Documents disponibles écrits par cet auteur

Assessment of existing structures based on identification / Alfred Strauss in Journal of structural engineering, Vol. 136 N° 1 (Janvier 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 86-97 Titre : Assessment of existing structures based on identification Type de document : texte imprimé Auteurs : Alfred Strauss, Auteur ; Dan M. Frangopol, Auteur ; Konrad Bergmeister, Auteur Année de publication : 2011 Article en page(s) : pp. 86-97 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Concrete  structures  Damage  location  Damage  identification  Sensitivity  factors  Degradation  assessment Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A nondestructive damage detection approach based on measured structural responses is presented and verified by controlled laboratory experiments and by tests on real structures. In the experiments, defined magnitudes of damages are assigned to reinforced concrete beams, and the dynamic responses of the undamaged and damaged specimens are measured. The measured frequencies of the specimens and their sensitivity to change in mechanical characteristics, called sensitivity factors, are used to predict the location and the magnitude of the damage. The damage locations associated with the investigated test series are predicted with high accuracy by the proposed identification approach. This approach has been applied to real structures, including an existing bridge in Switzerland. In order to provide successful damage detection in cases where the damage does not affect or only marginal affects dynamic structural characteristics, the approach has been extended to handle simultaneous multiple structural response characteristics, such as frequencies, and modal and static displacements. The identification approach satisfies ease-of-use requirements in existing reliability assessment methods for deteriorating structures. The main purposes of this paper are to (1) present the proposed identification algorithm; (2) discuss the adjustment of the stochastic algorithm inputs, such as cross-sectional stiffness, geometrical, and mechanical properties, by monitored structural responses; and (3) present the interaction between the developed identification algorithm and the stratified Monte Carlo randomization technique, thus allowing the application of the algorithm to large engineering structures. Additionally, it is shown that the developed code is suitable for incorporation into commercial software packages. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i1/p86_s1?isAuthorized=no [article] Assessment of existing structures based on identification [texte imprimé] / Alfred Strauss, Auteur ; Dan M. Frangopol, Auteur ; Konrad Bergmeister, Auteur . - 2011 . - pp. 86-97. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 86-97 Mots-clés : Concrete  structures  Damage  location  Damage  identification  Sensitivity  factors  Degradation  assessment Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A nondestructive damage detection approach based on measured structural responses is presented and verified by controlled laboratory experiments and by tests on real structures. In the experiments, defined magnitudes of damages are assigned to reinforced concrete beams, and the dynamic responses of the undamaged and damaged specimens are measured. The measured frequencies of the specimens and their sensitivity to change in mechanical characteristics, called sensitivity factors, are used to predict the location and the magnitude of the damage. The damage locations associated with the investigated test series are predicted with high accuracy by the proposed identification approach. This approach has been applied to real structures, including an existing bridge in Switzerland. In order to provide successful damage detection in cases where the damage does not affect or only marginal affects dynamic structural characteristics, the approach has been extended to handle simultaneous multiple structural response characteristics, such as frequencies, and modal and static displacements. The identification approach satisfies ease-of-use requirements in existing reliability assessment methods for deteriorating structures. The main purposes of this paper are to (1) present the proposed identification algorithm; (2) discuss the adjustment of the stochastic algorithm inputs, such as cross-sectional stiffness, geometrical, and mechanical properties, by monitored structural responses; and (3) present the interaction between the developed identification algorithm and the stratified Monte Carlo randomization technique, thus allowing the application of the algorithm to large engineering structures. Additionally, it is shown that the developed code is suitable for incorporation into commercial software packages. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i1/p86_s1?isAuthorized=no

