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Luisa Rovero - One of the best experts on this subject based on the ideXlab platform.

  • experimental investigation on masonry arches strengthened with pbo frcm composite
    Composites Part B-engineering, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Gianfranco Stipo, Mario De Stefano, Giulia Misseri, Luciano Feo, Raimondo Luciano
    Abstract:

    Abstract In the last two decades, Fiber Reinforced Polymer (FRP) composites were effectively used for increasing the load-carrying capacity of masonry arches and for improving their mechanical response against the most critical arch failure mechanisms. More recently, Fabric Reinforced Cementitious Matrix (FRCM) composites are appearing significantly promising for the strengthening of masonry arches, providing an alternative to the FRP composites, but only few experimental contributions are available to date. In the present paper, the structural performance of masonry arches strengthened both at Intrados and at extrados by using a polybenzoxazole (PBO) fabric reinforced cementitious mortar composite was experimentally investigated. Results, in terms of load-carrying capacity, post peak behavior and failure mechanism, were compared with those determined by using a Carbon Fiber Reinforced Polymer (CFRP) composite. The present experimental study contributes to improve the knowledge of the innovative PBO-FRCM composites and it provides mechanical data useful for defining masonry strengthening design guidelines.

  • Intrados strengthening of brick masonry arches with different FRCM composites: Experimental and analytical investigations
    Composite Structures, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Francesco Focacci, Gianfranco Stipo, Mario De Stefano
    Abstract:

    Abstract This paper examines the structural behavior of masonry arches strengthened at the Intrados with fabric reinforced cementitious matrix (FRCM) composites. Textiles made of poliparafenilenbenzobisoxazole (PBO) and carbon fibers are considered. The experimental results are compared with those obtained on unstrengthened arches and arches strengthened with a carbon fiber reinforced polymer (CFRP) composite. The arches tested are analyzed with the approach of the limit analysis of the collapse mechanisms. For the FRCM strengthened arches the maximum fibers strain has been assumed equal to the maximum strain attained by the fibers during double shear bond tests previously performed, while for the FRP strengthened arches the maximum fibers strain has been assumed equal to the debonding strain evaluated according to the CNR (Italian National Research Council) guidelines. The employed approach allowed to accurately estimate the collapse load of the arches strengthened with FRP material, while the collapse loads of the arches strengthened with FRCM materials evaluated based on the results of the double shear tests underestimate the failure loads of the arches.

  • Intrados strengthening of brick masonry arches with different frcm composites experimental and analytical investigations
    Composite Structures, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Francesco Focacci, Gianfranco Stipo, Mario De Stefano
    Abstract:

    Abstract Fabric-Reinforced Cementitious Matrix (FRCM) materials are becoming increasingly suitable for strengthening of historic masonry constructions but only few experimental studies are still available concerning their application on structural elements. In the paper, the structural behavior of masonry arches strengthened at the extrados with a poliparafenilenbenzobisoxazole (PBO) fabric reinforced cementitious mortar composite is investigated through an experimental and analytical approach. The experimental tests were performed both on unstrengthened and strengthened masonry arches in order to evaluate the contribution of the strengthening material in terms of maximum load and post-peak behavior. The failure mechanisms were also analyzed and discussed. Beam tests were carried out in order to evaluate the bond capacity of the FRCM–masonry interface. The tested arches were analyzed using the approach of the limit analysis of the collapse mechanisms, which was able to accurately estimate the experimental collapse loads.

