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Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas
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Corso di dottorato su Ottimizzazione Strutturale: ROBUSTEZZA STRUTTURALE - Gkoumas

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Introduzione ai concetti legati alla robustezza strutturale nell'ambito del corso di dottorato di OTTIMIZZAZIONE STRUTTURALE …

Introduzione ai concetti legati alla robustezza strutturale nell'ambito del corso di dottorato di OTTIMIZZAZIONE STRUTTURALE

Roma, 21 maggio 2015

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  1. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. “Structural robustness: definitions, examples and consequence based assessment of structures” Konstantinos Gkoumas, Ph.D., P.E. Corso di Dottorato: introduzione all'ottimizzazione strutturale Prof.-Ing. Franco Bontempi Dipartimento di Ingegneria Strutturale e Geotecnica Dottorato di Ricerca in Ingegneria delle Strutture Rome, June 21 2014
  2. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Index
  3. Ottimizzazione Strutturale franco.bontempi@uniroma1.it
  4. Ottimizzazione Strutturale franco.bontempi@uniroma1.it
  5. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Personal
  6. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References
  7. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  8. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Ronan Point Tower Block– May 16, 1968 Description: - apartments building; - built between 1966 and 1968; - 64 m tall with 22 story; - walls, floors, and staircases was precast concrete; - each floor was supported directly by the walls in the lower stories, (bearing walls system). The event: - May 16, 1968 a gas explosion blew out an outer panel of the 18th floor, - the loss of the bearing wall causes the progressive collapse of the upper floors, - the impact of the upper floors’ debris caused the progressive collapse of the lower floors. Cause Damage Pr. Collapse
  9. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Description: - apartments building; - precast concrete wall and floor components was the structural bearing system; - ductile detailing and effective ties between the precast components. Cause Damage Pr. Collapse The event: - June 25, 1996 9 tons of TNTeq detonated in front of the building; - the exterior wall was entirely destroyed; - collapse did not progress beyond areas of first damage. Khobar Towers Bombing – June 25, 1996
  10. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Description: - office facility for the Deutsche Bank in Manhattan; - constructed in the early ‘70s in steel-framed structure moment connected, 130 m tall, 40 story and 2 subterranean levels; The event: - On September 11, 2011, the WTC towers debris impact on a building’s façade, - heavy damage between the 9th and the 23rd floor, the column was lost from the 9th and the 18th floor; - the framing system was able to support and redistribute the loads. Deutsche Bank Building – September 11, 2001 Cause Damage Pr. Collapse
  11. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Probability of progressive collapse from an abnormal event P(F) = P(D|H) P(F|DH)P(H) x x damage is caused in the structure damage spreads in the structure occurrence of critical event occurrence of broad or global collapse STRUCTURAL INTEGRITY (ISO/FDS 2394) COLLAPSE RESISTANCE (Starossek&Wolff 2005) Faber (2006) STRUCTURALNON STRUCTURAL MEASURES HAZARD References: Ellingwood, B.R. and Dusenberry, D.O. (2005), “Building design for abnormal loads and progressive collapse”, Comput-Aided Civ. Inf., 20(3), 194-205.
