Roberto Gentile

Roberto Gentile
University College London | UCL · Institute for Risk and Disaster Reduction

PhD in Earthquake Engineering
Assistant Professor (Lecturer) in Catastrophe Risk Modelling

About

54
Publications
29,903
Reads
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576
Citations
Citations since 2016
52 Research Items
569 Citations
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2016201720182019202020212022050100150
Introduction
My research is focused on the seismic assessment of existing structures, with particular reference to reinforced concrete buildings and bridges. Along with numerically-based non-linear static and/or dynamic analyses, I try as much as possible to use “by hand” methods, such as the Displacement-Based Design/Assessment and the Simple Lateral Mechanism Analysis (SLaMA). In this way, I aim to achieve a greater impact with my research, trying to contribute both to the state of the art and practice. Currently I am involved in the INSPIRE project, which aims to assess the impact of earthquakes on school infrastructure in Indonesia and investigate the enhancement of the resilience of schools through retrofitting of buildings, and disaster risk reduction education.
Additional affiliations
August 2018 - present
University College London
Position
  • Research Associate
Description
  • Research Associate in resilience engineering
November 2015 - January 2017
University of Canterbury
Position
  • Researcher
Education
November 2014 - October 2017
Politecnico di Bari
Field of study
  • Seismic engineering