  • structural behavior of arch models strengthened using fiber reinforced polymer strips of different lengths
    Journal of Composites for Construction, 2013
    Co-Authors: Luisa Rovero, Francesco Focacci, Gianfranco Stipo
    Abstract:

    The authors address the structural behavior of masonry arches strengthened through carbon-fiber-reinforced polymer (CFRP) strips at Intrados or extrados surfaces and subjected to horizontal forces. The paper reports and compares results from experimental tests on 1:2-scale arches and from an analytical model that considers no-tensile strength, infinite rigid, and infinite compressive strength material. Under the assumption that the structure fails because of the formation of a four-hinge collapse mechanism, the model allows the calculation of the collapse load and the evaluation of the load-displacement diagram. The model is based on the equilibrium conditions and considers finite displacements. Results provide an evaluation of the dependence of arch structural behavior on the length of CFRP strengthening. In particular, the postpeak behavior is evaluated in the perspective of performance-based seismic design criteria, which regard the ultimate displacement as a key parameter for seismic capacity. The evaluation shows that, for the considered case study, an increase of Intrados reinforcement length produces an increase of maximum load but a decrease of the ultimate displacement.

  • towards a methodology for estimating strength and collapse mechanism in masonry arches strengthened with fibre reinforced polymer applied on external surfaces
    Materials and Structures, 2008
    Co-Authors: Silvia Briccoli Bati, Luisa Rovero
    Abstract:

    Assessment of the effects of the application of advanced materials and new technologies on traditional structures has assumed a major relevance within the ongoing debate on the preservation of historic buildings. The aim of the present paper is to discuss the validity of analytical models, by means of experimental investigations carried out on masonry arches reinforced with CFRP strips, bonded at the Intrados or extrados with distinct configurations. A theoretical prediction of ultimate strength for the different reinforcement configurations was derived in agreement with the occurrences observed during the experiments (masonry crushing, FRP rupture, debonding, sliding along the mortar joint). The results of the experimental trials allowed not only to validate the proposed analytical derivations but also to evaluate the impact of different reinforcement configurations on the strength of masonry arches and then to deduce considerations on sizing criteria for the CFRP strengthening of traditional masonry structures.

Gianfranco Stipo - One of the best experts on this subject based on the ideXlab platform.

  • experimental investigation on masonry arches strengthened with pbo frcm composite
    Composites Part B-engineering, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Gianfranco Stipo, Mario De Stefano, Giulia Misseri, Luciano Feo, Raimondo Luciano
    Abstract:

    Abstract In the last two decades, Fiber Reinforced Polymer (FRP) composites were effectively used for increasing the load-carrying capacity of masonry arches and for improving their mechanical response against the most critical arch failure mechanisms. More recently, Fabric Reinforced Cementitious Matrix (FRCM) composites are appearing significantly promising for the strengthening of masonry arches, providing an alternative to the FRP composites, but only few experimental contributions are available to date. In the present paper, the structural performance of masonry arches strengthened both at Intrados and at extrados by using a polybenzoxazole (PBO) fabric reinforced cementitious mortar composite was experimentally investigated. Results, in terms of load-carrying capacity, post peak behavior and failure mechanism, were compared with those determined by using a Carbon Fiber Reinforced Polymer (CFRP) composite. The present experimental study contributes to improve the knowledge of the innovative PBO-FRCM composites and it provides mechanical data useful for defining masonry strengthening design guidelines.

  • Intrados strengthening of brick masonry arches with different FRCM composites: Experimental and analytical investigations
    Composite Structures, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Francesco Focacci, Gianfranco Stipo, Mario De Stefano
    Abstract:

    Abstract This paper examines the structural behavior of masonry arches strengthened at the Intrados with fabric reinforced cementitious matrix (FRCM) composites. Textiles made of poliparafenilenbenzobisoxazole (PBO) and carbon fibers are considered. The experimental results are compared with those obtained on unstrengthened arches and arches strengthened with a carbon fiber reinforced polymer (CFRP) composite. The arches tested are analyzed with the approach of the limit analysis of the collapse mechanisms. For the FRCM strengthened arches the maximum fibers strain has been assumed equal to the maximum strain attained by the fibers during double shear bond tests previously performed, while for the FRP strengthened arches the maximum fibers strain has been assumed equal to the debonding strain evaluated according to the CNR (Italian National Research Council) guidelines. The employed approach allowed to accurately estimate the collapse load of the arches strengthened with FRP material, while the collapse loads of the arches strengthened with FRCM materials evaluated based on the results of the double shear tests underestimate the failure loads of the arches.

