No description available.

No description available.

Scottish sandstone buildings are now suffering the long-term effects of salt-crystallisation damage, owing in part to the repeated deposition of de-icing salts during winter months. The use of de-icing salts is necessary in order to maintain safe road and pavement conditions during cold weather, but their use comes at a price. Sodium chloride (NaCl), which is used as the primary de-icing salt throughout the country, is a salt known to be damaging to sandstone masonry. However, there remains a range of alternative, commercially available de-icing salts. It is unknown however, what effect these salts have on porous building materials, such as sandstone. In order to protect our built heritage against salt-induced decay, it is vital to understand the effects of these different salts on the range of sandstone types that we see within the historic buildings of Scotland. Eleven common types of sandstone were characterised using a suite of methods in order to understand their mineralogy, pore structure and their response to moisture movement, which are vital properties that govern a stone’s response to weathering and decay. Sandstones were then placed through a range of durability tests designed to measure their resistance to various weathering processes. Three salt crystallisation tests were undertaken on the sandstones over a range of 16 to 50 cycles, which tested their durability to NaCl, CaCl2, MgCl2 and a chloride blend salt. Samples were primarily analysed by measuring their dry weight loss after each cycle, visually after each cycle and by other complimentary methods in order to understand their changing response to moisture uptake after salt treatment. Salt crystallisation was identified as the primary mechanism of decay across each salt, with the extent of damage in each sandstone influenced by environmental conditions and pore-grain properties of the stone. Damage recorded in salt crystallisation tests was ultimately caused by the generation of high crystallisation pressures within the confined pore networks of each stone. Stone and test-specific parameters controlled the location and magnitude of damage, with the amount of micro-pores, their spatial distribution, the water absorption coefficient and the drying efficiency of each stone being identified as the most important stone-specific properties influencing salt-induced decay. Strong correlations were found between the dry weight loss of NaCl treated samples and the proportion of pores < 1µm in diameter. Crystallisation pressures are known to scale inversely with pore size, while the spatial distribution of these micro-pores is thought to influence the rate, overall extent and type of decay within the stone by concentrating crystallisation pressures in specific regions of the stone. The water absorption determines the total amount of moisture entering into the stone, which represents the total amount of void space for salt crystallisation. The drying parameters on the other hand, ultimately control the distribution of salt crystallisation. Those stones that were characterised by a combination of a high proportion of micro-pores, high water absorption values and slow drying kinetics were shown to be most vulnerable to NaCl-induced decay. CaCl2 and MgCl2 are shown to have similar crystallisation behaviour, forming thin crystalline sheets under low relative humidity and/or high temperature conditions. Distinct differences in their behaviour that are influenced by test specific criteria were identified. The location of MgCl2 crystallisation close to the stone surface, as influenced by prolonged drying under moderate temperature drying conditions, was identified as the main factor that caused substantial dry weight loss in specific stone types. CaCl2 solutions remained unaffected under these conditions and only crystallised under high temperatures. Homogeneous crystallisation of CaCl2 throughout the stone produced greater internal change, with little dry weight loss recorded. NaCl formed distinctive isometric hopper crystals that caused damage through the non-equilibrium growth of salts in trapped regions of the stone. Damage was sustained as granular decay and contour scaling across most stone types. The pore network and hydric properties of the stones continually evolve in response to salt crystallisation, creating a dynamic system whereby the initial, known properties of clean quarried stone will not continually govern the processes of salt crystallisation, nor indeed can they continually predict the behaviour of stone to salt-induced decay.

No description available.

