Assessment of earthquake resistance of an existing building according to new draft version of Eurocode 8

Namen magistrske naloge je bil na konkretnem primeru obstoječe armiranobetonske stavbe preučiti postopek za oceno potresne odpornosti stavb, ki ga podaja delovna različica novega standarda Evrokod 1998-3. Obravnavana stavba sodi v stavbni fond Fakultete za elektrotehniko Univerze v Ljubljani in je bila zgrajena na začetku šestdesetih let prejšnjega stoletja. Skladno s delovno različico novega Evrokoda 1998-3 smo najprej preučili razpoložljivo projektno in tehnično dokumentacijo stavbe. Na podlagi pridobljenih podatkov smo v programu ETABS izdelali linearni model konstrukcije. Izvedli smo preliminarno potresno analizo na osnovi linearne-elastične analize in v skladu s standardom za vsa kritična mesta preverili koeficient ?i??ki je definiran kot razmerje med potresnim vplivom in odpornostjo, izraženo s posplošenimi silami v prerezu konstrukcijskega elementa??Iz razmerja med maksimalno in minimalno vrednostjo koeficienta ?i smo ugotovili, da ocena potresne odpornosti z linearnimi metodami na podlagi pomikov ni upravičena in da je treba za natančnejšo oceno potresne odpornosti stavbe uporabiti nelinearno potresno analizo. Ne glede na to smo za tri izbrane stebre ocenili njihovo potresno odpornost na osnovi ocenjeno rotacijsko kapaciteto v vozliščih stebrov. Dobljene odpornosti smo primerjali z obremenitvami iz preliminarne analize in ugotovili, da dva od izbranih stebrov ne izpolnjujeta zahtev kriterijev po delovni različici novega Evrokoda 1998-3. Iz te ugotovitve smo sklepali, da stavba ni potresno odporna in zasnovali potresno utrditev stavbe z armiranobetonskimi stenami. Ob ponovni oceni potresne odpornosti z uporabo linearne analize se izkaže, da bi bila tako utrjena stavba potresno bistveno bolj odporna, vendar je treba takšne zaključke preveriti z izvedbo potisne analize utrjene stavbe.The aim of the master\u27s thesis was to examine, using a specific case of an existing reinforced concrete building, the procedure for assessing the seismic performance of buildings as presented by the working version of the new standard Eurocode 1998-3. The building under consideration is a part of the building stock of the Faculty of Electrical Engineering at the University of Ljubljana and was constructed in the early 1960s. In accordance with the working draft of the new Eurocode 1998-3, we first examined the available project and technical documentation of the building. Based on the acquired data, we created a linear model of the structure using the ETABS program. We conducted a preliminary seismic analysis based on linear-elastic analysis and, following the working draft of the standard, verified the coefficient i, which is defined as the ratio between seismic demand and resistance expressed by generalized forces in the cross-section of the structural element. From the ratio between the maximum and minimum values of the i, we concluded that assessing the building’s earthquake resistance using linear methods and displacements is not justified, and a nonlinear seismic analysis should be used for a more accurate assessment of the building\u27s earthquake resistance. Nevertheless, we assessed the earthquake resistance of three selected columns based on the estimated rotational capacity at the column ends. The obtained resistances were compared with the demand from the preliminary analysis. We found that two of the selected columns did not meet the criteria of the working draft of the new Eurocode 1998-3. Based on this finding, we inferred that the building is not earthquake-resistant and proposed strengthening the building using reinforced concrete walls. Upon re-assessing the building’s earthquake resistance using linear analysis, it was evident that the strengthened building would be significantly more earthquake-resistant. However, such conclusions should be verified by a pushover-based seismic performance assessment of the reinforced building