  12. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  13. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Reference: Bontempi, F. (2005) Frameworks for structural analysis, In: Innovation in Civil and Structural Engineering Topping, BHV ed., pp. 1-24 HPLC High Probability – Low Consequences LPHC Low Probability – High Consequences Complexity Non linear issues and interaction mechanisms Designapproach: StochasticDeterministic QUALITATIVE RISK ANALYSIS PROBABILISTIC RISK ANALYSIS PRAGMATIC ANALYSIS OF RISK SCENARIOS Secondary design Primary design Low Probability – High Consequences Events
  14. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. References: Taleb, Nassim Nicholas (April 2007). The Black Swan: The Impact of the Highly Improbable (1st ed.). London: Penguin. p. 400. ISBN 1-84614045-5. A Black Swan is an event with the following three attributes. 1. First, it is an outlier, as it lies outside the realm of regular expectations, because nothing in the past can convincingly point to its possibility. Rarity -The event is a surprise (to the observer). 2. Second, it carries an extreme 'impact'. Extreme “impact” - the event has a major effect. 3. Third, in spite of its outlier status, human nature makes us concoct explanations for its occurrence after the fact, making it explainable and predictable. Retrospective (though not prospective) predictability - After the first recorded instance of the event, it is rationalized by hindsight, as if it could have been expected; that is, the relevant data were available but unaccounted for in risk mitigation programs. The same is true for the personal perception by individuals. Black Swans
  15. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  16. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. QUALITY DAMAGE or ERROR REQUIRED PERFORMANCE NOMINAL PERFORMANCE NOMINAL SITUATION Structural Robustness
  17. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. • Capacity of a construction to exhibit regular decrease of its structural quality as a consequence of negative causes. • It implies: a) some smoothness of the decrease of structural performance due to negative events (intensive feature); b) some limited spatial spread of the rupture (extensive feature). Structural Robustness
  18. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Qualitative definitions of structural robustness [EN 1991-1-7: 2006 ]: ability of a structure to withstand actions due to fires, explosions, impacts or consequences of human errors, without suffering damages disproportionate to the triggering causes [SEI 2007, Beton Kalender 2008]: insensitivity of the structure to local failure structure B d P s STRUCTURE B: P s ROBUSTNESS CURVES P (performance) structure A STRUCTURE A damaged integer DP damaged more performant, less resistant integer (damage level) DPDP more performant, less robust less performant, more robust Structural Robustness A B
  19. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  20. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. CommonULS&SLS VerificationFormat Structural Robustness Assessment 1st level: Material Point 2nd level: Element Section 3rd level: Structural Element 4th level: Structural System Structural robustness in design
  21. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. STRUCTURAL DESIGN PRIMARY SECONDARY TERTIARY LOADS DEAD X LIVE X SNOW X EARTHQUAKE X FIRE X X EXPLOSIONS X X “BLACK SWAN” X Member-based structural design Consequence-based structural design Black Swan event: - unpredictable, - large impact on community, - easy to predict after its occurrence. References: Nafday, AM. (2011) Consequence-based structural design approach for black swan events. Structural Safety, 33(1): 108-114. Structural robustness in design
  22. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Uncertainty in the likelihood that the harmful consequences of a particular event will be realized Uncertainty in the consequences related to the specific event Primary design Secondary design Tertiary design Structural robustness in design
  23. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  24. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. STRUCTURE & LOADS Collapse Mechanism NO SWAY “IMPLOSION” OF THE STRUCTURE “EXPLOSION” OF THE STRUCTURE is a process in which objects are destroyed by collapsing on themselves is a process NOT CONFINED SWAY Bad VS Good collapse
