Razčlenitev potresne varnosti pri projektiranju armiranobetonske stavbe

diplomska naloga

Jure Žižmond (Avtor), Matjaž Dolšek (Mentor), Janko Logar (Član komisije za zagovor), Mojca Šraj (Član komisije za zagovor), Mitja Brilly (Član komisije za zagovor)

Povzetek

Ključne besede

gradbeništvo;diplomska dela;UNI;potresno inženirstvo;potresno tveganje;potresna nevarnost;potresnovarno projektiranje;Evrokod;faktor obnašanja;nelinearna statična (potisna) analiza;zanesljivost konstrukcij;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2012
Izvor:	Ljubljana
Tipologija:	2.11 - Diplomsko delo
Organizacija:	UL FGG - Fakulteta za gradbeništvo in geodezijo
Založnik:	[J. Žižmond]
UDK:	006:624.012.45:624.042.7(043.2)
COBISS:	5984609
Št. ogledov:	2119
Št. prenosov:	609
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Deaggregation of seismic safety in the design of the reinforced concrete buildings
Sekundarni povzetek:	Design of earthquake-resistant buildings according to Eurocode 8 is not based on the concept of acceptable probability of failure since standard introduces fundamental non-collapse and damage limitation requirements, which are associated with the design seismic action. It is foreseen that the non-collapse requirement is satisfied when the regular buildings are designed to withstand design earthquake, which corresponds to a return period of 475 years and thus to probability of occurrence of 10 % in 50 years. Therefore, it is obvious that structures, which would be designed strictly according to the fundamental non-collapse requirement of the standard, would be unacceptable for society. Due to design safety factors it appears that structures withstand much stronger earthquakes in comparison to the design earthquake. In order to assess whether the safety in design is sufficient and which factors have the greatest impact on it, an eight-storey reinforced concrete building is investigated in the thesis. The strength and system ductility of the six variants of the structure were evaluated on the basis of the pushover analysis, wherein the requirements of Eurocode 2 and 8 were gradually taking into account and the design assumptions were gradually excluded. Safety in design of the building was evaluated by the difference between the calculated and prescribed behavior factor, the ratio between the design and the near-collapse ground acceleration, which was assessed using the N2 method, and by the escalation of the safety in terms of probability of exceedance of the near collapse limit state. It is shown that the calculated behavior factor for the investigated building is 75 % higher than that prescribed by Eurocode 8. This is reflected by the near-collapse ground acceleration. However, questions arises whether the seismic risk of so designed building is acceptable, since estimated probability of exceedance of near collapse limit state is 8.5·10-4, which is significantly higher than the target reliability associated with other actions as prescribed by Eurocode 0.
Sekundarne ključne besede:	graduation thesis;civil engineering;earthquake engineering;seismic risk;seizmic hazard;design for earthqake safety;Eurocode;behaviour factor;nonlinear static (pushover) analysis;reliability of structures;
Vrsta datoteke:	application/pdf
Vrsta dela (COBISS):	Diplomsko delo
Komentar na gradivo:	Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo
Strani:	XII, 107 str.
Vrsta dela (ePrints):	thesis
Naslov (ePrints):	Deaggregation of seismic safety in the design of the reinforced concrete building
Ključne besede (ePrints):	potresno inženirstvo;potresno tveganje;potresna nevarnost;potresnovarno projektiranje;Evrokod;faktor obnašanja;nelinearna statična (potisna) analiza;zanesljivost konstrukcij
Ključne besede (ePrints, sekundarni jezik):	earthquake engineering;seismic risk;seismic hazard;design for earthquake safety;Eurocode;behaviour factor;nonlinear static (pushover) analysis;reliability of structures
