863 research outputs found

    Experimental verification of the interpolation method on a real damaged bridge

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    The identification of damage in a bridge from changes in its vibrational behavior is an inverse problem of important practical value. Significant advances have been obtained on this topic in the last two-three decades, both from the theoretical and applied point of view. One of the main problems when dealing with the assessment of vibration based damage identification methods is the lack of experimental data recorded on real damaged structures. Due to this, a large number of damage identification algorithms are tested using data simulated by numerical models. The availability of data recorded on a damaged bridge before its demolition gave the authors the uncommon chance to verify the sensitivity and reliability of the IDDM basing on data recorded on a real structure. Specifically data recorded on a reinforced concrete single-span supported bridge in the Municipality of Dogna (Friuli, Italy) were used to apply the damage localization algorithm. Harmonically forced tests were conducted after imposing artificial, increasing levels of localized damage. In this paper the sensitivity of the method is discussed with respect to the number of instrumented locations and to the severity of the damage scenarios considere

    The value of visual inspections for emergency management of bridges under seismic hazard

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    One of the major problems in the aftermath of an earthquake is the management of the emergency inspection operations. Traffic restriction, including limited emergency operations or bridge closure due to safety concerns, may be issued to keep an appropriate level of safety. Visual inspections may be conducted to provide useful information on the damage state of the bridge and support the decision of imposing traffic restriction up to the complete closure of the bridge, or for allowing the immediate use of safe bridges after the event. The cost related to the inspection shall be at least balanced by the uncertainty reduction provided by the inspection data and the benefit is higher when the costs associated with taking a wrong management decision are high, but may be negligible if this is not the case. Practical tools and methods to forecast this benefit before collecting the information exist in classical decision theory, but are seldom applied by engineers. In this paper a framework based on the concept of Value of Information (VoI) from the pre-posterior Bayesian decision analysis is adopted and applied to the case study of a two span reinforced concrete bridge

    The benefit of permanent monitoring for seismic emergency management

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    In this paper, a framework based on Value of Information (VoI) theory from pre-posterior Bayesian decision analysis is applied to the case of post-earthquake emergency management of traffic restrictions for a bridge. The decision context is the following: the operator of a bridge is concerned about the use of the structure in post-earthquake scenarios and wishes to know if it is worth to install a Structural Health Monitoring (SHM) system which gives information about the state of the bridge. The possible choices about traffic restrictions after the seismic event are Open or Close the bridge. The benefit of SHM is computed based on VoI and the influence of significant variables involved in the decisional framework is investigated

    ENAMA “Certification” of the inspection workshop activity: the necessary requirements

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    In European Directive 128/2009/EC it is stated that “each Member State shall establish certificate systems designed to allow the verification of sprayers inspections”, but no further indications are provided on how to make such certifications. In Italy the ENAMA (National Board for Agricultural Mechanization) working group – established to co-ordinate the sprayers inspection activities at national level – has prepared a specific document containing the guidelines on how to get, on a voluntary basis, an ENAMA certification which attests the conformity of test equipment and of test procedures adopted in the inspection workshops. In this document directions are reported on how to assess the conformity of the inspection workshops to a set of listed requirements, referred either to other ENAMA documents, or to the National Action Plan, or to ISO/IEC 17020.The ENAMA certification of conformity therefore represents an added value for the sprayers inspection and calibrations Workshops as it ensures, through periodical inspections, that workshops apply the correct administrative (e.g. management of data and record of test reports) and technical procedures in their inspection activity and that they use appropriate test equipment and instruments. In this paper the requirements needed to get and to maintain over time the ENAMA certification of conformity are described

    The necessity of a harmonized procedure for sprayers inspectors training: the Italian activity