  25. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Initial load-bearing element failure that triggers the rigid fall of a part of the structure onto another and leads to a sequential impacts on the rest of the structure, that collapses on itself. Characteristic feature is the force redistribution into alternative paths, impulsive loading due to sudden element failure and force concentration in elements to fail next. Zipper Domino Section Instability Mixed Pancake Initial cross-section cut and stress concentration that cause the rupture of further cross-sectional parts (fast fracture) and failure progression throughout the entire section. Initial element rigid overturning and falling over another element, that, by means of transformation of potential into kinetic energy, trigger the overturning of the following element. The destabilization of some load-carrying elements in compression due to an initial failure of stabilizing elements can trigger a failure progression throughout the structure. Some collapses are less amenable to generalization because the relative importance of the contributing basic categories of collapse can vary and combine in progression of failures. - DOMINO + PANCAKE (e.g. A.P.Murrah Building, Building during Izmit Earquake) - ZIPPER + INSTABILITY (e.g. cable-stayed bridges) Reference: Betoncalendar, 2008 (adapted from “Structural integrity: robustness assessment and progressive collapse susceptibility”, Luisa Giuliani, PhD Thesis, Sapienza University of Rome, Dipartimento di Ingegneria Strutturale e Geotecnica) Collapse types
  26. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Initial load-bearing element failure that triggers the rigid fall of a part of the structure onto another and leads to a sequential impacts on the rest of the structure, that collapses on itself. Characteristic feature is the force redistribution into alternative paths, impulsive loading due to sudden element failure and force concentration in elements to fail next. Zipper Domino Section Instability Mixed Pancake Initial cross-section cut and stress concentration that cause the rupture of further cross-sectional parts (fast fracture) and failure progression throughout the entire section. Initial element rigid overturning and falling over another element, that, by means of transformation of potential into kinetic energy, trigger the overturning of the following element. The destabilization of some load-carrying elements in compression due to an initial failure of stabilizing elements can trigger a failure progression throughout the structure. Some collapses are less amenable to generalization because the relative importance of the contributing basic categories of collapse can vary and combine in progression of failures. - DOMINO + PANCAKE (e.g. A.P.Murrah Building, Building during Izmit Earquake) - ZIPPER + INSTABILITY (e.g. cable-stayed bridges) Reference: Betoncalendar, 2008 (adapted from “Structural integrity: robustness assessment and progressive collapse susceptibility”, Luisa Giuliani, PhD Thesis, Sapienza University of Rome, Dipartimento di Ingegneria Strutturale e Geotecnica) Collapse types Islamabad Earthquake 2005 Münsterland, 2005 Viaduct after earthquake Izmit Earthquake 1999 Tanker S.S. Schenectady, 1941
  27. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. The Boeing B-17 Flying Fortress collided with another aircraft during World War II and, although sustaining large amount of structural damage, landed safely, due to the high redundancy of the fuselage connections. Design Strategy #1: Continuity (robust behavior-redundancy)
  28. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. On July 1945 a B-25 bomber crashed into the Empire State Building, The impact of the plane created a 5.5x6 m hole in the side of the tower. This crash caused extensive damage to the masonry exterior and the interior steel structure of the building. The 278 m building was rocked by the impact but resist the impact in consequence of the intrinsic redundancy of its framed system. Plane crash on the Empire State Building, 1945 Design Strategy #1: Continuity (robust behavior-redundancy)
  29. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Design Strategy #2: Segmentation (Compartmentalization) A service-induced damage led to explosive decompression and loss of large portion of fuselage skin when small fatigue crack suddenly linked together. The subsequent fracture was eventually arrested by fuselage frame structure and the craft landed safely. Aloha Boeing 737, April 1988 (compartmentalization by strengthening)
  30. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Design Strategy #2: Segmentation (Compartmentalization) The partial collapse, started in the roof and due design and execution errors, stoped at the two joints which separated the collapsing section from the adjacent structures. A higher continuity could have unlikely sustained the forces during collapse, since the construction deficiencies affected also adjacent sections.
  31. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  32. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. References: (EN 1991-1-7 2006): "Eurocode 1 – Actions on structures, Part 1-7: General actions – accidental actions." Comité European de Normalization (CEN). (Bontempi F, Giuliani L, Gkoumas K, 2007): "Handling the exceptions: robustness assessment of a complex structural system.“, Invited Lecture, Structural Engineering, Mechanics and Computation (SEMC) 3, 1747-1752. (Starossek U, 2009): “Progressive collapse of structures.” London: Thomas Telford Publishing, 2009. Definitions: 1- "The ability of a structure to withstand events like fire, explosions, impact or the consequences of human error without being damaged to an extent disproportionate to the original cause." (EN 1991-1-7 2006) 2- "The robustness of a structure, intended as its ability not to suffer disproportionate damages as a result of limited initial failure, is an intrinsic requirement, inherent to the structural system organization." (Bontempi F, Giuliani L, Gkoumas K, 2007) 3- “Robustness is defined as insensitivity to local failure." (Starossek U, 2009) Structural Robustness
