An Experimental Study on the Evaluation of Shear Performance of PVA Fiber Reinforced RC Deep Beam with High Strength Headed Rebar

Seunghun Kim,Kyuseon Lee,Yongtaeg Lee 대한건축학회 2017 Architectural research Vol.19 No.4

This study is done to evaluate how existence of shear-span ratio and shear reinforcing bar effects on shear performance from through shear experiment using PVA fiber reinforced ferroconcrete building. Ratio of shear-span was set 1, 1.7, and arrangement of shear reinforcing bar was set with KCI2012 regulation. In result, subject with less shear-span ratio, and shear reinforcing bar with arrangement of bar shows high stiffness. Subjects with high shear-span ratio show large difference depending on existence of shear reinforcing bar. Therefore, theoretical shear strength followed by CEB code underestimates experimental shear strength by 43.9%. Shear strength of the deep beam with headed bars is more affected by the bearing strength of head than the bond strength of bar.

집중하중을 받는 철근콘크리트 깊은 보의 전단거동에 관한 실험적 연구

이진섭,김상식,Lee, Jin-Seop,Kim, Sang-Sik 한국콘크리트학회 1999 콘크리트학회지 Vol.11 No.1

집중하중을 받는 단순지지 철근콘크리트 깊은 보를 대상으로 콘크리트의 압축강도, 전단스팬비, 웨브 수직 및 수평 보강철근비를 변수로 하여 깊은 보의 구조거동과 전단강도를 실험적으로 조사하였으며, 각 변수의 영향을 고찰하고 규준식 및 제안식 등과 비교, 검토하였다. 42개의 시험체를 실험한 결과, 모든 시험체는 전단스팬 내에서 콘크리트의 과도한 균열 및 압괴에 의해 파괴되었고, 시험체의 초기강성은 압축강도에 관계없이 전단 스팬비가 작을수록 크게 나타났으며, 경사균열 발생 이후 보의 강성이 점진적으로 감소되었다. 전단스팬비가 증가함에 따라 경사균열 및 최대하중은 일정하게 감소하며, 콘크리트 압축강도가 증가할수록 최대하중은 증가하나 경사균열 하중은 거의 변화가 없었고, 전단스팬비의 증가에 따라 콘크리트의 압축강도가 전단강도에 미치는 영향 또한 일정하게 감소하는 것으로 보인다. 웨브의 전단보강근 효과는 전단스팬비의 영향을 받으며, 전단스팬비가 작아지면 수평보강근의 효과가, 전단스팬비가 커지면 수직보강근의 효과가 상대적으로 커짐을 알 수 있었다. 실험결과와 비교하여, 이론식은 de Paiva의 제안식이, 규준식은 CIRIA guide가 실험결과에 가장 부합하는 것으로 나타났으며, 국내 규준식은 실험값에 비해 상당히 낮은 강도로 계산되고 있어 안전 측에 있는 것으로 판단된다. The shear behavior of simply supported reinforced concrete deep beams subject to concentrated loads has been scrutinized experimentally to verify the influence of the structural parameters such as concrete strength, shear span-depth ratio, and web reinforcements. A total of 42 reinforced concrete deep beams with compressive strengths of 250 kg/$cm^2$ and 500 kg/$cm^2$ has been tested at the laboratory under one or two-point top loading. The shear span-depth ratio have been taken as three types of 0.4, 0.8 and 1.2, and the horizontal and vertical shear reinforcements ratio, ranging from 0.0 to 0.57 percent respectively. In the tests, the effects of the shear span-depth ratio, concrete strength and web reinforcements on the shear strength and crack initiation and propagation have been carefully checked and analyzed. From the tests, it has been observed that the failures of all specimens were due to shear and the shear behaviors of specimens were greatly affected by inclined cracks from the load application points to the supports in shear span. The load bearing capacities have changed significantly depending on the shear span ratio, and the efficiency of horizontal shear reinforcements were increased as the shear span-depth ratio decreased. The test results have been analyzed and compared with the formulas proposed by previous researchers and the design equation from the code. While the shear strengths obtained from the tests showed around 1.4 and 1.9 times higher than the values calculated by CIRIA guide and the domestic code, they were closely coincident with the formulas given by de Paiva's equation.

