Model za oceno potresne odpornosti zidanih hiš na širši lokaciji Škofje Loke : diplomska naloga

Triller, Petra (author), Dolšek, Matjaž (mentor), Snoj, Jure (co-mentor)

V diplomski nalogi sta izdelana dva modela za oceno potresne odpornosti povprečne zidane hiše na širšem območju Škofje Loke. V začetnem poglavju obravnavamo obnašanje zidanih konstrukcij in možne porušne mehanizme njihovih elementov. V nadaljevanju je predstavljeno teoretično ozadje metode N2, ki je vključena v Evrokod 8 in s katero smo določili potresno odpornost obravnavanih zidanih objektov. Analizirali in interpretirali smo rezultate analiz za 11 hiš, ki se nahajajo v širšem območju Škofje Loke in so bile zgrajene v letih od 1970 do 1990. Na osnovi načrtov Projektov za pridobitev gradbenega dovoljenja smo vrednotili srednje vrednosti in koeficient variacije za izbrane geometrijske lastnosti stavb, ki imajo pomemben vpliv na njihovo obnašanje. Pričakovani delež tlorisnih površin sten glede na neto površino etaže znaša 11–12 %, delež efektivnih tlorisnih površin sten pa se giblje v območju 60-90 % bruto površine sten, pri čemer je odvisen od smeri objekta. Povprečen zid je širok 2,4 m, njegova efektivna višina pa znaša 80 % etažne višine objekta. V primerjavi izbranih lastnosti hiš s sorodnimi podatki, ki so dostopni na spletnem portalu e-Prostor, smo ugotovili večja odstopanja v vrednostih le teh. Nelinearno statično (potisno) analizo smo izvedli s programom 3Muri. Rezultati so pokazali, da so najbolj ranljivi medokenski slopi zidu, delno pa tudi prekladni deli. Običajno pri mejnem stanju blizu porušitve nastopa kombinacija upogibnih in strižnih poškodb. Glede na mejni pospešek smo izbrali merodajne potisne krivulje in jih normirali glede na težo objekta in njegovo višino oziroma glede na povprečno efektivno tlorisno etažno površino sten v obravnavani smeri in višino objekta. S tem smo dobili dva modela normiranih potisnih krivulj. Pričakovana maksimalna dosežena nosilnost v šibki smeri objekta znaša 15 % celotne teže stavbe oziroma dobrih 60 kN na kvadratni meter efektivne tlorisne površine sten. Prikazana je uporaba modelov na primeru dveh objektov in dodana ocena potresne odpornosti za mejno stanje močnih poškodb, ki kaže na to, da večina obravnavanih objektov ne izpolnjuje zahtev Evrokoda 8-3.

• Language: Slovenian
• Keywords: gradbeništvo, diplomska naloga, UNI, zidana konstrukcija, nearmirano zidovje, nelinearna statična (potisna) analiza, N2 metoda, program 3Muri, porušni mehanizmi, ocena potresne odpornosti
• Work type: Undergraduate thesis
• Typology: 2.11 - Undergraduate Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: P. Triller
• Year: 2014
• Number of pages: XX, 120 str.
• PID: 20.500.12556/RUL-32283
• UDC: 624.042.7(497.4)(043.2)
• COBISS.SI-ID: 6664801
• Publication date in RUL: 10.07.2015

Secondary language

• Language: English
• Title: Model for seismic performance assessment of masonry houses in Škofja Loka region

Abstract

Two models for seismic performance assessment of masonry houses in Škofja Loka region are developed. In first chapters the behaviour of masonry buildings under seismic actions with an emphasis on failure mechanisms of structural components are discussed. Follows an overview of the theoretical background of N2 method, which is included in the Eurocode 8 and which was used for determination of the seismic resistance of examined masonry structures. The results of numerical investigation of 11 masonry houses, built in the years from 1970 to 1990, are then presented and discussed. The project design for building permit was used to obtain input data of the buildings. The mean values and the coefficient of variation were assessed for those geometrical features of the buildings, which have great impact on the seismic performance assessment of the buildings. Expected percentage of the floor surface area of the walls in relation to the net surface of the floor varied from 11 to 12 % with respect to the direction of building. The proportion of the effective floor area of the walls is in the range from 60 to 90% of the gross surface area of the walls depending on the direction of the building. Average wall is 2,4 m wide and its effective height amounts to 80 % of the building`s floor height. It was found that the selected characteristics of houses with the corresponding data which are available on the web portal e-Prostor, are significantly different. Nonlinear static (pushover) analysis was performed by using computer software 3Muri. The results show that the combination of bending and shear damage occurred in piers and also spandrels in the region of deformation close to the ultimate limit state. Two models of the normalized expected pushover curves were obtained by taking into account the pushover curves which had a decisive impact on the seismic limit-state peak ground acceleration. The base shear was normalized by the weight of the building or with respect to the average effective floor area of the walls in the given direction and whereas the top displacement was normalized only by the building’s height. Maximum expected capacity in weak direction amounted 15 % of the total weight of the building and more than 60 kN per square meter of effective floor area of the walls. In the last chapter the normalized pushover curves were used for seismic performance assessment of two houses for which it was found that do not fulfil requirements of standard Eurocode 8-3.

• Keywords: masonry building, unreinforced masonry, nonlinear static ("pushover") analysis, N2 method, program 3Muri, failure mechanisms, evaluation of earthquake resistance