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Performance-based earthquake engineering (PBEE) has become an important framework for quantifying seismic losses. However, due to its computationally expensive implementation through a typically detailed component-based approach (i.e. Federal Emergency Management Agency (FEMA) P-58), it has primarily been used within academic research and specific studies. A simplified alternative more desirable for practitioners is based on story loss functions (SLFs), which estimate a building’s expected monetary loss per story due to seismic demand. These simplified SLFs reduce the data required compared to a detailed study, which is especially true at a design stage, where detailed component information is likely yet to be defined. This article proposes a Python-based toolbox for the development of user-specific and customizable SLFs for use within seismic design and assessment of buildings. It outlines the implementation procedure alongside a comparative demonstration of its application where dependency and correlation of damage states between different components are considered. Finally, a comparison of SLF-based and component-based loss estimation approaches is carried out through the application to a real case study school building. The agreement and consistency of the attained loss metrics demonstrate the quality and ease of the SLF-based approach in achieving accurate results for a more expedite assessment of building performance.

The improvement of the seismic performance of existing buildings is majorly accomplished by adopting one or more retrofitting interventions. The selection of the latter is generally made considerin...

Loss assessment methodologies have been introduced to assess the seismic performance of buildings using more meaningful metrics like direct monetary losses. Different approaches exist, each with va...

State-of-the-art seismic performance assessment of buildings requires a realistic estimation of the repair cost of structural and non-structural components. In this context, the US-based FEMA P-58 guidelines feature a procedure and repair cost database that have become a reference to many recent studies in the field. The number of cases in which it has been applied to Europe is however limited, and repair cost conversion factors have been generally adopted. Moreover, a rational methodology that covers multiple countries in a consistent manner is absent in the literature. This study attempts to address this gap, proposing an economy analysis–based repair cost conversion approach that will be useful for practical implementations of FEMA-P58 in Europe. The proposed conversion approach is validated with actual replacement costs monitored in the L’Aquila reconstruction process. While observing a good agreement between the real and estimated US-to-local repair cost ratios, limitations of the proposed methodology are also outlined and discussed, with a view to guide possible future research efforts to improve and consolidate the proposed conversion method.

Despite the wide range of possible scenarios in the aftermath of a disruptive event, each community can make choices to improve its resilience, or its ability to bounce back. A resilient community is one that has prepared for, and can thus absorb, recover from, and adapt to the disruptive event. One important aspect of the recovery phase is assessing the extent of the damage in the built environment through post-event building inspections. In this paper, we develop and demonstrate a resilience-based methodology intended to support rapid post-event decision-making about inspection priorities with limited information. The method uses the basic characteristics of the building stock in a community (floor area, number of stories, type of construction and configuration) to assign structure-specific fragility functions to each building. For an event with a given seismic intensity, the probability of each building reaching a particular damage state is determined, and is used to predict the actual building states and priorities for inspection. Losses are computed based on building usage category, estimated inspection costs, the consequences of erroneous decisions, and the potential for unnecessary restrictions in access. The aim is to provide a means for a community to make rapid cost-based decisions related to inspection of their building inventory. We pose the decision problem as an integer optimization problem that attempts to minimize the expected loss to the community. The advantages of this approach are that it: (i) is simple, (ii) requires minimal inventory data, (iii) is easily scalable, and (iv) does not require significant computing power. Use of this approach before the hazard event can also provide a community with the means to plan and allocate resources in advance of an event to achieve the desirable resiliency goals of the community.

Earthquake-induced structural damage, characterised by the exceedance of different damage states during ground shaking, is typically quantified using fragility curves generated through non-linear dynamic analyses often requiring a large computational effort. This level of effort has led to the necessity of simplified methods and approximate analysis tools. In this regard, SPO2IDA has emerged as a convenient tool for the assessment of structures. It relates a structure’s backbone characteristics to a set of incremental dynamic analysis (IDA) curves using static pushover analysis (SPO) results and a library of empirical fitting coefficients for the different branches of the idealised SPO backbone. It permits the quantification of structural performance up to structural collapse as a function of seismic intensity in a simple and efficient manner. It has been developed mainly for ductile structures that can be sufficiently represented via a SPO backbone with a certain ductile post-yield hardening followed by a post-peak degradation. This behaviour is quite representative of ductile RC and steel moment-resisting frames and has resulted in the tool being widely adopted. However, the same may not be observed when dealing with reinforced concrete (RC) frames with masonry infill, a structural typology that still requires significant addressing in the earthquake engineering field. The present study describes an extension to this methodology for structural typologies with a more particular backbone behaviour, typical of RC frames with masonry infill panels, since differences in backbone behaviour compared to typical structures render the extension of the original tool inappropriate and at times unconservative. Extensive analyses were conducted to investigate the behaviour and trends when pushing infilled RC frames up to complete structural collapse. A new library of empirical coefficients was then fitted and proposed by considering a large database of representative backbones to result in an extended SPO2IDA proposal for infilled RC frames. It is then shown how these coefficients provide a much-improved matching, when compared to the original tool for this specific case, both in terms of the produced IDA traces and also the drift-based mean annual rates of exceedance.

