• Title, Summary, Keyword: shear design

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Approximate Analysis for Shear Force Amplification Effect in Ordinary RC Shear Walls (철근콘크리트 보통전단벽의 전단력 증폭효과 근사해석)

  • Jeon, Seong-Ha;Park, Ji-Hun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.24 no.3
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    • pp.129-139
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    • 2020
  • An approximate analysis method is proposed to predict the dynamic amplification of shear forces in ordinary reinforced concrete shear walls as a preliminary study. First, a seismic design for three groups of ordinary reinforced concrete shear walls higher than 60 m was created on the basis of nonlinear dynamic analysis. Causes for the dynamic amplification effect of shear forces were investigated through a detailed evaluation of the nonlinear dynamic analysis result. A new modal combination rule was proposed on the basis of that observation, in which fundamental mode response and combined higher mode response were summed directly. The fundamental mode response was approximated by nonlinear static analysis result, while higher mode response was computed using response spectrum analysis for equivalent linear structural models with the effective stiffness based on the nonlinear dynamic analysis result. The proposed approximate analysis generally predicted vertical distribution of story shear and shear forces of individual walls from the nonlinear dynamic analysis with comparable accuracy.

Shear Behavior of Post-tensioning PSC Beams with High Strength Shear Reinforcement (고강도 전단보강철근을 사용한 포스트텐션 프리스트레스트 콘크리트 보의 전단거동 평가)

  • Jun, Byung-Koo;Lee, Jea-Man;Lim, Hye-Sun;Lee, Jung-Yoon
    • Journal of the Korea Concrete Institute
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    • v.28 no.1
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    • pp.33-40
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    • 2016
  • The KCI-12 and ACI 318-14 design codes limit the maximum yield strength of shear reinforcement to prevent concrete compressive crushing before the yielding of shear reinforcement. The maximum yield strength of shear reinforcement is limited to 420 MPa in the ACI 318-14 design code, while limited to 500 MPa in the KCI-12 design code. A total of eight post-tensioning prestressed concrete beams with high strength shear reinforcement were tested to observe the shear behavior of PSC beams and the applicability of the high strength reinforcement was thus assessed. In the all PSC beam specimens that used stirrups greater than maximum yield strength of shear reinforcement required by the ACI 318-14 design code, the shear reinforcement reached their yield strains. The observed shear strength of tested eight PSC beams was greater than the calculated ones by the KCI-12 design codes. In addition, the diagonal crack width of all specimens at the service load was smaller than the crack width required by the ACI 224 committee. The experimental and analytical results indicate that the limitation on the yield strength of shear reinforcement in the ACI 318-14 design code is somewhat under-estimated and needs to be increased for high strength concrete. Also the application of high strength materials to PSC is available with respect to strength and serviceability.

Experimental Study on Variation of Shear Strength of Reinforced Concrete Beams According to Design Parameters (설계변수에 따른 철근콘크리트 보의 전단강도 변화에 대한 실험연구)

  • Oh, Dong-Hyun;Choi, Kyung-Kyu;Park, Hong-Gun
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.279-282
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    • 2005
  • Experimental study is performed to investigate the variation of shear strength of reinforced concrete beams according to design parameters. The major parameters are loading condition, shear span-to-depth ratio, ratio of tensile longitudinal reinforcement, prestress and boundary rigidity.14 reinforced concrete beams without web reinforcement are tested under monotonic downward loading. The shear strength of the tested specimens were compared with the prediction by design code and Choi's method.

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Experimental investigation on the shear capacity of RC dapped end beams and design recommendations

  • Wang, Quanfeng;Guo, Zixiong;Hoogenboom, Pierre C.J.
    • Structural Engineering and Mechanics
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    • v.21 no.2
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    • pp.221-235
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    • 2005
  • In this paper, the shear resistance behaviour of reinforced concrete (RC) dapped end beams is investigated by 24 tests until failure load. The main parameters considered are the dapped end height, the type and effective range to provided the stirrups and the bent form of the longitudinal reinforcement. The failure behaviour of dapped end beams is presented and some conclusions are given. Inclined stirrups and longitudinal bent reinforcement have more influence on the shear capacity than vertical stirrups. Additionally, the shear mechanism of dapped end beams is analysed. Relatively simple semi-empirical equations for shear strength have been derived based on the results of 22 dapped end beams. The predicted results are in close agreement with the experimental ones. Finally, some design suggestions for the ultimate shear strength of dapped end beams are presented.

