Fire resistance of cross-laminated timber elements

V nalogi so predstavljene računske metode za določevanje požarne odpornosti križno lepljenih lesenih elementov. Analizirani sta dve metodi in sicer metoda, ki jo podaja standard EN 1995-1-2, ter metoda, ki je predstavljena v kanadskem priročniku CLT Handbook. Predstavljeni so tudi postopki numeričnega modeliranja križno lepljenih lesenih elementov in s pregledom stanja so podane tudi ugotovitve iz eksperimentalnih raziskav križno lepljenih plošč, ki so med drugim bile raziskane v naravnem merilu. Izkaže se, da sta pri določitvi požarne odpornosti skladno z metodo po EN 1995-1-2 najbolj vprašljivi določitev debeline nenosilnega sloja d0 in določitev debeline zoglenelega sloja dchar. Posredno težavo pri križno lepljeni ploščah predstavlja tudi delaminacija slojev in z njo povezano modeliranje oziroma upoštevanje v preprostih računskih postopkih, ki je zaenkrat dokaj nenatančno upoštevano. Težava je predvsem v določitvi kritične temperature, kdaj lepilo odpove in pride do delaminacije, ter pri določitvi povišane stopnje oglenenja lesa, do katere pride zaradi delaminacije sloja. Bistveni del naloge predstavlja zadnje poglavje, ki je namenjeno parametrični študiji določitve požarne odpornosti križno lepljene plošče skladno z EN 1995-1-2 in kanadskim priročnikom CLT Handbook. Analiziran je vpliv velikosti odprtin in požarnega sektorja na rezultate požarne odpornosti plošče za parametrično požarno krivuljo. Razvoj požara je določen skladno z EN 1991-1-2. Ugotovljeno je, da požar v izključno eni sobi ne predstavlja nevarnosti, v primeru, da bi se požar razširil po celotnem stanovanju, pa plošča požara ne bi prenesla. V zadnjem delu parametrične študije je prikazana razlika med metodama po EN 1995-1-2 in CLT Handbook za določitev standardne požarne odpornosti. Primerjava je narejena za križno lepljene plošče različnih debelin in slojevitosti plošč ter razponov. Glede na rezultate analiz je bilo ugotovljeno, da je metoda po kanadskem priročniku CLT Handbook praviloma bolj konzervativna.Thesis discusses methods for determining fire resistance of cross-laminated timber elements. Two different methods are presented, one according to EN 1995-1-2 and one according to CLT Handbook. Procedures of numerical modelling of cross-laminated elements are presented as well. Based on reports of experimental analyses, where some of them were made in real scale, comments, corrections and findings are offered. It appears that when determining fire resistance according to standard EN 1995-1-2, zero-strength layer d0 and charring depth dchar are most questionable. Indirect difficulty with crosslaminated elements is delamination phenomenon, and with latter connected numerical modelling and integration of phenomenon in current calculation methods, that are still relatively inaccurate. Specific problem is the determination of the critical temperature at which the glue separates and therefore lamination occurs as well as determination of higher degree of charred wood that occurs due to delamination. The last chapter presents the essential part of the thesis. In this chapter, parametric study for determining fire resistances of CLT slab according to European EN 1995-1-2 and Canadian CLT Handbook is performed. Parametric study discusses the effects of different sizes of openings and size of fire compartment where development of parametric fire is determined according to EN 1991-1-2. It was found out that fire limited to solely one room does not cause failure of the CLT slab, but in the case if fire progresses to entire apartment, fire would cause failure of the CLT element. Last part of the parametric study discusses deviation between both methods for determining the standard fire resistance of CLT elements. In the study influence of varying number of layers and length of CLT plate is compared. Comparison showed that more conservative results are obtained with CLT Handbook method

Fire design of steel building

This graduation thesis deals with static analysis and design of three story office building with the focus on fire resistance using simple design methods. Main structure consists of moment resisting frames in transverse direction and frames with bracings and composite beams in longitudinal direction. Second order analysis including global initial imperfections was used to determine internal forces. For this purpose SCIA Engineer software was used. Seismic analysis was made using method with horizontal forces. In longitudinal direction the horizontal forces were transferred using concentric braced system. Construction is deigned in accordance with special rules for medium ductility level. Fire-resistance class for structure is R30. To provide building’s fire resistance beams and columns are protected using gypsum slabs. Composite beams are partially embedded in concrete

