Behavior of Pocket-Type High-Strength RC Beams without or with Dapped Ends

Shakir, Qasim M.; Hamad, Sarah A.

doi:10.1061/(asce)sc.1943-5576.0000624

Cited by 11 publications

(5 citation statements)

References 21 publications

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“…The recorded enhancement in capacity ranged in 8-21%. Shakir and Hamad 2021 [37] investigated experimentally the behaviour of RC pocket beams with without or with dapped ends. It was reported that inclusion of the dapped ends within the pocket beams reduced the capacity in range of 9%-12%, and that the composite section proposal yielded the highest enhancements of 21% and 23% for the pocket beams without and with dapped ends respectively.…”

Section: Figure 1 Some Joints Configurations In Two Crossed Precast B...mentioning

confidence: 99%

Enhancement of the behaviour of reinforced concrete dapped end beams including single-pocket loaded by a vertical concentrated force

Shakir

Hamad

2023

Eng. rev. (Online)

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In precast building construction, some beams are designed to support one or several concentrated loads resulting from the reactions of the attached cross beams. Consequently, the pocket beams without or with dapped ends may represent one of the innovative solutions to constitute the joints between the two attached members. In the present research work, the behaviour of dapped end beams that included rectangular opening loaded with in-plane force, have been investigated. Several detailing have been proposed, in addition the vertical stirrups, to improve the strength of the opening region including the use of steel fibre concrete (SFC),Configuration of the inclined crossed bars, jacketing with steel plates and the composite section technique with two arrangements of the reinforcement of the dapped end . Ten specimens have been tested under gradually increased vertical static loading. The tested specimens are categorized into two sets based on the configuration of dapped end reinforcement. Two variable have been considered which are the strengthening configuration of the opening region and the configuration of the dapped end reinforcement. The response has been discussed in terms several indicators including, the cracking and failure loads, maximum deflection, mode of failure, load-deflection curves, crack patterns, crack width, to recognize the optimum strengthening proposal of the opening. Results revealed that using the inclined steel bars (modified arrangement) yield better response than the conventional (standard) reinforcement (vertical stirrups) within the dapped end. For beams with pockets strengthened with crossed inclined bars, failure load enhanced in range of (8.5-11%) whereas the enhancement was in ranged in (8-10%) for the steel SFC method. Moreover, an improvement by about (11-13%) in load capacity increased when the jacketing with steel plates was applied. The maximum improvement was obtained when using the embedded rolled section within the opening with values of (21-23%).

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Section: Figure 1 Some Joints Configurations In Two Crossed Precast B...mentioning

confidence: 99%

Enhancement of the behaviour of reinforced concrete dapped end beams including single-pocket loaded by a vertical concentrated force

Shakir

Hamad

2023

Eng. rev. (Online)

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“…Haber et al [8,9] studied the uniaxial tensile behavior of two kinds of commercial mechanical joints under different loading conditions, which further confirmed the reliability of the grouting sleeve. Grouting sleeve test pieces have also been employed in research on prefabricated deep beams, joint ends, corbels, and other related areas [10,11]. In 2013, Zheng et al [12,13] invented a new type of deformed seamless steel pipe grouting sleeve (GDPS sleeve) and carried out a series of uniaxial tensile and cyclic load tests.…”

Section: Introductionmentioning

confidence: 99%

Bond Performance of Seamless Steel Pipe Grouting Sleeves under Large-Deformation Repeated Tension and Compression after High Temperature

Zhao,

Wei,

Chen

et al. 2024

Buildings

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Grouting sleeves are widely used in the field of assembled construction. The present study aims to investigate the reliability of grouting sleeves under large-deformation repeated tension and compression after high temperature, considering the influences of steel bar diameter, the cooling method, and the protective layer. Through experimentation on 28 test pieces, we analyzed the bonding performance of the test pieces at different high temperatures. The results indicate that within the temperature range of 20–800 °C, the bond performance of the test pieces declines by no more than 9.8%. However, upon reaching a temperature of 1000 °C, the bond performance of the test pieces decreases by over 33.7%, with the compressive strength of the grout material reduced to only 27.50% of that kept at 20 °C. Employing larger-diameter steel bars is advantageous for maintaining the bond performance of the test pieces. Natural cooling shows relatively good bond performance, although its influence is not significant. Furthermore, the protective layer effectively attenuates the heating rate of the test pieces, thus safeguarding their bond performance. Scanning electron microscopy (SEM) analysis reveals that the decomposition of C-H and C-S-H phases is the primary cause of high-temperature degradation of the grouting material. Finally, a recommendation for the correlation coefficient (k) between the average bond strength and the compressive strength of the grout material is proposed, with a suggested value of k ≤ 2.58.

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“…More experimental and theoretical studies that mostly adopted STMs were published considering various variables including the concrete strength (Lu et al, 2012;Mohamed et al, 2019), using steel fibre in concrete (Mohammed and Elliot, 2008), shear span/depth ratio (Wang, 2005, Lu, 2015, detailing of dapped ends (Peng, 2009;Mata-Falcon et al, 2019;Shakir and Elliwi, 2020;Shakir and Hamad, 2021), corrosion effect using internal pre-stressing through dapped ends (Mattock and Theryo, 1986;Botros et al, 2017). Moreover, several proposals have been suggested to improve the performance of deficiently reinforced dapped ends.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Finite Element Analysis of High-strength Reinforced Concrete Beams with Severely Disturbed Regions

Shakir¹,

Al-Sahlawi²,

Abd³

et al. 2023

JJCE

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The inclusion of D-regions within a reinforced-concrete member may affect largely the general behavior of the structure. Different techniques and approaches were proposed to control the behaviour of D-regions, such as the shear-friction approach and the STM model. Such proposals may not be applicable for all types of Dregions. The current work presents a nonlinear finite element model using the ANSYS software, that is adopted to study three types of D-regions, which are dapped ends, deep beams with openings and beams with loaded openings. The results revealed that the proposed FE model predicted adequately the effects of the inclusion of D-regions in RC beams. It is found that reducing the hanger or the nib reinforcement of a dapped end by 25% resulted in reducing capacity by 15% and 32%, respectively. Also, the results showed that for these deficiently reinforced dapped ends, reducing a/d ratio from 1.5 to 0.75 improved capacity by 23% and 36%. For the deficiently shearreinforced flanged deep beams, it was found that the inclusion of large openings within the shear span resulted in a capacity drop by (41-49) %. An enhancement of 23% was obtained when using stirrups of 12mm on both sides of the openings. Moreover, it is confirmed that the optimum location of the openings is under the diagonal path. Furthermore, it has been concluded that for loaded openings, the use of T-rolled sections within the bottom chord of the opening yielded an enhancement of 23% relative to the rhombus-shaped configuration. KEYWORDS: Dapped ends, T-deep beams with openings, Loaded openings, Hanger reinforcement.

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Behavior of Pocket-Type High-Strength RC Beams without or with Dapped Ends

Cited by 11 publications

References 21 publications

Enhancement of the behaviour of reinforced concrete dapped end beams including single-pocket loaded by a vertical concentrated force

Enhancement of the behaviour of reinforced concrete dapped end beams including single-pocket loaded by a vertical concentrated force

Bond Performance of Seamless Steel Pipe Grouting Sleeves under Large-Deformation Repeated Tension and Compression after High Temperature

Nonlinear Finite Element Analysis of High-strength Reinforced Concrete Beams with Severely Disturbed Regions

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