The research reported herein aims at the proposal of an accurate and efficient simplified numerical modelling approach for circular concrete-filled steel tubular (CFST) members under flexural loading. Experimental tests were carried out to characterize the bending behaviour of CFST members under monotonic and cyclic loading. The observed behaviour was characterized by strength and stiffness deterioration effects, as a result of the development of local buckling of the steel tube and cracking of the concrete core. Numerical simulations of these tests were conducted by resorting to existing modelling approaches, namely through Distributed Plasticity (DP) and Concentrated Plasticity (CP) models. It was found that existing modelling approaches failed to accurately capture the levels of strength deterioration and pinching effects observed in the tests. Thus, a novel CP-based simplified model, designated by matCFSTdet, was implemented in OpenSees. The hysteretic response of the CP model is based on a novel rotational spring model. An advanced calibration framework was introduced with targets to calibrate the accuracy of the model. The validation analyses indicate that the model is able to capture well the deterioration in both strength and stiffness of CFST members under cyclic flexural loading. Furthermore, the elastic stiffness, ultimate strength and the pinching effects of the hysteretic loops were also well simulated. The proposed CP model, coupled with the advanced calibration framework, thus results in a more realistic simulation of the cyclic flexural response of circular CFST members.

This article presents a procedure for designing rockfill toe protections with a highly permeable downstream shoulder to avoid mass sliding in dams during extremely high through-flow episodes. This accidental through-flow may be caused by reasons such as overtopping or leakage flow due to the loss of sealing at the impervious element of the dam or its foundation. The proposed protection is located at the downstream toe of the dam, and it is composed of highly permeable material, typically compacted rockfill. This material can be different from the rockfill forming the downstream shoulder of the main dam. The work is a result of a combination of numerical and experimental research carried out to analyze the influence of the geometry of the toe protection for given material properties of both dam shoulder and protection, when they can be considered highly isotropic. As a result of these studies, a design methodology is obtained. A series of validation tests are presented to support the reliability of the method.

Conventional seismic design of steel buildings is typically conducted, at a preliminary stage, by resorting to idealisations of member joint behaviour (e.g. fully-articulated connections). After the main structural members are defined, one proceeds with the connection design process, whose actual behaviour may or may not deviate from the assumption initially made at the design stage. This research study assesses the implications of connection-related design assumptions for steel concentrically-braced frames (CBFs) designed to Eurocode 8. This goal is achieved through the use of a Python-OpenSees-based automated seismic analysis and design framework to define an extensive set of CBF archetypes. The effect of non-explicit consideration, at the design stage, of the diagonal-to-frame gusset connections is evaluated. Full compatibility of this assumption is shown to be unassured, particularly due to the combined effects of member length reduction and boundary condition flexibility on the member's normalized slenderness. Based on the extensive suite of frame and connection designs considered, a regression-based modified normalized slenderness factor is proposed to realistically estimate, at the design stage, the normalized brace slenderness.

A simple in-situ method for the quantification of the crossover in redox flow batteries, adapted from an electrochemical method currently used for quantifying the hydrogen crossover in fuel cells, is proposed and used for characterizing a vanadium redox flow battery. A linear sweep voltammetry (LSV) scan is performed with the pertinent redox species in one side of the electrochemical cell, while in the other side is the supporting electrolyte. The LSV plot should display a plateau where the current is limited by the crossover of the selected species. The crossover results were compared with an external analytical method using MP-AES, showing very good agreement with a maximum relative difference of 6%. This method was used to quantify the crossover of all vanadium species using both cation and anion exchange membranes. The proposed method can be applied for assisting the development and characterization of ion-exchange membranes for redox flow batteries and for in-situ diagnosis of component degradation and failure in RFB systems without disassembling them. (C) 2019 The Electrochemical Society.

On 14 August 2018 at 11:35 AM, a relevant portion (about 243 m) of the viaduct over the Polcevera river in Genoa collapsed, killing 43 people. The bridge was designed in the early 1960s by Riccardo...

Flow batteries exhibit relatively low power density owing to ohmic and concentration overpotentials, which leads to higher system costs. In this work, a phenomenological model of a vanadium redox flow battery (VRFB) equipped with an anion exchange membrane (AEM) was developed and validated. The model is used to assess the concentration overpotential during charge-discharge cycling at different operating conditions and a method to determine the mass transfer coefficient is presented. Also, a strategy to reduce the concentration overpotential is proposed. The simulated charge-discharge curve displays the lowest relative error reported in the literature for VRFB equipped with an AEM; the results reveal that the mass transfer coefficient is overestimated in most models in the literature. It is demonstrated that the concentration overpotentials during charging and discharging steps are not equal owing to a mismatch between the state of charge and the state of discharge. Also, the current density has a greater impact on this overpotential than the flow rate. Higher overpotentials were found near the membrane since the electronic conductivity is higher than the ionic conductivity. The simulation results show that positioning the distribution channels close to the membrane allows a reduction of the concentration overpotential up to 3.9%.

