder ledge.

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Mechanical Properties of Hybrid FRP Rebar (하이브리드 FRP 리바의 역학적 특성)

  • 박찬기;원종필
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.2
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    • pp.58-67
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    • 2003
  • Over the last decade fiber-reinforced polymer (FRP) reinforcement consisting of glass, carbon, or aramid fibers embedded in a resin such as vinyl ester, epoxy, or polyester has emerged as one of the most promising and affordable solutions to the corrosion problems of steel reinforcement in structural concrete. But reinforcing rebar for concrete made of FRP rebar has linear elastic behavior up to tensile failure. For safety a certain plastic strain and an elongation greater than 3% at maximum load is usually required for steel reinforcement in concrete structures. The same should be required for FRP rebar. Thus, the main object of this study was to develop new type of hybrid FRP rebar Also, this study was evaluated to the mechanical properties of Hybrid FRP rebar. The Manufacture of the hybrid FRP rebar was achieved by pultrusion, and braiding and filament winding techniques. Tensile and interlaminar shear test results of Hybrid FRP rebar can provide its excellent tensile strength-strain behavior and interlaminar stress-strain behavior.

Determining the shear strength of FRP-RC beams using soft computing and code methods

  • Yavuz, Gunnur
    • Computers and Concrete
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    • v.23 no.1
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    • pp.49-60
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    • 2019
  • In recent years, multiple experimental studies have been performed on using fiber reinforced polymer (FRP) bars in reinforced concrete (RC) structural members. FRP bars provide a new type of reinforcement that avoids the corrosion of traditional steel reinforcement. In this study, predicting the shear strength of RC beams with FRP longitudinal bars using artificial neural networks (ANNs) is investigated as a different approach from the current specific codes. An ANN model was developed using the experimental data of 104 FRP-RC specimens from an existing database in the literature. Seven different input parameters affecting the shear strength of FRP bar reinforced RC beams were selected to create the ANN structure. The most convenient ANN algorithm was determined as traingdx. The results from current codes (ACI440.1R-15 and JSCE) and existing literature in predicting the shear strength of FRP-RC beams were investigated using the identical test data. The study shows that the ANN model produces acceptable predictions for the ultimate shear strength of FRP-RC beams (maximum $R^2{\approx}0.97$). Additionally, the ANN model provides more accurate predictions for the shear capacity than the other computed methods in the ACI440.1R-15, JSCE codes and existing literature for considering different performance parameters.

Stress-Strain Behavior of Flexible Pavement Reinforced with Geosynthetics (토목섬유로 보강된 아스팔트포장의 응력-변형 거동특성)

  • Ahn, Tae-Bong;Yang, Sung-Chul;Cho, Sam-Deok;Kim, Nam-Ho
    • International Journal of Highway Engineering
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    • v.3 no.1 s.7
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    • pp.151-163
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    • 2001
  • Very few studies have been attempted to understand the stress-strain behavior of flexible pavements reinforced with geosynthetics in the middle of asphalt layer. In this study, the flexible asphalt layer was analyzed with finite element method to understand stress-strain behavior. The asphalt layer was reinforced with glass grid and geogrid. The reinforcement was applied in the asphalt layer to prevent its excessive deformation and shear failure. The location of installation and stiffness of the geosynthetics were varied to obtain optimum depth of reinforcement and proper modulus. The results indicate that geosynthetics are more effective for reducing maximum shear stress than those of vertical stress and vertical displacement. Maximum shear stress decreased 15$\sim$20%, and glass grid with high value of modulus was the most effective. Also, in order to prevent failure of asphalt layer, reinforcement should be installed in the 3cm$\sim$5cm depth.

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Experimental Study on the Hysteretic Behavior of R/C Low-Rise Shear Walls under Cyclic Loads (반복하중을 받는 철근콘크리트 저형 전단벽의 이력거동에 관한 실험적 연구(II) -바벨형 단면(Barbell Shape)의 내력과 연성을 중심으로-)

  • 최창식;이용재;윤현도;이리형
    • Proceedings of the Korea Concrete Institute Conference
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    • 1991.10a
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    • pp.68-73
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    • 1991
  • Results of an experimental investigation of low-rise reinforced concrete shear walls with barbell cross section under cyclic loads are discussed and evaluated. Four halr scale models of test specimens with height to length ratio of 0.75 were experimented. The dimension of all walls is 1500mm wide $\times$ 950 mm high $\times$ 100 mm thick and the section of all boundary column at both ends is 200 mm $\times$ 200mm. Main variables are : design concept, vertical flexural reinflrcement ratios and reinforcement details(including crossed diagonal shear reinforcement in SW7 specimen). In SW7 specimen, maximum strength and consequently dissipating energy index were 1.45 and 1.28 times greater than those of SW6 specimen, respectively.

