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Papers by Gianpiero Lignola

Bulletin of Earthquake Engineering, Jul 4, 2023

Original article has been corrected. Publisher's Note Springer Nature remains neutral with regard... more Original article has been corrected. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

An interdisciplinary investigation of the seismic performance of a historic tower in Istanbul during the 1999 Kocaeli earthquake

Bulletin of Earthquake Engineering, Feb 15, 2023

Materials

Fabric-reinforced cementitious matrix (FRCM) composites are currently considered a suitable solut... more Fabric-reinforced cementitious matrix (FRCM) composites are currently considered a suitable solution for strengthening existing structures. Confinement applications are still being investigated, since experimental programs showed significant scatter in the results and theoretical models are struggling to become established as a consequence. The main aim of this study is the identification of potential sources of scatter in the confinement efficiency of FRCM wrappings, in defects such as fiber slip within the matrix or imperfect straightening of fibers, or premature failure of fibers once exposed after complete matrix cracking. A theoretical incremental approach is proposed to simulate such effects. The approach is incremental, but not iterative, so that no convergence is required and the incremental step size has an impact only on the smoothness of the nonlinear theoretical stress vs. strain curves of the FRCM confined material, among other simulation results. Theoretical results ar...

Bulletin of Earthquake Engineering

Original article has been corrected. Publisher's Note Springer Nature remains neutral with regard... more Original article has been corrected. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

An interdisciplinary investigation of the seismic performance of a historic tower in Istanbul during the 1999 Kocaeli earthquake

Bulletin of Earthquake Engineering

Shear Strengthening of RC Elements by Means of EBR FRP Systems

RILEM State-of-the-Art Reports, 2015

ABSTRACT

Structural restoration of damaged XVIII century building: the military barracks "Caserma Principe Amedeo" in Nola, Italy

ABSTRACT

Residual life and degradation assessment of wood elements used in soil bioengineering structures for slope protection

Ecological Engineering, 2016

Abstract Soil bioengineering techniques to repair slope failures and increase slope stability are... more Abstract Soil bioengineering techniques to repair slope failures and increase slope stability are often used, when possible, as alternatives to traditional structures in order to mitigate environmental impact without compromising effectiveness. However, such techniques use live plants and entrust most of their structural resistance to wood members whose mechanical characteristics diminish with time. To date, the decay of mechanical characteristics of wood elements employed in soil bioengineering techniques and lifetime predictions has been little explored. Such information is also important for durability forecasting. In this paper we present the results of experimental analyses carried out to evaluate the degradation of mechanical properties of untreated timber elements which were collected from single and double live cribwalls or check-dams built about ten years ago in the Vesuvius National Park (Naples, Southern Italy). To help interpret the behavior of a complex material such as wood, a novelty of this study lies not only in combining ultrasonic and sclerometric nondestructive testing (NDT) methods so as to reduce measurement errors, but also in framing the outcomes from mechanical tests within the biological analysis of fungi detected on the timbers. Exploratory statistical analyses reveal that there exist hardly any correlations between moisture contents in the timber elements and both transversal and longitudinal ultrasonic velocities, although some clustering provides insights into the results obtained. Comparisons between results using data measured on “old” and “new” timber elements enable some evaluations of residual safety factor assessment to be carried out.

The goal of this research project is to model the effect of confinement on concrete members by me... more The goal of this research project is to model the effect of confinement on concrete members by means of externally bonded wrapping, hence to provide a simplified closed form solution to determine directly the ultimate confined concrete strength. Common cross-section shapes for reinforced concrete columns are considered herein, namely circular, solid and hollow, square and rectangular. Nowadays innovative materials are developing focusing on the sustainability of the intervention, improving "traditional" FRP materials, where the organic matrix is substituted by an inorganic matrix and fiber fabrics are substituted by biaxial grids, while almost the same fiber materials are adopted. The simplified model is practitioners and code oriented, while it is derived from a more research oriented refined iterative confinement model proposed by the same authors to evaluate the entire stress-strain relationship of confined concrete. Based on a detailed analysis of the stress state, a simplified closed form solution is proposed to account for the non-uniformly confined concrete performance exhibited in non-axisymmetric sections. The non-uniform confining stress field exhibited in such cross-sections is explicitly considered by means of the mean value integral of the pointwise variable stress state over the cross-section. The key aspect of the proposed methodology is the evaluation of the effective equivalent pressure to be inserted in a triaxial confinement model, to account for the peculiarities of square and rectangular cross-sections. Experimental data, available in the literature and representative of a wide stock of applications, were compared to the results of the theoretical simplified model to validate the proposed approach, and satisfactory results were found.