The importance of non-structural elements in performance-based seismic design of buildings is presently widely recognized. These elements may significantly affect the functionality of buildings even for low seismic intensities, in particular for the case of critical facilities, such as hospital buildings. One of the most important issues to deal with in the seismic performance assessment of non-structural elements is the definition of the seismic demand. This paper investigates the seismic demand to which the non-structural elements of a case-study hospital building located in a medium&ndash, high seismicity region in Italy, are prone. The seismic demand is evaluated for two seismic intensities that correspond to the definition of serviceability limit states, according to Italian and European design and assessment guidelines. Peak floor accelerations, interstorey drifts, absolute acceleration, and relative displacement floor response spectra are estimated through nonlinear time&ndash, history analyses. The absolute acceleration floor response spectra are then compared with those obtained from simplified code formulations, highlighting the main shortcomings surrounding the practical application of performance-based seismic design of non-structural elements. The absolute acceleration floor response spectra are then compared with those obtained from simplified code formulations. The results, both in terms of absolute acceleration and relative displacement floor response spectra, highlighted the influence of the higher modes of the structure and the inaccuracy of the code provisions, pointing out the need for more accurate simplified methodologies for the practical application of performance-based seismic design of non-structural elements.

Census-based exposure information is often outdated or incomplete. For seismic risk assessment, this is particularly relevant in regions with non-seismically designed buildings, whose modeling requ...

This article describes a specifically developed framework to produce a seismic physical vulnerability model of residential buildings in Nablus (Palestine) within the European project SASPARM2.0. Ba...

Seismic risk depends on three factors: seismic hazard, exposure of assets and communities, and vulnerability—physical and social. Whereas hazard and exposure are harder to act upon, vulnerability c...

Extensive damage to school buildings has been observed during past earthquakes in Italy and there is a need to better understand their potential vulnerability. As part of a national project to assess seismic risk in Italian schools, a database was compiled in terms of characteristics such as school location and construction typology. This paper examines a number of these buildings considered to be a representative sample of the Italian school building population. To quantify their seismic vulnerability, the induced damage with respect to increased shaking intensity need to be quantified. This characterisation of the building vulnerability, in combination with the seismic hazard, allows more informed, risk-based decisions to be made using performance metrics such as expected annual loss (EAL). This article outlines a case study application quantifying the EAL and collapse safety for three school buildings representative of the Italian school building stock. Detailed numerical models were developed using information collected during in-situ inspections in order to accurately represent the dynamic response of the school structures. To estimate economic losses, a structural and non-structural element inventory was compiled using in-situ survey information. This case study application is conducted in a systematic fashion to clearly illustrate the various details required to implement more advanced seismic assessment studies. Finally, a comparison is made with the seismic classification guidelines recently introduced in Italy to provide further insight into how these can be used to identify existing buildings vulnerable to excessive damage and potential collapse during earthquakes.

The importance of non-structural components in building performance under seismic action is well recognized in the scientific community. Damage to residential buildings registered in past earthquakes has demonstrated that the damage to non-structural components represents a substantial percentage to the resulting economic losses. In the context of performance-based earthquake engineering (PBEE), the probabilistic estimation of building-specific losses has highlighted the importance of non-structural walls, in particular, due to their direct influence on building response and contribution to the overall damage. However, limited research has been produced on the subject of seismic retrofit of non-structural components and their economic advantages. In this manuscript, focus is given to non-structural partition walls, with the aim of determining the potential economic benefit of implementing non-structural retrofit solutions, in terms of the corresponding reduction in average annual earthquake losses. Building on an extensive literature review on the state-of-the-art of non-structural retrofit solutions, representative retrofit options are investigated for six combinations of building class and seismic hazard at the building location (in Italy), by means of probabilistic seismic loss estimation and corresponding cost-benefit analysis. The results show that the seismic retrofit of non-structural partition walls only (as opposed to retrofitting both structural and non-structural components) can be sufficient to achieve a reduction of seismic losses that guarantees the return of the retrofit investment during the building’s life cycle, specifically when dealing with highly vulnerable buildings located in regions of high seismicity.

Purpose Portugal experienced very destructive earthquakes in the past, such as the well-known “Lisbon earthquake” in 1755. With such in mind, accurate estimates of human and economic losses can play a significant role in providing various societal key players with objective information for response strategies. This paper aims to present the contribution of the most recent study in Portugal (PRISE) concerning comprehensive seismic risk assessment, which can be used as good practice and reproduced in different contexts. Design/methodology/approach PRISE (earthquake loss assessment of the Portuguese building stock) covered three main lines of research, corresponding to the three components typically considered in any seismic risk assessment study: the characterization of the seismic hazard, the identification of the exposure to earthquakes and loss potential and the vulnerability of the exposed assets. Each of these components has been fully characterized through the collection of census and local data (exposure), used to carry out nonlinear analysis (hazard and fragility). Findings By involving different research institutions and partners with extensive knowledge and expertise in the earthquake domains, the developed model is capable of producing economic and human earthquake loss estimates in real time (through an innovative Web-based platform) or for specific event scenarios, considering exposed population, residential and industrial buildings. The platform uses open-source tools and hence, it can be reproduced in other countries or contexts. Research limitations/implications Research wise, the hazard, vulnerability and exposure models can still be significantly improved, e.g. by adding critical infrastructure (hospitals, school buildings and bridges) or updating the nonlinear models, for more accurate loss predictions. Practical implications The findings and loss estimates for different earthquake scenarios show that planned interventions are required. Decision-makers and other relevant stakeholders (Civil Protection) can make use of the developed platform to produce specific estimates, to test the effect of different retrofitting interventions or to plan for emergency scenarios. Originality/value A real-time Web-based framework to estimate building damage and economic/human losses because of seismic events has been developed, aiming to provide the Portuguese Civil Protection and other playmakers with a unique platform for planning and preparing for emergency scenarios.

