Uporaba nelinearne analize za oceno potresne odpornosti armiranobetonske stavbe po EC8

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Language:	Slovenian
Year of publishing:	2005
Source:	Ljubljana
Typology:	2.11 - Undergraduate Thesis
Organization:	UL FGG - Faculty of Civil and Geodetic Engineering
Publisher:	[S. Terčič]
UDC:	006(4):624.012.45:624.042.33(043.2)
COBISS:	2910305
Views:	2072
Downloads:	863
Average score:	0 (0 votes)
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Secondary language:	English
Secondary title:	Application of nonlinear analysis for seismic assesment of a reinforced concrete building according to EC8
Secondary abstract:	The present work deals with the the European standard EN 1998 (EC8), which is shortly to be adopted in Slovenia. We limited ourselves to the provisions for nonlinear analysis and to the part EC8-3 that applies to the provisions for seismic assessment and the retrofitting of existing buildings. For the determination of structural response to the expected seismic loading the N2 method was used, which has been implemented in the EC8. In order to demonstrate the application of this standard, we chose the existing building of the Faculty of Civil and Geodetic Engineering in Ljubljana. Before performing nonlinear analysis it was necessary to determine the inelastic behaviour of cross sections of the structural elements,. A model with plastic hinges placed at the both ends of each element was applied. The characteristics of these plastic hinges were determined according to the guidelines in the EC8-3. A nonlinear static (pushover) analysis was performed with the programme SAP 2000. The result of this analysis was the relation between the base shear and the displacement at the top of the building. From this relation the plastic mechanism can be observed. The target displacement, i.e. the top displacement corresponding to the expected seismic loading can be determined by the N2 method.. The target displacement determines the deformations of the structure used for the assessment of the structural response to expected earthquake ground motion. We also checked shear stresses in the most critical cross sections. Results of analyses indicate that the investigated structure is able to survive, with significant damage, the earthquake with 475 years return period. Critical is the transversal direction of the building. Among the elements, the most critical are concrete walls, especially in the I. story, because of the change of the stiffness and strength. Shear demand in some walls is much higher than the shear capacity determined according to EC8-3. Based on this observation it can be concluded that the results of the seimic assessment were less favourable if a more accurate and complex model was used which would take into account also shear plastic deformations.
Secondary keywords:	reinforced concrete building;standard Eurocode 8;pushover analysis;N2 method;seismic loading;plastic hinge
File type:	application/pdf
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. Ljubljana, Fakulteta za gradbeništvo in geodezijo, Oddelek za gradbeništvo, Konstrukcijska smer, Univerzitetni študij gradbeništva
Pages:	109 str., pril.
Type (ePrints):	thesis
Title (ePrints):	Application of nonlinear analysis for seismic assesment of a reinforced concrete building according to EC8
Keywords (ePrints):	armiranobetonska stavba;standard Evrokod 8;nelinearna stati na analiza;N2 metoda;potresna obtežba;plasti ni lenek
Keywords (ePrints, secondary language):	reinforced concrete building;standard Eurocode 8;pushover analysis;N2 method;seismic loading;plastic hinge
Abstract (ePrints):	Diplomsko delo obravnava evropski standard EN 1998 (EC8), ki bo v kratkem stopil v veljavo tudi v Sloveniji. Omejili smo se na določila za nelinearno analizo in na del EC8-3, ki obravnava določila za oceno potresne odpornosti in za potresno utrjevanje obstoječih stavb. Uporabljali smo N2 metodo, s katero se določi odziv konstrukcije pri predvideni potresni obtežbi in ki je predpisana tudi v EC8. Za prikaz uporabe omenjenega standarda smo izbrali obstoječi objekt Fakultete za gradbeništvo in geodezijo v Ljubljani. Za nelinearno analizo je bilo potrebno določiti obnašanje prerezov nosilnih elementov tudi izven linearnega območja. Uporabili smo model, pri katerem sta bila na obeh koncih vsakega elementa definirana upogibna plastična členka. Karakteristike plastičnih členkov so določene po navodilih v EC8-3. Nelinearna statična (»pushover«) analiza konstrukcije je bila izvedena s programom SAP 2000. Kot rezultat te analize dobimo odnos med celotno prečno silo konstrukcije in pomikom na vrhu stavbe. Iz tega odnosa je razviden plastični mehanizem konstrukcije. Ciljni pomik, tj. pomik na vrhu konstrukcije pri predvidenem potresnem vplivu je bil določen z N2 metodo. Pri ciljnem pomiku se preveri stopnjo poškodovanosti objekta. Preverili smo tudi strižne obremenitve v strižno najbolj obremenjenih prerezih. Rezultati analize kažejo, da je obravnavana konstrukcija s precejšnimi poškodbami sposobna prenesti potres s povratno dobo 475 let. Bolj kritična je prečna smer. Izmed elementov so najbolj kritična betonska jedra, in sicer v I. nadstropju spodaj zaradi skoka v togosti in nosilnosti konstrukcije. Kontrola strižnih sil kaže visoko prekoračitev predpisanih vrednosti v EC8-3 za betonska jedra, kar pomeni, da bi bili rezultati potresne ocene manj ugodni, če bi v analizi uporabili bolj natančen in zahteven model, ki bi upošteval tudi strižne poškodbe.
Abstract (ePrints, secondary language):	The present work deals with the the European standard EN 1998 (EC8), which is shortly to be adopted in Slovenia. We limited ourselves to the provisions for nonlinear analysis and to the part EC8-3 that applies to the provisions for seismic assessment and the retrofitting of existing buildings. For the determination of structural response to the expected seismic loading the N2 method was used, which has been implemented in the EC8. In order to demonstrate the application of this standard, we chose the existing building of the Faculty of Civil and Geodetic Engineering in Ljubljana. Before performing nonlinear analysis it was necessary to determine the inelastic behaviour of cross sections of the structural elements,. A model with plastic hinges placed at the both ends of each element was applied. The characteristics of these plastic hinges were determined according to the guidelines in the EC8-3. A nonlinear static (pushover) analysis was performed with the programme SAP 2000. The result of this analysis was the relation between the base shear and the displacement at the top of the building. From this relation the plastic mechanism can be observed. The target displacement, i.e. the top displacement corresponding to the expected seismic loading can be determined by the N2 method.. The target displacement determines the deformations of the structure used for the assessment of the structural response to expected earthquake ground motion. We also checked shear stresses in the most critical cross sections. Results of analyses indicate that the investigated structure is able to survive, with significant damage, the earthquake with 475 years return period. Critical is the transversal direction of the building. Among the elements, the most critical are concrete walls, especially in the I. story, because of the change of the stiffness and strength. Shear demand in some walls is much higher than the shear capacity determined according to EC8-3. Based on this observation it can be concluded that the results of the seimic assessment were less favourable if a more accurate and complex model was used which would take into account also shear plastic deformations.
Keywords (ePrints, secondary language):	reinforced concrete building;standard Eurocode 8;pushover analysis;N2 method;seismic loading;plastic hinge
ID:	8311106