Ertüchtigung seismisch beschädigter Rahmenknoten aus Stahlbeton mittels FRP‐Filamentbündelverbindungen

Golias, Emmanouil; Lindenthal, Heiko; Schlüter, Franz‐Hermann; Karabinis, Athanasios I.

doi:10.1002/bate.201900085

Cited by 9 publications

(8 citation statements)

References 11 publications

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“…Therefore, protection of the RC joints against detrimental damage accumulation is most crucial, together with the protection of the columns. Local retrofit of beam–column connections can be employed in many cases to avoid costly and time-consuming global interventions [ 1 , 2 , 3 , 4 , 5 ]. Some of the well-known retrofitting techniques of RC joints include RC jacketing, steel plate or steel rod jacketing, and advanced shear strengthening with fiber-reinforced polymer (FRP) sheets [ 6 , 7 , 8 ].…”

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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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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“…A novel technique has been proposed recently, so that both the complexity and the cost of nodes' restoration or/and strengthening can be reduced. In recent experimental techniques [13][14][15][16][17], external FRP flexural ropes have been used as an additional diagonal reinforcement to existing beam column joints. This type of reinforcement is encapsulated in U-shaped notches.…”

Section: Introductionmentioning

confidence: 99%

Cyclic response of RC beam-column joints strengthened with transverse steel bars and with C-FRP diagonal ties

et al. 2022

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The use of additional bars, internally placed through drill holes, in external beam-column connections subjected to cyclic loading, as shear reinforcement is experimentally investigated.The presented experimental work includes tests of full-scale specimens with different reinforcement arrangements in the joint area, they are as follows: (a) the JB0V control specimen with two (extra) vertical side bars without shear reinforcement in the joint area and, (b) the JB0R joint, same as in the case of the control specimen, without the extra vertical bars, but with four additional steel bars that were placed in holes, which were drilled through the concrete of the joint body for this purpose, (c) the JB0VFX joint, the damaged control specimen repaired and strengthened with C-FRP diagonal ties (rope connections) through the joint area. The effectiveness of these additional bars and ropes as a shear reinforcement on the overall seismic performance of the tested joint is examined.A comparison between the test results of the examined specimens indicated that the applied retrofitting technique is appropriate for the enhancement of the overall hysteretic performance of the beam-column joints in terms of load carrying capacity, stiffness and hysteretic energy dissipation.

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“…Therefore, the successful repair or strengthening of joints that have previously been damaged during cyclic loading caused by earthquakes is essential in order to enable the use of the affected structure again [14][15][16]. Detailed design recommendations have been introduced on the basis of the research and development of repair techniques in Europe and the United States in past decades [17][18][19][20][21]. Regardless, the further development of cost-effective rehabilitating strategies for RC frame joints remains of great interest.…”

Section: Introductionmentioning

confidence: 99%

“…A recent method introduced by the authors [69] involves replacing the FRP sheets with a bundle of unidirectional fibers (FRP rope), inserted either as near surface mounting (NSM) or as embedded through section (ETS) in joints, and it seems to be a promising technique. FRP ropes have been used in previous research as the main reinforcement for strengthening flexure deficient beams in the support area [21,70] as well for the shear strengthening of deep beams [71].…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of the Novel Rehabilitation Method of Seismically Damaged RC Joints Using C-FRP Ropes and Comparison with Widely Applied Method Using C-FRP Sheets—Experimental Investigation

et al. 2021

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The necessity of ensuring the long-term sustainability of existing structures is rising. An important issue concerning existing reinforced concrete (RC) structures in seismically active regions is that a significant number of them lack the required earthquake-resistant capacities to meet the increased design earthquake demands. Inexpensive, fast and long-term strengthening strategies for repairing/strengthening RC structures are urgently required, not only after destructive earthquakes, but even before they occur. Retrofitting existing buildings extending their service life rather than demolishing and rebuilding new ones is the best option in terms of economic gain and environmental protection. This paper experimentally investigates the effectiveness of externally applied (i) carbon fiber-reinforced polymer (C-FRP) ropes in X-type form and (b) C-FRP sheets that are bonded on both sides of the joint area of RC beam-column joint connections. Six comparative full-scale exterior RC beam-column joint specimens were tested under reverse cyclic deformation. Two of them were control specimens, two were strengthened using C-FRP ropes (novel technique) and two were retrofitted using C-FRP sheets (widely used technique). Extensive comparisons and discussion of the test results derive new quantitative and qualitative results concerning the seismic capacity and the service life extension of the strengthened RC members using the proposed retrofitting scheme.

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Ertüchtigung seismisch beschädigter Rahmenknoten aus Stahlbeton mittels FRP‐Filamentbündelverbindungen

Cited by 9 publications

References 11 publications

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

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

Cyclic response of RC beam-column joints strengthened with transverse steel bars and with C-FRP diagonal ties

Effectiveness of the Novel Rehabilitation Method of Seismically Damaged RC Joints Using C-FRP Ropes and Comparison with Widely Applied Method Using C-FRP Sheets—Experimental Investigation

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