This paper focuses on the characterization of the behaviour of Concrete Filled Steel Tubular (CFST) columns made with Rubberized Concrete (RuC), and on the development of an accurate numerical model for the simulation of CFST columns under monotonic and cyclic bending. The test campaign involves 18 CFST specimens with different configurations, namely the cross-section slenderness, the concrete strength, the axial load level and the lateral loading type. All CFST members tested exhibited good ductility under monotonic loading. The Eurocode 4 design provisions was verified against the test results and the design capacities of the CFST members were validated to be conservative. A comprehensive 3D Finite Element (FE) model was developed and calibrated based on test results. The FE model proved to be reliable in predicting the bending behaviour of CFST member, in terms of local buckling deformation modes, ultimate capacity and ductility of the CFST columns.

Considering the likely unfavorable behavior under seismic action of adobe construction, this article aims at providing a seismic fragility characterization of two adobe Portuguese traditional build...

This article addresses the laboratory testing of a full-scale double-T shaped adobe wall, under in-plane horizontal cyclic loading of increasing amplitude, with the aim of contributing to the understanding of the seismic behavior of adobe structures. The wall was built with lime adobes taken from an existing building and mortar with a traditional composition. The behavior of the wall was assessed in terms of: shear stress versus horizontal drift and moment versus rotation relationships; maximum lateral strength; drift and rotation at peak stress; evolution of stiffness, lateral displacements, dissipated energy, and natural frequency; and damage pattern. The wall exhibited brittle behavior and in-plane strength corresponding to 56% of the vertical load. Cracking was observed with an X-shaped pattern whereas no sliding occurred at its base. This research supported the subsequent development of a repair and retrofit solution and also of numerical models to simulate the seismic behavior of two adobe b...

This paper focuses on the assessment of the behaviour of Concrete Filled Steel Tube (CFST) columns with square/rectangular cross-section, made with Rubberized Concrete (RuC), under flexural loading. The study aims to evaluate the differences between this type of composite members and typical CFST members made with standard concrete (StdC), namely in terms of the influence of the rubber aggregate replacement ratio on member strength, ductility, and energy dissipation capacity. The experimental campaign comprised the testing of 16 square members, 12 RuCFST and 4 StdCFST, and 4 rectangular RuCFSTs. A number of parameters were investigated, namely the cross-section slenderness (i.e., the width-to-thickness ratio of the steel tube), the aggregate replacement ratio (i.e., the percentage of sand aggregate of the concrete mixture that is substituted by rubber particles), axial load level and lateral loading type. The test results are compared with the member capacities obtained with the application of Eurocode 4. The results show a minimal influence of the type of concrete infill on the monotonic and cyclic behaviour of the members and also allow concluding that the European code is conservative in predicting the capacity of the specimens. Furthermore, the results obtained demonstrate that the cross-section slenderness has an important role on the behaviour of these members. Nonetheless, the requirements pertaining this parameter that are currently defined in Eurocodes 4 and 8 can be relaxed.

Macro-scale seismic assessment of road networks requires the characterization of the vulnerability of the population of existing bridges, typically provided by fragility curves as they corr...

The seismic assessment of a road network depends largely on the characterization of the fragility of its bridge components. The accuracy of bridge seismic demand estimates and the use of pr...

The increasing awareness of the general society toward the seismic safety of structures has led to more restrictive performance requirements hence, many times, to the need of using new and more accurate methods of analysis of structures. Among these, nonlinear static procedures are becoming, evermore, the preferred choice of the majority of design codes, as an alternative to complete nonlinear time-history analysis for seismic design and assessment of structures. The many available software tools should therefore be evaluated and well understood, in order to be easily and soundly employed by the practitioners. The study presented herein intends to contribute to this need by providing further insight with respect to the use of commonly employed structural analysis software tools in nonlinear analysis of bridge structures. A comparison between different nonlinear modeling assumptions is presented, together with the comparison with real experimental results. Furthermore, alternative adaptive pushover procedures are proposed and applied to a case study bridge, based on a generic plastic hinge model. The adopted structural analysis program proved to be accurate, yielding reliable estimates, both in terms of local plastic hinge behavior and global structural behavior.

The assessment of shelter needs of displaced people in the aftermath of major earthquake events is one the main challenges that emergency responders currently have to face. Based on the scale of the disaster, the short-term shelter demand can turn into a temporary housing need for displaced population, which is a local government responsibility. The study presented in this paper is focused on a critical review of currently available methodologies and corresponding software packages that were developed specifically for estimating the number of displaced people and those who will most likely seek public sheltering and will need temporary housing. The main features and shortcomings of such tools are highlighted and interpreted with a view to future improvement and application in the disaster management field. Two software tools, ERGO-EQ and HAZUS-MH, have been identified as more exhaustive in considering all the different variables involved in the shelter needs estimation. For this reason, this study also includes a full application of those two software tools to a real case study. Specifically, the modelling of the February 22nd, 2011 Christchurch earthquake is presented, in which hazard, vulnerability and exposure (both physical and social) were characterized over a specific area of Christchurch urban area as input to the aforementioned software tools. The employed tools yielded different results in terms of dislocated people and shelter needs estimates, for which a brief discussion is presented on possible ways to improve and to better reflect the local conditions, in order to produce more realistic outputs.

