Diss. Lund : Lunds tekniska högskola, 2005.

Modern buildings increasingly include the usage of innovative materials aimed at improving sustainability and reducing the carbon footprint of the built environment. Phase Change Materials (PCMs) are one such group of novel materials which reduce building energy consumption. These materials are typically flammable and contained within wall linings yet there has been no detailed assessment of their fire performance. Current standard fire test methods provide means to compare similar materials but do not deliver knowledge on how they would behave in the event of a real fire. Thus, the aim of this thesis is to develop a novel testing framework to assess the behaviour of these materials in realistic fire scenarios. For PCMs, a flammability study is conducted in the bench-scale cone calorimeter to evaluate the fire risk associated with these materials. Then, micro-scale Thermogravimetric Analysis (TGA) is used to identify the fundamental chemical reactions to be able to confidently interpret the flammability results. Finally, intermediate-scale standard fire tests are conducted to evaluate the applicability of the bench-scale results to realistic fire scenarios. These take the form of modified Lateral Ignition and Flame spread Test (LIFT) and Single Burning Item (SBI) tests to understand flame spread and compartment fires respectively. Finally, a simplified method to combine this knowledge for use in building design is proposed. This method allows the balancing of potential energy benefits with quantified fire performance to achieve the specified goals of the designer. Hemp-lime insulation is a material which has also becoming increasingly popular in the drive towards sustainability. The porous nature of the material means that smouldering combustions are the dominant reaction mode but there is currently no standardised test method for this type of behaviour. Thus, hemp-lime materials also represent an unquantified risk. The work in this thesis defines a simple, accessible and economically viable bench-scale method for quantifying the fire risk associated with rigid porous materials. This is applicable for both downward opposed flow and upward forward flow smoulder propagation conditions. The behaviour is then interpreted using micro-scale thermogravimetric analysis to understand the underlying pyrolysis and oxidation reactions. Designers can utilise this framework to quantify the smouldering risk associated with hemp-lime materials to enable their usage in the built environment. The holistic fire risk assessment performed in this thesis has quantified the behaviour of PCMs and hemp-lime insulation applicable to realistic fire scenarios. The simplified design method empowers designers to be able to realise innovative buildings through fundamental understanding of the fire behaviour of these materials. The outcomes of this thesis allow designers to mitigate the fire risk associated with these materials and achieve optimised engineering solutions. Furthermore, the novel fire testing frameworks provide the economically viable means to assess the fire performance of future PCMs and hemp-lime products which ensures lasting relevance of this research in the future.

The main purpose of the Master paper is to make fire investigations analysis, to find its problems ant find a way to solve them. Also suggest new alternative fire investigation methods. In the first part of my work I studied fire investigation analysis disputed all the methods of fire investigation used in Lithuania. I found and disputed limitations of fire investigation methods and found few solutions for them. I describe new alternative fire investigation methods used abroad. In the second part of my work I have analyzed new fire investigation method- fire dynamic simulator. I Studied principles and use opportunities of FDS- MOKEWIEV and SMARTFIRE programs. In the third part I wrote few concrete examples when these two fire dynamic simulation programs were used. I have also described test computation with SMARTFIRE fire dynamic simulator. I have wrote conclusions and suggested about fire investigation.

