Utrjevanje poškodovanih zidov s steklenimi vrvicami in epoksidnimi smolami : diplomska naloga

Božič, Luka (avtor), Bosiljkov, Vlatko (mentor), Kržan, Meta (komentor)

V diplomski nalogi sem s pomočjo vrvice iz steklenih vlaken utrdil kamniti zid, ki je bil uporabljen že v predhodnih preiskavah in v le-teh tudi delno poškodovan. Imel je tipične strižne poškodbe, ki so bile sanirane z injektiranjem cementne mešanice. V prvem delu diplomske naloge sem na dveh vrstah kamna testiral sprijemno trdnost treh različnih vrst malt, pri čemer sem zasnoval postopek in način testiranja. Vsi testi so se izvajali v laboratoriju Fakultete za gradbeništvo in geodezijo v Ljubljani. Po nekaj neuspelih poizkusih smo se odločili za določanje sprijemnih trdnosti med malto in kamnom po t.i. pull-out testu. Vse kamnite vzorce je bilo potrebno ustrezno pripraviti in vanje vgraditi stekleno vrvico premera 6 mm. Pri testu sem spremljal izvlečno silo, pomik in vrsto porušitve. Epoksidno malto, ki je izmed testiranih izkazala najboljšo sprijemno trdnost, sem nato uporabil v drugem delu diplomske naloge in sicer pri strižni utrditvi kamnitega zidu. Kamniti zid je bilo potrebno pred utrjevanjem ustrezno pripraviti. Prečno čez zid sem zvrtal luknje in na licih zidu do določene globine izpraznil horizontalne spojnice med posameznimi vrstami kamna. Za vgradnjo steklene vrvice smo izbrali epoksidni sistem, ki je vključeval epoksidni temeljno sprijemni premaz, epoksidno smolo za impregnacijo, srednje viskozno epoksidno smolo za zapolnjevanje izvrtin in epoksidno malto. Po cikličnem strižnem obremenjevanju zidu in obdelavi podatkov sem rezultate primerjal z rezultati testiranj dveh neutrjenih zidov. Pri utrjenem zidu so bili horizontalni pomiki bistveno večji kot pri neutrjenih zidih. Pri neutrjenih zidih je bila v nekem trenutku dosežena maksimalna sila, ki je nato začela upadati, pri utrjenem zidu pa je vseskozi naraščala. Oba neutrjena zida, ki sta bila testirana pod enakimi pogoji kot utrjeni zid, sta imela tipične strižne poškodbe (razpoke), medtem ko je utrjeni zid pri primerjalnem pomiku ostal praktično brez poškodb.

• Jezik: Slovenski jezik
• Ključne besede: gradbeništvo, diplomska naloga, VSŠ, utrjevanje kamnitega zidu, vrvica iz steklenih vlaken, epoksidna smola/malta, strižne preiskave, sprijemne trdnosti kamen-malta
• Vrsta gradiva: Diplomsko delo
• Tipologija: 2.11 - Diplomsko delo
• Organizacija: FGG - Fakulteta za gradbeništvo in geodezijo
• Kraj izida: Ljubljana
• Založnik: [L. Božič]
• Leto izida: 2014
• Št. strani: XVI, 57 str.
• PID: 20.500.12556/RUL-32519
• UDK: 691.2:692.2(043.2)
• COBISS.SI-ID: 6915937
• Datum objave v RUL: 10.07.2015

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Retrofitting damaged walls with glass chord and epoxy resins

Izvleček

For the purpose of my thesis I have used a glass chords for retrofitting stone masonry wall already damaged through previous testing campaigns. The wall had typical shear damages, which were first restored by linear grouting with cement mixture. In the first part of the diploma thesis I have studied appropriate test set-up for testing bond strength between glass chords and substrate. Later on I have tested two types of stone in combination with three types of mortar and determined different failure modes. All tests were conducted in a laboratory of the Faculty of civil and geodetic engineering in Ljubljana. Following couple of unsuccessful attempts a decision was made to determine bond strengths between mortar and stone by performing so called pull-out test. For this purpose stone samples needed adequate preparation and a glass chord with a diameter of 6 mm was built into them. During testing I have monitored pull-out force, movements and a type of fracture. Epoxy mortar, which showed the best bond strength among the tested ones, was then used in the second part of the diploma thesis, namely at shear retrofitting of a stone wall. Before retrofitting the wall, it needed adequate preparation. Perpendicular to a wall direction I have drilled holes and emptied horizontal joints between individual rows of stones to a certain depth. For placing in glass chords we have chosen epoxy system, which included basic epoxy primer, epoxy resin for impregnation, epoxy resin of middle viscosity for filling boreholes and epoxy mortar. Following cyclic shear loading of a wall and data processing, a comparison of obtained results with the test results of two non-retrofitted walls carried out through previous testing campaigns was made. For retrofitted wall maximal obtained horizontal movements were significantly bigger than for non-retrofitted ones. For non-retrofitted walls following the achieved a maximal force resistance started to decline, while for a retrofitted wall it was constantly increasing. Both non-retrofitted walls that were tested under the same boundary conditions as a retrofitted one had typical shear damages (cracks). On the other hand, a retrofitted wall at the same levels of displacement practically stayed intact.

• Ključne besede: retrofitting damaged wall, glass chord, epoxy resin/mortar, shear tests, bonding strength of stone-mortar