  33. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. References: (ASCE 7-05 2005): "Minimum design loads for buildings and other structures." American Society of Civil Engineers (ASCE). (GSA 2003): "Progressive collapse analysis and design guidelines for new federal office buildings and major modernization projects." General Services Administration (GSA). (UFC 4-010-01 2003): "DoD minimum antiterrorism standards for buildings." Department of Defense (DoD). Progressive Collapse Definitions: 1-"Progressive collapse is defined as the spread of an initial local failure from element to element resulting, eventually, in the collapse of an entire structure or a disproportionate large part of it." (ASCE 7-05 2005) 2- "A progressive collapse is a situation where local failure of a primary structural component leads to the collapse of adjoining members which, in turn, leads to additional collapse. Hence, the total collapse is disproportionate to the original cause." (GSA 2003) 3-"Progressive collapse: a chain reaction failure of building members to an extent disproportionate to the original localized damage." (UFC 4-010-01 2003)
  34. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. References: Arup (2011), Review of international research on structural robustness and disproportionate collapse, London, Department for Communities and Local Government. Starossek, U. and Haberland, M. (2010), “Disproportionate Collapse: Terminology and Procedures”, J. Perf. Constr. Fac., 24(6), 519-528. Observations: − A progressive collapse is one which develops in a progressive manner akin to the collapse of a row of dominos. − A disproportionate collapse is one which is judged (by some measure defined by the observer) to be disproportionate to the initial cause. This is merely a judgement made on observations of the consequences of the damage which results from the initiating events. − A collapse may be progressive in nature but not necessarily disproportionate in its extents, for example if arrested after it progresses through a number of structural bays. Vice versa, a collapse may be disproportionate but not necessarily progressive if, for example, the collapse is limited in its extents to a single structural bay but the structural bays are large. − The terms of disproportionate collapse and progressive collapse are often used interchangeably because disproportionate collapse often occurs in a progressive manner and progressive collapse can be disproportionate. Progressive Collapse VS Disproportionate Collapse
  35. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Robustness and collapse resistance in a dependability framework Sgambi, L., Gkoumas, K. and Bontempi, F. (2012), “Genetic algorithms for the dependability assurance in the design of a long- span suspension bridge”, Comput-Aided Civ. Inf., 27(9), 655-675.
  36. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  37. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. The currently available design strategies and methods to prevent disproportionate collapse are as follows: − Prevent local failure of key elements (direct design) − Specific local resistance − Non-structural protective measures − Presume local failure (direct design) − Alternative load paths − Isolation by segmentation − Prescriptive design rules (indirect design) Reference: Starossek, U. 2008. Collapse resistance and robustness of bridges. IABMAS’08: 4th International Conference on Bridge Maintenance, Safety, and Management Seoul, Korea, July 13-17, 2008 Measures against disproportionate collapse
  38. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Reference: Giuliani, L., 2012. Structural safety in case of extreme actions. International Journal of Lifecycle Performance Engineering IJLCPE Special Issue on: "Performance and Robustness of Complex Structural Systems", Guest Editor Franco Bontempi, ISSN (Online): 2043-8656 - ISSN (Print): 2043-8648. Design strategies against progressive collapse
  39. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  40. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. RISK-BASED [Faber, 2005] R I inddir dir rob R R + = direct risk indirect riskDAMAGE-BASED ∑ = = n 1i ' i i )K(tr )K(tr .Deg.Stiff ithelement stiffness matrix (integer state) damaged elements ithelement stiffness matrix (damaged state) [Yan&Chang, 2006] [Biondini & Frangopol, 2008] 1 0 ∆Φ ∆Φ ρ =Φ ∆ energy between intact and damaged system (backward pseudo-loads) ∆ energy between intact and damaged system (forward pseudo-loads) Indirect Risk Direct Risk Indirect Risk Direct Risk Reference: Olmati, P., Brando, F., Gkoumas, K. “Robustness assessment of a Steel Truss Bridge”, ASCE/SEI Structures Congress, Pittsburgh, Pennsylvania, May 2-4, 2013. B A Withstand actions, events Withstand damages Structural Robustness assessment TOPOLOGY-BASED ENERGY-BASEDOther:
