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Pietro Croce

Università di Pisa, Ingegneria civile, Faculty Member

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PhD, Professor of Structural Engineering and Bridge design at Pisa UniversityConvenor of HGB (Horizontal Group Bridge) of CEN/TC250 "Structural Eurocodes)Member of the Expert Committee for Emergency management of the post Morandi bridge collapse phase in Genoa.

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MariaAntonia Barucco

IUAV University Venice

Pierfrancesco Fiore

University of Salerno

Giuseppina E Cinque

"Tor Vergata" University of Rome

University of Calabria

The University of Auckland

Carmine Fallico

Università della Calabria

University of East London

Gwen Robbins Schug

University of North Carolina at Greensboro

Gabriel Gutierrez-Alonso

University of Salamanca

Macquarie University

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Papers by Pietro Croce

New Frontiers of Composites Applications in Heritage Buildings: Repair of Exposed Masonry of St. Nicola Church in Pisa

Journal of composites science, Aug 13, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

Assessing the risk of disregarding urgent maintenance interventions on waterways infrastructures

We propose a method for the prioritization of maintenance interventions already classified as urg... more We propose a method for the prioritization of maintenance interventions already classified as urgent on waterways infrastructures, and especially locks. The method is based on the risk of the realization of a failure scenario due to damage processes. The probability of failure is computed by modelling the damage evolution as a stochastic process; the consequences which are considered are: additional cost of repairing after failure, number of fatalities, and the rate of lost customers upon an interruption of the lock service. Since quantifying all the consequences in economic terms could be difficult if not impossible, another approach is applied, which allows the aggregation of the consequences expressed in different scales. The suggested procedure, which has its roots in the probability applied to engineering, aims at supporting the planning of maintenance interventions on waterways infrastructures when resources and investment are limited.

Applying Queueing Theory for Managing Waterways Systems subject to Service Interruptions

Institutional Repository University of Antwerp (University of Antwerp), 2018

One of the main requisites for any public or private company operating in the transportation sect... more One of the main requisites for any public or private company operating in the transportation sector is to comply with high safety standards, besides providing to customers adequate service levels such as punctuality, comfort, reasonable prices and limited environmental impact. Those aspects are particularly critical within the public transport sector when dealing with passengers. To allow each passenger to reach its destination safely, public utility companies and/or private operators should built and maintain safe transport networks. Most of the time, to increase the overall service levels and or to comply with more stringent safety regulations, significant investments on modern technologies or infrastructure are needed. In fact, such safety investments could have significant impact in preventing accidents from happening or in reducing the consequences of such unwanted events. In this work, an optimization model is developed to support decision makers aimed at increasing the overall safety levels in a rail network. The model could be effectively used to select the optimal mix of safety measures depending on the specific features of each rail segment and given some major constraints such as a maximum budget and a strict deadline to complete the installation works. In addition, the user could use the model as a simulation tool to verify the impact on safety of different safety budgets and time horizons to support and/or influence public authorities when allocating priorities on different projects and finally make public investments more effective for citizens

Availability and Performance Measures for Planning Maintenance Actions on Waterways Networks

Proceedings of the 29th European Safety and Reliability Conference (ESREL), 2019

A today's challenge in civil engineering is to plan maintenance activities on network of infrastr... more A today's challenge in civil engineering is to plan maintenance activities on network of infrastructures. Among several difficulties, there is also a communication problem between engineers and managers. In particular, it is of paramount importance that engineers deliver results in a way that managers can understand. Only in this way optimal decision can be met. Pursuing this scope, and focusing the attention on the German network of waterways, whose infrastructures are affected by aging problems and require maintenance, we resort to queueing theory in order to express the networks performance and availability measures in a compact and analytic way. This approach allows us to easily compare and optimize maintenance plans, also facilitating the communication between engineers and managers. A case study is developed, in which we demonstrate how performance and availability measures can be implemented for planning maintenance intervention on a network of locks. The ultimate scope is to shift the current maintenance practice towards a more mature maintenance management system, in which the waterways networks morphology and the amount of traffic are also considered.

