magistrsko delo
Povzetek
V magistrskem delu obravnavamo potresno odpornost prizidka Inštituta za informacijske
znanosti v Mariboru v skladu s standardom Evrokod 8. V prvem delu smo se osredotočili na
linearno statično potresno analizo objekta. Želeli smo določiti najbolj optimalen način
modeliranja v programu ETABS, ki bi nam pri najkrajšem času modeliranja in izračuna podal
sprejemljivo točne rezultate. S tem namenom smo izdelali 15 modelov. Modele smo ločili na
inženirsko uporabne ter generične modele, ki zaradi nepravilnosti v praksi niso uporabni,
vendar pripomorejo k razumevanju vrednotenja napačnega modeliranja konstrukcije.
Rezultati dokazujejo, da se geometrijo modelov do neke mere izplača poenostaviti. V praksi
so uporabni tako ploskovni, linijski ali kombinirani modeli. Za kateri model se bomo odločili
pa je odvisno predvsem od zasnove konstrukcije in vrste potresne analize. Uporaba togih
odsekov za povezovanje vertikalnih elementov z gredami ter povezovanje linijskih in
ploskovnih elementov je pomembna za pravilno modeliranje togosti konstrukcije. Ročni vnos
mase konstrukcije v masna središča na nivojih etaž zahteva nekoliko več časa za
modeliranje, vendar se s tem pospeši sama analiza in omeji prostostne stopnje na trikratnik
števila etaž. Glede na primerjavo rezultatov analize modela z ročnim in avtomatskim
deljenjem, smo prišli do zaključka, da ročno deljenje ni smotrno, saj zahteva veliko časa,
rezultati pa niso bistveno bolj točni. Določili smo tudi optimalno velikost končnih elementov, ki
znaša 0,5/0,5 m. V drugem delu magistrske naloge smo na obravnavanem objektu
predstavili poenostavljeno nelinearno analizo – N2 metodo. Gre za kombinacijo nelinearne
statčine analize modela konstrukcije z več prostostnimi stopnjami (MDOF sistem) in
nelinearno spektralno analizo ekvivalentnega modela konstrukcije z eno prostostno stopnjo
(SDOF sistem). V modelu za nelinearno potisno analizo smo upoštevali bilinearen odnos
med momentom in rotacijo na robovih linijskih elementov. Na osnovi rezultatov potisne
analize smo določiti kapaciteto pomika za tri mejna stanja na nivoju konstrukcije, ki jih navaja
Evrokod: mejno sanje omejitve poškodb (DL), mejno stanje pomembnih poškodb (SD) in
mejno stanje blizu porušitve (NC). V našem primeru bi objekt dosegel mejno stanje blizu
porušitve pri pospešku 0,53 g za modalno oziroma 0,67 g za enakomerno porazdelitev sil.
Evrokod 8-1 eksplicitno ne podaja mejnega pospeška pri katerem bi bila konstrukcija še
sprejemljiva. Smatra se, da je objekt ustrezen, če je projektiran skladno s standardom. Za
bolj utemeljeno oceno obnašanja bi morali izhajati iz sprejemljive verjetnosti prekoračitve
mejnih stanj, kar presega okvire magistrske naloge.
Ključne besede
gradbeništvo;magistrska dela;potresno inženirstvo;N2 metod;poenostavljene nelinearne analize;nelinearna statična analiza;Evrokod 8;ocena obnašanja;
Podatki
Jezik: |
Slovenski jezik |
Leto izida: |
2015 |
Tipologija: |
2.09 - Magistrsko delo |
Organizacija: |
UL FGG - Fakulteta za gradbeništvo in geodezijo |
Založnik: |
[A. Snedic] |
UDK: |
624.042.7:004:(043.3) |
COBISS: |
7157857
|
Št. ogledov: |
2393 |
Št. prenosov: |
602 |
Ocena: |
0 (0 glasov) |
Metapodatki: |
|
Ostali podatki
Sekundarni jezik: |
Angleški jezik |
Sekundarni naslov: |
Seismic vulnerability analysis of the new six-storey reinforced concrete building |
Sekundarni povzetek: |
This master thesis deals with the seismic performance assessment of building of Institute of
Information science in Maribor. The analyses are performed in compliance with Eurocode 8.
First part of the thesis focuses on linear elastic seismic analysis of building with an objective
to achieve optimal modeling of the building by using ETABS. Fifteen different models, which
were split into two groups, were developed. First group contains models that are accurate
and can be used to solve real problems, while the second group contains generic models
that are mostly used to enhance our understanding of calculation errors that can be
introduced with incorrect models. Results show us that in some cases models can be
simplified. Shell, frame and combined models are useful in practical situations. For specific
situation we should choose the type of model based on structure type and type of seismic
analysis. The use of stiff elements for connection of vertical elements with beams and
connection of frame and area elements is important for correct modeling of construction
stiffness. Data about mass was also manually entered into the center of mass on storey
level. Such an approach is slightly more time consuming, but significantly simplify the
analysis and its results. However, it was also found that manual meshing of shell elements is
too time consuming and don't have large impact on analysis results. At the end optimal size
of finite elements was determined to 0,5/0,5 meters. The second part of the thesis presents
simplified non-linear analysis N2 method, which was applied to the investigated building. The
N2 method is combination of nonlinear static (pushover) analysis of entire building in
combination of inelastic spectra based on an equivalent model with single degree of freedom
(SDOF system). In model for non-linear pushover analysis, bilinear relationship between
moment and rotation was taken into account at the edges of frame element. On basis of
results, given by pushover analysis, limit-state displacements were determined for
three states proposed by Eurocode standard: damage limitation state (DL), significant
damage state (SD) and near collapse state (NC). The peak ground acceleration causing
collapse was estimated to 0,53 g and 0,67g in the case of modal distribution of forces and
uniform distribution of forces, respectively. It is assumed that the seismic performance of the
building is acceptable since it is designed according to Eurocode 8-1. For more informed
decision-making the estimated limit-state peak ground acceelerations should be compared
to those values based on tolerable risk, which is beyond objectives of this thesis. |
Sekundarne ključne besede: |
civil engineering;master of science thesis;earthquake engineering;N2 method;simplified nonlinear methods;pushover analysis;Eurocode 8;seismic evaluation; |
Vrsta datoteke: |
application/pdf |
Vrsta dela (COBISS): |
Magistrsko delo/naloga |
Komentar na gradivo: |
Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo |
Strani: |
XVI, 95 str. |
ID: |
8890243 |