Publications

Publications (54)
Article
Full-text available
This study focuses on scoring, selecting, and developing physical fragility (i.e., the probability of reaching or exceeding a certain DS given a specific hazard intensity) and/or vulnerability (i.e., the probability of impact given a specific hazard intensity) models for assets, with particular emphasis on buildings. Given a set of multiple relevan...
Presentation
Full-text available
Conference presentation on "Relative seismic and tsunami risk assessment: the Stromboli Island (UNESCO site, Italy) case study" for the Va Conference - A. Rittmann. Session S14 - Volcanic risk management in inhabited areas.
Preprint
Recent major earthquake disasters have highlighted the effectiveness of financial soft policies (e.g., earthquake insurance) in transferring seismic risk away from those directly impacted and complementing `hard' disaster risk mitigation measures. However, the benefits of existing financial soft policies are often not guaranteed. This may be attrib...
Preprint
Recent major earthquake disasters have highlighted the effectiveness of financial soft policies (e.g., earthquake insurance) in transferring seismic risk away from those directly impacted and complementing `hard' disaster risk mitigation measures. However, the benefits of existing financial soft policies are often not guaranteed. This may be attrib...
Article
Full-text available
An innovative method of estimating the relative risk of buildings exposed to seismic and tsunami hazards in volcanic islands is applied to Stromboli (Italy), a well-known stratovolcano affected by moderate earthquakes and mass-flow-induced tsunamis. The method uses a pre-existing quali-quantitative analysis to assess the relative risk indices of bu...
Article
Full-text available
This study proposes a practical fragility-oriented approach for the seismic retrofit design of case-study structures. This approach relies on mapping the increase of the global displacement-based ratio of capacity to life-safety demand ( CDR LS ) to the building-level fragility reduction. Specifically, the increase of CDR LS due to retrofitting is...
Technical Report
Full-text available
On the morning of Tuesday, November 26, 2019, at 3:54 local time, an MW 6.4 earthquake struck 16 km north of Durrës, a port city on the Adriatic coast and the second largest city in Albania. The epicenter was 33 km northwest of Tirana, the largest city and capital of Albania. Deaths and injuries were concentrated in Durrës and the village of Thuman...
Article
Full-text available
Earthquake-induced pulse-like ground motions are often observed in near-source conditions due to forward-directivity. Recent worldwide earthquakes have emphasised the severe damage potential of such pulse-like ground motions. This paper introduces a framework to quantify the impact of directivity-induced pulse-like ground motions on the direct econ...
Article
Full-text available
This study investigates the effects of ground-motion sequences on fragility and vulnerability of reinforced concrete (RC) moment-resisting frames (MRFs). Two four-storey, four-bay RC MRFs are selected as case studies. These structures, which share the same geometry, are representative of distinct vulnerability classes in the Mediterranean region an...
Conference Paper
This paper introduces a simplified methodology to develop state-dependent fragility relationships, based on nonlinear static analyses combined with the Cloud Capacity Spectrum Method. Capacity reduction factors for structural members are applied to simulate the attainment of a specific damage state under a mainshock. A cloud-based procedure is adop...
Article
This paper investigates a number of computational issues related to the use of nonlinear static procedures in fragility analysis of structures. Such approaches can be used to complement nonlinear dynamic procedures, reducing the computational and modelling effort. Specifically, this study assesses the performance of the Capacity Spectrum Method (CS...
Article
Full-text available
This paper proposes surrogate models (or metamodels) mapping the parameters controlling the dynamic behaviour of inelastic single‐degree‐of‐freedom (SDoF) systems (i.e., force‐displacement capacity curve, hysteretic behaviour) and the parameters of their probabilistic seismic demand model (PSDM, i.e., conditional distribution of an engineering dema...
Article
Full-text available
Economic earthquake losses can be mitigated through either building retrofit strategies and/or, to some extent, risk-transfer to the (re)insurance market. This paper proposes a computational framework to select the optimal combination of seismic retrofit and insurance policy parameters for buildings. First, a designer selects a suitable retrofit st...
Article
Fragility analysis of structures via numerical methods involves a complex trade-off between the desired accuracy, the explicit consideration of uncertainties (both epistemic and aleatory) related to the numerical structural model and the available computational performance. This paper introduces a framework for deriving numerical fragility relation...
Conference Paper
Full-text available
This study investigates the improvement in the seismic performance of an archetype reinforced concrete (RC) frame due to varying structural retrofit levels. Specifically, the study attempts to map the increase of the displacement-based global ratio between capacity and life-safety demand (CDRLS) to the reduction of seismic fragility. Such a reducti...
Conference Paper
Earthquake-induced ground-motion duration can be an important factor to consider when assessing ground-motion damage potential, as evidenced by recent earthquake events worldwide. In current practice, duration is commonly relegated to implicit, qualitative considerations. This study introduces a framework to explicitly quantify the influence of dur...
Article
Full-text available
This paper investigates the trade-off between simplicity (modelling effort and computational time) and result accuracy in seismic fragility analysis of reinforced concrete (RC) frames. For many applications, simplified methods focusing on “archetype” structural models are often the state-of-practice. These simplified approaches may provide a rapid-...
Article
Full-text available
On the 26th of November 2019, an earthquake of moment magnitude 6.4 struck the northwest region of Albania as the result of thrust faulting near the convergent boundary of the Africa and Eurasia plates causing widespread damage to buildings in the city of Durrës and the surrounding areas. Based on the official data from the national authorities, th...
Article
Full-text available
This paper investigates the relative effect of material properties and structural details in the joint panels on the seismic fragility of existing reinforced concrete (RC) frames. Five building classes with different structural details (particularly in the joint panels) and material characteristics are defined according to different past design cod...