Polymers, 2014

Adobe constructions were widespread in the ancient world, and earth was one of the most used cons... more Adobe constructions were widespread in the ancient world, and earth was one of the most used construction materials in ancient times. Therefore, the preservation of adobe structures, especially against seismic events, is nowadays an important structural issue. Previous experimental tests have shown that the ratio between mortar and brick mechanical properties (i.e., strength, stiffness and elastic modulus) influences the global response of the walls in terms of strength and ductility. Accurate analyses are presented in both the case of unreinforced and reinforced with fiberglass mesh when varying the mechanical properties of the materials composing the adobe masonry structure. The main issues and variability in the behavior of seismic resisting walls when varying the mechanical properties are herein highlighted. The aim of the overall research activity is to improve the knowledge about the structural behavior of adobe structural members unreinforced and reinforced with fiberglass mesh inside horizontal mortar joints.

Dynamic response of asymmetric bodies assuming a rocking behaviour

Proceedings of the Institution of Civil Engineers - Structures and Buildings

Soil bioengineering techniques to repair slope failures and increase slope stability are often us... more Soil bioengineering techniques to repair slope failures and increase slope stability are often used, when possible, as alternatives to traditional structures in order to mitigate environmental impact without compromising effectiveness. However, such techniques use live plants and entrust most of their structural resistance to wood members whose mechanical characteristics diminish with time. To date, the decay of mechanical characteristics of wood elements employed in soil bioengineering techniques and lifetime predictions has been little explored. Such information is also important for durability forecasting. In this paper we present the results of experimental analyses carried out to evaluate the degradation of mechanical properties of untreated timber elements which were collected from single and double live cribwalls or check-dams built about ten years ago in the Vesuvius National Park (Naples, Southern Italy). To help interpret the behavior of a complex material such as wood, a novelty of this study lies not only in combining ultrasonic and sclerometric nondestructive testing (NDT) methods so as to reduce measurement errors, but also in framing the outcomes from mechanical tests within the biological analysis of fungi detected on the timbers. Exploratory statistical analyses reveal that there exist hardly any correlations between moisture contents in the timber elements and both transversal and longitudinal ultrasonic velocities, although some clustering provides insights into the results obtained. Comparisons between results using data measured on " old " and " new " timber elements enable some evaluations of residual safety factor assessment to be carried out.

Bulletin of Earthquake Engineering, Jul 4, 2023

Original article has been corrected. Publisher's Note Springer Nature remains neutral with regard... more Original article has been corrected. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

An interdisciplinary investigation of the seismic performance of a historic tower in Istanbul during the 1999 Kocaeli earthquake

Bulletin of Earthquake Engineering, Feb 15, 2023

Materials

Fabric-reinforced cementitious matrix (FRCM) composites are currently considered a suitable solut... more Fabric-reinforced cementitious matrix (FRCM) composites are currently considered a suitable solution for strengthening existing structures. Confinement applications are still being investigated, since experimental programs showed significant scatter in the results and theoretical models are struggling to become established as a consequence. The main aim of this study is the identification of potential sources of scatter in the confinement efficiency of FRCM wrappings, in defects such as fiber slip within the matrix or imperfect straightening of fibers, or premature failure of fibers once exposed after complete matrix cracking. A theoretical incremental approach is proposed to simulate such effects. The approach is incremental, but not iterative, so that no convergence is required and the incremental step size has an impact only on the smoothness of the nonlinear theoretical stress vs. strain curves of the FRCM confined material, among other simulation results. Theoretical results ar...

Bulletin of Earthquake Engineering

Original article has been corrected. Publisher's Note Springer Nature remains neutral with regard... more Original article has been corrected. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

An interdisciplinary investigation of the seismic performance of a historic tower in Istanbul during the 1999 Kocaeli earthquake

Bulletin of Earthquake Engineering

Shear Strengthening of RC Elements by Means of EBR FRP Systems

RILEM State-of-the-Art Reports, 2015

ABSTRACT

Structural restoration of damaged XVIII century building: the military barracks "Caserma Principe Amedeo" in Nola, Italy

ABSTRACT

Residual life and degradation assessment of wood elements used in soil bioengineering structures for slope protection

