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Papers by Valentino Berardi
We investigate on the strength and ductility properties of recycled PET fiber-reinforced concrete... more We investigate on the strength and ductility properties of recycled PET fiber-reinforced concretes (RPETFRCs) showing different mix-designs and PET filaments with variable mechanical and geometric properties. Available literature results of compression tests and four-point bending tests on such materials are reviewed comparing laboratory results in terms of compressive strength, first crack strength and ductility indices. The examined tests highlight that most relevant effects of the recycled PET fiber reinforcement are concerned with material toughness and ductility. In the case of low-strength concretes, significant compression and flexural strength enhancements due to the addition of recycled PET fibers are also observed.
ABSTRACT Conference code: 106145, Export Date: 21 January 2015, References: Saadè, K., Espion, B.... more ABSTRACT Conference code: 106145, Export Date: 21 January 2015, References: Saadè, K., Espion, B., Warzèe, G., Non-uniform torsional behavior and stability of thin-walled elastic beams with arbitrary cross-sections (2004) Thin-Walled Structures, 42, pp. 857-881;
Mechanics Research Communications, 2012
ABSTRACT In this paper the authors present the results of a creep test programme on several glass... more ABSTRACT In this paper the authors present the results of a creep test programme on several glass fibre reinforced polymers (GFRPs) laminates and their constituent phases (matrix and fibre), subject to different stress values under constant environmental conditions. A validation of the mechanical model, recently formulated by the authors, capable of predicting the viscous properties of a FRP laminate starting from those of the single phase is also developed by matching the predicted behaviour with the experimental one recorded in the creep tests.
Mechanics Research Communications, 2013
ABSTRACT Polymer concretes represent challenging materials in the Civil Engineering field, with t... more ABSTRACT Polymer concretes represent challenging materials in the Civil Engineering field, with them being characterized by a high value of the compressive strength and ultimate compressive strain, as well as by a good chemical resistance when compared to that of traditional concretes. These innovative materials exhibit a limited value of the strength in tension and therefore need to be reinforced with either steel or FRP pultruded internal bars. Moreover, their structural performance is strongly affected by the rheological behavior of the resin as well as the internal bars, if made of FRP. In this paper, a mechanical model capable of analytically evaluating the long term behavior of reinforced polymer concrete beams is presented, which accounts for the linear viscoelastic behavior of the constituent materials. (c) 2013 Elsevier Ltd. All rights reserved.
Mechanics Research Communications, 2013
Please cite this article in press as: Ascione, L., et al., Macro-scale analysis of local and glob... more Please cite this article in press as: Ascione, L., et al., Macro-scale analysis of local and global buckling behavior of T and C composite sections. Mech. Re. Commun. (2013), http://dx.
Materials, 2012
ABSTRACT The static behavior of reinforced concrete (RC) beams plated with layers of fiber-reinfo... more ABSTRACT The static behavior of reinforced concrete (RC) beams plated with layers of fiber-reinforced composite material (FRP) is widely investigated in current literature, which deals with both its numerical modeling as well as experiments. Scientific interest in this topic is explained by the increasing widespread use of composite materials in retrofitting techniques, as well as the consolidation and upgrading of existing reinforced concrete elements to new service conditions. The effectiveness of these techniques is typically influenced by the debonding of the FRP at the interface with concrete, where the transfer of stresses occurs from one element (RC member) to the other (FRP strengthening). In fact, the activation of the well-known premature failure modes can be regarded as a consequence of high peak values of the interfacial interactions. Until now, typical applications of FRP structural plating have included cases of flexural or shear-flexural strengthening. Within this context, the present study aims at extending the investigation to the case of wall-systems with open cross-section under torsional loads. It includes the results of some numerical analyses carried out by means of a finite element approximation.