Performance-based earthquake engineering has created the need for practical ways to assess the response of non-structural components (NSCs), which may be affected by deformation and/or acceleration demands of the superstructure. In the research study detailed in this paper, peak floor accelerations (PFAs) and floor response spectra (FRS) are computed using non-linear time history analysis (NTHA) for a comprehensive suite of 30 steel moment-resisting frame (MRF) archetypes, designed in accordance to Eurocode 8, considering different levels of non-linear seismic demand. The mean trends observed were compared with the most recent approaches proposed in the literature for prediction of acceleration demands. It was found that for PFAs, the available methods provide accurate predictions of the actual structural response under elastic and inelastic demands. However, the estimation procedures for the FRS yielded relevant differences in comparison to the observed elastic and inelastic responses, which entails the need for further development of such methods. It was also concluded that the existing PFA and FRS estimation methodologies present in several guidelines for seismic design and/or assessment do not provide reliable estimates of the acceleration demands incurred by the building. This highlights the very important need for an improvement of these codified procedures for a more reliable prediction of the seismic structural response.

This paper proposes a new reference picture selection method for light field image coding using the pseudo-video sequence (PVS) format. State-of-the-art solutions to encode light field images using the PVS format rely on video coding standards to exploit the inter-view redundancy between each sub-aperture image (SAI) that composes the light field. However, the PVS scanning order is not usually considered by the video codec. The proposed solution signals the PVS scanning order to the decoder, enabling implicit optimized reference picture selection for each specific scanning order. With the proposed method each reference picture is selected by minimizing the Euclidean distance to the current SAI being encoded. Experimental results show that, for the same PVS scanning order, the proposed optimized reference picture selection codec outperforms HEVC video coding standard for light field image coding, up to 50% in terms of bitrate savings.

In 1997, Toledo developed a numerical model to characterize the flow through the downstream shell of a rockfill dam for the overtopping scenario. He performed a parametric study focused on ...

Extensive damage to school buildings has been observed during past earthquakes in Italy, with the 2002 Molise earthquake resulting in the complete collapse of a school building, leading to ...

This paper introduces a novel Satellite Precipitation-based Extreme Event Detection (SPEED) model to effectively support parametric or index insurance instruments specifically designed to cover flood risk. Such financial tools are intended to promote fast payouts in the aftermath of a disastrous event. They leverage on measured hazard parameters, gathered immediately after the event and defined as the trigger(s), which are used to identify such hazardous events and estimate their resulting consequences in terms of physical damage and losses. This paper addresses the first step of such a modeling approach, the detection of a flood event, which plays an important role in the overall methodology, determining its performance in terms of false and missed detections. Different types of triggers for identifying flood events, based on satellite precipitation estimates, are investigated, and the overall model performance is assessed for a case-study country (the Philippines). A statistical procedure for selecting the optimal configuration of model parameters is presented. Such an optimal configuration minimizes the so-called basis risk, defined in this study as the mismatch between modeled and actual events. Finally, the accuracy of the proposed approach in terms of event localization is investigated by subdividing the case-study country into three main areas, corresponding to the coarsest administrative levels, and assessing the model's capability to capture events in each considered area. The results from this study confirm that the proposed SPEED model can be effectively used as an input for parametric insurance products, given its ability to identify hazardous events correctly.

The seismic vulnerability and inadequate behaviour of existing school buildings observed during past earthquakes in Italy have raised awareness of the need to upgrade their performance. This paper examines different retrofit strategies for three case study school buildings, representing the main typologies found within the Italian school building stock. The three building typologies investigated in this study are representative of reinforced concrete (RC), precast concrete (PC) and unreinforced masonry (URM) school buildings. A seismic performance assessment was carried out using detailed numerical models that consider the main structural deficiencies documented for older buildings in Italy, generally designed and built before the 1970s. The retrofit interventions were specifically aimed at mitigating these main structural deficiencies in order to meet current building code limit state requirements. These requirements are set to limit the damage to non-structural elements and prevent non-ductile failure mechanisms in the structural system, following a typical building code and practitioner-oriented process. The retrofit alternatives were then evaluated through increasing ground shaking intensities to quantify risk-based decision variables, such as the expected annual loss and mean annual frequency of collapse. The results highlight the level of adequacy of each retrofit option in reducing both the economic losses and collapse vulnerability. To predict the economic feasibility of these interventions, a cost-benefit analysis was also conducted using estimated implementation costs of each retrofit alternative. Lastly, the results were also compared with the outcome of the seismic risk classification guidelines, recently proposed in Italy.

The main objective of the research presented in this paper is to study the bending behaviour of Concrete Filled Steel Tube (CFST) columns made with Rubberized Concrete (RuC), and to assess the seismic performance of moment-resisting frames with these structural members. The paper describes an experimental campaign where a total of 36 specimens were tested, resorting to a novel testing setup, aimed at reducing both the preparation time and cost of the test specimens. Different geometrical and material parameters were considered, namely cross-section type, cross-section slenderness, aggregate replacement ratio, axial load level and lateral loading type. The members were tested under both monotonic and cyclic lateral loading, with different levels of applied axial loading. The test results show that the bending behaviour of CFST elements is highly dependent on the steel tube properties and that the type of infill does not have a significant influence on the flexural behaviour of the member. It is also found that Eurocode 4 is conservative in predicting the flexural capacity of the tested specimens. Additionally, it was found that the seismic design of composite momentresisting frames with CFST columns, according to Eurocode 8, not only leads to lighter design solutions but also to enhanced seismic performance in comparison to steel frames.