Ecological Engineering, 2016

Abstract Soil bioengineering techniques to repair slope failures and increase slope stability are... more Abstract Soil bioengineering techniques to repair slope failures and increase slope stability are often used, when possible, as alternatives to traditional structures in order to mitigate environmental impact without compromising effectiveness. However, such techniques use live plants and entrust most of their structural resistance to wood members whose mechanical characteristics diminish with time. To date, the decay of mechanical characteristics of wood elements employed in soil bioengineering techniques and lifetime predictions has been little explored. Such information is also important for durability forecasting. In this paper we present the results of experimental analyses carried out to evaluate the degradation of mechanical properties of untreated timber elements which were collected from single and double live cribwalls or check-dams built about ten years ago in the Vesuvius National Park (Naples, Southern Italy). To help interpret the behavior of a complex material such as wood, a novelty of this study lies not only in combining ultrasonic and sclerometric nondestructive testing (NDT) methods so as to reduce measurement errors, but also in framing the outcomes from mechanical tests within the biological analysis of fungi detected on the timbers. Exploratory statistical analyses reveal that there exist hardly any correlations between moisture contents in the timber elements and both transversal and longitudinal ultrasonic velocities, although some clustering provides insights into the results obtained. Comparisons between results using data measured on “old” and “new” timber elements enable some evaluations of residual safety factor assessment to be carried out.

The goal of this research project is to model the effect of confinement on concrete members by me... more The goal of this research project is to model the effect of confinement on concrete members by means of externally bonded wrapping, hence to provide a simplified closed form solution to determine directly the ultimate confined concrete strength. Common cross-section shapes for reinforced concrete columns are considered herein, namely circular, solid and hollow, square and rectangular. Nowadays innovative materials are developing focusing on the sustainability of the intervention, improving "traditional" FRP materials, where the organic matrix is substituted by an inorganic matrix and fiber fabrics are substituted by biaxial grids, while almost the same fiber materials are adopted. The simplified model is practitioners and code oriented, while it is derived from a more research oriented refined iterative confinement model proposed by the same authors to evaluate the entire stress-strain relationship of confined concrete. Based on a detailed analysis of the stress state, a simplified closed form solution is proposed to account for the non-uniformly confined concrete performance exhibited in non-axisymmetric sections. The non-uniform confining stress field exhibited in such cross-sections is explicitly considered by means of the mean value integral of the pointwise variable stress state over the cross-section. The key aspect of the proposed methodology is the evaluation of the effective equivalent pressure to be inserted in a triaxial confinement model, to account for the peculiarities of square and rectangular cross-sections. Experimental data, available in the literature and representative of a wide stock of applications, were compared to the results of the theoretical simplified model to validate the proposed approach, and satisfactory results were found.

Polymers, 2014

Adobe constructions were widespread in the ancient world, and earth was one of the most used cons... more Adobe constructions were widespread in the ancient world, and earth was one of the most used construction materials in ancient times. Therefore, the preservation of adobe structures, especially against seismic events, is nowadays an important structural issue. Previous experimental tests have shown that the ratio between mortar and brick mechanical properties (i.e., strength, stiffness and elastic modulus) influences the global response of the walls in terms of strength and ductility. Accurate analyses are presented in both the case of unreinforced and reinforced with fiberglass mesh when varying the mechanical properties of the materials composing the adobe masonry structure. The main issues and variability in the behavior of seismic resisting walls when varying the mechanical properties are herein highlighted. The aim of the overall research activity is to improve the knowledge about the structural behavior of adobe structural members unreinforced and reinforced with fiberglass mesh inside horizontal mortar joints.

Dynamic response of asymmetric bodies assuming a rocking behaviour

Proceedings of the Institution of Civil Engineers - Structures and Buildings

Soil bioengineering techniques to repair slope failures and increase slope stability are often us... more Soil bioengineering techniques to repair slope failures and increase slope stability are often used, when possible, as alternatives to traditional structures in order to mitigate environmental impact without compromising effectiveness. However, such techniques use live plants and entrust most of their structural resistance to wood members whose mechanical characteristics diminish with time. To date, the decay of mechanical characteristics of wood elements employed in soil bioengineering techniques and lifetime predictions has been little explored. Such information is also important for durability forecasting. In this paper we present the results of experimental analyses carried out to evaluate the degradation of mechanical properties of untreated timber elements which were collected from single and double live cribwalls or check-dams built about ten years ago in the Vesuvius National Park (Naples, Southern Italy). To help interpret the behavior of a complex material such as wood, a novelty of this study lies not only in combining ultrasonic and sclerometric nondestructive testing (NDT) methods so as to reduce measurement errors, but also in framing the outcomes from mechanical tests within the biological analysis of fungi detected on the timbers. Exploratory statistical analyses reveal that there exist hardly any correlations between moisture contents in the timber elements and both transversal and longitudinal ultrasonic velocities, although some clustering provides insights into the results obtained. Comparisons between results using data measured on " old " and " new " timber elements enable some evaluations of residual safety factor assessment to be carried out.