Article
Full-text available
A framework to derive state-dependent fragility relationships of structures subjected to ground-motion sequences (e.g. mainshock-aftershock (MS-AS) or triggered earthquakes) is proposed. The hysteretic energy dissipated in the sequence is adopted as the main demand parameter, as it is a cumulative measure mono-tonically increasing with the length o...
Conference Paper
Fragility curves are commonly used in seismic performance assessment of structures. Various end users/stakeholders have different requirements on this matter: private owners likely need a detailed assessment focused on single buildings or small portfolios of buildings, while government agencies or (re)insurance companies might look at large portfol...
Technical Report
Full-text available
The 26th of November earthquake in northwest Albania affected at least 10 of the country’s 61 municipalities, including the two most populous, urbanized and developed cities Tirana and Durrës. This was the strongest earthquake in Albania for the last 40 years and the worldwide deadliest earthquake for 2019. The Earthquake Engineering Field Investig...
Article
Full-text available
Seismic performance assessment of existing bridges, especially those designed without seismic criteria, is paramount in earthquake-prone countries. To perform this task, the Displacement-Based Assessment (DBA) represents a satisfactory trade-off between simplicity and accuracy. After describing the modal analysis-based DBA procedure, a static-based...
Article
Full-text available
This study deals with selecting optimal seismic retrofit solutions for reinforced concrete (RC) buildings. To this aim, multi-criteria decision-making (MCDM) is implemented explicitly considering earthquake-induced economic loss as a decision criterion. Fragility (i.e. likelihood of damage levels vs intensity measure (IM) levels) and vulnerability...
Article
Full-text available
Seismic fragility assessment of building portfolios is often based on the analysis of “average” building models representative of structural types (or building classes), thus neglecting building-to-building variability within a structural type. This paper proposes the use of Gaussian process (GP) regressions to develop flexible and accurate metamod...
Conference Paper
Full-text available
The inadequacy of the seismic design criteria prior to the introduction of seismic codes decades induces the need to develop simple and reliable assessment procedures for the seismic vulnerability of bridges and viaducts. In this work, a recently-proposed displacement-based procedure is described, which is to represent a simple tool for the quick a...
Conference Paper
Uncertainties related to material properties and structural details in existing buildings can strongly influence the hierarchy of strength at both member and beam-column joint levels, particularly in the case of reinforced concrete frames. In turn, this can affect the global plastic mechanism, the force/displacement capacity of the structure and it...
Conference Paper
Located on the Ring of Fire, Indonesia is a highly earthquake- and tsunami-prone country, continuously experiencing disastrous events (e.g., the recent 2018 Sulawesi earthquake and tsunami). Educational facilities demand special attention in terms of priority for assessment and retrofit, given the strong bond between access to education and develop...
Conference Paper
This study attempts to shed some light on the selection of optimal retrofit solutions for seismically-deficient Reinforced Concrete (RC) buildings. Multi-Criteria Decision-Making (MCDM) analysis is used for the optimal retrofit selection. A discussion on the retrofit design strategy is first presented, recommending designing each retrofit solution...
Conference Paper
Seismic fragility assessment of building portfolios usually involves empirical approaches, or numerical, mechanics-based approaches applied to properly-sampled index buildings representative of defined structural typologies. These approaches often neglect the effect of building-to-building variability on portfolio seismic risk estimates. Alternativ...
Article
Full-text available
Regional seismic risk assessment is paramount in earthquake-prone areas, for instance, to define and implement prioritisation schemes for earthquake risk reduction. As part of the Indonesia School Programme to Increase Resilience (INSPIRE), this paper proposes an ad hoc rapid-visual-survey form, allowing one to (1) calculate the newly proposed INSP...
Article
Full-text available
Regional seismic risk assessment is paramount in earthquake-prone areas, for instance, to define and implement prioritisation schemes for earthquake risk reduction. As part of the Indonesia School Programme to Increase Resilience (INSPIRE), this paper proposes an ad hoc rapid-visual-survey form, allowing one to (1) calculate the newly proposed INSP...
Conference Paper
Seismic fragility assessment of building portfolios usually involves empirical approaches, or numerical, mechanics-based approaches applied to properly-sampled index buildings repre-sentative of defined structural classes. These approaches often neglect the effect of class varia-bility on portfolio seismic risk estimates. Alternatively, metamodelin...
Conference Paper
This study deals with the selection of optimal retrofit solutions for seismically-deficient Rein-forced Concrete (RC) buildings. To this aim, Multi-Criteria Decision-Making (MCDM) analy-sis is used. A discussion on the retrofit design strategy is first presented, recommending de-signing each retrofit solution for the same expected damage state unde...
Conference Paper
Full-text available
In the framework of seismic vulnerability assessment, the displacement-based analytical approaches allow the investigation of the non-linear response of structures with accuracy and low computational effort. This paper deals with a recently-proposed displacement-based analytical pushover addressed to the seismic performance assessment of multi-span...
Article
Full-text available
The Simple Lateral Mechanism Analysis (SLaMA) is an analytical method to assess the force–displacement capacity curve of Reinforced Concrete (RC) structures composed of frames, cantilever walls or dual wall/frame systems. The current version of the method was proposed in the 2017 New Zealand guidelines for the seismic assessment (NZSEE in New Zeala...
Article
Full-text available
Infill walls have significant effects on the global force–displacement curve of Reinforced Concrete (RC) frames, and possibly on the outcome of a seismic performance assessment. Therefore, it is paramount to explicitly consider their presence. An analytical procedure to derive the non-linear static force–displacement curve of infilled frame structu...
