20.500.12556/RUL-190979 Meritve nihajnih časov in analiza lastnega nihanja stavb za seizmični stresni test stavbnega fonda magistrsko delo Measurement of vibration periods and natural vibration analysis of buildings for seismic stress test of building stock Nihajni čas je ena izmed pomembnih dinamičnih karakteristik, ki vplivajo na potresni odziv stavbe in določitev potresnih zahtev, vendar je njegova ocena pri numeričnem modeliranju obstoječih stavb povezana z negotovostmi, zlasti v povezavi z določitvijo togosti stavbe. Meritve ambientalnih vibracij omogočajo neposredno oceno dinamičnih lastnosti stavb pri majhnih amplitudah nihanja in s tem preverjanje predpostavk numeričnega modeliranja. V magistrski nalogi smo analizirali tri obstoječe stavbe, vključene v seizmični stresni test stavbnega fonda Univerze v Ljubljani. Na podlagi meritev ambientalnih vibracij smo določili nihajne čase in nihajne oblike ter jih primerjali z rezultati modalnih analiz numeričnih modelov, izdelanih v programu ETABS. Analiziran je bil predvsem vpliv predpostavk glede togosti konstrukcijskih elementov vključno z upoštevanjem vpliva zidanih polnil. Rezultati so pokazali, da so pri stavbah NTF1 in NTF2 modeli z reducirano togostjo zaradi predpostavljene razpokanosti prerezov dali daljše nihajne čase in večja odstopanja od meritev, medtem ko se je ujemanje pri modelih brez redukcije togosti izboljšalo. Dodatno upoštevanje zidanih polnil je ujemanje še izboljšalo. Pri stavbi NTF2 so se odstopanja prvih treh nihajnih časov zmanjšala s približno 66 %, 62 % in 57 % na 20 %, 19 % in 7 %. Pri stavbi BF sprememba predpostavke glede togosti ni izboljšala ujemanja za vse nihajne oblike. Rezultate omejujejo negotovosti glede projektne dokumentacije, materialnih lastnosti in poenostavitev numeričnih modelov. Nadaljnje raziskave bi morale z nelinearnimi analizami ovrednotiti vpliv razpokanosti in polnil na potresni odziv ter pomen meritev ambientalnih vibracij za oceno potresne odpornosti in načrtovanje utrditve obstoječih stavb. The natural period of vibration is one of the important dynamic characteristics that influence the seismic response of a building and the determination of seismic demands. However, its estimation in the numerical modelling of existing buildings is subject to uncertainties, particularly regarding the determination of building stiffness. Ambient vibration measurements provide an estimate of the dynamic properties of buildings at low vibration amplitudes and can therefore be used to verify numerical modelling assumptions. In this master’s thesis, three existing buildings included in the seismic stress test of the University of Ljubljana building stock were analyzed. Natural periods and mode shapes were determined from ambient vibration measurements and compared with the results of modal analyses of numerical models developed in ETABS. The study focused primarily on assumptions regarding the stiffness of structural elements and the consideration of masonry infills. The results showed that, for the NTF1 and NTF2 buildings, models with reduced stiffness due to assumed section cracking resulted in longer natural periods and larger discrepancies with the measurements, whereas the agreement improved for models without stiffness reduction. Accounting for masonry infills further improved the agreement. For the NTF2 building, the discrepancies in the first three natural periods decreased from approximately 66 %, 62 % and 57 % to 20 %, 19 % and 7 %, respectively. For the BF building, changing the stiffness assumption did not improve the agreement for all mode shapes. The results are limited by uncertainties related to the available design documentation, material properties, and simplifications in the numerical models. Further research should use nonlinear analyses to evaluate the effects of cracking and masonry infills on seismic response and to assess the relevance of ambient vibration measurements for evaluating seismic performance and designing the strengthening of existing buildings. magistrska dela gradbeništvo pospeškomer ambientalne vibracije analiza lastnega nihanja nihajni čas nihajna oblika numerično modeliranje primerjava rezultatov master thesis civil engineering accelerometer ambient vibration modal analysis oscillation period mode shape numerical modeling comparison of results true false false [S. Ermanoska] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-11-09 15:57:17 2026-11-09 15:57:24 2026-11-10 13:02:50 0000-00-00 00:00:00 2026 0 Ljubljana 2026 Ljubljana 1 spletni vir (1 datoteka PDF (XI, 73 str.)) 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 624.042.7:534.1(043.2) 187953 304669443 24423.pdf 24423.pdf 1 5C94E0EBB2617D5B8597C0BCF2916D54 6625df7710168f14fe1fb2015292563c774acfbb49801ecd14fbbfd5c794f694 c7c9888d-dc4d-11f1-aea2-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=252818 Fakulteta za gradbeništvo in geodezijo 0 0 0