主筋比에 따른 高强度 콘크리트 보의 剪斷擧動에 관한 實驗硏究

윤승조 충주대 산업과학기술연구소 1998 産業科學論文集 Vol.6 No.-

The purpose of this study is to investigate experimentally the shear behavior of high-strength reinforced concrete beams for longitudinal steel ratio subjected to monotonic loading. The shear strength of reinforced concrete beams without stirrups is dependent on the compressive strength of concrete, the longitudinal steel ratio, the shear span to depth ratio. In this study, Ten reinforced concrete beams using high strength concrete(f'c = 98MPa) are tested to determine their ultimate shear capacity. The main variables are longitudinal steel ratio and shear span-depth ratio a/d = 1.0, 2.0, 3.0. All specimens are 125 mm wide and have a total depth of 250 mm. The effective depth is 215 mm. The test beams is simply supported at ends and loaded by one point loads. The test results were analyzed and compared with strength predicted by ACI code equation, Zsutty's equation, Bazant's equation and Shin's equation.

연결 플레이트를 사용한 프리캐스트 콘크리트 모듈러 보의 전단성능

조창근,노경민,이영학,Cho, Chang Geun,Ro, Kyong Min,Lee, Young Hak 한국공간구조학회 2021 한국공간구조학회지 Vol.21 No.4

The Precast concrete(PC) modular structures are a method of assembling pre-fabricated unit modules in the construction site. The essential aim of modular structures is to introduce a connection method that can ensure splicing performance and effectively resist shear strength. This study proposed PC module using a connecting plate that can replace splice sleeves and shear keys used in the conventional PC modular structures. To evaluate the splicing performance and shear capacity of the proposed method, the shear test was conducted by fabricating one monolithic reinforced concrete(RC) beam and two PC modular beams with a shear span-to-depth ratio as variables. The experimental results showed that the shear capacity of the PC modular beam was about 89% compared to that of the RC beam, and showed a failure of the RC beam according to the shear span-to-depth ratio. Therefore, it was considered that the connecting plate effectively transferred the stress between each PC module through the joint and ensure integrity. In addition, the applicability of shear strength equation of ACI 318-19 and Zsutty's equation to PC modular beams were evaluated. Results demonstrated that the improved shear strength equations are needed to consider reduction of shear strength in PC modules.

Shear strength of reinforced concrete beams with precast High-Performance Fiber-Reinforced Cementitious Composite permanent form

Wu, Xiangguo,Kang, Thomas H.-K.,Lin, Yang,Hwang, Hyeon-Jong Elsevier 2018 Composite structures Vol.200 No.-

<P><B>Abstract</B></P> <P>As a structural and constructional element, a thin-walled U-shaped precast permanent form consisting of High-Performance Fiber-Reinforced Cementitious Composites (HPFRCC) and steel wire mesh is considered. Prior to casting, transverse steel threaded bars are installed, as well as longitudinal reinforcing bars, connecting two sides of the U-shaped form for shear transfer between the precast and in-filled concrete sections and for fresh concrete pressure resistance. The present study investigated the effect of precast U-shaped HPFRCC section on the shear strength of the composite beams. As parameters for full-scale three-point bending tests, the type or materials of precast section, spacing of shear reinforcement, and shear span-to-depth ratio were considered. The test results showed that the precast U-shaped HPFRCC permanent form increased the shear contributions of in-filled concrete and shear reinforcement in the composite beam substantially. From the experimental and analytical assessment, the coefficients related to the composite action between precast HPFRCC and in-filled concrete sections, shear reinforcement along diagonal cracks, and shear span-to-depth ratio were proposed, which were applied to a previous shear strength model for the simplified shear design of proposed precast U-shaped HPFRCC-in filled concrete composite beams.</P>

Investigations on the Shear Mechanism of Steel-Tube-Reinforced Concrete Shear Walls with a Low Shear-Span Ratio

Liang Bai,Cai Zhang,Ergang Xiong 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.7

This paper describes the study of steel tube reinforced concrete (STRC) shear walls with a low shear-span ratio, in which steel tubes are embedded in the web of the shear wall. The addition of these steel tubes can significantly improve the shear behavior of ordinary RC shear walls. A series of cyclic loading tests allow us to examine the failure mode, hysteretic behavior, deformability, and energy dissipation capacity of the STRC shear walls. The investigation indicate the STRC shear walls transform from entire section walls to walls with vertical slits under loading. This prevents brittle shear failure and improves the deformation and energy dissipation capacity of the specimens. A softened strut-and-slip model is applied to analyze the shear mechanism of STRC shear walls, and is shown to predict the shear capacity accurately.

철근콘크리트 보의 전단에 대한 역학적 거동에 관한 연구

신영진,고봉수,은희창,서일교 제주대학교 공과대학 첨단기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.2

The shear capacity of reinforced concrete beams is characterized by various parameters as the strength of concrete, the shear-span ratio, the strength of shear reinforcement etc. Sixteen specimens were tested with those variables. All specimens showed the shear failure mode to accompany the diagonal shear cracks or the flexural failure. Through the experimental works, it was evidenced that the shear strength depends on the strength of concrete, the shear-span ratio, the confinement index including the strength and spacing of shear reinforcement bars etc. Although part of test results could not distinct the effects of test variables due to the yielding of longitudinal bars, it was shown that they almost satisfy the ACI code except several specimens confined by high-strength shear bars.