Tie Rod-Equivalent Non-Linear Constitutive Law for Uniformly Loaded Cables

Materials, Sep 23, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

Equivalent Axial Stiffness of Horizontal Stays

Applied sciences, Sep 9, 2020

Cable-stayed structures are widely employed in several fields of civil, industrial, electrical an... more Cable-stayed structures are widely employed in several fields of civil, industrial, electrical and ocean engineering. Typical applications are cable-stayed building roofs, bridges, guyed masts, overhead electrical lines, and floating device anchorages. Since the cable behavior is often highly nonlinear, suitable equivalent mechanical cable models are often adopted in analyzing this kind of structures. Usually, like in the classical Dischinger's approach, stays are treated as straight rods offering an equivalent axial tangent stiffness, so that each of them can be substituted with an appropriate equivalent nonlinear spring or truss element. Formulae expressing equivalent stiffness provided by classical methods are satisfactory only when the cable is highly stressed, and therefore its sag is small with respect to its chord; on the contrary, when the cable is slack, they give often contradictory or meaningless results. Aiming to remove that limitation, a more refined approach based on the application of the virtual work principle is discussed. Important products of that original rational criterion are accurate and closed form innovative expressions of the tangent stiffness of the cable, whose field of application is independent on the sag to chord ratio of the cable, as well as on the magnitude of the normal stresses. Referring to some relevant case studies, the results obtained applying these new formulae are critically discussed for cables made of different materials, also in comparison with the approximate expressions provided by simplified methods.

Nonlinear Dynamics of Swinging Clapper Bells under Arbitrary or Resonant Forcing Functions

Applied sciences, Aug 10, 2020

Innovative algorithms to solve the system of nonlinear ordinary differential equations governing ... more Innovative algorithms to solve the system of nonlinear ordinary differential equations governing free and forced oscillations of swinging clapper bells, duly considering the clapper impacts, are discussed. These algorithms provide the time histories of the relevant motion parameters of bell and clapper: rotations, angular velocities, angular accelerations, radial excitations at the pivots, and so on, also considering friction and viscous damping, if present. For its generality, the proposed method is particularly suitable not only to assess the bell "ringability", but also the determine the excitation transmitted by the swinging bell to the supporting structures under arbitrary forcing functions.

Impact of Road Traffic Tendency in Europe on Fatigue Assessment of Bridges

Applied sciences, Feb 19, 2020

Fatigue load models for road bridges given in the Eurocode EN1991-2 have been calibrated consider... more Fatigue load models for road bridges given in the Eurocode EN1991-2 have been calibrated considering real traffic measurements that became available around 1990. Since then, traffic composition has evolved considerably, also considering the issuing of the 96/53/EC Directive, which legitimated member states, on an equal and not discriminatory basis, to allow the circulation of Long and Heavy Vehicles (LHVs). Thus, the appropriateness of fatigue load models to cover also the effects of these vehicles, which are longer, heavier and potentially more damaging than common Heavy Goods Vehicles (HGVs), became an issue. The aim of the study is to assess how the evolution of European traffic influences the fatigue assessment of bridges. To capture the essence of the problem, three different real traffic measurements are compared in terms of fatigue damage: the Auxerre (FR) traffic, adopted to define fatigue load models in EN1991-2; the Moerdijk (NL) traffic, characterized by a high percentage of LHVs; and the Igualada (ES) traffic. To assess the current relevance of fatigue load models LM2 and LM4 of EN1991-2, the aptitude of these models to adequately reproduce the effects caused by LHVs is discussed in detail. The results demonstrate that the Auxerre traffic is still the most onerous; that the Moerdijk traffic is generally more severe than the Igualada traffic, and that the fatigue load models of Eurocode do not require major updates. The study is further supplemented by investigating the suitability of the formulae provided in the Eurocodes for the damage equivalence factors λ 2 and λ 3 to express the influence of the total lorry volume on the fatigue damage. In that latter case, the conclusion is that the formulae proposed in the Eurocodes, based on the assumption of a linear fatigue strength S-N curve with constant conventional slope m, could lead to erroneous, even unsafe, estimates of the fatigue life, especially when details are characterized by constant amplitude fatigue limit ∆σ D , thus calling for further improvements of the formulae themselves.