  • Intrados strengthening of brick masonry arches with different frcm composites experimental and analytical investigations
    Composite Structures, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Francesco Focacci, Gianfranco Stipo, Mario De Stefano
    Abstract:

    Abstract Fabric-Reinforced Cementitious Matrix (FRCM) materials are becoming increasingly suitable for strengthening of historic masonry constructions but only few experimental studies are still available concerning their application on structural elements. In the paper, the structural behavior of masonry arches strengthened at the extrados with a poliparafenilenbenzobisoxazole (PBO) fabric reinforced cementitious mortar composite is investigated through an experimental and analytical approach. The experimental tests were performed both on unstrengthened and strengthened masonry arches in order to evaluate the contribution of the strengthening material in terms of maximum load and post-peak behavior. The failure mechanisms were also analyzed and discussed. Beam tests were carried out in order to evaluate the bond capacity of the FRCM–masonry interface. The tested arches were analyzed using the approach of the limit analysis of the collapse mechanisms, which was able to accurately estimate the experimental collapse loads.

  • structural behavior of arch models strengthened using fiber reinforced polymer strips of different lengths
    Journal of Composites for Construction, 2013
    Co-Authors: Luisa Rovero, Francesco Focacci, Gianfranco Stipo
    Abstract:

    The authors address the structural behavior of masonry arches strengthened through carbon-fiber-reinforced polymer (CFRP) strips at Intrados or extrados surfaces and subjected to horizontal forces. The paper reports and compares results from experimental tests on 1:2-scale arches and from an analytical model that considers no-tensile strength, infinite rigid, and infinite compressive strength material. Under the assumption that the structure fails because of the formation of a four-hinge collapse mechanism, the model allows the calculation of the collapse load and the evaluation of the load-displacement diagram. The model is based on the equilibrium conditions and considers finite displacements. Results provide an evaluation of the dependence of arch structural behavior on the length of CFRP strengthening. In particular, the postpeak behavior is evaluated in the perspective of performance-based seismic design criteria, which regard the ultimate displacement as a key parameter for seismic capacity. The evaluation shows that, for the considered case study, an increase of Intrados reinforcement length produces an increase of maximum load but a decrease of the ultimate displacement.

Mario De Stefano - One of the best experts on this subject based on the ideXlab platform.

  • experimental investigation on masonry arches strengthened with pbo frcm composite
    Composites Part B-engineering, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Gianfranco Stipo, Mario De Stefano, Giulia Misseri, Luciano Feo, Raimondo Luciano
    Abstract:

    Abstract In the last two decades, Fiber Reinforced Polymer (FRP) composites were effectively used for increasing the load-carrying capacity of masonry arches and for improving their mechanical response against the most critical arch failure mechanisms. More recently, Fabric Reinforced Cementitious Matrix (FRCM) composites are appearing significantly promising for the strengthening of masonry arches, providing an alternative to the FRP composites, but only few experimental contributions are available to date. In the present paper, the structural performance of masonry arches strengthened both at Intrados and at extrados by using a polybenzoxazole (PBO) fabric reinforced cementitious mortar composite was experimentally investigated. Results, in terms of load-carrying capacity, post peak behavior and failure mechanism, were compared with those determined by using a Carbon Fiber Reinforced Polymer (CFRP) composite. The present experimental study contributes to improve the knowledge of the innovative PBO-FRCM composites and it provides mechanical data useful for defining masonry strengthening design guidelines.

