A parametric study on the effectiveness of the NSM technique for the flexural strengthening of continuous RC slabs

Breveglieri, Matteo; Barros, Joaquim A. O.; Dalfré, Gláucia; Aprile, Alessandra

doi:10.1016/j.compositesb.2012.02.008

Cited by 31 publications

(13 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Studies have shown that the NSM technique, based on the insertion of carbon fiber reinforced polymer (CFRP) laminates into grooves opened on the concrete cover of the RC elements to be strengthened, assures higher shear and flexural strengthening effectiveness than EBR technique. This higher effectiveness of the NSM technique can be attributed to the largest ratio of bond area to cross sectional area of the CFRP laminate, and higher confinement provided by the surrounding concrete to this reinforcement when using this technique [2,[9][10][11]. Combining NSM CFRP reinforcement for the flexural strengthening, with CFRP strips applied according to EBR technique, resulted to enhance the energy dissipation capacity of the strengthened structures due to increase in the concrete confinement [12].…”

Section: Introductionmentioning

confidence: 99%

Influence of prestress level on NSM CFRP laminates for the flexural strengthening of RC beams

Rezazadeh

Costa

2014

Composite Structures

View full text Add to dashboard Cite

This study presents an experimental program to evaluate the influence of the prestressing technique on the flexural behavior of reinforced-concrete (RC) beams strengthened with near-surface-mounted (NSM) carbonfiber-reinforced-polymer (CFRP) laminates. The experimental program was organized to highlight the benefits of this technique for flexural strengthening of RC beams with low reinforcement ratio, susceptible of not respecting serviceability-limit-state (SLS) conditions, namely the deflection limit. For this purpose, five RC beams were fabricated to be tested under monotonic four-point loading. One beam was kept unstrengthened as a control beam, and another one was strengthened with a non-prestressed NSM CFRP laminate. The remaining beams were reinforced with a NSM CFRP laminate prestressed at 20%, 30% and 40% of its nominal tensile strength. Based on the results, applying the prestress force provided an increase of load carrying capacity corresponding to the concrete cracking and steel yielding initiations compared to the non-prestressed strengthened beam. Moreover, the influence of prestress level on the prevailing failure mode of the tested beams was assessed, and the relevant results are presented and discussed. An advanced numerical strategy was also developed to simulate the tested beams, which was demonstrated capable of being used for the design of this type of structures.

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of prestress level on NSM CFRP laminates for the flexural strengthening of RC beams

Rezazadeh

Costa

2014

Composite Structures

View full text Add to dashboard Cite

show abstract

“…In particular, attention is focused on seven beams and seven slabs. For the beams reference is made to the experimental works of Ashour et al [2004], Lau and Pam [2010] and Vecchio and Shim [2004], while for the slabs the experimental works are those presented by Al-Rousan et al [2012], Breveglieri et al [2012] and Gilbert and Nejadi [2004]. Indeed, the above quoted papers face each a large number of experimental tests, carried out for purposes different from those pursued in the present work.…”

Section: Analyzed Rc Beams and Slabsmentioning

confidence: 99%

“…Among the seven slabs, once again prototypes with different geometrical configurations, reinforcement arrangements, loading and boundary conditions are investigated. The first three slabs, namely specimens SL15, SL30 and SL45, are taken from the experimental work of Breveglieri et al [2012]. These slabs are continuoussupported and comprise two equal spans each of which are subjected to the same line load Pp/2 (withp reference line load) at the two mid-spans.…”

Section: Analyzed Rc Beams and Slabsmentioning

confidence: 99%

Limit State Evaluation of Steel-Reinforced Concrete Elements by Von Mises and Menétrey–willam-Type Yield Criteria