Environmental and Economic Impact of Retrofitting Techniques to Prevent Out-of-Plane Failure Modes of Unreinforced Masonry Buildings

Sustainability, Oct 15, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

L'Acquedotto Mediceo: diagnosi dei dissesti

gPCE-Based Stochastic Inverse Methods: A Benchmark Study from a Civil Engineer’s Perspective

Infrastructures, Nov 5, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

Probabilistic Models for Vehicle Interactions in Fatigue Assessment of Bridges

Applied sciences, Dec 6, 2019

Fatigue assessments of bridges depend on vehicle interactions, occurring when several vehicles tr... more Fatigue assessments of bridges depend on vehicle interactions, occurring when several vehicles travel simultaneously on the bridge or when two individual stress histories, caused by vehicles traveling in different times, generate a more damaging combined stress history. When interactions are significant, stress histories cannot be directly determined using conventional fatigue load models provided in Codes, unless suitable theoretical models for vehicle interactions are available. In the paper, original approaches are proposed to study different aspects of the problem. Concerning interactions due to simultaneity, the novelty is to consider the bridge a service system. Since the process of vehicle arrivals is a Markov process, vehicle interactions can be studied in the framework of the queuing theory. In this way, in the appropriate context, interacting vehicles are equivalent to queued requests (vehicles) in the service system. The method considers two subcases, to be tackled in the given sequence, so that the solution is noticeably simplified. The first subcase refers to vehicles traveling simultaneously in one lane; the second subcase to vehicle and vehicle convoys traveling simultaneously on two or more lanes. In the first subcase the problem is solved considering each lane as a single channel system with a waiting queue, where the number of vehicles in the queue and the waiting time, depending on the number of vehicles in the queue, are limited. A modified vehicle flow on each bridge lane is thus obtained, composed by vehicles and vehicle convoys separately traveling the lane, which is, if relevant, the input for the second subcase. In the second subcase the multilane bridge is modeled as a multichannel system without the waiting queue. When the number of requests exceeds the number of channels, r, the surplus is lost and cannot reenter the system. The results regarding simultaneity are much more relevant than it appears at the first sight: Two relevant examples demonstrated that they can be fruitfully used to implement optimized Monte Carlo algorithms for artificial traffic generation, as well for adaptation of traffic measurements, when flows are modified. Finally, a "non-interacting traffic flow" is obtained, whose elements (vehicle, vehicle convoy, cluster of vehicles) travel individually on the bridge. The global stress history results thus a mere random assembly of the stress histories induced by each element of the non-interacting traffic flow. These stress histories can only combine, as simultaneity interactions are excluded for them. Combination of stress histories is a complex issue, especially when, as in the Eurocodes, fatigue load models are composed by a set of standardized lorries. In fact, questions concerning: Conditions for the combination; stress history which can combine; expected number of occurrences of combined stress histories and of the remaining individual ones; are still open. Really, they can be tackled resorting to sophisticated and time-consuming simulations based on Monte Carlo methods, but elementary solutions have not been proposed so far. The original method proposed here, whose practical application is illustrated referring to an important case study, allows to solve the problem providing simple recursive formulae. Finally, two relevant examples illustrate, with specific reference to the Eurocodes, some important implications of the study.

