Influence of Materials Knowledge Level on the Assessment of the Characteristic Value of the Shear Strength of Existing RC Beams

Lavorato, Davide; Bergami, Alessandro Vittorio; Forte, Angelo; Quaranta, Giuseppe; Nuti, Camillo; Monti, Giorgio; Santini, Silvia

doi:10.1007/978-3-319-78936-1_39

Cited by 4 publications

(6 citation statements)

References 16 publications

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“…The concrete jacket contribution (V Rd,cj ) was calculated by Equation (10), assuming b w •d is equal to A e in Equation (11), the mean experimental UHS and UHP concrete mechanical characteristics given in Section 2, the partial coefficient (γ c ) is equal to one, and ten rebar under tension according the predicted height of the section zone in compression by the results of the numerical analyses in Section 7.…”

Section: Shear Strength Of Columnsmentioning

confidence: 99%

“…Finally, the concrete jacket contribution (V Rd,cj ) was calculated using Equation 10, but assuming the minimum experimental concrete characteristics in Section 2 and the shear area given by CSA and ACI design codes [60][61][62], it is smaller than the value given by Equation (11).…”

Section: Shear Strength Of Columnsmentioning

confidence: 99%

“…In seismic regions such as Italy, the evaluation of the capacity and fragility of structural and infrastructural systems subjected to seismic events [1][2][3][4][5][6][7][8][9], and implementing proper survey programs to monitor the evolution of their capabilities [10,11] are important for preventing severe seismic damage being observed in recent seismic events [12] by means of retrofitting interventions [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

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Severely Damaged Reinforced Concrete Circular Columns Repaired by Turned Steel Rebar and High-Performance Concrete Jacketing with Steel or Polymer Fibers

et al. 2018

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A new strategy that repairs severely damaged reinforced concrete (RC) columns after an earthquake is proposed as a simpler and quicker solution with respect to the strategies currently available in the literature. The external concrete parts are removed from the column surface along the whole plastic hinge region to uncover the steel reinforcement. The transverse steel is cut away, and each longitudinal rebar is locally substituted by steel rebar segments connected by welding connections to the original undamaged rebar pieces outside the intervention zone. The new rebar segments have a reduced diameter achieved by turning to ensure plastic deformation only in the plastic hinge, protecting the original rebar and the welding connections. The connection is specifically designed to be effective and simple, and is directly realized on column reinforcement. Finally, the removed concrete is restored by a jacket built with high-performance concrete with steel or polymer fibers. The use of concrete with high volume fraction of polymer fibers to repair the column is investigated for the first time in this paper. This concrete was characterized by compression and flexural tests in the laboratory and its mechanical characteristics were compared with those of the concrete with steel fibers, which are being increasingly used in construction. The repair strategy was applied to two RC columns (1:6 scaled bridge piers), tested by asymmetric cyclic tests. The results show that the column strength, stiffness, and ductility were restored, and the energy dissipation capacity improved. The experimental evidence was investigated by fiber models in OpenSees.

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Section: Shear Strength Of Columnsmentioning

confidence: 99%

Section: Shear Strength Of Columnsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Severely Damaged Reinforced Concrete Circular Columns Repaired by Turned Steel Rebar and High-Performance Concrete Jacketing with Steel or Polymer Fibers

et al. 2018

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“…These experimental results should be investigated better by further experimental research on "real" existing beams and closely considered to assess the beam strength and deformation capacity [60,61].…”

Section: Compressive Strength Of Concretementioning

confidence: 99%

“…Finally, experimental measures showed a significant variation of the concrete compressive strength in adjacent beams as well as in different portion of each beam. This uncertainty about the compressive strength should be closely considered by a designer to define properly the beam capacity [60,61].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Shear Strength of RC Beams Extracted from an Old Structure and Strengthened by Carbon FRP U-Strips

2018

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Featured Application: This study presents the experimental results of the shear strength of reinforced concrete (RC) "real" beams extracted from an old RC building in Rome, built in 1929. The concrete strength is very small as in the case of many existing old RC structures. These results about "real" beams are innovative in the literature because the beams are usually built purposely to be retrofitted and tested. The data presented in this paper improve the literature database giving original data about the measured concrete strength variation along the beams, the stiffness, the deflections, and the strengths of the beams before and after retrofitting, and the Carbon FRP U-Strips strains. The shear strengths of these "real" beams, together with the ones obtained in other experimental studies, are in good agreement with the predicted strengths by design code equations.Abstract: In recent years, old reinforced concrete (RC) buildings have increasingly been protected as historic symbols in Italy. The conversion of these buildings can resolve the increasing need for new structures, reducing much social, economic, and environmental impact. Retrofitting solutions by carbon fiber reinforced polymer (CFRP) reinforcements are very common nowadays. Code predictions present uncertainties due to the brittle behavior and the debonding of CFRP strips resulting from concrete cracking. Therefore, especially in the case of old beams, experimental validation is necessary. This paper deals the experimental evaluation of the shear strength of two beams extracted from an old RC building in Rome built in 1929 with modest-quality concrete. Preliminary tests were carried out to evaluate the beam elastic response and the material characteristics. These beams were tested until failure (three-point load shear/bending tests) after strengthening for shear by CFRP U-jacketing and for bending by new steel rebars. The results obtained, together with the extensive data taken from the literature, were compared with the predictions by design code equations. The influence of construction details on beam shear strength and the experimental maximum CFRP strain were also analyzed. Code predictions can be effective to estimate the shear strength of the retrofitted beams.

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Investigation of the concrete parameters of existing RC buildings by operational modal analysis

Aras

2023

Bull Earthquake Eng

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Influence of Materials Knowledge Level on the Assessment of the Characteristic Value of the Shear Strength of Existing RC Beams

Cited by 4 publications

References 16 publications

Severely Damaged Reinforced Concrete Circular Columns Repaired by Turned Steel Rebar and High-Performance Concrete Jacketing with Steel or Polymer Fibers

Severely Damaged Reinforced Concrete Circular Columns Repaired by Turned Steel Rebar and High-Performance Concrete Jacketing with Steel or Polymer Fibers

Experimental Investigation of the Shear Strength of RC Beams Extracted from an Old Structure and Strengthened by Carbon FRP U-Strips

Investigation of the concrete parameters of existing RC buildings by operational modal analysis

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