Die Digitalisierung im Bauwesen schreitet immer weiter voran und während in diesem Zusammenhang oftmals das Stichwort Building Information Modeling (BIM) fällt, entwickeln sich Disziplinen wie das Brandschutzingenieurwesen (BSI) unabhängig weiter. Das Brandschutzbüro Brandschutz Consult Ingenieurgesellschaft mbH Leipzig (BCL) verwendet das BSI, um ingenieurtechnische Verfahren heranzuziehen. BCL verfolgt als Unternehmensphilosophie das Ziel, mit neuen Methoden und Erkenntnissen ständig die eigenen Prozesse zu optimieren und zu erweitern. Unter diesem Gesichtspunkt soll in dieser Arbeit in Kooperation mit BCL untersucht werden, inwieweit sich die Ergebnisse aus einer Brandsimulation, darunter besonders der Rauch, in einer virtuellen Realität (engl. Virtual Reality (VR)) darstellen und in bestehende oder potenzielle Anwendungsfälle integrieren lassen. Dazu soll zunächst mit einer Betrachtung der brandschutztechnischen Grundlagen inklusive des BSIs und einer Analyse zum Stand des Brandschutzes in BIM begonnen werden. Im nächsten Schritt sind für die Brandsimulation bestimmte Fragen zu klären, wie z.B. eine entsprechende Berechnung technisch abläuft und welche Ausgabedaten und -formate eine solche Simulation bereitstellt. Zur Darstellung der Simulationsergebnisse in virtuellen Realitäten werden Grafik.Engines benötigt, die VR-Anwendungen ermöglichen. Wichtige Untersuchungsgegenstände sind z.B. die anwendbaren Programmier- und Skriptsprachen, mit deren Einsatz die Daten eingelesen und visualisiert werden können. Für die gefundenen Grafik-Engines wird dann recherchiert, ob es bereits bestehende Anwendungen oder Prozesse zur Darstellung von Brandsimulationen gibt. Ist dies der Fall, sollen deren Workflows untersucht werden, um anschließend ihre grundsätzliche Einsatzfähigkeit zu bewerten und Verbesserungsvorschläge zu äußern...:1. Prozesse im Brandschutz 1.1. Brandschutztechnische Grundlagen 1.2. Angewandte Ingenieurmethoden 1.3. Brandschutz mit Building Information Modeling 2. Ablauf einer Brandsimulation 2.1. Verfügbare Software 2.2. Aufbau einer FDS-Eingabedatei 2.3. Generieren von Simulationsdaten in FDS 2.4. Ausgabedaten und -formate 3. Software zur Darstellung in VR 3.1. Blender 3.2. Unity Engine 3.3. Unreal Engine 3.4. Vergleich der Engines 4. Visualisierung der Brandsimulation 4.1. Konzept der Datenübertragung 4.2. Bestehende Workflows für VR-Programme 4.3. Versuchsdurchführung 4.4. Auswertung der Versuche 5. Anwendungsfälle und Optimierungspotenzial 5.1. Potenzielle Einsatzmöglichkeiten 5.2. Optimierungspotenzial 6. Fazit A. Beispielmodell Blender B. Beispielmodell VRSmokeVis C. Prüfmodell Abkürzungsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Literaturverzeichnis / Digitization in the construction industry is progressing and while the keyword Building Information Modeling (BIM) is frequently mentioned, disciplines like the fire safety engineering are also evolving independently. The fire protection office Brandschutz Consult Ingenieurgesellschaft mbH Leipzig (BCL)) uses fire safety engineering for including engineering procedures. As a corporate philosophy BCL pursues the goal of constantly optimizing and expanding its own processes with new methods and scientific findings. From this point of view, in cooperation with BCL, this master thesis will examine to which extent it is possible to visualize the results of a fire simulation, in particular including the smoke, in Virtual Reality (VR) and to integrate them into existing or evolving applications. For this purpose, a consideration of the fire protection basics including fire protection engineering and an analysis of the status of fire protection in BIM has been started. In the next step the fire simulation must be investigated, i.e. how the corresponding calculation technically works and which output data and formats such a simulation provides. Graphic engines that enable VR applications are required to display the simulation results in VR. Important objects of investigation are e.g. the applicable programming and scripting languages. Those scripting languages are used to import and visualize the data. For the graphic engines found, research is initiated to determine whether there are already existing applications or processes for displaying fire simulations. If this is the case these workflows should be examined in order to subsequently evaluate their fundamental usability and to express suggestions for improvement. If possible, some of the optimizations should be carried out. Based on the existing processes in fire protection helpful application options are derived, for which the use must be proven in future projects.:1. Prozesse im Brandschutz 