Implication of Climate Change on Climatic Actions on Structures: the Update of Climatic Load Maps

IABSE Symposium, Wroclaw 2020: Synergy of Culture and Civil Engineering – History and Challenges

Climate change could heavily affect climatic actions on structures. Indeed, the current definitio... more Climate change could heavily affect climatic actions on structures. Indeed, the current definition of climatic actions in structural codes, snow wind thermal and icing loads, is based on the assumption of stationary climate conditions but climate is not stationary and the observed accelerated rate of changes must be considered. A proper evaluation of the consequences of climate change requires the set-up of procedures able to deal with the analysis of climate projections and their intrinsic uncertainties.In the paper, a general methodology is illustrated, aiming to evaluate the impact of climate change on structural design. The proposed procedure is based on the definition of factors of change for climate extremes in moving time windows derived from the analysis of an ensemble of climate projections according different greenhouse gas emission scenarios, combined with an innovative weather generator to obtain a probabilistic description of future changes.The definition of a suitable ...

An Integrated BIM Methodology for the Seismic Assessment of Masonry Buildings

IABSE Symposium, Wroclaw 2020: Synergy of Culture and Civil Engineering – History and Challenges

Building Information Modelling is one of the most innovative and promising technologies that are ... more Building Information Modelling is one of the most innovative and promising technologies that are taking place in the construction industry. However, BIM implementation in structural engineering is not as common as in architectural design and this becomes more evident dealing with the maintenance and refurbishment of existing buildings. In this context, the implementation of an integrated BIM methodology for the assessment of the seismic performance of existing masonry buildings is proposed based on a non-linear static algorithm, called E-PUSH, previously developed by the authors. An effective workflow is defined, relying on software’s interoperability at the architectural and structural level, able to create a dynamic, customized and flexible procedure. The proposed methodology has been developed and critically analysed through real case studies and it may be extended to an increasingly broad collection of existing buildings. It offers an integrated solution for the assessment and m...

The Definition of Drift Capacity of Walls in the Seismic Assessment of Masonry Buildings

IABSE Symposium, Wroclaw 2020: Synergy of Culture and Civil Engineering – History and Challenges

The global assessment of the seismic performance of masonry buildings is commonly obtained perfor... more The global assessment of the seismic performance of masonry buildings is commonly obtained performing nonlinear static analysis. Since the mechanical properties and the drift capacity of masonry walls are characterized by significant uncertainties, the definition of suitable capacity curves for masonry walls is topical. A comparative study is performed considering: the different formulations given in structural codes (Eurocode 8, Italian, Swiss, New Zealand Building Code), FEMA guidelines, the empirical formulations proposed by recent studies and the first definition of drift capacity in terms of ductility factors proposed for the implementation of the non-linear static analysis. The results are illustrated for a relevant case study of a three storey masonry buildings, and show that high differences in terms of seismic risk indexes are obtained according the different formulations, even leading to divergent conclusions about the structural safety of the building. The critical discus...

Evaluating the effect of climate change on thermal actions on structures

6th International Symposium on Life-Cycle Civil Engineering, IALCCE 2018, 2019

Moderne tendenze di traffico e verifiche a fatica dei ponti in acciaio

XXII Congesso CTA - L'acciaio per un futuro sostenibile, 2009

Control of dynamic stability of stays using passive viscous dampers

Since cable vibrations cause cable-stayed bridge users discomfort and may also lead to bridge col... more Since cable vibrations cause cable-stayed bridge users discomfort and may also lead to bridge collapse, assessment and control of dynamic behavior of stays are key aspects in designing such a bridge type. Mounting viscous dampers close to deck anchorages is an efficient way to control all kind of cable vibrations. In the paper, relevant issues as parametric excitation, external excitation and cable-structure interaction are investigated in order to define the required damping ratio to control the dynamic stability of stays. The study ends with a damper design example, referring to a relevant case study. Keywords—cable-stayed bridge, cable vibrations, cablestructure interaction, viscous damper.