Povzetek (ePrints):	Projektiranje potresnoodpornih konstrukcij po standardu Evrokod 8 ne izhaja iz sprejemljive verjetnosti prekoračitve mejnega stanja blizu porušitve, temveč vpelje osnovni zahtevi po neporušitvi in omejitvi poškodb, ki se nanašata na projektno potresno obtežbo. Prvi zahtevi je zadoščeno, če dokažemo, da se konstrukcija ne poruši za potres s povratno dobo 475 let. Ker je verjetnost pojava projektnega potresa 10% v 50 letih, je jasno, da bi bila verjetnost porušitve konstrukcije, ki bi jo projektirali dosledno glede na osnovno načelo po neporušitvi, bistveno prevelika in zato nespr41ejemljiva za družbo. Izkaže pa se, da konstrukcije zaradi varnosti pri projektiranju prenesejo bistveno močnejše potrese, kot je predpisan projektni potres. Z namenom, da bi ugotovili, ali je varnost pri projektiranju zadostna in kateri dejavniki najbolj vplivajo nanjo, smo v okviru diplomske naloge obravnavali primer osemetažne armiranobetonske stavbe. Za šest variant konstrukcije smo s potisno analizo izračunali nosilnost in globalno duktilnost konstrukcije, pri čemer smo postopoma uvajali zahteve standardov Evrokod 2 in 8 ter izločali projektne predpostavke. Varnost pri projektiranju objekta smo vrednotili z razliko med izračunanim in predpostavljenim faktorjem obnašanja, z deležem med projektnim pospeškom tal in pospeškom tal za mejno stanje blizu porušitve, ki smo ga izračunali z metodo N2, in s stopnjevanjem varnosti v smislu verjetnosti prekoračitve mejnega stanja blizu porušitve. Izkaže se, da je izračunani faktor obnašanja, ki smo ga določili iz principa redukcije potresnih sil in projektne potresne obtežbe, za 75% večji od predpostavljenega faktorja obnašanja, kar se odraža tudi s pospeškom tal, ki povzroči mejno stanje blizu porušitve. Kljub temu se pojavlja vprašanje, ali je potresno tveganje za tako projektirano konstrukcijo sprejemljivo, saj znaša ocenjena verjetnost prekoračitve mejnega stanja blizu porušitve konstrukcije 8,5·10-4, kar je bistveno več od ciljne zanesljivosti, ki je predpisana v Evrokodu 0.
Povzetek (ePrints, sekundarni jezik):	Design of earthquake-resistant buildings according to Eurocode 8 is not based on the concept of acceptable probability of failure since standard introduces fundamental non-collapse and damage limitation requirements, which are associated with the design seismic action. It is foreseen that the non-collapse requirement is satisfied when the regular buildings are designed to withstand design earthquake, which corresponds to a return period of 475 years and thus to probability of occurrence of 10 % in 50 years. Therefore, it is obvious that structures, which would be designed strictly according to the fundamental non-collapse requirement of the standard, would be unacceptable for society. Due to design safety factors it appears that structures withstand much stronger earthquakes in comparison to the design earthquake. In order to assess whether the safety in design is sufficient and which factors have the greatest impact on it, an eight-storey reinforced concrete building is investigated in the thesis. The strength and system ductility of the six variants of the structure were evaluated on the basis of the pushover analysis, wherein the requirements of Eurocode 2 and 8 were gradually taking into account and the design assumptions were gradually excluded. Safety in design of the building was evaluated by the difference between the calculated and prescribed behavior factor, the ratio between the design and the near-collapse ground acceleration, which was assessed using the N2 method, and by the escalation of the safety in terms of probability of exceedance of the near collapse limit state. It is shown that the calculated behavior factor for the investigated building is 75 % higher than that prescribed by Eurocode 8. This is reflected by the near-collapse ground acceleration. However, questions arises whether the seismic risk of so designed building is acceptable, since estimated probability of exceedance of near collapse limit state is 8.5·10-4, which is significantly higher than the target reliability associated with other actions as prescribed by Eurocode 0.
Ključne besede (ePrints, sekundarni jezik):	earthquake engineering;seismic risk;seismic hazard;design for earthquake safety;Eurocode;behaviour factor;nonlinear static (pushover) analysis;reliability of structures
ID:	8312511