Materials, 2012
ABSTRACT Polymer concretes (PCs) represent a promising alternative to traditional cementitious ma... more ABSTRACT Polymer concretes (PCs) represent a promising alternative to traditional cementitious materials in the field of new construction. In fact, PCs exhibit high compressive strength and ultimate compressive strain values, as well as good chemical resistance. Within the context of these benefits, this paper presents a study on the time-dependent behavior of polymer concrete columns reinforced with different bar types using a mechanical model recently developed by the authors. Balanced internal reinforcements are considered (i.e., two bars at both the top and bottom of the cross-section). The investigation highlights relevant stress and strain variations over time and, consequently, the emergence of a significant decrease in concrete's stiffness and strength over time. Therefore, the results indicate that deferred effects due to viscous flow may significantly affect the reliability of reinforced polymer concrete elements over time.
Construction and Building Materials, 2014
We present an experimental study on the mechanical properties and seawater curing of RPETFRC. We ... more We present an experimental study on the mechanical properties and seawater curing of RPETFRC. We examine compressive strength, first crack strength, and energy absorption capacity of RPETFRC. Special attention is given to the influence of the mix-design on RPETFRC properties. The presented results show that seawater conditioning significantly lowers the ultimate ductility of the analysed RPETFRC. The same conditioning instead leads to minor modifications of the compressive strength and first-crack strength.
Composites Part B: Engineering, 2013
Fiber reinforced composite materials are frequently used in the rehabilitation or upgrading of ex... more Fiber reinforced composite materials are frequently used in the rehabilitation or upgrading of existing structures. From a design point of view, current international guidelines on FRP strengthening applications do not give rules based on rigorous approaches to evaluate the reliability and durability of strengthening interventions with respect to long-term behavior. In order to give a contribution on this topic, the authors have carried out a creep experimental program on retrofitting systems, either of carbon or glass fibers and subject to different stress values in regime of constant temperature. The tests have been carried out by means of a dedicated test device that provided a pure bending stress state in the strengthened beam, being the external loads held constant over time. In this paper the results of their investigation and critical analysis are presented.
Composites Part B: Engineering, 2011
In this paper the authors present a mechanical model capable of predicting the long term behavior... more In this paper the authors present a mechanical model capable of predicting the long term behavior of PC beams externally plated with prestressed FRP laminates, starting from the rheological properties of composites. It is based on a mechanical approach that assumes there is a perfect adhesion between concrete core and external reinforcement.
Composites Part B: Engineering, 2013
A study on buckling phenomena in pultruded Fiber Reinforced Polymer (FRP) beams, based on two mec... more A study on buckling phenomena in pultruded Fiber Reinforced Polymer (FRP) beams, based on two mechanical models recently formulated by the authors with regard to composite thin-walled beams, is presented in this paper. Global buckling behavior is analyzed by means of a one-dimensional model in which cross-section torsional rotation is divided into two parts: the first one, associated with Vlasov's axial warping, the second one, associated entirely with shear strains. The study of local behavior is based on the individual buckling analysis of the components of FRP profile, assumed as elastically restrained transversely isotropic plates. Both mechanical models take into account, within the field of small strains and moderate rotations, the contribution of shear deformation in the kinematic hypotheses. Design charts suitable to evaluate the buckling load of FRP ''I'' beams with either narrow or wide flanges are obtained and presented in this paper.
Composite Structures, 2014
ABSTRACT The seismic rehabilitation techniques of masonry structures based on the use of plasters... more ABSTRACT The seismic rehabilitation techniques of masonry structures based on the use of plasters reinforced with steel nets have been widely utilized in the last decades. More recently nets made of materials other than steel have been used as plaster reinforcement, among them there are the polymeric nets. These nets allow to overcome some of the limitations of the other strengthening materials and present a good cost–benefit ratio. Experimental campaigns performed on masonry panels reinforced with polymeric nets have allowed to define their mechanical properties for practical design applications and for assessing their seismic capacity. Considering the results of these experimental campaigns in the present study analysis methods of masonry structures made of masonry brick panels strengthened with plasters reinforced with polymeric nets are proposed. The strength and ductility increments of the strengthened panels are accounted for in the global analysis of the construction adopting suitable values of the behavior factor. In the ambit of the limit analysis of the in plane and out of plane collapse mechanisms criteria that allow to account for the contribution of the polymeric net in the containment of the evolution of these mechanisms are defined.
