Failure Behavior of External Beam-column Joints with Mechanical Anchorage in Subassemblage Frames

Murakami, Masahide; Fuji, Tatsuya; Kubota, Toshiyuki

doi:10.3151/crt1990.9.1_1

Cited by 9 publications

(4 citation statements)

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“…102 to No. 104, M8D16, M4D19, M3D19, and M2D22 tested by Murakami et al 9 ; specimen No. 8 tested by Kiyohara et al 19 ; and specimens M0.7S and M0.7U tested by Chun and Shin.…”

Section: Analysis Of Test Resultsmentioning

confidence: 97%

“…A database of previous tests was assembled from 23 studies that included 84 exterior and seven roof-level interior beam-column joints subjected to reversed cyclic loading by Bashandy, 8 Murakami et al, 9 Wallace et al, 10 Matsushima et al, 11 Nakazawa et al, 12 Tasai et al, 13 Yoshida et al, 14 Takeuchi et al, 15 Ishibashi et al, 16 Ishibashi and Inokuchi, 17 Kiyohara et al, 18,19 Kato, 20 Masuo et al, 21 Adachi and Masuo, 22 Chun et al, 23 Ishida et al, 24 Tazaki et al, 25 Lee and Yu, 26 Kang et al, 27,28 Chun and Shin, 29 and Dhake et al 30 In the exterior joint specimens, the beam reinforcement was anchored in the column using headed bars (Fig. 1(a)), and in the roof-level interior joint specimens, the column reinforcement was anchored in the beam using headed bars (Fig.…”

Section: Headed Bar Database For Members Subjected To Reversed Cyclic...mentioning

confidence: 99%

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Headed Bars in Beam-Column Joints Subjected to Reversed Cyclic Loading

Ghimire,

Darwin,

Lepage

2021

ACI Structural Journal

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Descriptive equations developed for the anchorage strength of headed bars in beam-column joints under monotonic load are evaluated for beam-column joints subjected to reversed cyclic loading. Test results from 23 studies that include 84 exterior and seven roof-level interior beam-column joints are used in the evaluation. Concrete compressive strengths and reinforcement yield strengths ranged from 3480 to 21,500 psi (24 to 148 MPa) and 53,700 to 150,000 psi (370 to 1030 MPa), respectively. Headed bar sizes ranged from slightly smaller than a No. 4 (No. 13) to No. 11 (No. 36) with net-bearing areas ranging from 1.7 to 8.6 times the bar area. The embedment lengths and center-to-center spacing between the headed bars ranged from eight to 18 bar diameters and from two to eight bar diameters, respectively. Analysis of the test data shows that descriptive equations based on headed bars under monotonic loading are also applicable to headed bars in beam-column joints subjected to reversed cyclic loading. These comparisons were used to justify the single approach used within the ACI Building Code for calculating the development length of headed bars.

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“…102 to No. 104, M8D16, M4D19, M3D19, and M2D22 tested by Murakami et al 9 ; specimen No. 8 tested by Kiyohara et al 19 ; and specimens M0.7S and M0.7U tested by Chun and Shin.…”

Section: Analysis Of Test Resultsmentioning

confidence: 97%

Section: Headed Bar Database For Members Subjected To Reversed Cyclic...mentioning

confidence: 99%

Headed Bars in Beam-Column Joints Subjected to Reversed Cyclic Loading

Ghimire,

Darwin,

Lepage

2021

ACI Structural Journal

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“…From the published literature [10,[20][21][22][23][24][25][26], a total of 30 experimental RC beam-column connections with headed bars was collected. All of the specimens were subjected to quasi-static cyclic lateral loading and were at least one-third scale.…”

Section: Database Collectedmentioning

confidence: 99%

Sustainable RC Beam-Column Connections with Headed Bars: A Formula for Shear Strength Evaluation

et al. 2018

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Beam-column joints are critical regions for reinforced concrete (RC) frames subjected to earthquakes. The steel reinforcement is, in general, highly concentrated in these zones. This is why in many cases, headed bars are used. A headed bar is a longitudinal steel reinforcement whose end has a special button added to reduce the bonding length of the steel rebar. This paper establishes a formula predicting the shear strength of exterior RC beam-column connections where the beam longitudinal reinforcements use headed bars. A database was collected, which contained 30 experimental data about the exterior beam-column joints using headed bars and subjected to quasi-static cyclic loading. First, from the collected database, a statistical study was carried out to identify the most influencing parameters on the shear strength of the beam-column joints tested. The three most important parameters were identified and an empirical modified formula was developed based on the formula existing in the standards. The study showed that the results obtained from the modified formula proposed in the present study were closer to the experimental results than that obtained from the formula existing in the standards. Finally, a numerical study was performed on two T-form RC structures and the numerical results were compared with the prediction calculated from the modified formula proposed. For two investigated cases, the proposed formula provided the results in the safety side and the differences with the numerical results were less than 20%. Thus, the proposed formula can be used for a rapid assessment of the shear strength of RC joints using headed bars.

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“…2 Test setup of headed bars in exterior beam -column joint specimen (Bashandy, 1996) 접합부 모의실험이다. Marques and Jirsa(1975) (Bashandy 1996;Wallace et al 1998), 한국 (Chun et al 2007;Kang et al 2008), 일본 (Murakami et al 1998;Matsushima et al 2000;Yoshida et al 2000;Tasai et al 2000;Takeuchi et al 2001;Kiyohara et al 2005;Kato 2005;Ishida et al 2007;Adachi and Masuo 2007)…”

Section: Variedmentioning

confidence: 99%

A Reevaluation of Anchorage Strength of Headed Bars in Exterior Beam-Column Joints

Sim¹,

Chun²

2018

JKCI

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Failure modes of exterior beam-column joints, where headed bars as beam longitudinal bars are terminated, are classified into concrete breakout, pullout, side-face blowout, and joint shear failures. The design equation for the development length of headed bars of KCI (2012) is derived from lap splice tests and does not consider the characteristics of applied members and failure modes. For safe and economical design, the anchorage of headed bars should be designed considering each failure mode. This study reevaluates the anchorage strengths of headed bars in exterior beam-column joints of previous studies using the current design code and previous models. Pullout failure does not occur due to the existence of the head in headed bars and concrete breakout failure can be prevented by adjusting the effective depth of beam and anchorage length. For the side-face blowout failure, the current design code significantly underestimates the anchorage strength of headed bars and Chun et al. (2017)'s model including the effects of side cover and transverse reinforcement can properly evaluate the anchorage strengths of headed bars. For the joint shear failure, the design provisions of KCI (2012) on transverse reinforcement and joint shear strength can be applied. For the specimens satisfying the requirements for the transverse reinforcement, beam flexural failures with ductile behavior were observed or joint shear failures occurred with a shear strength ratio (V j /V n) of 1.0 or higher. Consequently, exterior beam-column joints where headed bars were anchored as beam longitudinal bars can be safely and economically designed if side-face blowout and joint shear failures are prevented.

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Failure Behavior of External Beam-column Joints with Mechanical Anchorage in Subassemblage Frames

Cited by 9 publications

References 0 publications

Headed Bars in Beam-Column Joints Subjected to Reversed Cyclic Loading

Headed Bars in Beam-Column Joints Subjected to Reversed Cyclic Loading

Sustainable RC Beam-Column Connections with Headed Bars: A Formula for Shear Strength Evaluation

A Reevaluation of Anchorage Strength of Headed Bars in Exterior Beam-Column Joints

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