Shear strength of RC deep beams with web openings based on two‐parameter kinematic theory

The behaviour of reinforced concrete deep beams is complex due to small shear span-to-depth ratios, which deviates its behaviour from the classical Bernoullis beam behaviour. Such behaviour is predominant in cases where members are supported over small spans carrying heavy concentrated or distributed loads. Such is the case in the structural members like pile cap, transfer girder, panel beam, strap beam in foundation, walls of rectangular water tank, shear wall etc. This paper reports on the influence of Poly propylene fibers combined with and without steel fibers on the stiffness, spall resistance and shear strength of RC deep beams. A total of 21 beams were tested to failure under two-point loading, which were compared with the ACI code provisions. The shear span-to-depth ratios adopted were 0.7 to 0.9 incorporating three steel fiber volume fractions of 0%, 1%, 1.25% along with two different fibers of Steel and Poly propylene with volume fractions of (1.0 + 0.0) %, and (1.0 + 1.0) %. The beams with shear span-to-depth ratios 0.7, 0.8 and 0.9 showed an increase of 21.9%, 23.43% and 23.9% in the ultimate load carrying capacity with combined steel and poly propylene fibers as replacement of web reinforcement with reference to that of the beam without web reinforcement. With the above combinations, the shear strength and stiffness of the beams have been found to be improved. When the horizontal shear reinforcement was increased, the shear strength was found to increase.

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Empirical modelling of shear strength of RC deep beams by genetic programming

Computers & Structures ◽

10.1016/s0045-7949(02)00437-6 ◽

2003 ◽

Vol 81 (5) ◽

pp. 331-338 ◽

Cited By ~ 66

Author(s):

A.F. Ashour ◽

L.F. Alvarez ◽

V.V. Toropov

Keyword(s):

Shear Strength ◽

Genetic Programming ◽

Deep Beams ◽

Empirical Modelling ◽

Rc Deep Beams

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Shear Response of Recycled Aggregates Concrete Deep Beams Containing Steel Fibers and Web Openings

Sustainability ◽

10.3390/su14020945 ◽

2022 ◽

Vol 14 (2) ◽

pp. 945

Author(s):

Nancy Kachouh ◽

Tamer El-Maaddawy ◽

Hilal El-Hassan ◽

Bilal El-Ariss

Keyword(s):

Fiber Volume Fraction ◽

Volume Fraction ◽

Shear Capacity ◽

Steel Fibers ◽

Deep Beams ◽

Fiber Volume ◽

Web Openings ◽

Shear Response ◽

Conventional Steel ◽

Rc Deep Beams

Replacement of natural aggregates (NAs) with recycled concrete aggregates (RCAs) in complex reinforced concrete (RC) structural elements, such as deep beams with openings, supports environmental sustainability in the construction industry. This research investigates the shear response of RC deep beams with openings made with 100% RCAs. It also examines the effectiveness of using steel fibers as a replacement to the minimum conventional steel stirrups in RCA-based deep beams with web openings. A total of seven RC deep beams with a shear span-to-depth ratio (a/h) of 0.8 were constructed and tested. A circular opening with an opening height-to-depth ratio (h0/h) of 0.3 was placed in the middle of each shear span. Test parameters included the type of the coarse aggregate (NAs and RCAs), steel fiber volume fraction (vf = 1, 2, and 3%), and presence of the minimum conventional steel stirrups. The deep beam specimens with web openings made with 100% RCAs exhibited 13 to 18% reductions in the shear capacity relative to those of their counterparts made with NAs. The inclusion of conventional steel stirrups in RC deep beams with openings was less effective in improving the shear response when 100% RCAs was used. The addition of steel fibers remarkably improved the shear response of the tested RCA-based beams. The gain in the shear capacity of the RCA-based beams caused by the inclusion of steel fibers was in the range of 39 to 84%, whereas the use of conventional steel stirrups resulted in 18% strength gain. The use of 1% steel fiber volume fraction in the RCA-based beam with openings without steel stirrups was sufficient to restore 96% of the original shear capacity of the NA-based beam with conventional steel stirrups. The shear capacities obtained from the tests were compared with predictions of published analytical models. The predicted-to-measured shear capacity was in the range of 0.71 to 1.49.

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