We investigate on the strength and ductility properties of recycled PET fiber-reinforced concrete... more We investigate on the strength and ductility properties of recycled PET fiber-reinforced concretes (RPETFRCs) showing different mix-designs and PET filaments with variable mechanical and geometric properties. Available literature results of compression tests and four-point bending tests on such materials are reviewed comparing laboratory results in terms of compressive strength, first crack strength and ductility indices. The examined tests highlight that most relevant effects of the recycled PET fiber reinforcement are concerned with material toughness and ductility. In the case of low-strength concretes, significant compression and flexural strength enhancements due to the addition of recycled PET fibers are also observed.
ABSTRACT Conference code: 106145, Export Date: 21 January 2015, References: Saadè, K., Espion, B.... more ABSTRACT Conference code: 106145, Export Date: 21 January 2015, References: Saadè, K., Espion, B., Warzèe, G., Non-uniform torsional behavior and stability of thin-walled elastic beams with arbitrary cross-sections (2004) Thin-Walled Structures, 42, pp. 857-881;
Mechanics Research Communications, 2012
ABSTRACT In this paper the authors present the results of a creep test programme on several glass... more ABSTRACT In this paper the authors present the results of a creep test programme on several glass fibre reinforced polymers (GFRPs) laminates and their constituent phases (matrix and fibre), subject to different stress values under constant environmental conditions. A validation of the mechanical model, recently formulated by the authors, capable of predicting the viscous properties of a FRP laminate starting from those of the single phase is also developed by matching the predicted behaviour with the experimental one recorded in the creep tests.
Mechanics Research Communications, 2013
ABSTRACT Polymer concretes represent challenging materials in the Civil Engineering field, with t... more ABSTRACT Polymer concretes represent challenging materials in the Civil Engineering field, with them being characterized by a high value of the compressive strength and ultimate compressive strain, as well as by a good chemical resistance when compared to that of traditional concretes. These innovative materials exhibit a limited value of the strength in tension and therefore need to be reinforced with either steel or FRP pultruded internal bars. Moreover, their structural performance is strongly affected by the rheological behavior of the resin as well as the internal bars, if made of FRP. In this paper, a mechanical model capable of analytically evaluating the long term behavior of reinforced polymer concrete beams is presented, which accounts for the linear viscoelastic behavior of the constituent materials. (c) 2013 Elsevier Ltd. All rights reserved.
Mechanics Research Communications, 2013
Please cite this article in press as: Ascione, L., et al., Macro-scale analysis of local and glob... more Please cite this article in press as: Ascione, L., et al., Macro-scale analysis of local and global buckling behavior of T and C composite sections. Mech. Re. Commun. (2013), http://dx.
Materials, 2012
ABSTRACT The static behavior of reinforced concrete (RC) beams plated with layers of fiber-reinfo... more ABSTRACT The static behavior of reinforced concrete (RC) beams plated with layers of fiber-reinforced composite material (FRP) is widely investigated in current literature, which deals with both its numerical modeling as well as experiments. Scientific interest in this topic is explained by the increasing widespread use of composite materials in retrofitting techniques, as well as the consolidation and upgrading of existing reinforced concrete elements to new service conditions. The effectiveness of these techniques is typically influenced by the debonding of the FRP at the interface with concrete, where the transfer of stresses occurs from one element (RC member) to the other (FRP strengthening). In fact, the activation of the well-known premature failure modes can be regarded as a consequence of high peak values of the interfacial interactions. Until now, typical applications of FRP structural plating have included cases of flexural or shear-flexural strengthening. Within this context, the present study aims at extending the investigation to the case of wall-systems with open cross-section under torsional loads. It includes the results of some numerical analyses carried out by means of a finite element approximation.