  41. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. [Baker et al. 2008] R I inddir dir rob R R + = direct risk indirect risk Reference: Baker J.W., Schubert M., Faber M.H., (2008). On the Assessment of Robustness, Journal of Structural Safety, Volume 30, Issue 3, pp. 253-267, DOI:10.1016/j.strusafe.2006.11.004 “A robust system is considered to be one where indirect risks do not contribute significantly to the total system risk” Rdir˃˃Rind Rdir: associati con il danni iniziali Rind: associati con danni successivi EXBD: Exposure before damage D : Damage D : No Damage F : Probability of system failure Cdir : Direct consequences Cind: Indirect consequences Risk Based Structural Robustness assessment
  42. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. − ≥ 0 member-based design − ≥ 0limit state design Resistance (probabilistic) Solicitation (probabilistic) Resistance (design values) Solicitation (design values) (1 − ) − ≥ 0 Member consequence factor based design 0 ≤ ≤ 1 • Cf quantifies the influence that a loss of a structural element has on the load carrying capacity. • Cf provides to the single structural member an additional load carrying capacity, in function of the nominal design (not extreme) loads that can be used for contrasting unexpected and extreme loads. • Essentially, if Cf tends to 1, the member is more likely to be important to the structural system; instead if Cf tends to 0, the member is more likely to be unimportant to the structural system. Member consequence factor and robustness assessment 0EγγRγγ kEMEk 1 Rd 1 MR ≥− ∑−− 0E)R(*)C1( kEdMEk 1 Rd 1 MRf ≥γγ−γγ− ∑−−
  43. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. • The structure is subjected to a set of damage scenarios and the consequence of the damages is evaluated by the member consequence factor ( ) that for convenience can be easily expressed in percentage. • For damage scenario is intended the failure of one or more structural elements. • Robustness can be expressed as the complement to 100 of , intended as the effective coefficient that affects directly the resistance. • is evaluated by the maximum percentage difference of the structural stiffness matrix eigenvalues of the damaged and undamaged configurations of the structure. = − 100 !"# where, and are respectively the i-th eigenvalue of the structural stiffness matrix in the undamaged and damaged configuration, and N is the total number of the eigenvalues. Member consequence factor and robustness assessment
  44. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. • The corresponding robustness index ( ) is therefore defined as: =1 - • Values of Cf close to 100% mean that the failure of the structural member most likely causes a global structural collapse. • Low values of Cf do not necessarily mean that the structure survives after the failure of the structural member: this is something that must be established by additional analysis that considers the loss of the specific structural member. • A value of Cf close to 0% means that the structure has a good structural robustness. The proposed method for computing the consequence factors, for different reasons, should not be used for: 1. Structures that have high concentrated masses (especially non-structural masses) in a particular zone; and, 2. Structures that have cable structural system (e.g., tensile structures, suspension bridges). Member consequence factor and robustness assessment
  45. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  46. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Cost of robustness measures ≤ Reduction of failure consequences • The objective function for optimization may be very complex and depend on the type of the structural system, robustness measures, characteristics of failure consequences and probabilities of occurrence and intensities of various hazards. • If the total cost of robustness measures exceeds the reduction in failure consequences, then the system may be considered as robust but uneconomic. In such a situation, probabilistic methods of risk assessment may be effectively used Reference: COST Action TU0601 Robustness of Structures STRUCTURAL ROBUSTNESS DESIGN FOR PRACTISING ENGINEERS. EUROPEAN COOPERATION IN SCIENCE AND TECHNOLOGY, Editor T. D. Gerard Canisius. Robustness in Optimization
  47. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Reference: Casciati, S. and Faravelli, L. (2008) Building a Robustness Index. Robustness of Structures COST Action TU0601, 1st Workshop, February 4-5, ETH Zurich, Switzerland. Robustness in Optimization Example: Hierarchy of the failure modes (“weak beam/strong column”) ...develop the less catastrophic failure modes first. ...ranking the failure modes in terms of a hierarchy in such a way that the less harmful ones are generated at lower loading levels Objective function: Robustness term: Pfi: probability of the i-th failure mode m: number of failure modes A robust structure requires the plastic moment of the column, MPc, being larger than the one of the beam, MPb; that is, Z = MPc– MPb≥ 0 µc, σc, µb, σb: means and the standard deviations of the plastic moments of the columns and of the beam, respectively. To ensure robustness, the index I needs to be kept positive. The objective is, therefore, to minimize FI=-I.
