magistrsko delo
Filip Andolšek (Author), Matjaž Dolšek (Mentor), Drago Saje (Thesis defence commission member), Sebastjan Bratina (Thesis defence commission member), Drago Saje (Thesis defence commission member), Goran Turk (Thesis defence commission member), Anže Babič (Co-mentor)

Abstract

Širjenje informacij o tveganjih, povezanih z ekstremnimi naravnimi dogodki, je izjemno težavno, saj večina ljudi nima osebne izkušnje s katastrofalnimi naravnimi nesrečami, ki lahko ohromijo razvoj družbe za več let ali celo desetletje. Zato se v zadnjem času na področju potresnega inženirstva vse bolj uveljavlja koncept seizmičnega stresnega testa, ki je uporaben kot orodje za preverbo in komunikacijo potresne varnosti gradbenih objektov z upoštevanjem kratkoročno in dolgoročno sprejemljivega tveganja. V magistrski nalogi je izveden stresni test stavbe Fakultete za gradbeništvo in geodezijo Univerze v Ljubljani. Za potrebe stresnega testa smo izdelali tri linearne in štiri nelinearne modele, pri čemer smo posebno pozornost posvetili vplivu nelinearnosti zaradi strižne porušitve elementov in zidanim polnilom. Nelinearne modele smo postopoma nadgrajevali, tako da je vsak naslednji nadgradnja predhodnega. V sklopu analize smo najprej določili poškodovanost konstrukcije in deformacijsko kapaciteto mejnih stanj vseh računskih modelov. Na podlagi potisnih krivulj smo izdelali deterministično oceno, ki je vključena v standard Evrokod 8. Sledi določitev potresnega tveganja, ki je izraženo z verjetnostjo nastopa mejnega stanja blizu porušitve. Na podlagi ocenjenega tveganja smo konstrukcijo umestili v razrede tveganja, z ozirom na ocenjeno kumulativno tveganje pa določili čas znižanja začetne ocene. V zadnjem delu magistrske naloge je podan konceptualni predlog o utrditvi konstrukcije. Rezultati stresnega testa kažejo, da je verjetnost nastopa stanja blizu porušitve (3,2% / 50 let) večja od dolgoročno sprejemljivega tveganja (0,7% / 50 let). Potresna varnost je zato ocenjena z razredom tveganja "B". Na osnovi izbranega modela kratkoročno sprejemljivega tveganja (3,5% / 50 let) in dolgoročno sprejemljivega tveganja se izkaže, da stavba v enem letu preide v razred tveganja "C", v šestih letih pa v razred "D". Ugotovili smo tudi, da je pri oceni potresnega tveganja treba upoštevati vpliv polnil in strižne porušitve armiranobetonskih jeder, sicer je potresno tveganje podcenjeno za več kot štirikrat. Na osnovi konceptualne utrditve stavbe sklepamo, da je možno objekt uvrstiti v razred tveganja "A", če s primernimi ukrepi povečamo strižno nosilnost armiranobetonskih jeder v vzdolžni smeri za 40 odstotkov, v prečni smeri pa za 60 odstotkov glede na trenutno ocenjene vrednosti strižne nosilnosti.

Keywords

gradbeništvo;magistrska dela;nelinearna statična analiza;razširjena N2 metoda;porušni mehanizem;zidana polnila;krivulja potresne ranljivosti;krivulja potresne nevarnosti;stresni test;potresno tveganje;odločitveni model;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL FGG - Faculty of Civil and Geodetic Engineering
Publisher: [F. Andolšek]
UDC: 624.042.7:727(043.3)
COBISS: 8600161 Link will open in a new window
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Downloads: 507
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Other data

Secondary language: English
Secondary title: Seismic stress test of the building of the Faculty of Civil and Geodetic Engineering
Secondary abstract: The dissemination of information about the risk of losses due to the occurrence of extreme natural events is extremely difficult, since most people do not have personal experience of catastrophic natural disasters that can retard the development of society for many years, or even a decade. For this reason, seismic stress tests are increasingly being used in the field of earthquake engineering as a tool for checking and communicating the earthquake safety of buildings, taking into account both short-term and long-term acceptable risks. In the scope of this master%s thesis a seismic stress test of the building of the Faculty of Civil and Geodetic Engineering, University of Ljubljana is performed. For the purpose of conducting the stress test, three linear and four nonlinear models were developed. A special attention was paid to nonlinearities regarding the shear failure and to masonry infills. The nonlinear models were gradually upgraded, so that each model was an upgrade version of the previous model. In the analysis, the damage of the structure and the deformation capacity of the limit states for all calculation models are first determined. On the basis of the pushover curves, a deterministic evaluation is performed, which is included in the standard Eurocode 8. This is followed by the determination of the seismic risk, which is expressed by the probability of the near collapse limit state. Based on the estimated risk and the cumulative risk, the initial grade and the time of grade reduction are, respectively, determined. In the final part, a conceptual proposal for strengthening of the building is presented. The results of the stress test show that the probability of the near collapse limit state (0.7% / 50 years) exceeds the long-term acceptable risk (3.2% / 50 years). Its seismic risk class was therefore estimated as "B". Taking into account the selected models of short-term (3.5% / 50 years) and long-term acceptable risk, the building's seismic risk class would be re-assessed as "C" after one year, and "D" after six years. It was also found that in the case when the effect of masonry infills is disregarded, as well as the possible shear failure of reinforced concrete cores, then the seismic risk is underestimated by a factor of more than four. On the basis of the conceptual proposal for strengthening of the building, it can be concluded that the building could be re-classified as seismic risk class "A" if appropriate measures were taken. These measures consist of increasing the shear strength of the reinforced concrete cores in the longitudinal direction by 40%, and in the transverse direction by 60%, in comparison with the currently estimated shear load-carrying capacities of the reinforced concrete cores.
Secondary keywords: civil engineering;master thesis;nonlinear static analiysis;extended N2 method;failure mode;masonry infills;seismic fragility curve;seismic hazard curve;stress test;seismic risk;decision model;
Type (COBISS): Master's thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo
Pages: XIV, 141 str.
ID: 10980155