Shear capacity in concrete beams reinforced by stirrups with two different inclinations

Colajanni, Piero; Mendola, Lidia La; Mancini, Giuseppe; Recupero, Antonino; Spinella, Nino

doi:10.1016/j.engstruct.2014.10.011

Cited by 34 publications

(18 citation statements)

References 19 publications

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“…The proposed model also represents the extension of a model based on the stress field approach, able to assess shear strength of retrofitted RC beams with vertically-oriented FRP reinforcement only [23]. On the basis of the same assumption of the models proposed in [22,24], shear capacity of a strengthened RC beam can be assessed by means of three different equations, obtained by calculating the vertical equilibrium of beam segments, identified via three different sections parallel to stress field directions of concrete strut, steel stirrups, and FRP reinforcement, respectively (Figure 1). By doing so, each of the three equilibrium equations, which are given below, depends only on two stress fields, and can be easily solved: A f b s f are the nondimensional stresses and the mechanical ratios of FRP reinforcement and steel stirrups, respectively, ffu is the nominal rupture stress of the fiber, R the strain and stress "effective" coefficient (effective strain fe= fu R, effective stress ffe=ffu R=Ef fe), and r is the reduction factor of the efficiency of the steel stirrups.…”

Section: Design-oriented Modelmentioning

confidence: 99%

Influence of the Effectiveness Factors in Assessing the Shear Capacity of Rc Beams Strengthened With FRP

Colajanni¹,

Pagnotta²

2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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Shear failure of RC beams strengthened with composite textiles is often affected by the different failure modes characterizing the FRP reinforcement. The most relevant analytical models for evaluating the shear capacity of RC beams strengthened with FRP take into account these failure modes by introducing an effectiveness factor "R", which reduces the ultimate FRP tensile stress. Moreover, the interaction between stirrups and FRP reinforcement leads to a reduced efficiency of the transverse steel reinforcement due to the brittle failure of composite textile which hinders the yielding of all the stirrups involved by critical crack. In this regard, some analytical models introduce an effectiveness factor "r", aiming at reducing the yielding stress of stirrups. The procedures to calculate the above two parameters represent the main differences characterizing most of analytical models, significantly influencing their results. For this reason, the present paper focuses on the comparison of the different procedures to assess the effectiveness factors, proposing a new procedure for each effectiveness factor by modification of already existing formulations. Influence of the arrangement of composite reinforcement on the efficacy of stirrups, affected by brittle failure of FRP, is considered by means of the ratio between effective strain of composite to yielding strain of steel. The proposed procedures are employed in a design-oriented analytical model able to calculate the shear strength of RC beams retrofitted with FRP reinforcement arranged in any direction. The model is formulated aiming at representing an extension of EN1992 shear model to beams strengthened with FRP. The efficacy of the proposed procedures is assessed by comparing the experimental results against the predictions obtained via the design-oriented model and the above-mentioned analytical models.

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Section: Design-oriented Modelmentioning

confidence: 99%

Influence of the Effectiveness Factors in Assessing the Shear Capacity of Rc Beams Strengthened With FRP

Colajanni¹,

Pagnotta²

2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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“…Several models, also based on the MCFT equations, have been proposed in the literature to evaluate the shear-displacement curve of RC beams with and without FRP reinforcement [31][32][33][34].…”

Section: Analytical Model For the Ultimate Shear Of Corrosion-damagedmentioning

confidence: 99%

Ultimate Shear of RC Beams with Corroded Stirrups and Strengthened with FRP

et al. 2019

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Transverse reinforcement plays a key role in the response behavior of reinforced concrete beams. Therefore, corrosion of steel stirrups may change the failure mode of elements from bending to shear, leading to a brittle and catastrophic crisis. It is important to strengthen reinforced concrete beams with corroded stirrups to enhance the shear resistance. This paper presents a formulation, based on the modified compression field theory, to estimate the ultimate shear of reinforced concrete beams strengthened with FRP, because of stirrup corrosion. The detrimental effect of corrosion on steel stirrup yield strength was taken into account by introducing an empirical decay law. The effective strain of FRP reinforcement was adequately evaluated by considering both debonding and tensile stress rupture. The proposed model was validated against collected experimental results, showing a good ability to evaluate shear strength. Moreover, a numerical analysis was carried out to highlight the role of the key parameters predicting the ultimate shear.

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“…Lastly, it has to be stressed that, among the models derived for conventional reinforced concrete beams, those derived for beams reinforced by means of stirrups with two different inclinations [46], recently improved for beams strengthened by external reinforcement [47], have also been successfully applied for prediction of the shear strength of HSTCBs [17].…”

Section: Mechanical Models For Shear Strengthmentioning

confidence: 99%

Review of Push-Out and Shear Response of Hybrid Steel-Trussed Concrete Beams

2018

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The hybrid steel trussed concrete beams examined in the present study are comprised of two principal components, i.e., a steel joist with inclined rebars, realized in industry, which is welded to a smooth steel plate and then embedded within the concrete cast in situ. The paper presents first the state of the art on laboratory tests and analytical modeling of the steel-to-concrete stress transfer mechanism investigated by push-out tests. Next, the most relevant scientific contributions currently available in the technical literature regarding experimental investigation on actual shear behavior are summarized and discussed. Lastly codes and analytical models are reviewed.

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Shear capacity in concrete beams reinforced by stirrups with two different inclinations

Cited by 34 publications

References 19 publications

Influence of the Effectiveness Factors in Assessing the Shear Capacity of Rc Beams Strengthened With FRP

Influence of the Effectiveness Factors in Assessing the Shear Capacity of Rc Beams Strengthened With FRP

Ultimate Shear of RC Beams with Corroded Stirrups and Strengthened with FRP

Review of Push-Out and Shear Response of Hybrid Steel-Trussed Concrete Beams

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