  48. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  49. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Stiffness matrix Kun λi un Eigenvalues Kdam λi dam Consequence factor Robustness indexRscenario= 100 - Cf scenario N1i un i dam i un iscenario f 100 )( maxC −=       λ λ−λ = Structural Robustness assessment - overview
  50. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. ka kb x y K%& = 10 0 0 10 C(! 1 = 0% C(* 1 = 30% R1 = 70% R1 = 100 − C( 1N: total eigenvalues number i: single eigenvalue number a and b: elements a b N1i un i dam i un iscenario f 100 )( maxC −=       λ λ−λ = K./0 = 10 0 0 7 Scenario 1 Single damage – analytic calculation
  51. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. • Single bay frame structure with a diagonal beam brace, composed in total of 5 members • IPE 300, S235 steel, one meter length, pinned boundary conditions. The evaluated scenarios consist in the removal of elements 1, 2 and 3 sequentially, so the damage is cumulative: this means that the each scenario includes the damage from the previous one. Cumulative damage – numerical assessment DSj = Σi=(1-j) di
  52. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Cumulative damage – numerical assessment • star-shaped structure – 8 members - pipe cross section - 20 centimeters outside diameter - 20 millimeters thickness - S235 steel. • members 1, 3, 5, and 7 are 0.5 meters long and members 2, 4, 6, and 8 are 0.7 meters long. All the members are connected to each other by a fixed type connection. Also the boundary conditions are of the fixed type and the structure is plane. DSj = Σi=(1-j) di
  53. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  54. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. • Built 1967 • 3 spans, 1067 feet long • 1977 – new wearing surface • 1998 – curbs and railings replaced I-35 West Bridge, Minneapolis, MN
  55. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. North Downtown I-35 West Bridge, Minneapolis, MNPhotofromaircraftflyingoverhead. • At 6:05 pm on August 1st 2007 Bridge Collapsed • 13 People killed & approximately 145 Injured
  56. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. I-35 W bridge I-35 West Bridge, Minneapolis, MN NTSB 2007
  57. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Undamaged Damaged scenario I-35 West Bridge, Minneapolis, MN – damage scenarios
  58. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. I-35 West Bridge, Minneapolis, MN – damage scenarios 3D 2D
  59. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. d1 d2d3 d4 d5 d7 d6 37 59 42 45 35 38 23 63 41 58 55 65 62 77 0 20 40 60 80 100 1 2 3 4 5 6 7 Robustness% Scenario Cf max Robustness 1 2 3 4 5 6 7 Scenario Cf max Robustness Damage scenario d1 d2 d3 d4 d5 d6 d7 DSj = di I-35 West Bridge, Minneapolis, MN – single damage
  60. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. d1 d2d3 d4 d5 d7 d6 83 87 88 53 60 86 64 17 13 12 47 40 14 36 0 20 40 60 80 100 1 2 3 4 5 6 7 Robustness% Scenario Cf max Robustness Damage scenario d1 d2 d3 d4 d5 d6 d7 I-35 West Bridge, Minneapolis, MN/ enhanced– single damage DSj = di
  61. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Black Swan Vulnerability Cause Damage Index • Significant collapse cases • LPHC events and Black Swans • Structural robustness in qualitative terms • Structural robustness in civil engineering design • Collapse types • Structural robustness and progressive collapse definitions • Measures against progressive collapse • Quantification of robustness • Robustness and optimization • Member consequence factor • Assessment of simple structures • Assessment of complex structures • References Robustness Collapse resistance Progressive collapse Photo Credit: Wikipedia Commons. Member consequence factor
  62. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. References Alashker, Y., Li, H. and El-Tawil, S. (2011), “Approximations in Progressive Collapse Modeling”, J. Struct. Eng.- ASCE, 137(9), 914-924. Arup (2011), Review of international research on structural robustness and disproportionate collapse, London: Department for Communities and Local Government. ASCE 7-05 (2005), Minimum design loads for buildings and other structures, American Society of Civil Engineers (ASCE). Biondini, F. and Frangopol, D. (2009), “Lifetime reliability-based optimization of reinforced concrete cross-sections under corrosion”, Struct. Saf., 31(6), 483-489. Biondini, F., Frangopol, D.M. and Restelli, S. (2008), “On structural robustness, redundancy and static indeterminancy”, Proceedings of the 2008 Structures Congress, April 24-26, 2008, Vancouver, BC, Canada. Bontempi, F. and Giuliani, L. (2008), “Nonlinear dynamic analysis for the structural robustness assessment of a complex structural system”, Proceedings of the 2008 Structures Congress, April 24-26, 