Cost-based optimum scheduling of inspection and monitoring for fatigue-sensitive structures under uncertainty / Sunyong Kim in Journal of structural engineering, Vol. 137 N° 11 (Novembre 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1319-1331 Titre : Cost-based optimum scheduling of inspection and monitoring for fatigue-sensitive structures under uncertainty Type de document : texte imprimé Auteurs : Sunyong Kim, Auteur ; Dan M. Frangopol, Auteur Année de publication : 2012 Article en page(s) : pp. 1319-1331 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Inspection  Monitoring  Uncertainty  Damage  detection  Optimization  Failure  cost  Fatigue Résumé : Inspection and monitoring of deteriorating structures are generally performed to assess structural integrity and predict the remaining service life. For deteriorating structures, a reliable prediction of damage occurrence and the time-dependent damage evaluation depend on the accuracy of deterioration models under uncertainty. A probabilistic approach to establish optimum cost-based inspection and monitoring schedules of fatigue-sensitive structures is proposed in this paper. The inspection schedule is the solution of an optimization problem to minimize the expected total cost, including the costs of inspections or monitorings, and the expected failure cost. The failure criterion uses damage detection time and time for damage to reach the critical state. The uncertainties associated with damage occurrence/propagation and damage detection time are both considered. The solution of the optimization provides the inspection times and quality of inspections. The formulation of the optimization for inspection scheduling is extended to monitoring scheduling. Effects of the failure cost on inspection and monitoring scheduling are also studied. The proposed approach is applied to a fatigue-sensitive structure. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i11/p1319_s1?isAuthorized=no [article] Cost-based optimum scheduling of inspection and monitoring for fatigue-sensitive structures under uncertainty [texte imprimé] / Sunyong Kim, Auteur ; Dan M. Frangopol, Auteur . - 2012 . - pp. 1319-1331. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1319-1331 Mots-clés : Inspection  Monitoring  Uncertainty  Damage  detection  Optimization  Failure  cost  Fatigue Résumé : Inspection and monitoring of deteriorating structures are generally performed to assess structural integrity and predict the remaining service life. For deteriorating structures, a reliable prediction of damage occurrence and the time-dependent damage evaluation depend on the accuracy of deterioration models under uncertainty. A probabilistic approach to establish optimum cost-based inspection and monitoring schedules of fatigue-sensitive structures is proposed in this paper. The inspection schedule is the solution of an optimization problem to minimize the expected total cost, including the costs of inspections or monitorings, and the expected failure cost. The failure criterion uses damage detection time and time for damage to reach the critical state. The uncertainties associated with damage occurrence/propagation and damage detection time are both considered. The solution of the optimization provides the inspection times and quality of inspections. The formulation of the optimization for inspection scheduling is extended to monitoring scheduling. Effects of the failure cost on inspection and monitoring scheduling are also studied. The proposed approach is applied to a fatigue-sensitive structure. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i11/p1319_s1?isAuthorized=no

