3D RC beam–column joints retrofitted by joint enlargement using steel angles and post-tensioned bolts

Maddah, Armin; Golafshar, Ali; Saghafi, Mohammad Hossein

doi:10.1016/j.engstruct.2020.110975

Cited by 21 publications

(6 citation statements)

References 48 publications

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“…On the other hand, the strengthened frame accomplished a much better performance than the control frame in terms of lateral load capacity and failure mechanism. The presence of large hysteresis loops without a pinching effect confirms the ductile behavior of the strengthened frame [12,55]. The peak load in the strengthened frame reached 39.51 kN, corresponding to a drift ratio of 3.5%.…”

Section: Force Displacement Hysteretic Responsesupporting

confidence: 60%

“…Several conventional schemes were employed to rehabilitate beam-column connections, including RC jacketing [5], shotcrete jacketing [6], stiffened steel plates [7], steel cages [8][9][10], steel angles connected by bars [11,12], steel diagonal bolts [13], epoxy injection [14], and use of the ultra-high-performance concrete (UHPC) [15]. The implemented strengthening techniques proved effective in improving the seismic characteristics of BCJ.…”

Section: Introductionmentioning

confidence: 99%

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An Improved Anchorage System for L-Shaped FRP Composites to Enhance the Seismic Response of Beam-Column Joints in a Low-Strength Substandard Reinforced Concrete (RC) Frame

Adil,

Rahman,

Ali

et al. 2024

Buildings

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Reinforced concrete buildings are prone to collapse during seismic events due to the brittle shear failure of non-seismic beam-column joints (BCJ). In this study, two one-third scale reinforced concrete (RC) frames incorporating various non-seismic details were tested under lateral cyclic loading. One of the RC frames was used as control, while the other was strengthened using externally bonded carbon-fiber-reinforced polymer (CFRP) sheets in a L-Shaped configuration with particular attention to anchorage to evade debonding. For the strengthening process, L-shaped CFRP sheets were bonded to the inner face of columns, extended on beams both above and below the joint up to a hinge length. To avert debonding, the L-shaped CFRP sheets were fully wrapped with CFRP sheets around the column, both near the joint and at the end of the sheet. The sheets were also wrapped around the beam, through two slots in the slab that were adjacent to the beam-column interface and at the far end of the sheet. Test results confirmed that the installation of CFRP sheets in an L-shaped configuration altered the brittle-shear failure mechanism of the beam-column joints to a ductile failure by repositioning the hinges away from the columns. Additionally, the proposed anchorage method successfully eradicated the debonding and peel-off of the CFRP sheets. Moreover, strengthening with the CFRP sheets in the L-shaped configuration enhanced the strength and ductility of the RC frame by 45% and 43%, respectively. According to the findings of this study, the application of L-shaped CFRP sheets proved effective in strengthening RC frame structures.

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Section: Force Displacement Hysteretic Responsesupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

An Improved Anchorage System for L-Shaped FRP Composites to Enhance the Seismic Response of Beam-Column Joints in a Low-Strength Substandard Reinforced Concrete (RC) Frame

Adil,

Rahman,

Ali

et al. 2024

Buildings

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“…OpenSees can model various types of elements as well as their connections built with different types of uniaxial materials and sections under a wide range of loading patterns and linear and nonlinear analyses. Furthermore, OpenSees has advanced capabilities for analysing the nonlinear response of systems through different types of solution algorithms and methods [ 37 ]. The definition of the modelling including geometry, materials, sections, etc.…”

Section: Numerical Modellingmentioning

confidence: 99%

Enhancement of the Fragility Capacity of RC Frames Using FRPs with Different Configurations at Joints

Jafari

Mahini

2023

Polymers

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This paper reports the results of an investigation into the effectiveness of different lengths of Fiber-Reinforced Polymer (FRP) sheets in retrofitting the joints of Reinforced Concrete (RC) frames to improve the fragility function of ordinary RC frames. Several 8-storey RC buildings were investigated through FE modelling. The accuracy of the FE models was verified using peer research results. Fragility curves of FRP-retrofitting joints of two referenced RC frames were carried out by OpenSees, through Incremental Dynamic Analysis (IDA) analysis under 22 far-field earthquake records from 0.1 g to 4.0 g (with 0.1 g interments), based on FEMA P-695. Two types of retrofitting methods, web and flange bonding, were modeled and studied. The results showed that the fragility capacity of the retrofitted RC frames was significantly improved. Moreover, frames with longer sheets of FRP showed increased performance. In the complete state, the range of probability of exceedance grew from 2–2.5 g to 3–3.5 g (nearly 1 g), whereas, in the minor state, this growth was nearly 0.05 g. However, the fragility function of the flange-bonding was enhanced at a higher rate compared with that of the web-bonding RC frames. Carbon Fiber-Reinforced Polymer (CFRP) and Glass Fiber-Reinforced Polymer (GFRP) materials improved the probability of exceedance of the complete state from 3 g to 4.5 g and 4.8 g in flange bonding frames. This enhancement for both types of frames was more significant when joints were retrofitted with 400 and 500 mm compared with 600, 700, and 800 mm. The midpoint of the PGA at the complete damage state in the web-bonding frame increased from 1.076 g to 1.664 g and in the flange-bonding frame retrofitted with GFRP and CFRP raised from 1.551 g to 2.769 and 3.076, respectively. The collapse margin ratio (CMR) indicates an acceptable improvement in the retrofitted frames. Overall, the rate of enhancement in fragility function from the original frame to the frame with 500 mm FRP was significant; however, the slope of this rate declined for longer FRP sheets. The fragility performance improvement resulted in controlling plastic hinging by FRPs.

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“…Despite that the plastic hinge relocation has been widely studied for both new constructed BCJs [15][16][17][18][19][20] and retrofitted BCJs [21][22][23][24][25][26][27], there are limited studies focusing on the effect of relocating distance of plastic hinges on the performance of BCJs. Park and Milburn [15] used additional straight bars with 90° hooks to relocate beam plastic hinges for both exterior and interior BCJs.…”

Section: Introductionmentioning

confidence: 99%

Relocating plastic hinges in reinforced concrete beam-column joints by mechanically anchored diagonal bars

Shen

Chen

et al. 2022

Engineering Structures

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3D RC beam–column joints retrofitted by joint enlargement using steel angles and post-tensioned bolts

Cited by 21 publications

References 48 publications

An Improved Anchorage System for L-Shaped FRP Composites to Enhance the Seismic Response of Beam-Column Joints in a Low-Strength Substandard Reinforced Concrete (RC) Frame

An Improved Anchorage System for L-Shaped FRP Composites to Enhance the Seismic Response of Beam-Column Joints in a Low-Strength Substandard Reinforced Concrete (RC) Frame

Enhancement of the Fragility Capacity of RC Frames Using FRPs with Different Configurations at Joints

Relocating plastic hinges in reinforced concrete beam-column joints by mechanically anchored diagonal bars

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