Operational Methods for the Assessment and Management of Aging Infrastructure

This project has been funded with support from the European Commission. This publication [communi... more This project has been funded with support from the European Commission. This publication [communication] reflects the views only of the author, and the Commission cannot be held responsible for any use which may be made of the information contained therein. OPERATIONAL METHODS FOR THE ASSESSMENT AND MANAGEMENT OF AGING INFRASTRUCTURE

Analisi sperimentale del comportamento statico e ciclico di connessioni tegolo-trave di strutture prefabbricate

New Frontiers of Composites Applications in Heritage Buildings: Repair of Exposed Masonry of St. Nicola Church in Pisa

Journal of composites science, Aug 13, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

Assessing the risk of disregarding urgent maintenance interventions on waterways infrastructures

We propose a method for the prioritization of maintenance interventions already classified as urg... more We propose a method for the prioritization of maintenance interventions already classified as urgent on waterways infrastructures, and especially locks. The method is based on the risk of the realization of a failure scenario due to damage processes. The probability of failure is computed by modelling the damage evolution as a stochastic process; the consequences which are considered are: additional cost of repairing after failure, number of fatalities, and the rate of lost customers upon an interruption of the lock service. Since quantifying all the consequences in economic terms could be difficult if not impossible, another approach is applied, which allows the aggregation of the consequences expressed in different scales. The suggested procedure, which has its roots in the probability applied to engineering, aims at supporting the planning of maintenance interventions on waterways infrastructures when resources and investment are limited.

Applying Queueing Theory for Managing Waterways Systems subject to Service Interruptions

Institutional Repository University of Antwerp (University of Antwerp), 2018

One of the main requisites for any public or private company operating in the transportation sect... more One of the main requisites for any public or private company operating in the transportation sector is to comply with high safety standards, besides providing to customers adequate service levels such as punctuality, comfort, reasonable prices and limited environmental impact. Those aspects are particularly critical within the public transport sector when dealing with passengers. To allow each passenger to reach its destination safely, public utility companies and/or private operators should built and maintain safe transport networks. Most of the time, to increase the overall service levels and or to comply with more stringent safety regulations, significant investments on modern technologies or infrastructure are needed. In fact, such safety investments could have significant impact in preventing accidents from happening or in reducing the consequences of such unwanted events. In this work, an optimization model is developed to support decision makers aimed at increasing the overall safety levels in a rail network. The model could be effectively used to select the optimal mix of safety measures depending on the specific features of each rail segment and given some major constraints such as a maximum budget and a strict deadline to complete the installation works. In addition, the user could use the model as a simulation tool to verify the impact on safety of different safety budgets and time horizons to support and/or influence public authorities when allocating priorities on different projects and finally make public investments more effective for citizens

Availability and Performance Measures for Planning Maintenance Actions on Waterways Networks

Proceedings of the 29th European Safety and Reliability Conference (ESREL), 2019

A today's challenge in civil engineering is to plan maintenance activities on network of infrastr... more A today's challenge in civil engineering is to plan maintenance activities on network of infrastructures. Among several difficulties, there is also a communication problem between engineers and managers. In particular, it is of paramount importance that engineers deliver results in a way that managers can understand. Only in this way optimal decision can be met. Pursuing this scope, and focusing the attention on the German network of waterways, whose infrastructures are affected by aging problems and require maintenance, we resort to queueing theory in order to express the networks performance and availability measures in a compact and analytic way. This approach allows us to easily compare and optimize maintenance plans, also facilitating the communication between engineers and managers. A case study is developed, in which we demonstrate how performance and availability measures can be implemented for planning maintenance intervention on a network of locks. The ultimate scope is to shift the current maintenance practice towards a more mature maintenance management system, in which the waterways networks morphology and the amount of traffic are also considered.