In macro-scale roadway networks, bridges are the main point-site components and tend to be among the most vulnerable elements in case an earthquake occurs. Given this weakness, the proper assessment of the seismic vulnerability is of high importance to obtain reliable estimates of losses in the immediate aftermath of seismic events or to manage emergency situations. In this sense, the use of real data (e.g. geometrical and material parameters drawn from national bridge inventory databases), accounting for its variability, is preferable and increases the accuracy of estimated fragility or vulnerability functions of the bridge portfolio of a certain region. However, complete information for each single bridge is typically not available. One way to address this limitation is to use statistical tools to handle large-scale loss estimation studies and to gauge the parametric characterization of relevant structural behaviour properties. In view of these considerations, the present paper addresses the first step towards the development of supporting tools for improved large-scale seismic assessment of bridges by characterizing the geometrical and material properties of typical Italian reinforced concrete (RC) bridges. With this characterization, we generate a large bridge stock for a specific bridge typology using the Latin Hypercube sampling scheme. Such bridge stock is then assessed with a view to establish simplified relationships between the fundamental period of vibration and the geometrical configuration of the bridge. The developed formulae, defined as a function of two geometrical variables, can be used to quickly estimate the period of vibration and the seismic demand (and fragility) of the structure in expedite large-scale seismic assessment studies.

The accurate estimation of fragility functions requires the proper selection of ground motion records at different intensity levels. However, most of the available fragility assessments of concrete dams use the same records at all intensity levels and often selects them with an inadequate target spectrum. In order to improve the fragility assessment of such structures, this paper proposes the use of records selected with the Conditional Spectrum (CS) method within a multiple stripes analysis. The approach is applied to a dam in Eastern Canada, and a comparison with the methodology used by other studies is done. It is shown that the approach proposed herein allows for the reduction of the seismic response and fragility of the dam. Moreover, the uncertainty related to material properties becomes less significant when using the CS method, and the fragility curves could be reasonably estimated by considering the ground motions as the only source of uncertainty.

The seismic response of RC structures is dictated by a number of aleatory and epistemic uncertainties, related to material properties and seismic hazard. Typically, when following a probabilistic approach, the different variables are statistically defined using a random simulation tool that will take into account the different sources of uncertainty. This manuscript addresses the seismic reliability of RC bridge structures, particularly through the assessment of a random sampling scheme based on the Latin Hypercube algorithm for numerical simulation of material and ground motion properties. An optimal use of such sampling technique is thus sought so as to ensure higher accurateness in the calculation of the failure probability of a set of different existing bridges, through a relatively simple framework. The study demonstrates the robustness of the Latin Hypercube algorithm, which secured accuracy of the estimated probability of failure for both regular and irregular configurations. Recommendations to researchers and practitioners are made accordingly, particularly with respect to the minimal sampling size, which does not need to exceed one to two hundred realisations.

The main objective of the research presented in this paper is to investigate the flexural behaviour of concrete filled steel tube (CFST) columns of circular cross-section, made with rubberized concrete (RuC). A second objective is to identify behavioural differences between this type of composite members and typical CFST members made with standard concrete (StdC), namely in terms of the influence of the rubber aggregate replacement ratio on member strength, ductility, and energy dissipation capacity. The paper describes the preparation and development of an experimental campaign, involving the testing of 16 circular specimens, 12 RuCFST and 4 StdCFST. The definition of the test campaign considered a number of parameters, namely cross-section slenderness, aggregate replacement ratio, axial load level and loading type. A special device was developed as part of an innovative testing setup, aimed at reducing both the cost and preparation time of the specimens. This paper also describes the comparison of the test results with design provisions from Eurocode 4. The test results show a marginal influence of the type of concrete infill on the monotonic and cyclic behaviour of the members and also allow concluding that Eurocode 4 is conservative in predicting the capacity of the tested specimens. Moreover, it is found that the cross-section slenderness does not have a significant influence on the monotonic and cyclic behaviour of the specimens, pointing out for the possible relaxation of the cross-section slenderness limits currently specified in Eurocodes 4 and 8.