1.1. Brandschutztechnische Grundlagen 1.2. Angewandte Ingenieurmethoden 1.3. Brandschutz mit Building Information Modeling 2. Ablauf einer Brandsimulation 2.1. Verfügbare Software 2.2. Aufbau einer FDS-Eingabedatei 2.3. Generieren von Simulationsdaten in FDS 2.4. Ausgabedaten und -formate 3. Software zur Darstellung in VR 3.1. Blender 3.2. Unity Engine 3.3. Unreal Engine 3.4. Vergleich der Engines 4. Visualisierung der Brandsimulation 4.1. Konzept der Datenübertragung 4.2. Bestehende Workflows für VR-Programme 4.3. Versuchsdurchführung 4.4. Auswertung der Versuche 5. Anwendungsfälle und Optimierungspotenzial 5.1. Potenzielle Einsatzmöglichkeiten 5.2. Optimierungspotenzial 6. Fazit A. Beispielmodell Blender B. Beispielmodell VRSmokeVis C. Prüfmodell Abkürzungsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Literaturverzeichnis

Utbredningen av en brand inuti en byggnad kan leda till global eller lokal strukturell kollaps, särskilt i stålramkonstruktioner. Faktum är att stålkonstruktioner är särskilt utsatta för termiska angrepp på grund av ett högt värde av stålkonduktivitet och tvärsnitten med små tjockleken. Som en viktig aspekt av konstruktionen bör brandsäkerhetskrav uppnås antingen enligt föreskrivande regler eller enligt antagande av prestationsbaserad brandteknik. Trots möjligheten att använda enkla metoder som involverar membersanalys kombinerat med nominella brandkurvor, är en mer exakt analys av det termomekaniska beteendet hos en stålkonstruktion ett tilltalande alternativ eftersom det kan leda till mer ekonomiska och effektiva lösningar genom att ta hänsyn till möjliga gynnsamma mekanismer. Denna analys kräver vanligtvis utredning av delar av strukturen eller till och med av hela strukturen. För detta ändamål och för att få en djupare kunskap om strukturelementens beteende vid förhöjd temperatur bör numerisk simulering användas. I denna avhandling utvecklades och användes termomekaniska finita element som är lämpliga för analys av stålkonstruktioner utsätta för brand. Relevanta fallstudier utfördes. Utvecklingen av både ett termomekaniskt skal- och 3D balkelement baserade på en korotationsformulering presenteras. De flesta relevanta strukturfall kan undersökas på ett adekvat sätt genom att antingen använda något av dessa element eller kombinera dem. Korotationsformuleringen är väl lämpad för analyser av strukturer där stora förskjutningar, men små töjningar förekommer, som i fallet med stålkonstruktioner i brand. Elementens huvuddrag beskrivs, liksom deras karakterisering i termomekaniskt sammanhang. I detta avseende övervägdes materialnedbrytningen på grund av temperaturökningen och den termiska expansionen av stål vid härledningen av elementen. Dessutom presenteras en grenväxlingsprocedur för att utföra preliminära instabilitetsanalyser och få viktig inblick i efterknäckningsbeteendet hos stålkonstruktioner som utsätts för brand. Tillämpningen av de utvecklade numeriska verktygen ges i den del av avhandlingen som ägnas åt det publicerade forskningsarbetet. Flera aspekter av knäckningen av stålkonstruktionselement vid förhöjd temperatur diskuteras. I Artikel I tillhandahålls överväganden om påverkan av geometriska imperfektioner på beteendet hos komprimerade stålplattor och kolonner vid förhöjda temperaturer, liksom implikationer och resultat av användningen av grenväxlingsprocedur. I Artikel II valideras det föreslagna 3D-balkelementet genom meningsfulla fallstudier där torsionsdeformationer är signifikanta. De utvecklade balk- och skalelementen används i en undersökning av knäckningsmotstånd hos komprimerade vinkel-, Tee- och korsformade stålprofiler vid förhöjd temperatur som presenteras i Artikel III. En förbättrad knäckningskurva för design presenteras i detta arbete. Som ett exempel på tillämpningen av principerna för brandsäkerhetsteknik presenteras en omfattande analys i Artikel IV. Två relevanta brandscenarier identifieras för den undersökta byggnaden, som modelleras och analyseras i programmet SAFIR. / The ignition and the propagation of a fire inside a building may lead to global or local structural collapse, especially in steel framed structures. Indeed, steel structures are particularly vulnerable to thermal attack because of a high value of steel conductivity and of the small thickness that characterise the cross-sections. As a crucial aspect of design, fire safety requirements should be achieved either following prescriptive rules or adopting performance-based fire engineering. Despite the possibility to employ simple methods that involve member analysis under nominal fire curves, a more accurate analysis of the thermomechanical behaviour of a steel structural system is an appealing