Tie Rod-Equivalent Non-Linear Constitutive Law for Uniformly Loaded Cables

Materials, Sep 23, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

Equivalent Axial Stiffness of Horizontal Stays

Applied sciences, Sep 9, 2020

Cable-stayed structures are widely employed in several fields of civil, industrial, electrical an... more Cable-stayed structures are widely employed in several fields of civil, industrial, electrical and ocean engineering. Typical applications are cable-stayed building roofs, bridges, guyed masts, overhead electrical lines, and floating device anchorages. Since the cable behavior is often highly nonlinear, suitable equivalent mechanical cable models are often adopted in analyzing this kind of structures. Usually, like in the classical Dischinger's approach, stays are treated as straight rods offering an equivalent axial tangent stiffness, so that each of them can be substituted with an appropriate equivalent nonlinear spring or truss element. Formulae expressing equivalent stiffness provided by classical methods are satisfactory only when the cable is highly stressed, and therefore its sag is small with respect to its chord; on the contrary, when the cable is slack, they give often contradictory or meaningless results. Aiming to remove that limitation, a more refined approach based on the application of the virtual work principle is discussed. Important products of that original rational criterion are accurate and closed form innovative expressions of the tangent stiffness of the cable, whose field of application is independent on the sag to chord ratio of the cable, as well as on the magnitude of the normal stresses. Referring to some relevant case studies, the results obtained applying these new formulae are critically discussed for cables made of different materials, also in comparison with the approximate expressions provided by simplified methods.

Nonlinear Dynamics of Swinging Clapper Bells under Arbitrary or Resonant Forcing Functions

Applied sciences, Aug 10, 2020

Innovative algorithms to solve the system of nonlinear ordinary differential equations governing ... more Innovative algorithms to solve the system of nonlinear ordinary differential equations governing free and forced oscillations of swinging clapper bells, duly considering the clapper impacts, are discussed. These algorithms provide the time histories of the relevant motion parameters of bell and clapper: rotations, angular velocities, angular accelerations, radial excitations at the pivots, and so on, also considering friction and viscous damping, if present. For its generality, the proposed method is particularly suitable not only to assess the bell "ringability", but also the determine the excitation transmitted by the swinging bell to the supporting structures under arbitrary forcing functions.

Impact of Road Traffic Tendency in Europe on Fatigue Assessment of Bridges

Applied sciences, Feb 19, 2020

Fatigue load models for road bridges given in the Eurocode EN1991-2 have been calibrated consider... more Fatigue load models for road bridges given in the Eurocode EN1991-2 have been calibrated considering real traffic measurements that became available around 1990. Since then, traffic composition has evolved considerably, also considering the issuing of the 96/53/EC Directive, which legitimated member states, on an equal and not discriminatory basis, to allow the circulation of Long and Heavy Vehicles (LHVs). Thus, the appropriateness of fatigue load models to cover also the effects of these vehicles, which are longer, heavier and potentially more damaging than common Heavy Goods Vehicles (HGVs), became an issue. The aim of the study is to assess how the evolution of European traffic influences the fatigue assessment of bridges. To capture the essence of the problem, three different real traffic measurements are compared in terms of fatigue damage: the Auxerre (FR) traffic, adopted to define fatigue load models in EN1991-2; the Moerdijk (NL) traffic, characterized by a high percentage of LHVs; and the Igualada (ES) traffic. To assess the current relevance of fatigue load models LM2 and LM4 of EN1991-2, the aptitude of these models to adequately reproduce the effects caused by LHVs is discussed in detail. The results demonstrate that the Auxerre traffic is still the most onerous; that the Moerdijk traffic is generally more severe than the Igualada traffic, and that the fatigue load models of Eurocode do not require major updates. The study is further supplemented by investigating the suitability of the formulae provided in the Eurocodes for the damage equivalence factors λ 2 and λ 3 to express the influence of the total lorry volume on the fatigue damage. In that latter case, the conclusion is that the formulae proposed in the Eurocodes, based on the assumption of a linear fatigue strength S-N curve with constant conventional slope m, could lead to erroneous, even unsafe, estimates of the fatigue life, especially when details are characterized by constant amplitude fatigue limit ∆σ D , thus calling for further improvements of the formulae themselves.