2008, Vancouver, BC, Canada. Bontempi, F., Giuliani, L. and Gkoumas, K. (2007), “Handling the exceptions: dependability of systems and structural robustness”, Invited Lecture, Proceedings of the 3rd International Conference on Structural Engineering, Mechanics and Computation (SEMC), Cape Town, South Africa, September 10-12. Brando, F., Testa, R.B. and Bontempi, F. (2010), “Multilevel structural analysis for robustness assessment of a steel truss bridge”, Bridge Maintenance, Safety, Management and Life-Cycle Optimization - Frangopol, Sause and Kusko (eds), Taylor & Francis Group, London, ISBN 978-0-415-87786-2. Canisius, T.D.G., Sorensen, J.D. and Baker, J.W. (2007), “Robustness of structural systems - A new focus for the Joint Committee on Structural Safety (JCSS)”, Proceedings of the 10th Int. Conf. on Applications of Statistics and Probability in Civil Engineering (ICASP10), Taylor and Francis, London. Casciati, S. and Faravelli, L. (2008) Building a Robustness Index. Robustness of Structures COST Action TU0601, 1st Workshop, February 4-5, 2008, ETH Zurich, Zurich, Switzerland. Cha, E. J. and Ellingwood, B. R. (2012), “Risk-averse decision-making for civil infrastructure exposed to low-probability, high- consequence events”, Reliab. Eng. Syst. Safe., 104(1), 27-35. Choi, J-h. and Chang, D-k. (2009), “Prevention of progressive collapse for building structures to member disappearance by accidental actions”, J. Loss Prevent. Proc., 22(6), 1016-1019. COST (2011), TU0601 - Structural Robustness Design for Practising Engineers, Canisius, T.D.G. (Editor). Crosti, C. and Duthinh, D. (2012), “Simplified gusset plate model for failure prediction of truss bridges”, Bridge Maintenance, Safety, Management, Resilience and Sustainability - Proceedings of the 6th International Conference on Bridge Maintenance, Safety and Management, IABMAS 2012, Italy, Stresa, 8-12 July 2012. Crosti, C., Duthinh, D. and Simiu, E. (2011), “Risk consistency and synergy in multihazard design”, J. Struct. Eng.- ASCE, 137(8), 844- 849.
  63. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. References DoD - Department of Defense (2009), Unified Facilities Criteria (UFC). Report No. UFC 4-023-03: Design of buildings to resist progressive collapse. Washington DC: National Institute of Building Sciences. Ellingwood, B. (2002), “Load and resistance factor criteria for progressive collapse design”, Proceedings of Workshop on Prevention of Progressive Collapse, National Institute of Building Sciences, Washington, D.C Ellingwood, B.R. and Dusenberry, D.O. (2005), “Building design for abnormal loads and progressive collapse”, Comput-Aided Civ. Inf., 20(3), 194-205. Ellingwood, B.R., Smilowitz, R., Dusenberry, D.O., Duthinh, D. and Carino, N.J. (2007), Report No. NISTIR 7396: Best practices for reducing the potential for progressive collapse in buildings. Washington DC: National Institute of Standards and Technology (NIST) EN 1990 (2002), Eurocode - Basis of structural design. Faber, M.H. and Stewart, M.G. (2003), “Risk assessment for civil engineering facilities: critical overview and discussion”, Reliab. Eng. Syst. Safe., 80(2), 173-184. FHWA (2011), Framework for Improving Resilience of Bridge Design, Publication No IF-11-016. Galal, K. and El-Sawy, T. (2010), “Effect of retrofit strategies on mitigating progressive collapse of steel frame structures”, J. Constr. Steel Res., 66(4), 520-531. Ghosn, M. and Moses, F. (1998), NCHRP Report 406: Redundancy in Highway Bridge Superstructures, TRB, National Research Council, Washington, D.C. Giuliani, L. (2012), “Structural safety in case of extreme actions”, Special Issue on: “Performance and Robustness of Complex Structural Systems”, Int. J. of Lifecycle Performance Engineering (IJLCPE), 1(1), 22-40. GSA - General Service Administration (2003), Progressive collapse analysis and design guidelines for new federal office buildings and major modernization project, Washington DC: GSA. Hoffman, S. T. and Fahnestock, L. A. (2011), “Behavior of multi-story steel buildings under dynamic column loss scenarios”, Steel Compos. Struc., 11(2), 149-168. HSE - Health and Safety Executive (2001), Reducing risks, protecting people, HSE’s decision-making process, United King: Crown copyright. Izzuddin, B. A., Vlassis, A. G., Elghazouli, A. Y. and Nethercot, D. A. (2008a), “Progressive collapse of multi-storey buildings due to sudden column loss - Part I: Simplified assessment framework”, Eng. Struct., 30(5), 1308-1318. Izzuddin, B. A., Vlassis, A. G., Elghazouli, A. Y. and Nethercot, D. A. (2008b), “Progressive collapse of multi-storey buildings due to sudden column loss - Part II: Application”, Eng. Struct., 30(5), 1424-1438. Kim, J. and Kim, T. (2009), “Assessment of progressive collapse-resisting capacity of steel moment frames”, J. Constr. Steel Res., 65(1), 169-179.