alternative, as it may lead to more economical and efficient solutions by taking into account possible favourable mechanisms. This analysis typically requires the investigation of parts of the structure or even of the whole structure. For this purpose, and in order to gain a deeper knowledge about the behaviour of structural members at elevated temperature, numerical simulation should be employed. In this thesis, thermomechanical finite elements, suited for the analyses of steel structures in fire, were developed and exploited in numerical simulation of relevant case studies. The development of a shell and of a 3D beam thermomechanical finite element based on a corotational formulation is presented. Most of the relevant structural cases can be adequately investigated by either using one of these elements or combining them. The corotational formulation is well suited for the analyses of structures in which large displacements, but small strains occur, as in the case of steel structures in fire. The main features of the elements are described, as well as their characterization in the thermomechanical context. In this regard, the material degradation due to the temperature increase and the thermal expansion of steel were considered in the derivation of the elements. In addition, a branch-switching procedure to perform preliminary instability analyses and get important insight into the post-buckling behaviour of steel structures subjected to fire is presented. The application of the developed numerical tools is provided in the part of the thesis devoted to the published research work. Several aspects of the buckling of steel structural elements at elevated temperature are discussed. In paper I, considerations about the influence of geometrical imperfections on the behaviour of compressed steel plates and columns at elevated temperatures are provided, as well as implications and results of the employment of the branch-switching procedure. In Paper II, the proposed 3D beam element is validated for meaningful case studies, in which torsional deformations are significant. The developed beam and shell elements are employed in an investigation of buckling resistance of compressed angular, Tee and cruciform steel profiles at elevated temperature presented in Paper III. An improved buckling curve for design is presented in this work. Furthermore, as an example of the application of Fire Safety Engineering principles, a comprehensive analysis is proposed in Paper IV. Two relevant fire scenarios are identified for the investigated building, which is modelled and analysed in the software SAFIR.

<p>Composite Plate Shear Walls - Concrete Filled (C-PSW/CF), also known as SpeedCore walls, are increasingly used in commercial buildings. C-PSW/CF offer the advantages of modularization and expedited construction time. The performance of C-PSW/CF under wind and seismic loading has been extensively studied. As such, building codes permit the use of these walls in non-seismic and seismic regions. In addition to these lateral loads, C-PSW/CF may be exposed to fire loading during their service life. Elevated temperatures resulting from the fire loading subject structural components to a set of forces and deformations. These elevated temperatures result in the significant degradation of the material properties. Thus, fire loading may lead to the failure of structural components during fire incidents within the buildings.</p> <p>This dissertation describes (i) experimental, numerical, and analytical studies conducted to evaluate the performance of C-PSW/CF and (ii) the development of design guidelines for C-PSW/CF subjected to fire and gravity loading. The results from prior experimental investigations were compiled, and five additional fire tests were conducted to address gaps in the experimental data. The fire tests were conducted on laboratory-scale specimens subjected to axial compressive loading and simulated standard fire loading (heating). The parameters considered in the tests were axial compressive loading (21% – 30% of section compressive strength, <em>Ag f’c</em>), steel plate slenderness (24 – 48, tie spacing-to-steel plate thickness ratio), and uniformity of heating (all-sided versus three-sided heating).