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    European Directive on Sustainable Use of Pesticides requires that the people making inspections of sprayers in use have an official license, recognized at national level, released by the competent Authority. In Italy, Authorities responsible of training and upgrading of sprayers inspectors are Regional and Provincial administrations. They make this job in collaboration with research institutes that provide qualified teachers.With the aim to homogenize in the whole country the activity of training and licensing of sprayers inspectors the rules for training courses and the criteria for releasing licenses have been defined by ENAMA. Training courses shall have a duration of at least 40 hours subdivided between theory (60% of total time) and practical (40% of total time).Topics treated during courses are: criteria to apply pesticides, main sprayer types used in agriculture and relative components, test methods and equipment used to carry out the inspections of sprayers in use and to adjust them. The exam to get the inspector license shall consist in: a) filling of a questionnaire with multiple answers (at least 80% of answers have to be correct); the questions are selected among a database approved by ENAMA Working Group; b) oral test; c) practical exam consisting in the complete inspection of one sprayer.In order to guarantee the same quality level of sprayers inspections in the different European countries and to guarantee the mutual recognition of inspections made it is considered necessary to reach in short terms an agreement to harmonize the activity of training, licensing and upgrading of sprayers inspectors across Europe

    A proposal for an EU (SPISE) database of the licensed sprayers inspectors and inspection centres

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    In order to guarantee at European level the easy identification of sprayers inspected and to allow mutual recognition of inspections as recommended by the European Directive on Sustainable Use of Pesticides (128/2009/EC) it would be necessary to create a SPISE database enabling to collect the list of the technicians authorized to make inspections of sprayers in use and of the licensed inspection centers. This database should be managed at SPISE level and should be linked to the national databases for getting regular updates.Actually in Italy there is a public national online database (www.centriprovairroratrici.unito.it) that was realized by the ENAMA working group. Only the sprayers inspected by the test stations listed in this database are recognized all over the country.This national database contains also the results of all the inspections made in the different Italian Regions and therefore provides a support for monitoring the inspection activity at national level. Independently of the software used at local level for managing data of sprayer inspections, some key information have to be necessarily provided in order to identify the sprayer inspected.They are the coordinates of the test station, the name of the technician who inspected the sprayer, the name of the owner of the sprayer, the data of the machine inspected, the date of the inspection and its response

    Risk-based bridge scour management:a survey

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    Scour is one of the major causes of bridge failure worldwide and results in significant economic losses through disruption to operation. This phenomenon naturally affects bridges with underwater foundations and is exacerbated during high river and/or turbulent flows (e.g. due to extreme events). When scour reaches the bottom or undermines shallow foundations it is likely to trigger various damage mechanisms that may in-fluence the safety of the structure and force asset managers to reduce traffic capacity. Currently, assessing risk of scour is a heuristic process, heavily reliant on qualitative approaches and expert opinion (e.g. visual inspections). These types of assessments typically suffer from insufficient knowledge of influencing factors (e.g. hydraulic parameters) and the requirement to rely on several assumptions (e.g. foundation depth). As a result, current scour assessment and bridge management practices do not provide reliable solutions for ad-dressing the potential risk of bridge failures. In this paper, cross-cutting needs and challenges related to the development of decision support tools for scour-risk management are highlighted and some preliminary re-sults of a literature survey are reported. The review has been performed with several objectives: (i) identify-ing scour-risk indicators describing hydrodynamic actions and the asset condition; (ii) defining indirect and direct consequences needed to assess the risks associated to different decision alternatives related to scour management; and (iii) identifying existing approaches to scour inspections and monitoring as support tools for informed decisions. The results of this survey will serve as a base for future research aimed to develop an informed decision support tool to manage scour risk at both the bridge and at the network level

    Septal ablation versus surgical myomectomy for hypertrophic obstructive cardiomyopathy

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    Patients with hypertrophic cardiomyopathy (HCM) who have left ventricular outflow tract obstruction (LVOTO) often experience severe symptoms and functional limitation. Relief of LVOTO can be achieved by two invasive interventions, i.e., surgery myectomy and alcohol septal ablation (ASA), leading in experienced hands to a dramatic improvement in clinical status. Despite extensive research, however, the choice of the best option in individual patients remains challenging and poses numerous clinical dilemmas
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