Napredna numerička simulacija ponašanja drvenih elemenata u požaru

professional thesis

• Title (english): Advanced numerical simulation of the behaviour of timber members in fire
• Author: Nikola Perković
• Mentor: Davor Skejić (mentor)
• Committee member: Miodrag Drakulić (predsjednik povjerenstva)
• Committee member: Davor Skejić (član povjerenstva)
• Committee member: Ivica Boko (član povjerenstva)
• Granter: University of Zagreb; Faculty of Civil Engineering; Zagreb
• Defense date and country: 2024-07-19, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Civil Engineering

Abstract

Požar predstavlja ozbiljan izazov za sigurnost i integritet građevinskih konstrukcija, a posebno drvenih konstrukcija koje su izložene visokim temperaturama i intenzivnom toplotnom zračenju. Međutim, drvo neće bitno promijeniti mehanička svojstva dok gori. Razlog tome je što se nedugo nakon požara na površini drva stvara ugljeni sloj koji sprječava razvoj topline prema unutrašnjosti elementa. Međutim, zapaljivost drveta je jedan od glavnih razloga zašto regulativa strogo ograničava drvo kao građevinski materijal, posebno za gradnju višekatnih zgrada. Stoga, glavni preduvjet za uporabu drva u građevinama je osigurati adekvatnu požarnu otpornost, koristeći pasivne i aktivne mjere zaštite od požara. U ovom radu provedena je numerička simulacija utjecaja požarnog opterećenja na drvene elemente (CLT), kao sastavne dijelove nosivih konstrukcija. Pregledom stanja područja, uočava se nedostatak istraživanja u području numeričkih (MKE i CFD) simulacija drvenih konstrukcija izloženih požarnom opterećenju. U ovom radu istražen je utjecaj geometrijskih i materijalnih karakteristika CLT-a, te protupožarnih zaštitnih sustava na širenje požara, brzinu pougljenja, i u konačnici, požarnu otpornost drvenih elemenata. U Republici Hrvatskoj ne postoje zahtjevi zaštite od požara koji se odnose posebno na drvene konstrukcije - svi zahtjevi postavljaju se prema skupini građevina definiranoj u pravilniku o otpornosti na požar i drugim zahtjevima koje građevine moraju zadovoljiti u slučaju požara. Rezultat takvog pristupa je predimenzioniranje konstrukcijskih elemenata i vrlo često nepotrebna ili nedovoljno argumentirana protupožarna zaštita nosivih drvenih konstrukcija, koja zahtijeva velika financijska ulaganja. U cilju izbjegavanja nepotrebnih troškova, kod projektiranja drvenih građevina mogu se primijeniti proračunske metode i/ili modeli koji se temelje na novijim dostignućima u području požarne otpornosti što je i praktični doprinos ovog rada.

Abstract (english)

Fire represents a serious challenge for the safety and integrity of building structures, especially timber structures t exposed to high temperatures and intense heat radiation. However, timber does not significantly change its mechanical properties during a fire. The reason for this is that carbon layer forms on the surface of the wood shortly after a fire, which prevents heat from developing into the interior of the element. However, the combustibility of timber is one of the main reasons why regulations strictly limit timber as a building material, especially for the construction of multi-storey buildings. Therefore, the most important requirement for the use of timber in buildings is to ensure adequate fire resistance, through passive and active fire protection measures. In this work, a numerical simulation of the effects of fire loads on CLT as integral component of load-bearing structures, is carried out. A overreview of the state of the research in this field shows that there is a lack of research in the field of numerical (FEM and CFD) simulations of timber structures exposed to fire loads. In this work, the influence of the geometric and material propierties of CLT and fire protection systems on the spread of fire, the charring rate, and ultimately, the fire resistance of timber elements is investigated. In the Republic of Croatia, there are no fire safety requirements that apply specifically to timber structures - all requirements are based on to the structure group defined in the Regulation on Fire Resistance and other requirements that buildings must meet in the event of a fire. The result of such an approach is over dimensioning of building components and very often unnecessary or insufficiently argued fire protection of load-bearing timber structures, which requires high financial investments. In order to avoid unnecessary costs, calculation methods and/or models based on the latest achievements in the field of fire resistance can be used in the design of timber structures, which is also the practical contribution of this work.

• Keywords: drvo; lamelirano; CLT; požar; MKE; CFD
• Keywords (english): timber; laminated; CLT; fire; MKE; CFD
• Language: croatian
• URN:NBN: urn:nbn:hr:237:519674
• Study programme: Title: Postgraduate specialist study of the Faculty of civil Engineering; Study programme type: university; Study level: postgraduate specialist; Academic / professional title: sveučilišni/a specijalist/specijalistica građevinarstva (sveučilišni/a specijalist/specijalistica građevinarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-07-23 08:56:05