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Xiaopeng Li - One of the best experts on this subject based on the ideXlab platform.
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alternative Shear Reinforcement for reinforced concrete flat slabs
Journal of Structural Engineering-asce, 2003Co-Authors: Kypros Pilakoutas, Xiaopeng LiAbstract:This paper presents the first series of validation tests for a patented Shear Reinforcement system for reinforced concrete flat slabs. The system, called “Shearband,” consists of elongated thin steel strips punched with holes, which undulate into the slab from the top surface. The main advantages of the new Reinforcement system are structural effectiveness, flexibility, simplicity, and speed of construction. Four reinforced concrete slabs were tested in a specially designed test rig. The slabs reinforced in Shear exhibited ductile behavior after achieving their full flexural potential, thus proving the effectiveness of the new Reinforcement. This paper reviews briefly existing types of Shear Reinforcement and identifies the need for more efficient and economic solutions. Details of the experimental setup and results are given, including strain and deflection measurements as well as photographs of sections through the slabs. Finally, comparisons are made with the ACI 318 and BS8110 code predictions, which confirm that the system enabled the slabs to avoid punching Shear failure and achieve their flexural potential. In addition, both codes are shown to lead to conservative estimates of flexural and punching Shear capacities of reinforced concrete slabs.
Hongsuk Yang - One of the best experts on this subject based on the ideXlab platform.
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Shear behavior of continuous reinforced concrete t beams using wire rope as internal Shear Reinforcement
Construction and Building Materials, 2011Co-Authors: Keunhyeok Yang, Hongsuk YangAbstract:Abstract The use of wire ropes with high-strength and high flexibility as internal Shear Reinforcement can solve the difficulties encountered in bending higher strength steel bar and can provide a better Shear behavior to concrete beams. Three two-span reinforced concrete T-beams were tested to failure in order to examine the possibility of the practical application of wire ropes as Shear Reinforcement. The measured Shear capacities of beams were compared with predictions obtained from equations specified in ACI 318-08 and the mechanism analysis based on the upper-bound theorem of concrete plasticity. Test results showed that using spiral-type wire rope as Shear Reinforcement is highly favourable for controlling the diagonal crack width and enhancing the ductility of beams failing in Shear. In particular, the high-strength of the wire ropes significantly promoted the Shear capacity of concrete beams. When a limit stress of 420 MPa for wire ropes is employed, ACI 318-08 is highly conservative in beams with spiral-type wire ropes compared with the control beams with closed stirrups. In addition, ACI 318-08 is still conservative when using the equivalent yield strength of wire ropes. On the other hand, the predictions obtained from the mechanism analysis are in good agreement with test results, regardless of the type of Shear Reinforcement.
Kypros Pilakoutas - One of the best experts on this subject based on the ideXlab platform.
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alternative Shear Reinforcement for reinforced concrete flat slabs
Journal of Structural Engineering-asce, 2003Co-Authors: Kypros Pilakoutas, Xiaopeng LiAbstract:This paper presents the first series of validation tests for a patented Shear Reinforcement system for reinforced concrete flat slabs. The system, called “Shearband,” consists of elongated thin steel strips punched with holes, which undulate into the slab from the top surface. The main advantages of the new Reinforcement system are structural effectiveness, flexibility, simplicity, and speed of construction. Four reinforced concrete slabs were tested in a specially designed test rig. The slabs reinforced in Shear exhibited ductile behavior after achieving their full flexural potential, thus proving the effectiveness of the new Reinforcement. This paper reviews briefly existing types of Shear Reinforcement and identifies the need for more efficient and economic solutions. Details of the experimental setup and results are given, including strain and deflection measurements as well as photographs of sections through the slabs. Finally, comparisons are made with the ACI 318 and BS8110 code predictions, which confirm that the system enabled the slabs to avoid punching Shear failure and achieve their flexural potential. In addition, both codes are shown to lead to conservative estimates of flexural and punching Shear capacities of reinforced concrete slabs.
Josef Hegger - One of the best experts on this subject based on the ideXlab platform.
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Variable strut inclination model for Shear design of FRP reinforced concrete members with Shear Reinforcement
Engineering Structures, 2020Co-Authors: Sophia Kueres, Josef HeggerAbstract:Abstract To avoid brittle Shear failures, the Shear strength of reinforced concrete beams has to be verified at ultimate limit state. For this purpose, simple but accurate Shear design provisions or Shear resistance models are required. In this paper, the derivation of a simple Shear design model for beams with FRP Shear Reinforcement is presented. At first, the suitability of existing code provisions and Shear resistance models is evaluated using a large databank on Shear tests on members with FRP Shear Reinforcement. Based on the results, a Shear resistance model is developed based on a truss model with variable strut inclination, which is also the basis of the Shear design of members with steel Shear Reinforcement according to current Eurocode 2. An important aspect regarding the derivation of the model is the definition of an appropriate method to determine the angle of the compression strut. For this purpose, a compression field model originally developed for steel reinforced concrete beams is adopted. The proposed resistance model is validated by means of a databank evaluation. Moreover, an equation to determine the minimum Shear Reinforcement ratio of FRP reinforced concrete members is derived based on the Shear design provisions according to Eurocode 2.
