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Multi hazard approach to design of civil structures. Domenico Asprone Dipartimento di Ingegneria Strutturale Università degli Studi di Napoli Federico II. Introduction. A strategic structure could be subject to more than one critical action during its service life.
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Multi hazard approach to design of civil structures Domenico Asprone Dipartimento di Ingegneria Strutturale Università degli Studi di Napoli Federico II
Introduction A strategic structure could be subject to more than one critical action during its service life. A sustainable design needs to consider all the possible critical actions which the structure could be subjected to. Given the uncertainty involved, the sustainable design needs to be addressed based on a probabilistic framework.
Risk, hazard, vulnerability and exposure are probabilistic quantities. Multi-hazard structural design/assessment vulnerability risk exposure hazard
Hazard (a) (a) (b)
Vulnerability Seismic vulnerability
Vulnerability Non-structural elements vulnerability
Vulnerability Tsunami vulnerability
Vulnerability Termite vulnerability
Exposure Time dependence
Exposure Seismic zones
Multi-hazard structural design/assessment Structural engineering issue: In case of multiple hazard, the design/assessment criterion can be written as Acceptable threshold Total probability of collapse
Italian hazardfor civil structures Earthquake; Extreme service conditions; Wind; Snow; Explosions; Fire; Flood; Landslide; Vulcan eruptions; …
Seismic hazard Peak Ground Acceleration
Seismic hazard 36 Seismogenic zones
Seismic hazard Attenuation law
Seismic hazard PGA distribution
Seismic hazard Grid spacing 0.05° long-lat
Seismic hazard Pratica di Mare hazard Limit states Return Period PGA
Man-made blast hazardScenario definition Blast scenario 30% 70% Explosion takes place inside the structure Explosion takes place outside a 10 m stand-off distance from the structure 20% 20% 20% 20% 20% 10% 90% 1st floor: Car bomb W=200 kg – 500 kg 2nd floor: Backpack bomb W=15 kg – 35 kg 3rd floor: Backpack bomb W=15 kg – 35 kg 4th floor: Backpack bomb W=15 kg – 35 kg 5th floor: Backpack bomb W=15 kg – 35 kg Car bomb W=200 kg - 500kg Truck bomb W=15,000kg - 25,000kg
Blast loading The induced overpressure normally consists of a positive decaying phase followed by a weaker negative phase. The most critical aspect with respect to the safety of the structure regards progressive collapse mechanisms on the damaged structure.
Wind hazard Critical issues: Wind direction; Low velocity characterization; Spatial mesh refining; Season variation; Reliable hazard characterization.
Multi-hazard structural design/assessment Structural engineering issue: In case of multiple hazard, the design/assessment criterion can be written as Acceptable threshold Total probability of collapse