Environmental and Economic Impact of Retrofitting Techniques to Prevent Out-of-Plane Failure Modes of Unreinforced Masonry Buildings

Sustainability, Oct 15, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

L'Acquedotto Mediceo: diagnosi dei dissesti

gPCE-Based Stochastic Inverse Methods: A Benchmark Study from a Civil Engineer’s Perspective

Infrastructures, Nov 5, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

Probabilistic Models for Vehicle Interactions in Fatigue Assessment of Bridges

Applied sciences, Dec 6, 2019

Fatigue assessments of bridges depend on vehicle interactions, occurring when several vehicles tr... more Fatigue assessments of bridges depend on vehicle interactions, occurring when several vehicles travel simultaneously on the bridge or when two individual stress histories, caused by vehicles traveling in different times, generate a more damaging combined stress history. When interactions are significant, stress histories cannot be directly determined using conventional fatigue load models provided in Codes, unless suitable theoretical models for vehicle interactions are available. In the paper, original approaches are proposed to study different aspects of the problem. Concerning interactions due to simultaneity, the novelty is to consider the bridge a service system. Since the process of vehicle arrivals is a Markov process, vehicle interactions can be studied in the framework of the queuing theory. In this way, in the appropriate context, interacting vehicles are equivalent to queued requests (vehicles) in the service system. The method considers two subcases, to be tackled in the given sequence, so that the solution is noticeably simplified. The first subcase refers to vehicles traveling simultaneously in one lane; the second subcase to vehicle and vehicle convoys traveling simultaneously on two or more lanes. In the first subcase the problem is solved considering each lane as a single channel system with a waiting queue, where the number of vehicles in the queue and the waiting time, depending on the number of vehicles in the queue, are limited. A modified vehicle flow on each bridge lane is thus obtained, composed by vehicles and vehicle convoys separately traveling the lane, which is, if relevant, the input for the second subcase. In the second subcase the multilane bridge is modeled as a multichannel system without the waiting queue. When the number of requests exceeds the number of channels, r, the surplus is lost and cannot reenter the system. The results regarding simultaneity are much more relevant than it appears at the first sight: Two relevant examples demonstrated that they can be fruitfully used to implement optimized Monte Carlo algorithms for artificial traffic generation, as well for adaptation of traffic measurements, when flows are modified. Finally, a "non-interacting traffic flow" is obtained, whose elements (vehicle, vehicle convoy, cluster of vehicles) travel individually on the bridge. The global stress history results thus a mere random assembly of the stress histories induced by each element of the non-interacting traffic flow. These stress histories can only combine, as simultaneity interactions are excluded for them. Combination of stress histories is a complex issue, especially when, as in the Eurocodes, fatigue load models are composed by a set of standardized lorries. In fact, questions concerning: Conditions for the combination; stress history which can combine; expected number of occurrences of combined stress histories and of the remaining individual ones; are still open. Really, they can be tackled resorting to sophisticated and time-consuming simulations based on Monte Carlo methods, but elementary solutions have not been proposed so far. The original method proposed here, whose practical application is illustrated referring to an important case study, allows to solve the problem providing simple recursive formulae. Finally, two relevant examples illustrate, with specific reference to the Eurocodes, some important implications of the study.

Implication of Climate Change on Climatic Actions on Structures: the Update of Climatic Load Maps

IABSE Symposium, Wroclaw 2020: Synergy of Culture and Civil Engineering – History and Challenges

Climate change could heavily affect climatic actions on structures. Indeed, the current definitio... more Climate change could heavily affect climatic actions on structures. Indeed, the current definition of climatic actions in structural codes, snow wind thermal and icing loads, is based on the assumption of stationary climate conditions but climate is not stationary and the observed accelerated rate of changes must be considered. A proper evaluation of the consequences of climate change requires the set-up of procedures able to deal with the analysis of climate projections and their intrinsic uncertainties.In the paper, a general methodology is illustrated, aiming to evaluate the impact of climate change on structural design. The proposed procedure is based on the definition of factors of change for climate extremes in moving time windows derived from the analysis of an ensemble of climate projections according different greenhouse gas emission scenarios, combined with an innovative weather generator to obtain a probabilistic description of future changes.The definition of a suitable ...