Article
A paramount step in seismic assessment of existing structures is the determination of the structural capacity. It is widely recognised that non-linear numerical approaches are arguably the most reliable tool to achieve this goal. However, reliable yet simple analytical procedures are needed to identify potential structural weaknesses and their infl...
Article
The 2017 New Zealand Society for Earthquake Engineering (NZSEE) guidelines for seismic assessment of buildings recommends using Simple Lateral Mechanism Analysis (SLaMA) before implementing numerical analyses. The method and the NZSEE guidelines have been enhanced from the 2006 version, resulting into an efficient procedure, balancing simplicity an...
Article
Full-text available
The seismic vulnerability analysis of multi-span bridges can be based on the response of the piers, provided that deck, bearings and foundations remain elastic. The lateral response of an RC bridge pier can be affected by different mechanisms (i.e., flexure, shear, lap-splice or buckling of the longitudinal reinforcement bars, second order effects)...
Article
Full-text available
The seismic vulnerability analysis of multi-span bridges can be based on the response of the piers, provided that deck, bearings and foundations remain elastic. The lateral response of an RC bridge pier can be affected by different mechanisms (i.e., flexure, shear, lap-splice or buckling of the longitudinal reinforcement bars, second order effects)...
Article
Full-text available
The behaviour of regular multi-span simply-supported bridges is strongly dependent on the behaviour of its piers. The response of a pier is governed, in general, by different mechanisms: flexure, shear, second order effects, lap-splice of longitudinal bars or their buckling. The flexural behaviour is an important part of the problem, and it can be...
Article
Full-text available
The new guidelines for the seismic assessment of existing buildings recently introduced by the New Zealand Society for Earthquake Engineering (NZSEE) recommend the Simple Lateral Mechanism Analysis (SLaMA) as an “analytical” first phase of any other numerically-based analysis. This article illustrates the development of the SLaMA method and its val...
Conference Paper
The presence of infills has substantial effects on the behaviour of frame structural systems, both in the linear and non-linear behaviour. Different effects might arise at global (increase in strength and stiffness, modification of the plastic mechanism) and local level (e.g. triggering of shear failures in the columns). The global effects can be c...
Code
RC section Rect and RC section Circ are two Graphical User Interface softwares for Moment-Curvature analysis of Reinforced Concrete sections. The softwares are freely downloadable at https://www.robertogentile. org/en/rcr and https://www.robertogentile. org/en/rcc, respectively.
Thesis
Full-text available
This dissertation is focused on the extension, refinement and validation of the Simple Lateral Mechanism Analysis (SLaMA) method for the seismic assessment of RC buildings. Suggested in the 2017 New Zealand guidelines for seismic assessment, NZSEE (2017), SLaMA is an analytical non-linear analysis technique that provides a first estimation of the g...
Conference Paper
Seismic assessment of existing buildings is typically based on a Safety-Index (SI) defined as a Capacity/Demand ratio (e.g. “%New-Building-Standard” in New-Zealand or the “Indice di Sicurezza” IS-V in Italy). However, the relationship between the SI and the probability of exceeding the life-safety limit state (LS) is not linear nor univocal. Hence,...
Conference Paper
The seismic response of multi-span RC bridges is often based on the response of the piers, provided that deck, bearings and foundations remain elastic. The seismic response of a RC bridge pier is influenced, in general, by different mechanisms (i.e. flexure, shear, lap-splice or buckling of the longitudinal reinforcement bars, second order effects)...
Technical Report
Full-text available
This report presents the simplified seismic assessment of a case study reinforced concrete (RC) building following the newly developed and refined NZSEE/MBIE guidelines on seismic assessment (NZSEE/MBIE, semi-final draft 26 October 2016). After an overview of the step-by-step ‘diagnostic’ process, including an holistic and qualitative description o...
Conference Paper
Full-text available
The seismic assessment of an existing structure is a complex procedure. In the evaluation of the structural capacity, difficulties arise in the definition of the lateral resisting members , in the estimation of the lateral capacity from component to system level. The identification of the local and global mechanisms, depending on the hierarchy of s...
Article
The transport infrastructure was majorly affected by the 14lh November 2016 Kaikōura Earthquake. Severe vertical and horizontal peak ground accelerations generated high inertial forces, land-slides, and liquefaction. Most of the bridges in the Hurunui, Malborough and Kaikōura districts were critical nodes to the railway and road networks. In total,...
Conference Paper
Per un’analisi di vulnerabilità di un ponte a travata è possibile assumere che la curva di capacità della struttura sia approssimabile con la curva di capacità della pila critica. Il comportamento della pila critica può essere, in generale, influenzato da vari meccanismi quali la flessione, il taglio, gli effetti del second’ordine, lo sfilamento de...
Conference Paper
Full-text available
A seismic vulnerability analysis of a multi-span simply supported bridge is often based on the seismic response of the most critical pier. This response is influenced by different collapse modes (flexural, shear, second order effects, lap-splice of longitudinal bars or their buckling). Among these the flexural behaviour is important and it's known...

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Projects (3)
Archived project
We welcome researchers, students, practioners, NGOs, city professionals and the interested public to a day of thought-provoking discussions where our in-house and guest experts will present the latest research and issues in cascading and interconnected risk, through a combination of talks, panel discussion, conversation, and poster presentations. The conference themes and presentations will promote a better understanding of the multidisciplinary components of cascading and interconnected risk. For more information and registration go to: https://bit.ly/2Kju3TX
Project
Development and Validation of: a) Seismic Assessment Methodologies and Procedures; b) Retrofit Strategies and Techniques for individual buildings or classes of Building; c) Seismic Classifications and Risk Reduction strategies at Territorial Scale. The Project comprise Analytical, Numerical, Experimental Investigations and post-earthquake damage observations.