Obnašanje lameliranega konstrukcijskega stekla pri povišanih temperaturah : diplomska naloga: št. 370/B-GR

Podobnik, Maksi (author), Bosiljkov, Vlatko (mentor), Antolinc, David (co-mentor)

V sodobni arhitekturi so vedno večje zahteve po transparentnosti fasadnega stavbnega ovoja. Unikaten in najbolj primeren material kateri nam to omogoča je steklo. V primeru, da so stekleni elementi tudi v funkciji konstrukcijskega materiala, jim je potrebno zagotoviti ustrezno nosilnost, togost in obstojnost. Izboljšanje mehanskih lastnosti lahko dosežemo s toplotno obdelavo oziroma kaljenjem stekla, večjo varnost po porušitvi pa z lepljenjem steklenih šip med seboj. Tako obdelano in lamelirano steklo imenujemo konstrukcijsko steklo. Ker je tovrstno steklo kot element stavbnega ovoja izpostavljeno različnim vremenskim razmeram, so pomembne lastnosti stekla ter vmesnega povezovalnega sloja, ki je bil uporabljen v postopku lameliranja. Izpostavljenost lameliranega stekla vlažnim pogojem okolja lahko povzroči delaminacijo, prav tako lahko UV žarki povzročijo obarvanje in propadanje vmesnega povezovalnega sloja. Velik vpliv na togost in nosilnost lameliranega stekla ima temperatura. Pri neposredni izpostavljenosti sončnim žarkom se steklo in polimerni material med šipami segrejeta kar povzroči, da se polimernemu materialu spremeni viskoznost. V sklopu diplomske naloge smo preizkušali vpliv povišane temperature na obnašanje lameliranega konstrukcijskega stekla. Meritve smo izvajali na dveh vrstah preizkušancev v temperaturni komori pri povišanih temperaturah. Prvi so imeli za vmesni sloj EVA, drugi pa PVB folijo. Vse preizkušance smo obremenjevali s konstantno hitrostjo in opazovali njihov odziv pri tritočkovnem upogibu. Merili smo poves na sredini preizkušanca, deformacije na natezni strani na sredini razpona preizkušanca in strižni zdrs med steklenima paneloma. Rezultati so pokazali, da so preizkušanci z EVA vmesnem sloju že pri sobni temperaturi bolj togi v primerjavi s preizkušanci kateri so imeli PVB vmesno povezovalno plast. Vse vrednosti deformacij, pomikov in zdrsov pa so se pričakovano pri obeh vrstah preizkušancev povečevale z višanjem temperature, zaradi spremembe viskoznosti vmesne povezovalne plasti in s tem znižanja njenega strižnega modula.

• Language: Slovenian
• Keywords: gradbeništvo, diplomska naloga, lamelirano steklo, EVA, PVB, upogibna obremenitev, povišana temperatura
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [M. Podobnik]
• Year: 2019
• Number of pages: XII, 35 str.
• PID: 20.500.12556/RUL-124784
• UDC: 666.1(043.2)
• COBISS.SI-ID: 63206403
• Publication date in RUL: 18.02.2021

Secondary language

• Language: English
• Title: Behaviour of laminated structural glass at elevated temperatures : graduation thesis: no. 370/B-GR

Abstract

One of the common requirements in modern architecture is the transparency of building envelope and its structural elements. The material which can provide this at very high aesthetic level beside load bearing capacity, stiffness and durability is glass. The enhancement of glass can be achieved with tempering of glass plates and with gluing them together into laminate with the polymer interlayers. This type of glass can be named structural glass and it can be in real application exposed to atmospheric conditions which can dramatically influence the short or long term behaviour of laminated glass. Under external atmospheric conditions the laminated glass become prone to delamination and UV degradation of interlayer. The essential influence on laminated glass stiffness has temperature due to the changed viscosity of polymeric interlayer. Within this thesis the influence of elevated temperature on the behaviour of laminated glass was investigated. We conducted the three point bending test in the environmental chamber under elevated temperature for two types of laminated glass, one with EVA and the other with PVB interlayer. All specimens were loaded with the constant load rate. During the experiment conduction we observed and measured the midspan deflection, longitudinal tension deformation at the bottom glass sheet and shear deformation between the glass sheets. The results show that the specimens with EVA interlayer have higher stiffness at room temperature comparing to those with PVB interlayer. Based on the measured values and results at elevated temperatures we can confirm and conclude that both types of specimens lost the initial stiffness because of viscosity change of interlayer and thus lower shear modulus.

• Keywords: civil engineering, graduation thesis, laminated glass, EVA, PVB, bending load, elevated temperature