One of the most determinant components of any seismic safety assessment procedure is the estimate of the nonlinear seismic demand, particularly if such procedure is probabilistic rather than deterministic. Indeed, the prediction of the seismic demand of RC structures is dictated by a number of variables, related to the seismic action or to the geometrical and material properties, with different relevancy and uncertainty levels. From a macro-viewpoint one can distinguish the different approaches for nonlinear demand prediction in two major groups: nonlinear static and dynamic. Whereas the latter is widely recognised as the most accurate approach, the former, particularly by means of nonlinear static procedures (NSPs), represents a valid alternative tool for performance-based seismic assessment of structures, quite accepted among the scientific community worldwide. Significant effort has therefore been made, over the past few years, to improve those simplified methods and several different proposals in terms of application methodology have come up. Simultaneously, validation studies have thoroughly been carried out, even though focusing mainly on regular, building structures, rather than typically irregular bridges, and have focused the validation through the direct comparison of response prediction. The capability of such procedures within a probabilistic framework that yields the collapse probability of randomly sampled RC viaducts is herein investigated. A commonly employed nonlinear static procedure (N2) is further validated against nonlinear dynamic analysis using two distinct probabilistic procedures, described and tested in a companion paper, which account differently for the uncertainty of the concerned variables (geometry, material properties, earthquake records, intensity level). A case study of seven bridge configurations, with different (ir)regularity levels, is considered together with a relatively large set of real earthquake records and random simulation is carried out using the Latin Hypercube Sampling scheme. The conclusions have further probed the suitability of nonlinear static analysis in estimating seismic demand by leading, under probabilistic conditions, to slightly conservative probabilities of collapse of RC bridges with respect to nonlinear dynamic analysis.

This study is aimed at the identification of the institutional and social decisions that increase the resilience of the communities exposed at risk, by analysing observations during seismic sequences occurred in Italy in the last decades. Extensive surveys were carried out to rebuild the entire seismic phase with the documentation collected by the scientific/authority entities and the media/press review database. The April-May 2000 seismic swarm affecting the Faenza-Forli districts is used as case-study, enabling the identification of the emergency response techniques and means that were utilized to cope with the seismic storm in each coeval and/or collateral situation. Several practical and still useful lessons emerging from the past have been drawn.

A common definition of seismic risk entails the quantification of three main elements: hazard, exposure of properties and societies, and corresponding vulnerability. When properly characterised, the vulnerability of a community or an asset is the easiest component to act upon, through governmental agencies and decentralised frameworks, when facing natural hazards. Algeria is a country with a relatively short history of seismic risk mitigation even though, in the past, the population suffered from many devastating earthquakes leading to large human and economic losses. Furthermore, until now, the actions taken to reduce such devastating effects have been of reduced impact. With this in mind, this paper investigates the social vulnerability and resilience level to natural hazards, with a specific focus on seismic risk, in the province of Blida, an important cultural and economic region in Northern Algeria. The evaluation is carried out through a hybrid methodology that puts together results from the well-known social vulnerability index or SoVI®, obtained from population data and national statistics, integrated with the Resilience Performance Scorecard (RPS) method, which qualitatively assesses the resilience of a population with reference to qualitative information gathered through public interest and participation. With such a methodology, this study aims to evaluate the societal factor and the impact on the population at risk through vulnerability mapping. The results allow identifying the areas and the social vulnerability dimensions requiring immediate addressing by regulatory and institutional frameworks that can increase preparedness levels, resource allocation, contingency planning, and efforts in raising public awareness. Following the use of census data and the participatory scheme, as well as a hybrid approach combining the two, it is seen that the province of Blida is characterised by medium levels of vulnerability. Following a simplified comparison, the SoVI approach results tend to underestimate the RPS ones. Such information will be useful to aid decision-makers and the exposed society itself to endure the effects of disastrous events.

Reinforced concrete (RC) frame buildings with masonry infills represent one of the most common structural typologies worldwide. Although, in the past, masonry infills were frequently considered as non-structural elements and their interaction with the structure was neglected, earthquakes occurring over the last decades have demonstrated the important role of these elements in the seismic response of all RC-infilled building typologies. In this regard, the selection of the most suitable numerical modelling approaches to reproduce the hysteretic response of the masonry infills&mdash, and their interaction with the RC frames&mdash, is still an open issue. To deal with this issue, in this study, a macro-classification based on different available databases of experimental tests on infilled RC frames, is firstly proposed to understand the variability in the infill properties and the corresponding numerical modelling uncertainties. Five masonry infill types are selected as representative for the typical existing configurations in Italy and other Mediterranean countries. Three of those masonry infill types are then selected to carry out a more detailed analysis, namely their numerical modelling validation using experimental testing results, considering and comparing the main formulations available in the literature for the definition of the hysteretic behaviour of infills. From such a comparison, the model that minimizes the prediction error, according to specific features of the selected masonry infill, is identified for each masonry infill type.

The main objective of this study is to investigate the implications of the explicit brace-to-frame gusset connection modelling on the seismic performance assessment of steel concentrically-braced frames (CBFs). Two key modelling alternatives are considered, namely through the simulation of CBFs with: i) a benchmark experimentally-validated model, in which the gusset plates are explicitly designed and simulated; and ii) a more simplified option, whereby diagonals are simulated through a centreline-to-centreline approach with fully-pinned boundary conditions. Anticipating the consequences of a less refined modelling approach, a simplified regression-based design process to Eurocode 8 for these gusset connections is proposed, therefore avoiding the need for an explicit connection design for seismic assessment purposes. A third modelling option, an identical approach to the benchmark but with the gusset dimensions being determined through the aforementioned regression-based design process, is also considered. The importance of the explicit modelling of the gusset plate connections to obtain reliable estimates of seismic performance is shown through the comparison of the seismic performance of various building archetypes, considering different metrics (e.g. lateral deformations, earthquake-induced collapse risk and economic losses). Furthermore, the validity of the proposed gusset-design methodology is discussed, by comparing the resulting gusset dimensions against those associated with a rigorous seismic design process, as well as by comparing the seismic performance assessed with numerical models incorporating explicitly-designed or simplified-designed gusset geometries.