  • Intrados strengthening of brick masonry arches with different frcm composites experimental and analytical investigations
    Composite Structures, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Francesco Focacci, Gianfranco Stipo, Mario De Stefano
    Abstract:

    Abstract Fabric-Reinforced Cementitious Matrix (FRCM) materials are becoming increasingly suitable for strengthening of historic masonry constructions but only few experimental studies are still available concerning their application on structural elements. In the paper, the structural behavior of masonry arches strengthened at the extrados with a poliparafenilenbenzobisoxazole (PBO) fabric reinforced cementitious mortar composite is investigated through an experimental and analytical approach. The experimental tests were performed both on unstrengthened and strengthened masonry arches in order to evaluate the contribution of the strengthening material in terms of maximum load and post-peak behavior. The failure mechanisms were also analyzed and discussed. Beam tests were carried out in order to evaluate the bond capacity of the FRCM–masonry interface. The tested arches were analyzed using the approach of the limit analysis of the collapse mechanisms, which was able to accurately estimate the experimental collapse loads.

  • Intrados strengthening of brick masonry arches with different FRCM composites: Experimental and analytical investigations
    Composite Structures, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Francesco Focacci, Gianfranco Stipo, Mario De Stefano
    Abstract:

    Abstract This paper examines the structural behavior of masonry arches strengthened at the Intrados with fabric reinforced cementitious matrix (FRCM) composites. Textiles made of poliparafenilenbenzobisoxazole (PBO) and carbon fibers are considered. The experimental results are compared with those obtained on unstrengthened arches and arches strengthened with a carbon fiber reinforced polymer (CFRP) composite. The arches tested are analyzed with the approach of the limit analysis of the collapse mechanisms. For the FRCM strengthened arches the maximum fibers strain has been assumed equal to the maximum strain attained by the fibers during double shear bond tests previously performed, while for the FRP strengthened arches the maximum fibers strain has been assumed equal to the debonding strain evaluated according to the CNR (Italian National Research Council) guidelines. The employed approach allowed to accurately estimate the collapse load of the arches strengthened with FRP material, while the collapse loads of the arches strengthened with FRCM materials evaluated based on the results of the double shear tests underestimate the failure loads of the arches.

Valerio Alecci - One of the best experts on this subject based on the ideXlab platform.

  • experimental investigation on masonry arches strengthened with pbo frcm composite
    Composites Part B-engineering, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Gianfranco Stipo, Mario De Stefano, Giulia Misseri, Luciano Feo, Raimondo Luciano
    Abstract:

    Abstract In the last two decades, Fiber Reinforced Polymer (FRP) composites were effectively used for increasing the load-carrying capacity of masonry arches and for improving their mechanical response against the most critical arch failure mechanisms. More recently, Fabric Reinforced Cementitious Matrix (FRCM) composites are appearing significantly promising for the strengthening of masonry arches, providing an alternative to the FRP composites, but only few experimental contributions are available to date. In the present paper, the structural performance of masonry arches strengthened both at Intrados and at extrados by using a polybenzoxazole (PBO) fabric reinforced cementitious mortar composite was experimentally investigated. Results, in terms of load-carrying capacity, post peak behavior and failure mechanism, were compared with those determined by using a Carbon Fiber Reinforced Polymer (CFRP) composite. The present experimental study contributes to improve the knowledge of the innovative PBO-FRCM composites and it provides mechanical data useful for defining masonry strengthening design guidelines.

  • Intrados strengthening of brick masonry arches with different frcm composites experimental and analytical investigations
    Composite Structures, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Francesco Focacci, Gianfranco Stipo, Mario De Stefano
    Abstract:

    Abstract Fabric-Reinforced Cementitious Matrix (FRCM) materials are becoming increasingly suitable for strengthening of historic masonry constructions but only few experimental studies are still available concerning their application on structural elements. In the paper, the structural behavior of masonry arches strengthened at the extrados with a poliparafenilenbenzobisoxazole (PBO) fabric reinforced cementitious mortar composite is investigated through an experimental and analytical approach. The experimental tests were performed both on unstrengthened and strengthened masonry arches in order to evaluate the contribution of the strengthening material in terms of maximum load and post-peak behavior. The failure mechanisms were also analyzed and discussed. Beam tests were carried out in order to evaluate the bond capacity of the FRCM–masonry interface. The tested arches were analyzed using the approach of the limit analysis of the collapse mechanisms, which was able to accurately estimate the experimental collapse loads.