An Integrated BIM Methodology for the Seismic Assessment of Masonry Buildings

IABSE Symposium, Wroclaw 2020: Synergy of Culture and Civil Engineering – History and Challenges

Building Information Modelling is one of the most innovative and promising technologies that are ... more Building Information Modelling is one of the most innovative and promising technologies that are taking place in the construction industry. However, BIM implementation in structural engineering is not as common as in architectural design and this becomes more evident dealing with the maintenance and refurbishment of existing buildings. In this context, the implementation of an integrated BIM methodology for the assessment of the seismic performance of existing masonry buildings is proposed based on a non-linear static algorithm, called E-PUSH, previously developed by the authors. An effective workflow is defined, relying on software’s interoperability at the architectural and structural level, able to create a dynamic, customized and flexible procedure. The proposed methodology has been developed and critically analysed through real case studies and it may be extended to an increasingly broad collection of existing buildings. It offers an integrated solution for the assessment and m...

The Definition of Drift Capacity of Walls in the Seismic Assessment of Masonry Buildings

IABSE Symposium, Wroclaw 2020: Synergy of Culture and Civil Engineering – History and Challenges

The global assessment of the seismic performance of masonry buildings is commonly obtained perfor... more The global assessment of the seismic performance of masonry buildings is commonly obtained performing nonlinear static analysis. Since the mechanical properties and the drift capacity of masonry walls are characterized by significant uncertainties, the definition of suitable capacity curves for masonry walls is topical. A comparative study is performed considering: the different formulations given in structural codes (Eurocode 8, Italian, Swiss, New Zealand Building Code), FEMA guidelines, the empirical formulations proposed by recent studies and the first definition of drift capacity in terms of ductility factors proposed for the implementation of the non-linear static analysis. The results are illustrated for a relevant case study of a three storey masonry buildings, and show that high differences in terms of seismic risk indexes are obtained according the different formulations, even leading to divergent conclusions about the structural safety of the building. The critical discus...

Evaluating the effect of climate change on thermal actions on structures

6th International Symposium on Life-Cycle Civil Engineering, IALCCE 2018, 2019

Moderne tendenze di traffico e verifiche a fatica dei ponti in acciaio

XXII Congesso CTA - L'acciaio per un futuro sostenibile, 2009

Control of dynamic stability of stays using passive viscous dampers

Since cable vibrations cause cable-stayed bridge users discomfort and may also lead to bridge col... more Since cable vibrations cause cable-stayed bridge users discomfort and may also lead to bridge collapse, assessment and control of dynamic behavior of stays are key aspects in designing such a bridge type. Mounting viscous dampers close to deck anchorages is an efficient way to control all kind of cable vibrations. In the paper, relevant issues as parametric excitation, external excitation and cable-structure interaction are investigated in order to define the required damping ratio to control the dynamic stability of stays. The study ends with a damper design example, referring to a relevant case study. Keywords—cable-stayed bridge, cable vibrations, cablestructure interaction, viscous damper.

Operational Methods for the Assessment and Management of Aging Infrastructure

This project has been funded with support from the European Commission. This publication [communi... more This project has been funded with support from the European Commission. This publication [communication] reflects the views only of the author, and the Commission cannot be held responsible for any use which may be made of the information contained therein. OPERATIONAL METHODS FOR THE ASSESSMENT AND MANAGEMENT OF AGING INFRASTRUCTURE

Analisi sperimentale del comportamento statico e ciclico di connessioni tegolo-trave di strutture prefabbricate