Cost-effective lifetime structural health monitoring based on availability / Sunyong Kim in Journal of structural engineering, Vol. 137 N° 1 (Janvier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 1 (Janvier 2011) . - pp. 22-33 Titre : Cost-effective lifetime structural health monitoring based on availability Type de document : texte imprimé Auteurs : Sunyong Kim, Auteur ; Dan M. Frangopol, Auteur Année de publication : 2011 Article en page(s) : pp. 22-33 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Availability  Structural  health  monitoring  Optimization  Uncertainty  Monitoring  cost Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The state of a structural system subjected to deterioration processes is changing continuously. This state cannot be reliably predicted without considering both aleatory and epistemic uncertainties. To reduce the epistemic uncertainty, inspection and structural health monitoring (SHM) should be performed, and the performance prediction model should be updated periodically. Continuous monitoring is needed to reliably assess and predict the performance of structures. However, due to limited financial resources, continuous monitoring is not practical. Therefore, a cost-effective SHM strategy is necessary. In this paper, the probability that the performance prediction model based on monitoring data is usable in the future is computed by using the statistics of extremes and availability theory. This probability represents the availability of the monitoring data over nonmonitoring periods. The monitoring cost and availability can be found by solving a biobjective optimization problem. This problem consists in simultaneously minimizing the total monitoring cost and maximizing the availability of the monitoring data for performance prediction. Pareto solutions associated with monitoring duration and prediction duration are obtained. The proposed approach is applied to an existing bridge. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i1/p22_s1?isAuthorized=no [article] Cost-effective lifetime structural health monitoring based on availability [texte imprimé] / Sunyong Kim, Auteur ; Dan M. Frangopol, Auteur . - 2011 . - pp. 22-33. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 1 (Janvier 2011) . - pp. 22-33 Mots-clés : Availability  Structural  health  monitoring  Optimization  Uncertainty  Monitoring  cost Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The state of a structural system subjected to deterioration processes is changing continuously. This state cannot be reliably predicted without considering both aleatory and epistemic uncertainties. To reduce the epistemic uncertainty, inspection and structural health monitoring (SHM) should be performed, and the performance prediction model should be updated periodically. Continuous monitoring is needed to reliably assess and predict the performance of structures. However, due to limited financial resources, continuous monitoring is not practical. Therefore, a cost-effective SHM strategy is necessary. In this paper, the probability that the performance prediction model based on monitoring data is usable in the future is computed by using the statistics of extremes and availability theory. This probability represents the availability of the monitoring data over nonmonitoring periods. The monitoring cost and availability can be found by solving a biobjective optimization problem. This problem consists in simultaneously minimizing the total monitoring cost and maximizing the availability of the monitoring data for performance prediction. Pareto solutions associated with monitoring duration and prediction duration are obtained. The proposed approach is applied to an existing bridge. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i1/p22_s1?isAuthorized=no

Generalized probabilistic framework for optimum inspection and maintenance planning / Sunyong Kim in Journal of structural engineering, Vol. 139 N° 3 (Mars 2013) 

Public ISBD [article]  in Journal of structural engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 435–447 Titre : Generalized probabilistic framework for optimum inspection and maintenance planning Type de document : texte imprimé Auteurs : Sunyong Kim, Auteur ; Dan M. Frangopol, Auteur ; Mohamed Soliman, Auteur Année de publication : 2013 Article en page(s) : pp. 435–447 Note générale : structural engineering Langues : Anglais (eng) Mots-clés : damage  detection;  decision  making;  inspection;  maintenance  delay;  optimization;  probability;  service  life;  uncertainty Résumé : This paper proposes a generalized probabilistic framework for optimum inspection and maintenance planning of deteriorating structures. The proposed framework covers (1) the damage occurrence and propagation and service life prediction under uncertainty, (2) the relation between degree of damage and probability of damage detection of an inspection method, and (3) the effects of inspection and maintenance on service life and life-cycle cost. Optimum inspection and maintenance types and times are obtained through an optimization formulation by maximizing the expected service life and minimizing the expected total life-cycle cost consisting of inspection and maintenance costs. The service life, life-cycle cost, and maintenance delay, along with inspection and maintenance actions, are formulated using a decision tree model. The selection of the appropriate maintenance type depends on the degree of damage. The proposed framework is general and can be applied to any types of deteriorating structures or materials. Applications of the proposed framework may include, but are not limited to, bridges, buildings, aircrafts, and naval ships. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000676 [article] Generalized probabilistic framework for optimum inspection and maintenance planning [texte imprimé] / Sunyong Kim, Auteur ; Dan M. Frangopol, Auteur ; Mohamed Soliman, Auteur . - 2013 . - pp. 435–447. structural engineering Langues : Anglais (eng) in Journal of structural engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 435–447 Mots-clés : damage  detection;  decision  making;  inspection;  maintenance  delay;  optimization;  probability;  service  life;  uncertainty Résumé : This paper proposes a generalized probabilistic framework for optimum inspection and maintenance planning of deteriorating structures. The proposed framework covers (1) the damage occurrence and propagation and service life prediction under uncertainty, (2) the relation between degree of damage and probability of damage detection of an inspection method, and (3) the effects of inspection and maintenance on service life and life-cycle cost. Optimum inspection and maintenance types and times are obtained through an optimization formulation by maximizing the expected service life and minimizing the expected total life-cycle cost consisting of inspection and maintenance costs. The service life, life-cycle cost, and maintenance delay, along with inspection and maintenance actions, are formulated using a decision tree model. The selection of the appropriate maintenance type depends on the degree of damage. The proposed framework is general and can be applied to any types of deteriorating structures or materials. Applications of the proposed framework may include, but are not limited to, bridges, buildings, aircrafts, and naval ships. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000676