Residual Shear Capacity of Reinforced Concrete Beams after Fire Exposure

Yamin Song,Chuanguo Fu,Shuting Liang,Dong Li,Longji Dang,Chongfang Sun,Weiyi Kong 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.11

The mechanical properties of concrete and steel are seriously degraded under high temperature, so that reinforced concrete (RC) members after fire may not be able to satisfy the prescribed performance. In this study, 27 full-scale RC beams were carried out shear tests to investigate the shear behaviour after fire. A total of 20 beams were subjected to fire on three sides in accordance with ISO 834 standard fire curve, and the remaining 7 beams (which were not subjected to fire) were employed as a reference. The influences of fire time, stirrup ratio, shear span ratio, longitudinal reinforcement ratio, and preloading (40% loading level) were considered. The experimental results indicated that the shear failure mode of the RC specimens after fire exposure was similar to that of the reference specimens. Both the residual shear load bearing capacity and stiffness of the RC beams decreased after being subjected to fire. The loss of shear bearing capacity increased with the heating time. In addition, the ultimate load bearing capacity of specimens with stirrups subjected to the same fire exposure time decreased with an increasing shear span ratio.

An evolutionary fuzzy modelling approach and comparison of different methods for shear strength prediction of high-strength concrete beams without stirrups

Mohammad Mohammadhassani,Hossein Nezamabadi-pour,Meldi Suhatril,Mahdi shariati 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.14 No.5

In this paper, an Adaptive nerou-based inference system (ANFIS) is being used for the prediction of shear strength of high strength concrete (HSC) beams without stirrups. The input parameters comprise of tensile reinforcement ratio, concrete compressive strength and shear span to depth ratio. Additionally, 122 experimental datasets were extracted from the literature review on the HSC beams with some comparable cross sectional dimensions and loading conditions. A comparative analysis has been carried out on the predicted shear strength of HSC beams without stirrups via the ANFIS method with those from the CEB-FIP Model Code (1990), AASHTO LRFD 1994 and CSA A23.3 – 94 codes of design. The shear strength prediction with ANFIS is discovered to be superior to CEB-FIP Model Code (1990), AASHTO LRFD 1994 and CSA A23.3 – 94. The predictions obtained from the ANFIS are harmonious with the test results not accounting for the shear span to depth ratio, tensile reinforcement ratio and concrete compressive strength; the data of the average, variance, correlation coefficient and coefficient of variation (CV) of the ratio between the shear strength predicted using the ANFIS method and the real shear strength are 0.995, 0.014, 0.969 and 11.97%, respectively. Taking a look at the CV index, the shear strength prediction shows better in nonlinear iterations such as the ANFIS for shear strength prediction of HSC beams without stirrups.

An evolutionary fuzzy modelling approach and comparison of different methods for shear strength prediction of high-strength concrete beams without stirrups

Mohammadhassani, Mohammad,Nezamabadi-pour, Hossein,Suhatril, Meldi,shariati, Mahdi Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.5

In this paper, an Adaptive nerou-based inference system (ANFIS) is being used for the prediction of shear strength of high strength concrete (HSC) beams without stirrups. The input parameters comprise of tensile reinforcement ratio, concrete compressive strength and shear span to depth ratio. Additionally, 122 experimental datasets were extracted from the literature review on the HSC beams with some comparable cross sectional dimensions and loading conditions. A comparative analysis has been carried out on the predicted shear strength of HSC beams without stirrups via the ANFIS method with those from the CEB-FIP Model Code (1990), AASHTO LRFD 1994 and CSA A23.3 - 94 codes of design. The shear strength prediction with ANFIS is discovered to be superior to CEB-FIP Model Code (1990), AASHTO LRFD 1994 and CSA A23.3 - 94. The predictions obtained from the ANFIS are harmonious with the test results not accounting for the shear span to depth ratio, tensile reinforcement ratio and concrete compressive strength; the data of the average, variance, correlation coefficient and coefficient of variation (CV) of the ratio between the shear strength predicted using the ANFIS method and the real shear strength are 0.995, 0.014, 0.969 and 11.97%, respectively. Taking a look at the CV index, the shear strength prediction shows better in nonlinear iterations such as the ANFIS for shear strength prediction of HSC beams without stirrups.