</p> <p>Numerical and analytical studies were conducted using two independent methods namely Finite Element (FE) and Finite Difference (FD) methods. The developed models were benchmarked to test data, and the benchmarked models were used to conduct parametric studies to expand the database. The thermal and structural material properties recommended by Eurocode standards were applied in these models. The parameters considered were the wall thickness (200 mm – 600 mm), wall slenderness (story height-to-concrete thickness ratio, <em>H/tc</em>= 5 – 25), axial load ratio (<em>Pu</em> ≤ 30% section concrete strength, <em>Ac f’c</em>), heating uniformity (uniform versus non-uniform heating), boundary conditions (pinned versus fixed), cross-sectional steel plate reinforcement ratio (<em>As/Ag</em> =1.3% – 5.3%), steel plate slenderness ratio (<em>stie/tp</em> = 20 – 75), tie bar spacing-to-wall concrete thickness ratio (<em>stie/tc</em> = 0.5 – 1.0), and concrete compressive strength (<em>f’c</em> = 40 MPa – 55 MPa).</p> <p>Symmetric nonlinear thermal gradients were developed through wall thickness for the walls exposed to uniform fire loading. Due to the low thermal conductivity of concrete, the temperature decreased nonlinearly through the wall thickness towards the mid-thickness of the walls. For the non-uniform fire exposure, temperatures through the wall thickness decreased nonlinearly towards the unexposed surface of the walls. A consistent trend was observed in the axial displacements of C-PSW/CF under combined fire and gravity loading. The observed trend consisted of several steps including (i) thermal expansion, (ii) gradual axial shortening, (iii) fast axial shortening, and (iv) failure.</p> <p>Local buckling of steel plates between tie bars was observed in all walls. However, this phenomenon did not cause any significant degradation in structural performance or failure of the walls. The results from parametric studies indicated that wall slenderness ratio (story height-to-wall thickness ratio), wall thickness, applied axial load ratio, and end boundary conditions have a significant influence on the fire resistance of C-PSW/CF. Higher wall slenderness ratios and load ratios had a detrimental effect on the fire resistance of walls. Global buckling was the dominant failure mode for the walls with high slenderness ratios (e.g., <em>H</em>/<em>tc </em>³ 15). In thicker walls, the lower temperatures in the middle regions of the concrete helped to maintain the axial compressive capacity of walls under fire loading. Limiting the steel plate slenderness ratio could slightly improve the fire resistance of unprotected walls by arresting the extent of local buckling between tie bars.</p> <p>The results from the parametric studies have been used to develop an approach for designing C-PSW/CF subjected to combined fire and gravity loading. The total (linear) length of the wall was discretized into unit width columns, where each unit width column corresponded to a length of wall equal to the tie bar spacing (<em>stie</em>). Thus, each unit is like a column with steel plates on two opposite surfaces, concrete infill, and tie bars distributed uniformly along the height. The axial load capacity of C-PSW/CF can be estimated as the axial load capacity of the unit width column, calculated using the developed approach, multiplied by the linear length of the wall divided by the unit width (tie bar spacing). For this approach, the wall slenderness ratio (<em>H/tw</em>), has a limiting value of 20. Walls with wall slenderness ratios greater than 20 should be fire protected. The expansion of the material on the exposed surface of walls generated moments through the wall cross-section in non-uniform fire scenarios. This phenomenon caused the early failure of walls (~40 minutes) with wall slenderness ratios greater than 20. An approach was developed to conservatively estimate the fire-resistance rating (in hours) of unprotected C-PSW/CF exposed to the standard fire time-temperature curve. The fire-resistance rating of C-PSW/CF depends directly on the applied axial load ratio, wall slenderness ratio, and wall thickness.</p> <p>The temperature profile through the wall thickness can be calculated by discretizing the section into fibers (or elements). Since the temperature of the elements is uniform along the height and length of walls, 1D thermal analysis (through wall thickness) can be performed using heat transfer equations or the fiber-based program developed in the study.</p> <p>Vent holes are recommended to relieve the buildup steam pressure as the moisture content of concrete evaporates at temperatures exceeding the boiling point of water. A rational method was developed to design the vent holes as a function of the maximum temperature and thermal gradient through the wall thickness, heating duration, moisture content, and the acceptable level of pressure buildup on the steel plates. However, in typical cases, unprotected C-PSW/CF walls can be provided with 25 mm diameter vent holes spaced at a distance equal to story height or 3.6 m (maximum) in the horizontal and vertical directions to relieve the buildup of steam or water vapor pressure.