Materials, 2012
ABSTRACT Polymer concretes (PCs) represent a promising alternative to traditional cementitious ma... more ABSTRACT Polymer concretes (PCs) represent a promising alternative to traditional cementitious materials in the field of new construction. In fact, PCs exhibit high compressive strength and ultimate compressive strain values, as well as good chemical resistance. Within the context of these benefits, this paper presents a study on the time-dependent behavior of polymer concrete columns reinforced with different bar types using a mechanical model recently developed by the authors. Balanced internal reinforcements are considered (i.e., two bars at both the top and bottom of the cross-section). The investigation highlights relevant stress and strain variations over time and, consequently, the emergence of a significant decrease in concrete's stiffness and strength over time. Therefore, the results indicate that deferred effects due to viscous flow may significantly affect the reliability of reinforced polymer concrete elements over time.
Construction and Building Materials, 2014
We present an experimental study on the mechanical properties and seawater curing of RPETFRC. We ... more We present an experimental study on the mechanical properties and seawater curing of RPETFRC. We examine compressive strength, first crack strength, and energy absorption capacity of RPETFRC. Special attention is given to the influence of the mix-design on RPETFRC properties. The presented results show that seawater conditioning significantly lowers the ultimate ductility of the analysed RPETFRC. The same conditioning instead leads to minor modifications of the compressive strength and first-crack strength.
Composites Part B: Engineering, 2013
Fiber reinforced composite materials are frequently used in the rehabilitation or upgrading of ex... more Fiber reinforced composite materials are frequently used in the rehabilitation or upgrading of existing structures. From a design point of view, current international guidelines on FRP strengthening applications do not give rules based on rigorous approaches to evaluate the reliability and durability of strengthening interventions with respect to long-term behavior. In order to give a contribution on this topic, the authors have carried out a creep experimental program on retrofitting systems, either of carbon or glass fibers and subject to different stress values in regime of constant temperature. The tests have been carried out by means of a dedicated test device that provided a pure bending stress state in the strengthened beam, being the external loads held constant over time. In this paper the results of their investigation and critical analysis are presented.
Composites Part B: Engineering, 2011
In this paper the authors present a mechanical model capable of predicting the long term behavior... more In this paper the authors present a mechanical model capable of predicting the long term behavior of PC beams externally plated with prestressed FRP laminates, starting from the rheological properties of composites. It is based on a mechanical approach that assumes there is a perfect adhesion between concrete core and external reinforcement.
Composites Part B: Engineering, 2013
A study on buckling phenomena in pultruded Fiber Reinforced Polymer (FRP) beams, based on two mec... more A study on buckling phenomena in pultruded Fiber Reinforced Polymer (FRP) beams, based on two mechanical models recently formulated by the authors with regard to composite thin-walled beams, is presented in this paper. Global buckling behavior is analyzed by means of a one-dimensional model in which cross-section torsional rotation is divided into two parts: the first one, associated with Vlasov's axial warping, the second one, associated entirely with shear strains. The study of local behavior is based on the individual buckling analysis of the components of FRP profile, assumed as elastically restrained transversely isotropic plates. Both mechanical models take into account, within the field of small strains and moderate rotations, the contribution of shear deformation in the kinematic hypotheses. Design charts suitable to evaluate the buckling load of FRP ''I'' beams with either narrow or wide flanges are obtained and presented in this paper.
Composite Structures, 2014
ABSTRACT The seismic rehabilitation techniques of masonry structures based on the use of plasters... more ABSTRACT The seismic rehabilitation techniques of masonry structures based on the use of plasters reinforced with steel nets have been widely utilized in the last decades. More recently nets made of materials other than steel have been used as plaster reinforcement, among them there are the polymeric nets. These nets allow to overcome some of the limitations of the other strengthening materials and present a good cost–benefit ratio. Experimental campaigns performed on masonry panels reinforced with polymeric nets have allowed to define their mechanical properties for practical design applications and for assessing their seismic capacity. Considering the results of these experimental campaigns in the present study analysis methods of masonry structures made of masonry brick panels strengthened with plasters reinforced with polymeric nets are proposed. The strength and ductility increments of the strengthened panels are accounted for in the global analysis of the construction adopting suitable values of the behavior factor. In the ambit of the limit analysis of the in plane and out of plane collapse mechanisms criteria that allow to account for the contribution of the polymeric net in the containment of the evolution of these mechanisms are defined.