Shear strength of connections between open and closed steel-concrete composite sandwich structures

  • Kim, Woo-Bum;Choi, Byong Jeong
    • Steel and Composite Structures
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    • v.11 no.2
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    • pp.169-181
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    • 2011
  • The behavior of connections between open sandwich slabs and double steel skin composite walls in steel plate-concrete(SC) structure is investigated by a series of experimental programs to identify the roles of components in the transfer of forces. Such connections are supposed to transfer shear by the action of friction on the interface between the steel surface and the concrete surface, as well as the shear resistance of the bottom steel plate attached to the wall. Experimental observation showed that shear transfer in slabs subjected to shear in short spans is explained by direct force transfer via diagonal struts and indirect force transfer via truss actions. Shear resistance at the interface is enhanced by the shear capacity of the shear plate as well as friction caused by the compressive force along the wall plate. Shear friction resistance along the wall plate was deduced from experimental observation. Finally, the appropriate design strength of the connection is proposed for a practical design purpose.

Shear Strength and Seismic Behavior of the Composite Shear Wall with the Steel Plate Embedded in the RC Wall (철판삽입 합성전단벽의 전단강도와 내진거동)

  • Chun, Young-Soo;Park, Ji-Young;Lee, Jong-Yoon
    • LHI Journal of Land, Housing, and Urban Affairs
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    • v.8 no.3
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    • pp.211-221
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    • 2017
  • This study proposed hybrid coupled shear wall in the steel plate insertion method, which is capable of reinforcing the shear strength of the entire wall without increasing wall thickness in the wall-slab apartment buildings. The proposed hybrid coupled shear wall was tested for its effectiveness, shear strength and seismic behavior in experiment. As a test result, the shear strength improvement by the proposed hybrid coupled shear was found effective. Integral-type of steel plate insertion was found more effective than separate-type steel plate insertion. In this case, if the stud enforcement method proposed in this study was used, the shear strength of hybrid coupled shear wall was recommended to calculate using the KBC2016 0709.4.1(3) method. The steel plate inserted in the proposed method was found to have no significant impact on the final fracture behavior and bending strength of hybrid coupled shear wall. The shear strength at the final destruction of the wall was merely about 1/50 of the entire design shear strength. Thus, it is deemed that the wall was over excessively designed regarding the shear force in the existing design method. This finding indicates further study on wall designing to ensure effective and economic designing based on appropriate strength estimation under the destruction mechanism.

Ductility Confinement of RC Rectangular Shear Wall (장방형 철근 콘크리트 전단벽의 연성 보강)

  • 강수민;박홍근
    • Journal of the Korea Concrete Institute
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    • v.14 no.4
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    • pp.530-539
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    • 2002
  • In designing the boundary confinement of shear walls, the current design provisions and recommendations are empirical and prescriptive; they specify a certain confinement length and details, regardless of the actual requirement of ductility Therefore, they are inappropriate to the performance based-design. The purpose of the present study is to develop a ductility design method that Is applicable to the performance based-design of shear wall. For the purpose, experimental studies were performed to investigate variations in the ductility of shear walls with the length of the boundary confinement. Five specimens modeling the compressive zone of cross sections with different confinement area were tested against eccentric vertical load. Through the experimental studies, strength, ductility, and failure mode of the compression zone were investigated. In addition, nonlinear numerical analyses for the overall cross-sections of shear wall were performed to investigate variations of the stress and strain profiles with the length of compression zone. On the basis of the experimental and numerical studies, a ductility design method for shear wall was developed. By using the proposed design method, for a given ductility demand, the area of lateral confinement and corresponding reinforcement ratio can be precisely determined so that the ductile behavior and economical design are assured.