Damage models are fundamental elements within probabilistic frameworks, such as Performance-Based Earthquake Engineering (PBEE), for the seismic assessment of RC structures. For bridges, in specific, there are not many available experimental results for the characterization of damage in the RC columns hence the numerical counterpart acquires particular relevance. In this paper, via Monte Carlo simulation and comparison with complementary experimental results, a damage model consisting of a library of median and logarithmic dispersion values for curvature ductility, displacement ductility and drift, describing the probability of reaching a particular damage limit state are generated as a function of key parameters of circular RC bridge columns. Four damage limit states are considered: slight, moderate, extensive and complete. Simplified relationships based on the full datasets are proposed for easier implementation. The proposed damage models can be used for threshold identification and economic loss assessment in performance-based earthquake engineering of RC bridges.

The main objective of this paper is to understand and characterize the level of expected earthquake-induced economic losses of steel buildings designed to Eurocode 8. This is attained through the use of a comprehensive population of case-study buildings that considers different lateral load resisting systems, plan configurations and building heights. Different locations of low and high seismicity, reflecting the majority of the European seismic reality, are considered. The results indicate that EC8-compliant steel moment-resisting frame (MRF) buildings and concentrically-braced frame (CBF) buildings generally exhibit good seismic performance in terms of mean annual frequency of reaching collapse. Although all buildings showed good performance against collapse, when compared to the requirements present in literature, clear indications on a lower performance of chevron-braced CBFs are observed. Furthermore, low expected annual losses (EALs) are recorded across the population of steel buildings considered, with a predominant contribution of losses coming from structural and non-structural damage. Based on the findings reported in this paper, different insights towards the incorporation of loss performance objectives in the European seismic design code are provided.

Social vulnerability helps to explain why communities experience the consequences of an extreme event, such as an earthquake, differently, even when they are subjected to similar levels of intensity (ground shaking). The differential impacts of an earthquake can indeed be a consequence of social vulnerability, hence, it is a critical element for fostering mitigation plans and developing policies to reduce seismic risk. This study addresses the assessment of the social vulnerability and resilience level of the city of Nablus, Palestine, a region affected by seismic events and political conflicts. The method employed is the Scorecard Approach, a self-assessment and participatory tool that measures resilience with qualitatively derived information at two different urban levels: population and local administration. The results enable the resilience assessment of different districts of Nablus concerning several themes relevant to disaster risk reduction. The latter facilitate the better understanding of how different variables – such as gender, age, educational level, monthly income and membership neighbourhood – influence the social vulnerability level. Furthermore, by applying a spatial analysis method to the case study region, it is observed that resilient indicators are not spatially random, but rather geographically correlated.

Traditionally, business processes are analyzed in a qualitative or quantitative form with the purpose to exploit, reduce or eliminate existing problems in the processes, such as bottlenecks, financial or resources waste, cycle time and handworks. Business process analysis is an important phase of the Business Process Management (BPM) lifecycle because it provides a critical examination of problems and potential improvements of business processes. However, few studies have been conducted to provide novel analysis techniques and methods to explore external and future opportunities, in addition to satisfying clients’ expectations, needs and experience. In this context, we used the Design Science Research approach to build the Ambidextrous Analysis of Business Process (A2BP) method, which enables process analysts to balance exploration and exploitation thinking. We defined the problem and the research questions through a systematic literature mapping. Then, we empirically evaluate the proposed method through an expert opinion survey and an observational case study to assess the usefulness and ease-of-use of the method. Overall, the participants of the empirical study evaluated the method positively and suggested feedbacks to refine it.

International audience; Social vulnerability helps to explain why communities experience the consequences of an earthquake differently, even though they are subjected to similar levels of ground shaking. The differential impacts of an earthquake can be a consequence of social vulnerability and, for this reason, it is a critical element for fostering mitigation plans and developing policies to reduce earthquake risk. Measuring resilience is not an easy task and, in this study, is performed through the Scorecard Approach. The latter is a self-assessment and participatory tool that measures resilience with qualitatively derived information at two different urban levels: population and local administration. The case study is the city of Nablus in the Palestinian region which is not only affected by seismic events but also by political conflicts. The provided results enable the resilience assessment of different districts of Nablus concerning several themes of disaster risk reduction. These will help to better understand how different variables – such as gender, age, educational level, monthly income and membership neighbourhood influence the vulnerability assessment.

Presently, hand-held mobile devices, such as smartphones, generate and record large amounts of data (e.g., multimedia files like photos or videos). The off-the-shelf mechanisms for data sharing among these devices include: i) centralized cloud-based data storage services like Dropbox or Flickr, which rely on good quality Internet access for file uploading and downloading, and ii) application-based device-to-device file exchange over wireless technologies (e.g., Bluetooth). Thus, sharing multiple files among multiple devices is far from being a trivial task. In this paper, we propose EPHESUS, an ephemeral distributed data storage system for networks of hand-held mobile devices, where users can publish their own files and obtain files that have been shared by others. The system does not require Internet access and follows a best effort approach to data persistence and availability, also tolerating churn. Experimental results show that the system provides reasonable response times, as perceived by the users, and that it may be used continuously in medium duration events without draining the devices' batteries.