Pisano

Fuschi

Domenico

2014

Int. J. Appl. Mechanics

View full text Add to dashboard Cite

An advanced version of a recently developed numerical limit analysis procedure for the prediction of peak loads and failure modes of steel-reinforced concrete elements is proposed. The modified procedure allows to take into account possible yielding of reinforcement thus capturing the actual behavior at the collapse of both steel and concrete. This implies a finite element (FE) modeling of the reinforced concrete (RC) elements in which concrete is governed by a Menétrey-Willam-type yield criterion, with cap in compression, while steel bars are governed by a von Mises yield criterion. The peak load of a wide range of RC structures whose behavior at ultimate state is dominated either by the concrete crushing or by the steel bars yielding is then predicted with a very good accuracy.to such approaches embracing limit analysis, see e.g. Spiliopoulos and Weichert [2013], or shakedown analysis, also endowed with apposite constitutive assumptions [Fuschi, 1999]. Several contributions concern direct methods based on finite elements method (FEM) in conjunction with optimization algorithms such as linear [Sloan, 1988] and nonlinear programming [Le et al., 2010], [Garcea and Leonetti, 2011]. These approaches indeed do not allow the treatment of post elastic phenomena that may arise in concrete structures, such as localization, fracture, damage, creep, etc. and that can be faced by coupling plasticity with fracture or damage mechanical theories within step-by-step analyses (see e.g., Lubliner et al. [1989], Lee and Fenves [1998] and Zhang et al. [2010]); however, they can give information on the behavior at limit (collapse) states of structures, which are very useful for design purposes. In this context, with an approach not based on an optimization algorithm but grounding on sequences of FE elastic analyses, it has to be inserted to the present study.The promoted approach belongs to a wider research program started by the authors in the context of laminates of fibres reinforced polymers [Pisano and Fuschi, 2007;Pisano et al., 2012Pisano et al., , 2013bDe Domenico et al., 2014] and then extended in the context of RC structures with reference to a Menétrey-Willam (M-W)-type yield criterion with cap in compression [Pisano et al., 2013a[Pisano et al., , 2013cDe Domenico et al., 2014]. In both the latter quoted studies, two limit analysis methods, namely the linear matching method (LMM), and the elastic compensation method (ECM), have been applied under the simplified hypothesis where reinforcements behave as indefinitely elastic. This hypothesis implies, as explicitly declared, the limitation of applicability to those structures whose behavior, at incipient collapse, is dominated by crushing of concrete, being the steel bars far from yielding which is the case of the so-called over-reinforced structures. To overcome this limitation and to improve the overall modeling of the RC structural elements at collapse, the present study proposes an advanced version of the above numerical limit analysis procedure for dealing with possible ...

show abstract

“…Limited studies have also been conducted by other researchers (Silva and Ibell, 2008;Aiello and Ombres, 2011;Dalfré and Barros, 2011;Breveglieri et al, 2012;Santos et al, 2013;Lou et al, 2015), which show that MR can occur to a significant extent after FRP strengthening, provided that an appropriate strengthening configuration is adopted. This paper initially presents the findings of a set of experiments, aiming at quantifying MR in FRPstrengthened continuous RC T-beams.…”

Section: Introductionmentioning

confidence: 96%

Prediction of Capacity for Moment Redistribution in FRP-Strengthened Continuous RC T-Beams

Tajaddini

Ibell²,

Darby³

et al. 2017

J. Compos. Constr.

View full text Add to dashboard Cite

Due to the premature debonding of fiber-reinforced polymer (FRP) materials which results in a reduction in ductility, the problem of how to exploit moment redistribution (MR) in FRP-strengthened continuous reinforced concrete (RC) structures is still unresolved. To date, limited research has been conducted into MR in such structures, so that a reliable and rigorous solution for quantifying MR throughout the loading cycle remains elusive. This paper aims to quantify MR and predict the capacity at reasonable accuracy, to encourage the use of FRP for the strengthening of existing continuous RC structures. Experiments conducted on twelve continuous T-beams are reported, and the findings are discussed. Strengthening configuration and anchorage scheme are the main variables. A new analytical strategy is described for quantifying MR, and the analytical results are then validated against the experimental results. Both experimental and analytical results confirm that there is no reason to restrict MR into strengthened zones. More importantly, MR out of FRP-strengthened zones can indeed occur, provided that the FRP is sufficiently anchored, and reliable exploitation of this is now possible.

show abstract

A parametric study on the effectiveness of the NSM technique for the flexural strengthening of continuous RC slabs

Cited by 31 publications

References 19 publications

Influence of prestress level on NSM CFRP laminates for the flexural strengthening of RC beams

Influence of prestress level on NSM CFRP laminates for the flexural strengthening of RC beams

Limit State Evaluation of Steel-Reinforced Concrete Elements by Von Mises and Menétrey–willam-Type Yield Criteria

Prediction of Capacity for Moment Redistribution in FRP-Strengthened Continuous RC T-Beams

Contact Info

Product

Resources

About