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Contribution of concrete and Shear Reinforcement to the punching Shear resistance of flat slabs
Engineering Structures, 2020Co-Authors: Philipp Schmidt, Dominik Kueres, Josef HeggerAbstract:Abstract The punching strength of flat slabs and footings without and with high amounts of Shear Reinforcement on the level of maximum punching Shear capacity has been investigated extensively by various researchers over the last decades. The existing investigations suggest that the punching strength of RC slabs with Shear Reinforcement can be described by means of a contribution of concrete and a contribution of the Shear Reinforcement (steel contribution). However, a systematic evaluation of concrete and steel contribution depending on the amount of Shear Reinforcement has not yet been adequately possible since only few test series with low and medium amounts of Shear Reinforcement and a failure within the Shear-reinforced zone have been available. This lack of experimental data has been partly filled with eleven systematic punching tests on flat slabs and eleven further tests on footings conducted at RWTH Aachen University, Germany. In this paper, the development of the concrete and steel contributions in Shear-reinforced flat slabs is investigated in detail and a method for calculating and analyzing both contributions is presented. The development of concrete and steel contribution depending on the amount of Shear Reinforcement is discussed and compared to the design provisions according to Eurocode 2, Model Code 2010 and the draft (of April 2018) of the next generation of Eurocode 2.
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New Punching Shear Reinforcement System for Footings and Ground Slabs
Lecture Notes in Civil Engineering, 2019Co-Authors: Marcus Ricker, Dominik Kueres, Frank Häusler, D. Carminati, Josef HeggerAbstract:Punching Shear tests on footings indicated that the inclination of compression struts is much steeper compared to flat slabs. The resulting steeper inclination of Shear cracks leads to the assumption that vertically arranged punching Shear Reinforcement elements are less efficient in footings than in flat slabs. On that basis, a new punching Shear Reinforcement element with inclined bars was developed. At RWTH Aachen University, 14 punching Shear tests on reinforced concrete footings including the new punching Shear Reinforcement elements were conducted. The test specimens partly failed inside the Shear‐reinforced zone and at maximum load level. In spite of a reduction of total steel cross sectional area, the test specimens with the new punching Shear elements showed a significant increase in punching Shear capacity (40–50%) compared to previous test series. The new punching Shear Reinforcement system allows for a significant reduction of footing’s dimensions.
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Influence of Support Conditions on Shear in RC Members Without Shear Reinforcement
High Tech Concrete: Where Technology and Engineering Meet, 2017Co-Authors: Viviane Adam, Karin Reissen, Josef HeggerAbstract:The present rules for Shear design of reinforced concrete (RC) members without Shear Reinforcement according to Eurocode 2 are semi-empirical. The underlying database to calibrate the Shear design approach comprises test data of more than 600 simply supported beams. In reality, various other support conditions occur, for instance in continuous beams. In that case, the moment-Shear ratio in the member differs compared to simply supported beams. This influence is not considered in the Shear design according to Eurocode 2. However, alternative design approaches, such as those according to Model Code 2010 or SIA 262, allow for the influence of the moment. In order to investigate the influence of the support conditions on the Shear resistance, numerous Shear tests on continuous members without Shear Reinforcement are carried out at the Institute of Structural Concrete at RWTH Aachen University. Full scale beams with a height of 0.28 m, a width of 0.3 to 0.5 m and a span of 3 to 4 m are tested under concentrated loads. The specimens are simply supported at one side and continuous at the other with varying levels of the hogging moment. As a result, the point of infection (P.I.) is varied. Also, simply supported reference tests are carried out. Further investigated influences are the distance from the load to the support, the longitudinal Reinforcement ratio and the size of the load area. The experimental Shear capacities are compared to the calculated Shear capacities according to the presented design approaches to assess the influence of the moment-Shear ratio. Possible modifications concerning the Shear design for reinforced concrete continuous members without Shear Reinforcement are presented.
P. E. Regan - One of the best experts on this subject based on the ideXlab platform.
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Shear Reinforcement of flat slabs
2020Co-Authors: P. E. ReganAbstract:This paper attempts to address problems which have to be solved if the design of Shear Reinforcement to increase the punching capacities of slabs is to be placed on a more rational footing. It describes the basic effect of such Reinforcement and its interaction with the Shear resistance of the concrete. The issues associated with the anchorage of Shear steel, its connection to the flexural tension and compression zones, and its plan arrangement are illustrated. A final section discusses the use of Shear Reinforcement in slabs with openings and presents some test results for such slabs.
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Shear Reinforcement AGAINST PUNCHING IN REINFORCED CONCRETE FLAT SLABS
The Structural engineer, 2001Co-Authors: P. E. Regan, F SamadianAbstract:Ten tests were made on slabs with various forms of Shear Reinforcement used to increase punching resistance. Comparisons with predictions using current codes of practice show shortcomings in present design methods and proposals are made for a modified approach. This approach is compared with a wide range of test data and shown to be satisfactory. (A)
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PUNCHING RESISTANCE OF RC FLAT SLABS WITH Shear Reinforcement
Journal of Structural Engineering-asce, 1999Co-Authors: Ronaldo B. Gomes, P. E. ReganAbstract:A theoretical model is proposed for analyzing the punching resistance of reinforced concrete (RC) flat slabs with Shear Reinforcement for concentric loading. Kinnunen and Nylander's and Shehata's treatments of slabs without Shear Reinforcement and Andersson's theoretical model for slabs with Shear Reinforcement together with the results of tests found in the literature and those made by Gomes constitute the basis of the proposed model. Two failure criteria are proposed. The first one is for the case of a failure surface reaching to the column, which is assumed to occur when a local mechanism is formed and the Shear stress in this region reaches the sliding resistance. The second failure criterion is for the failure surface occurring outside the Shear Reinforcement region. This is assumed to occur when the maximum principal stress at a section 1.35d (an empirical number) outside the Shear Reinforcement region reaches the splitting strength of the concrete.