Influence of charring on the fire resistance of timber columns

Influence of charring on the fire resistance of timber columns is under consideration in this Graduation thesis. In the second section timber charring and the phenomenon of the pyrolysis of timber is explained. Further, the literature review in the field of empirical and numerical models of timber charring is given. In the third section, the main procedures of the structural fire-buckling design in accordance with EN 1995-1-1:2005 are analysed. In the fourth section, the numerical and empirical models are further explained through numerical examples. The calculations in numerical examples are carried out with a computer program developed in Matlab environment. The empirical models are carried out using program MS Excel.\ud Based on the heat transfer analysis in the numerical model a distribution of char is calculated. The empirical equations for determination of char distribution are given in the second section. The calculated distribution of char is used then to calculate the buckling capacity of timber columns exposed to fire. In the fifth section the selected empirical and numerical models are compared to each other. The conclusions are given in the last section

Fire protection of timber structures

In civil engineering wooden structures are in use from the very beginning of the science. Timber is one of the most suitable materials for building fire safe constructions. The problem is that, even though timber has a good behavior when exposed to fire, is still a combustable material. That is also the crucial property of timber. On one hand a timber component provides fuel stock for a fire, on the other hand, because of the type of burning, the outside layer of a timber member becomes char, which provides protection for the core of the exposed element. This char layer prevents oxigen to come in contact with combustable\ud gases that are a product of timber exposed to high temperatures. To extend the time of resistance of a timber structure, different kinds of protection are used. These materials differ in efficiency and layout. I analyzed four basic kinds of fire protective materials, comparing them in regard of the resistance results. For the analysis I made a tool in Microsoft Excel to help me calculating resistance for a timber column with the use of different fire protective materials

Calculation of fire resistance of a steel portal frame

Magistrsko delo obravnava izračun požarne odpornosti jeklene okvirne konstrukcije in je vsebinsko razdeljeno na dva dela. V prvem delu določimo požarno odpornost konstrukcije po poenostavljenem postopku skladno s standardom SIST EN 1993-1-2 in z uporabo programa SCIA Engineer 16.0. V drugem delu pa je požarna odpornost konstrukcije preverjena z napredno metodo, pri čemer je uporabljen program POŽAR. Požarna odpornost je v obeh analizah izračunana za standarden ISO 834 in parametričen požar. Parametrične požarne krivulje so določene s programom Ozone V2.2 za dva požarna sektorja, in sicer za skladiščne prostore in pisarne. Obravnavamo šest različnih primerov, ki zajemajo izračune z ISO 834 požarno krivuljo in parametričnimi požarnimi krivuljami. Cilj dela je preveriti morebitne razlike med poenostavljeno in napredno računsko metodo ter prikazati vpliv vhodnih parametrov pri izračunu parametričnih požarnih krivulj na požarno odpornost obravnavane jeklene konstrukcije.The thesis discusses the calculation of fire resistance of a steel portal framein terms of the content, it is divided in two sections. In the first section fire resistance of a structure is determined in line with the simplified calculation method in accordance with the SIST EN 1993-1-2 standard and by applying the software SCIA Engineer 16.0. In the second section, fire resistance of a structure is verified against the advanced method, by the use of software POŽAR. In both analyses, fire resistance has been calculated for a standard-temperature fire scenario ISO 834 and a "natural" (parametric) fire scenario. Parametric fire curves have been determined by applying software Ozone V2.2 for two fire sections, specifically, for warehouse premises and for offices. Several situations are examined which include analyses based on ISO 834 fire curve and parametric fire curves. The aim of the thesis is to present any potential differences between the simplified and the advanced calculation method and to present the impact of input parameters for the calculation of parametric fire curves in regard to fire resistance of the steel construction in question

Fire safety in multi-storey residential-commercial timber buildings

Master thesis discusses fire safety in multi-storey timber buildings. Emphasis is on residential\ud and commercial buildings. The Slovenian legislation in domain of fire safety is discussed in\ud detail, while the key laws and policies from field of fire safety are only presented graphically.\ud Exactly Slovenian, German and English technical guideline of fire safety in timber buildings\ud and discussed in detail and their comparation is presented in form of table. The differences\ud between the discussed guidelines appear mainly in the permissible limits of heights of timber\ud structures with a guaranteed fire protection or without it, in the prescribed fire resistance of\ud the bearing structures and in the allowed classes of reaction to fire for the interior linings of a\ud structure. Assessment of fire safety of the commercial building in Komenda (Slovenian tallest\ud timber building) is made in accordance with Slovene (TSG-1-001:2010: Fire safety in\ud buildings) and English (The BS 9999 Handbook: Effective fire safety in the design,\ud management and use of buildings) technical guideline. Assessment is made on the basis of\ud key criteria, which were introduced during the thesis, those bein: the spread of fire to the\ud neighbouring buildings, the spread of fire through the building and evacuation routes and\ud system for reporting and alarm