  64. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. References Kwasniewski, L. (2010), “Nonlinear dynamic simulations of progressive collapse for a multistory building”, Eng. Struct., 32(5), 1223- 1235. Malla, R.B., Agarwal, P. and Ahmad, R. (2011), “Dynamic analysis methodology for progressive failure of truss structures considering inelastic postbuckling cyclic member behavior”, Eng. Struct., 33(5), 1503-1513. Miyachi, K., Nakamura, S. and Manda, A. (2012), “Progressive collapse analysis of steel truss bridges and evaluation of ductility”, J. Constr. Steel Res., 78, 192-200. Nafday, A.M. (2008), “System Safety Performance Metrics for Skeletal Structures”, J. Struct. Eng.- ASCE, 134(3), 499-504. Nafday, A.M. (2011), “Consequence-based structural design approach for black swan events”, Struct. Saf., 33(1), 108-114. Olmati, P., Gkoumas, K., Brando, F., Cao, L. (2013) “Consequence-based robustness assessment of a steel truss bridge”, Steel and Composite Structures, An International Journal, 14(4), 379-395. Rezvani, F. H. and Asgarian, B. (2012), “Element loss analysis of concentrically braced frames considering structural performance criteria”, Steel Compos. Struc., 12(3), 231-248. Saydam, D. and Frangopol, D. M. (2011), “Time-dependent performance indicators of damaged bridge superstructures”, Eng. Struct., 33(9), 2458-2471. Starossek, U. (2009), Progressive collapse of structures, London: Thomas Telford Publishing. Starossek, U. and Haberland, M. (2010), “Disproportionate Collapse: Terminology and Procedures”, J. Perf. Constr. Fac. 24(6), 519-528. Starossek, U. and Haberland, M. (2012), “Robustness of structures”, Special Issue on: “Performance and Robustness of Complex Structural Systems”, Int. J. of Lifecycle Performance Engineering (IJLCPE), 1(1), 3-21. Taleb, Nassim Nicholas (April 2007). The Black Swan: The Impact of the Highly Improbable (1st ed.). London: Penguin. p. 400. ISBN 1- 84614045-5. Yuan, W. and Tan, K. H. (2011), “Modeling of progressive collapse of a multi-storey structure using a spring-mass-damper system”, Struct. Eng. Mech., 37(1), 79-93.
  65. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. Acknowledgements - Luisa Giuliani, PhD. Associate Professor, DTU, Denmark. - Francesca Brando, PhD. Senior Engineer, Thornton Tomasetti, NY. - Pierluigi Olmati, PhD. Post-doc, Surrey University, UK.
  66. Corso di Dottorato: Introduzione all'o mizzazione strutturale Roma, 21 Giugno 2014 Prof.-Ing. Franco Bontempi, Ing. Konstantinos Gkoumas, Ph.D. “Structural robustness: definitions, examples and consequence based assessment of structures” Konstantinos Gkoumas, Ph.D., P.E. Corso di Dottorato: introduzione all'ottimizzazione strutturale Prof.-Ing. Franco Bontempi Dipartimento di Ingegneria Strutturale e Geotecnica Dottorato di Ricerca in Ingegneria delle Strutture Rome, June 21 2014

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