Novel approach for multicriteria optimization of life-cycle preventive and essential maintenance of deteriorating structures / Nader M. Okasha in Journal of structural engineering, Vol. 136 N° 8 (Août 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 8 (Août 2010) . - pp. 1009-1022 Titre : Novel approach for multicriteria optimization of life-cycle preventive and essential maintenance of deteriorating structures Type de document : texte imprimé Auteurs : Nader M. Okasha, Auteur ; Dan M. Frangopol, Auteur Année de publication : 2011 Article en page(s) : pp. 1009-1022 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Structural  systems  Lifetime  functions  Redundancy  Availability  Lifetime  performance  Maintenance  Multi-objective  optimization  GA Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this paper, the performance of structures is modeled using lifetime functions. Specifically, the unavailability and redundancy are used as performance indicators, based on which optimum maintenance strategies are sought. Models that reflect the separate or combined effects of essential and preventive maintenance on the unavailability are presented. A novel optimization approach is proposed in which the problem is formulated to provide optimum maintenance strategies with either or both essential and preventive maintenance actions. Genetic algorithms are used to solve this problem. In this paper, multiple essential maintenance types and multiple preventive maintenance types are considered, and regular or irregular preventive maintenance time-intervals are considered. Furthermore, essential maintenance is treated as performance-based, i.e., essential maintenance is only applied when a performance threshold is reached, and an algorithm is proposed for conducting the optimization under uncertainty. Although applicable to any type of structure, the proposed approach is illustrated on a highway bridge example. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i8/p1009_s1?isAuthorized=no [article] Novel approach for multicriteria optimization of life-cycle preventive and essential maintenance of deteriorating structures [texte imprimé] / Nader M. Okasha, Auteur ; Dan M. Frangopol, Auteur . - 2011 . - pp. 1009-1022. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 8 (Août 2010) . - pp. 1009-1022 Mots-clés : Structural  systems  Lifetime  functions  Redundancy  Availability  Lifetime  performance  Maintenance  Multi-objective  optimization  GA Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this paper, the performance of structures is modeled using lifetime functions. Specifically, the unavailability and redundancy are used as performance indicators, based on which optimum maintenance strategies are sought. Models that reflect the separate or combined effects of essential and preventive maintenance on the unavailability are presented. A novel optimization approach is proposed in which the problem is formulated to provide optimum maintenance strategies with either or both essential and preventive maintenance actions. Genetic algorithms are used to solve this problem. In this paper, multiple essential maintenance types and multiple preventive maintenance types are considered, and regular or irregular preventive maintenance time-intervals are considered. Furthermore, essential maintenance is treated as performance-based, i.e., essential maintenance is only applied when a performance threshold is reached, and an algorithm is proposed for conducting the optimization under uncertainty. Although applicable to any type of structure, the proposed approach is illustrated on a highway bridge example. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i8/p1009_s1?isAuthorized=no

Risk-based approach for optimum maintenance of bridges under traffic and earthquake loads / Benjin Zhu in Journal of structural engineering, Vol. 139 N° 3 (Mars 2013) 

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Use of lifetime functions in the optimization of nondestructive inspection strategies for bridges / André D. Orcesi in Journal of structural engineering, Vol. 137 N° 4 (Avril 2011) 

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