Punching shear behavior of reinforced concrete footings with a varying amount of shear reinforcement

2018 ◽  
Vol 20 (2) ◽  
pp. 552-563 ◽  
Author(s):  
Dominik Kueres ◽  
Philipp Schmidt ◽  
Josef Hegger
Keyword(s):  
Reinforced Concrete ◽  
Shear Behavior ◽  
Punching Shear ◽  
Shear Reinforcement

scholarly journals Punching Shear Strength of Reinforced Concrete Flat Plates with GFRP Vertical Grids

2021 ◽  
Vol 11 (6) ◽  
pp. 2736
Author(s):  
Min Sook Kim ◽  
Young Hak Lee
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Fiber Reinforced Polymer ◽  
Punching Shear ◽  
Test Results ◽  
Shear Reinforcement ◽  
Flat Plates ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Vertical Grids

In this study, the structural behavior of reinforced concrete flat plates shear reinforced with vertical grids made of a glass fiber reinforced polymer (GFRP) was experimentally evaluated. To examine the shear strength, experiments were performed on nine concrete slabs with different amounts and spacings of shear reinforcement. The test results indicated that the shear strength increased as the amount of shear reinforcement increased and as the spacing of the shear reinforcement decreased. The GFRP shear reinforcement changed the cracks and failure mode of the specimens from a brittle punching to flexure one. In addition, the experimental results are compared with a shear strength equation provided by different concrete design codes. This comparison demonstrates that all of the equations underestimate the shear strength of reinforced concrete flat plates shear reinforced with GFRP vertical grids. The shear strength of the equation by BS 8110 is able to calculate the punching shear strength reasonably for a concrete flat plate shear reinforced with GFRP vertical grids.

Analysis on Punching Shear Behavior of the Raft Slab Reinforced with Steel Fibers

2008 ◽  
Vol 400-402 ◽  
pp. 335-340
Author(s):  
Xiao Wei Wang ◽  
Wen Ling Tian ◽  
Zhi Yuan Huang ◽  
Ming Jie Zhou ◽  
Xiao Yan Zhao
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Steel Fibers ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Mass Concrete ◽  
Reinforced Concrete Slab ◽  
The Common

The thickness of the raft slab is determined by punching shear. The raft slab is commonly thick, which causes concrete volume is large. Mass concrete can bring disadvantage to the foundation. In order to increase the bearing capacity and reduce the thickness, it is suggested that the raft slab to be reinforced by steel fibers. There are five groups of specimens in this paper. S1 is the common reinforced concrete slab. S2 and S3 are concrete slabs reinforced by steel fibers broadcasted layer by layer when casting specimen. S4 and S5 are concrete slabs reinforced by steel fibers mixed homogeneously when making concrete. The punching shear tests of these slabs were done. The test results indicate that the punching shear capacity of the slab reinforced with steel fibers is higher than that of concrete slab, the stiffness and crack resistance of the steel fibers reinforced concrete slab are better than those of the common concrete slab and the punching shear of the slabs with different construction methods of steel fibers is similar. It analyses the punching shear behavior of the slab reinforced with steel fibers and suggests the ultimate bearing formula. The calculative values are coincided with the measured values well.

Punching Shear Capacity of Steel Fiber Reinforced Concrete Slab- Column Connections

2019 ◽  
Author(s):  
Josef Landler ◽  
Oliver Fischer
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Fiber Type ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Punching Shear ◽  
Slab Thickness ◽  
Shear Reinforcement ◽  
Fiber Reinforced

<p>To design flat slabs directly supported on columns, the punching shear resistance of the slab is a main factor. It can be increased in the vicinity of the slab-column connection with punching shear reinforcement, like bent up bars or shear studs, to bear the high reaction forces. However, the usage of punching shear reinforcement requires the knowledge of special design rules and often leads to problems and deficiencies in construction.</p><p>Fiber reinforced concrete seems to be a promising alternative to conventional punching shear reinforcement. To investigate the load bearing behavior of the slab-column connection using fiber reinforced concrete, a total of eight punching shear tests were performed. The specimens were realized with a typical top and bottom flexural reinforcement, but without punching shear reinforcement. Varied parameters were the slab thickness with 250 mm and 300 mm and the fiber content V<sub>f</sub> with 0.5 Vol.-% and 1.0 Vol.-%. To investigate the influence of modern fiber types, normal- and high-strength steel fibers with normal- and double-hooked-ends were used.</p><p>In all eight experimental tests, the intended punching shear failure was achieved. The capable load using fiber reinforced concrete increased by 20 % to 50 % compared to the reference tests without steel fibers, depending on the fiber type and the fiber content V<sub>f</sub>. Additionally, this load increase was accompanied by a significant improvement in ductility. The post-cracking behavior was noticeably influenced by the used steel fiber type. An influence of the slab thickness or steel fiber type on the shear strength contributed by the fiber reinforced concrete could not be determined.</p>

