Numerical simulation of the influence of bond strength degradation on the behavior of reinforced concrete beam-column joints externally strengthened with FRP sheets

Al-Rousan, Rajai Z.; Alkhawaldeh, Ayah A.

doi:10.1016/j.cscm.2021.e00567

Cited by 9 publications

(9 citation statements)

References 26 publications

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“…It is worth mentioning that the SOLID65 element is distinguished for having the capabilities of cracking, crushing, and plastic deformation in three perpendicu-lar directions. However, in this experimental work, the SOLID65 element's capability of crushing failure has been overlooked because this type of failure was not noticed when the load was applied [23][24][25][26][27][28][29][30]. Hence, the simulated models' tensile strains depended only on ultimate failure and emerging of cracking [23][24][25][26][27][28][29][30].…”

Section: Modeling Methodologymentioning

confidence: 99%

“…However, in this experimental work, the SOLID65 element's capability of crushing failure has been overlooked because this type of failure was not noticed when the load was applied [23][24][25][26][27][28][29][30]. Hence, the simulated models' tensile strains depended only on ultimate failure and emerging of cracking [23][24][25][26][27][28][29][30]. The used Poisson's ratio for concrete ranges from 0.15 to 0.22 thus a representative value of 0.2 was selected [34].…”

Section: Modeling Methodologymentioning

confidence: 99%

“…Few in-depth studies have adopted the NLFEA method to numerically model structural elements that are exposed to seismic loadings [23][24][25][26][27][28][29][30] and to simulate the behavior of the structural elements that are reinforced/rehabilitated with FRP. The reason behind this limitation of such studies is that modeling concrete's shear cracking is rather difficult, especially in the region of confinement and bonding.…”

Section: Introductionmentioning

confidence: 99%

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NLFEA of Sulfate-Damaged Circular CFT Steel Columns Confined with CFRP Composites and Subjected to Axial and Cyclic Lateral Loads

et al. 2022

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It is rather costly and difficult to experimentally evaluate the performance of concrete-filled tubular (CFT) circular steel columns exposed to combined axial and cyclic lateral loads. This research paper uses the nonlinear finite element (NLFEA) technique to assess the influence of using carbon-fiber-reinforced polymer (CFRP) laminates on the structural response and failure mode of damaged-by-sulfate CFT circular steel columns. At the beginning, twenty-one CFT circular steel column models were devised and checked for soundness using the findings of previously conducted research. Next, the models were broadened to investigate how the models’ behavior was influenced by the CFRP number of layers and the level of sulfate damage. For experimental purposes, the numbers of CFRP layers were set to be zero, five, six, seven, eight, nine, and ten, while there were three levels of sulfate damage, namely: level 0 (undamaged), level 1 (73 days), and level 2 (123 days). Some of the models were left unconfined with CFRP wraps for comparison. The CFRP confinement was at the end of the models due to its importance regarding the models’ capacity of lateral load. The columns’ ends were confined to prevent the models from outward local buckling, which led to higher strength, bigger net drift, and enhanced energy dissipation. The NLFEA models were then appropriately modified and adjusted in accordance with credible previously conducted experimental research; after which, a parametric study was performed to investigate how the models’ behavior was affected by the number of CFRP layers and the level of axial load. The study found that the CFT circular steel column models’ performance significantly enhanced when the models were wrapped with five to ten CFRP layers. It must be mentioned, though, that using eight, nine, and ten CFRP layers gave almost similar results. In addition, the NLFEA results revealed that when the damaged-by-sulfate models were repaired externally with CFRP wraps, there was an improvement in the models’ cyclic behavior, as they showed a raise in the load capacity, an enhancement in the horizontal displacement, a greater displacement ductility, better energy dissipation, and little deterioration in secant stiffness. The study found that using wraps of CFRP proved a great efficiency with the change in the sulfate damage level.

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Section: Modeling Methodologymentioning

confidence: 99%

Section: Modeling Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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NLFEA of Sulfate-Damaged Circular CFT Steel Columns Confined with CFRP Composites and Subjected to Axial and Cyclic Lateral Loads

et al. 2022

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“…Externally-bonded composite materials have been extensively used in different configurations in strengthening of RC columns and beams as well as in joints [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. FRPs, or even SRPs [ 17 ], have been used as a lightweight, flexible and corrosion-resistant local retrofitting alternative to traditional RC or steel jacketing, especially in T-shaped RC joints [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ], as well as in beams and columns [ 25 , 26 , 27 , 28 , 29 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