Retrofitting by adhesive bonding steel plates to the sides of R.C. beams. Part 2: Debonding of plates due to shear and design rules

  • Oehlers, Deric. J.;Nguyen, Ninh T.;Bradford, Mark A.
    • Structural Engineering and Mechanics
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    • v.9 no.5
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    • pp.505-518
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    • 2000
  • A major cause of premature debonding of tension face plates is shear peeling (Jones et al. 1988, Swamy et al. 1989, Ziraba et al. 1994, Zhang et al. 1995), that is debonding at the plate ends that is associated with the formation of shear diagonal cracks that are caused by the action of vertical shear forces. It is shown in this paper how side plated beams are less prone to shear peeling than tension face plated beams, as the side plate automatically increases the resistance of the reinforced concrete beam to shear peeling. Tests are used to determine the increase in the shear peeling resistance that the side plates provide, and also the effect of vertical shear forces on the pure flexural peeling strength that was determined in the companion paper. Design rules are then developed to prevent premature debonding of the plate ends due to peeling and they are applied to the strengthening and stiffening of continuous reinforced concrete beams. It is shown how these design rules for side plated beams can be adapted to allow for propped and unpropped construction and the time effects of creep and shrinkage, and how side plates can be used in conjunction with tension face plates.

Shear Design of Trapezoidally Corrugated Steel Webs (제형 파형강판 복부판의 전단 설계)

  • Moon, Jiho;Yi, Jongwon;Choi, Byung-Ho;Lee, Hak-Eun
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.4A
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    • pp.497-505
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    • 2008
  • Corrugated steel webs resist only shear force because of the accordion effects. The shear force in the web can cause three different buckling mode: local, global, and interactive shear buckling modes. The shear behavior of the corrugated steel webs have been investigated by several researchers. However, shear buckling behavior of the corrugated webs are not clearly explained yet. And, it lead the conservative design. This paper presents shear strength of trapezoidally corrugated steel webs. A series of the tests were also conducted to verified proposed shear strength. Firstly, local, global, and interactive shear buckling equations provided by previous researchers were rearranged as a simple form considering the profiles of the existing bridges with corrugated steel webs. And, global and interactive shear buckling coefficient, and shear buckling parameter for corrugated webs were suggested in this study. Inelastic buckling strength can be determined from buckling curves based on the proposed shear buckling parameter. From the test results of this study and those of previous researchers, it can be found that suggested shear strength provides good estimation of those of trapezoidally corrugated steel webs.

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Shear Capacity of Cold-Formed Light-Gauge Steel Framed Shear-Wall Panels with Fiber Cement Board Sheathing

  • Khaliq, Wasim;Moghis, Ahmed
    • International journal of steel structures
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    • v.17 no.4
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    • pp.1405-1415
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    • 2017
  • Being light in weight, cold-formed steel shear wall panels (SWPs) made with light gauge steel are extensively used in residential and office buildings (low to mid-rise), particularly in structures under seismic loadings. Many design practices involve the use of fiber cement board (FCB) as sheathing material both for hollow and infilled walls. FCB is a preferred choice as cladding material due to many advantages it provides such as water resistance, lower cost, withstand temperature variation, resistance to humidity and termite attack, better acoustic insulation, and superior fire resistance properties. In the absence of design guidelines, based on cold-formed light gauge steel shear walls with FCB sheathing, the designers resolve to use the guideline available for gypsum wall board (GWB) and fiberboard (FB) available in American Iron and Steel Institute Lateral Design. As a pioneer study, an experimental program was designed to investigate the behavior of cold-formed light gauge steel shear walls, both hollow and infilled with expanded polystyrene (EPS) foam concrete, with FCB sheathing on both sides under monotonic loading. The tests were performed according to ASTM E564 standard. Results show that the strength of shear walls with FCB sheathing is much higher than GWB and FB sheathing, suggesting that substitute design practices are highly conservative. Test results can help designers choose desired lateral stiffness and load carrying capacity of light gauge steel SWPs more efficiently, by selecting appropriate framing, infill, and sheathing material.