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Main factors determining the shear behavior of interior RC beam-column joints

  • Costa, Ricardo;Providencia, Paulo
    • Structural Engineering and Mechanics
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    • v.76 no.3
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    • pp.337-354
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    • 2020
  • Reinforced concrete beam-column (RCBC) joints of laterally loaded unbraced frames are sometimes controlled by their shear behavior. This behavior relies on multiple and interdependent complex mechanisms. There are already several studies on the influence of some parameters on the shear strength of reinforced concrete joints. However, there are no studies methodically tackling all the most relevant parameters and quantifying their influence on the overall joint behavior, not just on its shear strength. Hence, considering the prohibitive cost of a comprehensive parametric experimental investigation, a nonlinear finite element analysis (NLFEA) was undertaken to identify the key factors affecting the shear behavior of such joints and quantify their influence. The paper presents and discusses the models employed in this NLFEA and the procedure used to deduce the joint behavior from the NLFEA results. Three alternative, or complementary, quantities related to shear are considered when comparing results, namely, the maximum shear stress supported by the joint, the secant shear stiffness at maximum shear stress and the secant shear stiffness in service conditions. Depending on which of these is considered, the lower or higher the relevance of each of the six parameters investigated: transverse reinforcement in the joint, intermediate longitudinal bars and diagonal bars in the column, concrete strength, column axial load and confining elements in transverse direction.

Load Transfer Test of Spirally Reinforced Anchorage Zone for Banded Tendon Group (나선형 원형철근으로 보강된 집중배치 텐던 정착구역에 대한 하중전달시험)

  • Cho, Ah Sir;Kang, Thomas H.K.
    • Journal of Korean Association for Spatial Structures
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    • v.17 no.1
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    • pp.59-67
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    • 2017
  • In this study, load transfer tests based on KCI-PS101 were conducted to verify the performance of spiral anchorage zone reinforcement for banded post-tensioning (PT) monostrands. With results, the compressive strength of spiral reinforcement was increased by about 20% than that of specimens with two horizontal steel bars and 8% than that of U-shaped bars. Advanced spiral reinforcement for corner increases compressive strength and can resist the spalling forces or fall-out effect at the corner by shear. The ratio of maximum load to amount of steel of the spiral reinforcement is about twice than that of U-shaped reinforcement. With increase of compressive strength capacity and improvement of constructability, the spiral reinforcement is considered to have advantages of promoting the performance of PT anchorage zone compared to conventional methods.

Equivalent Plastic Hinge Length Model for Flexure-Governed RC Shear Walls (휨 항복형 철근콘크리트 전단벽의 등가소성힌지길이 모델)

  • Mun, Ju-Hyun;Yang, Keun-Hyeok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.2
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    • pp.1-8
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    • 2014
  • The present study proposes a simple equation to straightforwardly determine the potential plastic hinge length in boundary element of reinforced concrete shear walls. From the idealized curvature distribution along the shear wall length, a basic formula was derived as a function of yielding moment, maximum moment, and additional moment owing to diagonal tensile crack. Yielding moment and maximum moment capacities of shear wall were calculated on the basis of compatability of strain and equilibrium equation of internal forces. The development of a diagonal tensile crack at web was examined from the shear transfer capacity of concrete specified in ACI 318-11 provision and then the additional moment was calculated using the truss mechanism along the crack proposed by Park and Paulay. The moment capacities were simplified from an extensive parametric study; as a result, the equivalent plastic hinge length of shear walls could be formulated using indices of longitudinal tensile reinforcement at the boundary element, vertical reinforcement at web, and applied axial load. The proposed equation predicted accurately the measured plastic hinge length, providing that the mean and standard deviation of ratios between predictions and experiments are 1.019 and 0.102, respectively.

Dynamic Deformation Characteristics of Fiber Reinforced Soils with Various Gradation (여러 가지 입도분포를 갖는 섬유혼합토의 동적변형특성)

  • Mok, Young-Jin;Jung, Sung-Yong;Park, Chul-Soo
    • International Journal of Highway Engineering
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    • v.7 no.1 s.23
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    • pp.39-47
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    • 2005
  • Fiber reinforced soils have recently implemented to fills and base layers of highways and railroads, and deformation behaviors of reinforced soils in turn should be investigated. The paper evaluated deformation characteristics of fiber reinforced sands and their effectiveness of reinforcement using resonant column tests. The specimens were prepared by varying gradation and mixing polypropylene staple fibers of 0.3% fiber content. Maximum shear moduli of reinforced sands were increased by up to 30% with increasing uniformity coefficient. Shear moduli of well-graded reinforced sands were larger than those of poorly-graded ones regardless of confining pressure in the whole range of shearing strain and reinforcement was, in turn, more effective with higher uniformity coefficient.

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New metal connectors developed to improve the shear strength of stone masonry walls

  • Karabork, Turan;Kocak, Yilmaz
    • Structural Engineering and Mechanics
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    • v.50 no.1
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    • pp.121-135
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    • 2014
  • Stone masonry structures are widely used around the world, but they deteriorate easily, due to low shear strength capacity. Many techniques have been developed to increase the shear strength of stone masonry constructions. The aim of this experimental study was to investigate the performance of stone masonry walls strengthened by metal connectors as an alternative shear reinforcement technique. For this purpose, three new metal connector (clamp) types were developed. The shear strength of the walls was improved by applying these clamps to stone masonry walls. Ten stone masonry walls were structurally tested in diagonal compression. Various parameters regarding the in-plane behavior of strengthening stone masonry walls, including shear strength, failure modes, maximum drift, ductility, and shear modulus, were investigated. Experimentally obtained shear strengths were confirmed by empirical equations. The results of the study suggest that the new clamps developed for the study effectively increased the levels of shear strength and ductility of masonry constructions.