Design and assesment of fire resistance of isolated RC column in a multi-storey office building

The B.Sc. Thesis deals with the design of reinforced concrete column under conditions of normal use and under conditions of fire. The treated column is located in the ground floor of a multi-storey office building. At the ceiling height the columns are interconnected with reinforced concrete beams and form reinforced concrete spatial frames. Frames together with the walls represent structural systems for the transfer of loads in vertical and horizontal directions. It is determined that the stiffness of columns in the horizontal direction is compared to the rigidity of the walls negligible, so we assume that columns are only involved in taking vertical loads, while the takeover of the load due to the effect of wind and earthquake is not involved. First, we designed a column to axial and shear loads in normal conditions of use. For the design we must take into account the effects of second-order theory. The appropriate design in case of fire. Fire resistance of reinforced concrete column is estimated using tabulated values. It is determined that the fire resistance of the column cross-section of 40/40 cm according to the criterion load is R 120, of column cross-section 35/35 cm is R 90 and column with section 30/30 cm is R 60.\ud ?\u

Analysis and design of ribbed slabs

This graduation thesis comprises the range of possible design solutions for reinforced concrete slab structures with an emphasis on the ribbed and the waffle slabs. The scope of an application of such slabs has been shown, along with the design process, and preparation of a numerical model for the finite element analysis. The comparison of computational models for ribbed slabs has been made and the influence of different distances between ribs on the entire structure has been analysed. A comparison of different systems of ribbed slabs with band beams and drop panels has been made. The advantages and disadvantages of ribbed and waffle have been discussed in comparison to flat slabs

Fire safety of timber structures

Namen diplomske naloge je prikaz postopkov izračuna požarne varnosti lesenih konstrukcij. Predstavljeni so predlogi izboljšave izračunov po standardu SIST EN 1995-1-2, ki temeljijo na požarnih testih in so opisani v Evropskih tehničnih smernicah. Praktični izračuni so prikazani na primerih lesenih elementov Vrtca Preddvor.The aim of this graduation thesis is to show procedures for calculating the fire safety of timber structures. Presented are proposals of improvements of calculations according to standard EN 1995-1-2, based on fire tests and described in European technical guideline. The practical calculations are shown on examples of timber structures of Kindergarten Preddvor

Development of contemporary hollow clay masonry unit suitable for infill walls in the Adriatic region

Pogost konstrukcijski sistem za večstanovanjske stavbe v jadranski regiji, natančneje v Sloveniji in na Hrvaškem, je armiranobetonski okvir z zidanimi polnili. Razlogi za široko uporabo takšnega sistema so predvsem hitra gradnja, razpoložljivost materialov, odlične toplotno-izolacijske lastnosti opečnih zidakov ter dobra požarna odpornost. Opečni zidaki, ki so danes dobavljivi na slovenskem in hrvaškem trgu, so namenjeni za izdelavo konstrukcijskih elementov zidanih stavb in kot taki precej presegajo zahteve za polnilna zidovja. V okviru magistrskega dela je prikazan postopek načrtovanja sodobnega opečnega zidaka, ki je optimiziran za polnilna zidovja armiranobetonskih okvirov. Pri tem so zajete različne faze razvoja novega proizvoda, od analize trga in predpisov za gradnjo do koncipiranja in numeričnega modeliranja predlagane rešitve. Definirane so različne konstrukcijske, energijske, ergonomske in tehnološke razvojne zahteve. Predlagana rešitev je numerično modelirana v programu Abaqus/CAE, kjer je analizirano mehansko obnašanje in prevajanje toplote skozi zidak.A very common construction system for multi-storey buildings in the Adriatic region, namely in Slovenia in Croatia is the reinforced concrete frame with masonry infill walls. The reasons for the widespread use of such system are faster completion of the build, market availability of the materials with their insulative and fire resistance properties of masonry. Currently available masonry units on the Slovenian and Croatian markets are designed and produced for load-bearing purposes in masonry constructions and as such go far beyond the requirements for infill walls. In this thesis, we show the process of design of contemporary hollow clay masonry unit, which is optimized for infill walls in reinforced concrete frames. We cover several different phases of product development: from market analysis and construction regulations to the product design and numerical modelling of proposed solution. Various construction, energy, ergonomic and technological requirements are defined. Proposed solution is numerically analyzed with the Abaqus/CAE software solution, where mechanical behavior and heat transfer of the developed product are analyzed