  • Intrados strengthening of brick masonry arches with different FRCM composites: Experimental and analytical investigations
    Composite Structures, 2016
    Co-Authors: Valerio Alecci, Luisa Rovero, Francesco Focacci, Gianfranco Stipo, Mario De Stefano
    Abstract:

    Abstract This paper examines the structural behavior of masonry arches strengthened at the Intrados with fabric reinforced cementitious matrix (FRCM) composites. Textiles made of poliparafenilenbenzobisoxazole (PBO) and carbon fibers are considered. The experimental results are compared with those obtained on unstrengthened arches and arches strengthened with a carbon fiber reinforced polymer (CFRP) composite. The arches tested are analyzed with the approach of the limit analysis of the collapse mechanisms. For the FRCM strengthened arches the maximum fibers strain has been assumed equal to the maximum strain attained by the fibers during double shear bond tests previously performed, while for the FRP strengthened arches the maximum fibers strain has been assumed equal to the debonding strain evaluated according to the CNR (Italian National Research Council) guidelines. The employed approach allowed to accurately estimate the collapse load of the arches strengthened with FRP material, while the collapse loads of the arches strengthened with FRCM materials evaluated based on the results of the double shear tests underestimate the failure loads of the arches.

Gabriele Milani - One of the best experts on this subject based on the ideXlab platform.

  • Single lap shear tests of masonry curved pillars externally strengthened by CFRP strips
    Composite Structures, 2018
    Co-Authors: Tommaso Rotunno, Mario Fagone, Elisa Bertolesi, Ernesto Grande, Gabriele Milani
    Abstract:

    Abstract The paper presents an experimental study concerning the bond behaviour of Carbon Fiber Reinforced Polymers (CFRP) sheet reinforcements applied to curved masonry surfaces. Such strengthening technique is more and more used in structural rehabilitation and retrofitting of existing buildings. Its effectiveness has been demonstrated by several studies published in the literature, mostly devoted to flat bonded surfaces. Observing that CFRPs are extensively applied on arches and vaults but only few research activities concern curved bonded surfaces, the experimental study described in this paper is aimed to contribute to fill this gap. The experimental program was carried out on portions of masonry arches, reinforced by CFRP sheets bonded at extrados or Intrados, tested by a single lap shear test. The experimental results allowed to analyse the effectiveness of such reinforcements, loaded by actions tangent to an end of the reinforcement itself, with respect to its position (Intrados or extrados) and to the curvature of the bonding surface. As expected, the results highlight that the bond behaviour strongly depend on the position of the reinforcement. In particular, the capacity of reinforcements bonded at the extrados increases with the curvature, while decreases with the curvature for those bonded at Intrados.

  • Fast and reliable non-linear heterogeneous FE approach for the analysis of FRP-reinforced masonry arches
    Composites Part B: Engineering, 2016
    Co-Authors: Elisa Bertolesi, Gabriele Milani, Roberto Fedele
    Abstract:

    A simple and reliable finite element model is presented, specifically conceived for the analysis of FRP-reinforced masonry arches. The approach proposed relies on the reduction of mortar joints to interfaces exhibiting a non-linear holonomic behaviour under mixed mode conditions, whilst bricks are discretized by means of four-noded elements remaining linearly elastic up to failure. The FRP reinforcements glued at the Intrados or at the extrados are modelled by means of truss bar 2-node elements connecting contiguous nodes of the discretized support, with elastic-brittle behaviour in tension and no strength in compression. The predictions provided by the plane stress model, exploiting also the Italian CNR Recommendations for the engineering practice, are validated against some recent experimental results concerning circular and parabolic masonry arches reinforced by glass and carbon FRP