Punching Shear Strengthening at the New Station Square in Berne, Switzerland

2010 ◽  
pp. 35-56
Author(s):  
Dominic Joray ◽  
Martin Diggelmann
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Shear Strengthening ◽  
Reinforced Concrete Slab

<p>The reinforced concrete slab of the reconstructed Station Square in Berne needed to be strengthened against punching shear. The case study led to the application of a newly developed post-installed punching shear reinforcement with inclined bonded bars.</p>

Shear behavior of reinforced concrete beams strengthened in flexure with bonded carbon fibre reinforced polymers laminates

2005 ◽  
Vol 32 (5) ◽  
pp. 812-824 ◽  
Author(s):  
Francesco Bencardino ◽  
Vincenzo Colotti ◽  
Giuseppe Spadea ◽  
Ramnath Narayan Swamy
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Shear Behavior ◽  
Structural Performance ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Brittle Behavior ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

The aim of this paper is to clarify the structural performance of reinforced concrete (RC) beams with weak or without any internal shear reinforcement and externally strengthened in flexure with carbon fibre reinforced polymer (CFRP) laminates, when subjected to a shear-dominant-loading regime. Seven RC beams were specifically designed, without and with an external anchorage system, which was carefully detailed to enhance the benefits of the strengthening laminate and counteract the destructive effects of shear forces. All the beams were identical in terms of their geometry, longitudinal internal reinforcement, and concrete strength but varied, to highlight the role of shear behavior, in terms of their internal and external shear reinforcement as well as in their loading test regime. The beams were tested under four-point bending and extensively instrumented to monitor strains, deflection, cracking, load carrying capacity, and failure modes. The structural response of the tested beams has, then, been critically analyzed in terms of deformability, strength, and failure processes that occur under a shear-dominant loading regime. It is shown that with a carefully designed anchorage system, a brittle behavior without yielding of tension steel reinforcement of a flexural strengthened beam can be transformed to a less brittle behavior with yielding of tension steel reinforcement and a well-defined enhancement of structural performance in terms of both deformation and strength. The results presented in this paper should enable engineers to counteract shear failure of externally strengthened beams with little or even no internal shear reinforcement.Key words: carbon fibre reinforced polymer, shear behavior, external flexural strengthening, structural performance.

scholarly journals Punching shear behavior of thick reinforced concrete slabs according to Strut-and-Tie model

2014 ◽  
Vol 13 (3) ◽  
pp. 183-192
Author(s):  
Tadeusz Urban ◽  
Jakub Krakowski
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Shear Behavior ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Test Results ◽  
Strut And Tie ◽  
Reinforced Concrete Slabs ◽  
Symmetric Loading ◽  
Strut And Tie Model

The punching shear behavior of thick reinforced concrete slabs was analyzed in this paper by using strut-and-tie model (S-T). Calculating procedures were compared to our own experimental test results. The analyzed elements were subjected to symmetric loading and without shear reinforcement.

scholarly journals Shear behavior of reinforced concrete wide beams strengthened with CFRP sheet without stirrups

2019 ◽  
Vol 12 (1) ◽  
pp. 80-98
Author(s):  
Ali Laftah Abass
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Strength ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Control Beam ◽  
Cfrp Sheet ◽  
Wide Beams

Reinforced concrete wide beams (WBS) have been used in construction buildings because its provide many advantages; reducing the reinforcement congestion, reducing the quantity of the required formwork, providing simplicity for replication, and decreasing the storey height. The current study presents the results of four full-scale wide RC beams in order to study their shear behavior and investigate the effectiveness of carbon fiber reinforced polymer (CFRP) when using as shear reinforcement to improve the shear capacity of wide RC beams, one these beams was fabricated by (ANSYS) program this beam was unstrengthened with CFRP and without stirrups (control beam), the other two beams was strengthened with vertical and inclined CFRP sheet without stirrups and the last beam reinforced with shear stirrups (WBS). All beams casted with normal concrete strength (30 MPa), simply supported and under two point loads. The performances of these beams were measured in terms of; ultimate load, crack patterns, concrete and steel strains, deflection, and mode of failure. The results showed an increasing in ultimate load of strengthened beams with inclined, vertical CFRP and beam with shear reinforcement by (19.9%), (7.14%) and (39.8%) respectively as compared with the control beam, and this results means possibility of replacing the internal shear reinforcement with externally bonded CFRP.

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