</p> <p>This research study also led to the development and validation of a computer program that can be used instead of the design equations to more accurately model and calculate the thermal and structural performance of composite C-PSW/CF. This program is based on a fiber-based section and member analysis method that can be used to evaluate the performance and axial (gravity) load capacity of unprotected and protected C-PSW/CF subjected to uniform or non-uniform heating. The analysis can be conducted by implementing standard (ISO 834 or ASTM E119), Eurocode parametric, or user input gas (or surface) time-temperature curves.</p> <p>The proposed equations and the recommendations in this study can be used to develop design guidelines and specifications for fire resistance design of C-PSW/CF under combined fire and gravity loading. A code change proposal will be proposed to AISC <em>Specification</em> - Appendix 4 (Structural Design for Fire Condition).</p>

<p dir="ltr">Composite Plate Shear Wall/ Concrete Filled (C-PSW/CF), also referred to as SpeedCore walls, are being used as innovative shear wall commercial high-rise buildings. These walls offer advantages such as modularity and construction schedule contraction. The cross-section of C- PSWs/CF consists of concrete infill sandwiched between the steel faceplates, where the steel plates are tied together by steel tie bars. Elevated temperatures will result in a deterioration in the mechanical properties of steel and concrete during a fire event in buildings. Such degradation can lead to stability-related failure of structural components. Composite floors are connected to these walls through simple shear connections. The floor-to-wall connections will be exposed to elevated temperatures, which may result in connection failure and progressive collapse of structures.</p><p dir="ltr">Designing SpeedCore walls without fire protection raises concerns regarding the performance of other structural components connected to SpeedCore walls under fire loading including composite floor systems and wall-to-floor connections. Numerical studies conducted on the connections and the floor systems indicated that these structural components undergo thermal compression forces during heating and tensile forces during the cooling phases of a fire event. The goal of this research was to develop an approach for performance-based fire resistance design of complete floor systems consisting of SpeedCore walls, composite floor slabs, and wall-to-floor connections.</p><p dir="ltr">This research includes experimental and numerical analyses to gain insight into the behavior of the floor-to-SpeedCore wall connections under fire and gravity loading. The specimens included steel beams connected to SpeedCore walls through simple shear connections. Three types of floor-to-wall connections were tested including connections with through-plate, reinforcing plate, and unreinforced plate. The parameters considered in the test matrix included: connection type, temperature, loading angle, and loading direction. These parameters in the test matrix were based on results obtained from previous numerical and experimental studies in the literature. The experimental results can fill the existing knowledge gap on floor-to-wall connections for steel-concrete composite members, develop design recommendations, and benchmark numerical models.</p><p dir="ltr">Numerical models were developed to simulate the behavior of the connections (member level) and whole structures (structure level) at ambient and elevated temperatures. Finite Element (FE) analysis and Component-based Models (CB) were utilized to develop the numerical models. The developed models were benchmarked by comparing the obtained numerical results with experimental data reported in the literature. FE models have been validated at two different levels, namely member level, and system level. The performance of the designed connection for the archetype structures was studied using benchmarked FE and CB models. The behavior of various wall-to-floor connections with different steel plate (C-PSW/CF) detailing was investigated.</p><p dir="ltr">Benchmarked numerical models were used to perform a parametric study to evaluate the performance of these connections. UP connection detail was used to perform the study due to its promising experimental performance, which does not need any special detail or plate reinforcement. The study was performed by evaluating the effects of critical parameters on the connection behavior namely, bolt size, target temperature, loading angles, and loading direction</p>