Seismic Tests of Full Scale Reinforced Concrete T Joints with Light External Continuous Composite Rope Strengthening—Joint Deterioration and Failure Assessment

et al. 2023

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Beam–column connections (joints) are one of the most critical elements which govern the overall seismic behavior of reinforced concrete (RC) structures. Especially in buildings designed according to previous generation codes, joints are often encountered with insufficient transverse reinforcement detailing, or even with no stirrups, leading to brittle failure. Therefore, externally bonded composite materials may be applied, due to the ease of application, low specific weight and corrosion-free properties. The present work assesses the seismic performance of insufficiently reinforced large-scale T beam–column connections with large and heavily reinforced beams. The joints receive externally bonded NSM X-shaped composite ropes with improved versatile continuous detailing. The columns are subjected to low normalized axial load, while the free end of the beam is subjected to transverse displacement reversals. Different failure criteria are investigated, based on the beam free-end transverse load, as well as on the joint region shear deformations, to critically assess the structural performance of the subsystem. The experimental investigation concludes that cyclic loading has a detrimental effect on the performance of the joint. Absence of an internal steel stirrup leads to earlier deterioration of the joint. The unstrengthened specimens disintegrate at 2% drift, which corresponds to 34 mm beam-end displacement, and shear deformation of the joint equal to 30 × 10−4 rad. The composite strengthening, increases the structural performance of the joint up to 4% drift which corresponds to 68 mm of beam-end displacement and shear deformation of the joint equal to 10 × 10−4 rad. The investigated cases of inadequate existing transverse reinforcement in the joint and light external FRP strengthening provide a unique insight into the required retrofits to achieve different levels of post-yielding displacement ductility under seismic loading at 2%, 3% and 4% drift. It allows for future analytical refinements toward reliable redesign analytical models.

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“…Other forms of materials and techniques, like fully-fastened-haunches [ 16 ], steel meshes [ 17 ], external bars [ 18 ], and steel plates with shear connectors [ 19 ], have also been experimentally investigated for the upgrading of RC elements and BCJs. Analytical efforts have also been reported, as well [ 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Efficacy and Damage Diagnosis of Reinforced Concrete Columns and Joints Strengthened with FRP Ropes Using Piezoelectric Transducers

Karayannis

Golias

Naoum

et al. 2022

Sensors

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Recent research has indicated that the implantation of a network of piezoelectric transducer patches in element regions of potential damage development, such as the beam–column joint (BCJ) area, substantially increases the efficacy and accuracy of the structural health monitoring (SHM) methods to identify damage level, providing a reliable diagnosis. The use of piezoelectric lead zirconate titanate (PZT) transducers for the examination of the efficiency of an innovative strengthening technique of reinforced concrete (RC) columns and BCJs is presented and commented on. Two real-scale RC BCJ subassemblages were constructed for this investigation. The columns and the joint panel of the second subassemblage were externally strengthened with carbon fiber-reinforced polymer (C-FRP) ropes. To examine the efficiency of this strengthening technique we used the following transducers: (a) PZT sensors on the ropes and the concrete; (b) tSring linear variable displacement transducers (SLVDTs), diagonally installed on the BCJ, to measure the shear deformations of the BCJ panel; (c) Strain gauges on the internal steel bars. From the experimental results, it became apparent that the PZT transducers successfully diagnosed the loading step at which the primary damage occurred in the first BCJ subassemblage and the damage state of the strengthened BCJ during the loading procedure. Further, data acquired from the diagonal SLVDTs and the strain gauges provided insight into the damage state of the two tested specimens at each step of the loading procedure and confirmed the diagnosis provided by the PZT transducers. Furthermore, data acquired by the PZT transducers, SLVDTs and strain gauges proved the effectiveness of the applied strengthening technique with C-FRP ropes externally mounted on the column and the conjunction area of the examined BCJ subassemblages.

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Numerical simulation of the influence of bond strength degradation on the behavior of reinforced concrete beam-column joints externally strengthened with FRP sheets

Cited by 9 publications

References 26 publications

NLFEA of Sulfate-Damaged Circular CFT Steel Columns Confined with CFRP Composites and Subjected to Axial and Cyclic Lateral Loads

NLFEA of Sulfate-Damaged Circular CFT Steel Columns Confined with CFRP Composites and Subjected to Axial and Cyclic Lateral Loads

Seismic Tests of Full Scale Reinforced Concrete T Joints with Light External Continuous Composite Rope Strengthening—Joint Deterioration and Failure Assessment

Efficacy and Damage Diagnosis of Reinforced Concrete Columns and Joints Strengthened with FRP Ropes Using Piezoelectric Transducers

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