Fire in building structures represents a risk both to life and property that cannot be fully eliminated. It is the aim of fire safety engineering to reduce this risk to an acceptable level through the application of scientific and engineering principles to evaluate the risk posed by fire and to determine the optimal set of protective measures. This is increasingly being achieved through performance-based design methods. Performance-based design sets out performance requirements, typically related to life safety and control of property losses, and the designer is free to choose the most suitable approach to meet these requirements. Accurate performance-based design requires the evaluation of the risks to a structure through the evaluation of the range of hazards that may occur and the resulting structural responses. The purpose of this research is to develop simplified methodologies for the reliability based design of steel framed structures in fire. These methodologies are incorporated into a software package, FireLab, which is intended to act as a tool for practicing engineers to aid in learning and applying performance-based design. FireLab is a Matlab based program that incorporates a number of different models for analysing the response of structural elements exposed to fire. It includes both deterministic and probabilistic analysis procedures. A range of simple fire models are presented for modelling compartment fires. A set of heat transfer processes are discussed for calculating the temperature distribution within common structural elements exposed to fire. A variety of structural models are discussed which may be used to model the effects of fire on a structure. An analytical model for the analysis of composite beams has been implemented in the software program. Interfaces between the software and 2 separate third party programs have also been created to allow for the analysis of composite beams using the finite element method. Analytical methods for the analysis of composite slabs under thermo-mechanical load have been implemented in the software. These methods account for the additional load carrying capacity that slabs have in fire due to the positive effects of tensile membrane action. A numerical analysis method for the vertical stability of structures subjected to multi-floor fires has been implemented using the direct stiffness method. This method uses an elastic 2nd order solution in order to check the stability of a column under the fire induced horizontal loads from sagging floors. These models of potential failure scenarios provide the basis for the probabilistic analysis methods. A variety of methods for reliability analysis are evaluated based on ease of use, accuracy and efficiency. A selection of these methods has been implemented in the software program. A selection of sample cases are examined in order to illustrate the procedures and to evaluate the important input variables. These methods provide the probability of failure of a structure under specific loads. The probability of failure is a useful parameter in comparing the level of safety between various design options. A more comprehensive framework is developed for the evaluation of the probable costs due to fire associated with a given design. This framework is based on an existing framework from earthquake engineering. It involves calculating the statistical spread of both the magnitude and likelihood of occurrence of fire and the resulting structural responses. The damage that occurs from the structural response may be then estimated. Finally, given the likely level of damage that will occur it is possible to estimate the cost of the damage either in terms of monetary cost of repair or downtime due to repair works. This method is applied to a variety of design options for a typical office building in order to illustrate the application of the framework.

This thesis examines a much neglected area of Scottish building and construction history, brickwork. It will be conclusively shown that brick has seen far more widespread use in Scottish buildings than has been appreciated to date. This is true not just in terms of the range of building types which have been found to incorporate brick into their construction but also when the geographical spread of these buildings is considered. It will also be shown that in the period the research covers, 1700-1900, brickwork in Scotland underwent a series of technical developments. This saw brick transformed from a material used in a limited capacity for specific purposes such as garden wall construction and ice houses in the early 18th century to one which, by 1900, saw extensive use in the construction of housing, industrial buildings and engineered structures. Specific technical developments within areas of brick construction have also emerged. This can be seen in areas as diverse as bond, the height to which four courses of brickwork rise, arch construction and cavity walling. The technical developments within Scottish brickwork are considerable and this thesis represents the first comprehensive analysis of these. In addition to demonstrating the extent of the use of the material and the considerable technical developments there within, this thesis will present substantial evidence in support of the view that Scotland developed specific craft practices in using brick which are not reflected in contemporary technical reference works. This is most significant in the bonding of brickwork with a specifically Scottish bond being dominant in the 19th century. Survey work of surviving buildings will also show that there was a specifically Scottish gauge of brickwork when measuring the height to which four courses rose. Other differences in craft practice can be seen when the construction of brickwork at an angle other than 90 degrees and arch construction are examined to give but two examples. This thesis will also present evidence for a number of areas. When brick making is considered new evidence is presented to both the extent of the industry in Scotland which can be seen to be more extensive both in the 18th and 19th centuries than has previously been appreciated, and also for specific Scottish developments in kilns and brick making machines. The influence which developments in manufacturing had on the use of brick will also be demonstrated. Finally, it will be shown that, whilst Scottish brickwork often served functional requirements, this was never entirely true and the use of brick in this country can be shown to have a decorative as well as functional element to it. As the first comprehensive examination of brickwork in Scotland this thesis presents a wide ranging view of both the extent of the use of the material and the developments therein. By so doing, brick can begin to receive the level of analysis and understanding that has hitherto been lacking and be rightfully considered an integral part of Scottish construction between 1700-1900.

Im Rahmen dieser Abschlussarbeit „Strohballenbau-Vergleich dreier Bauvorhaben unter konstruktiven, ausführungstechnischen und bauphysikalischen Aspekten“ werden alle für den Strohballenbau relevanten Detailpunkte der drei Bauvorhaben beschrieben, verglichen und bewertet. Weiterhin wird das Gesamtsystem der Bauvorhaben bauteilübergreifend analysiert. Dabei wird vorrangig auf bauphysikalische, baubiologische, bautechnologische und ausführungstechnische Aspekte eingegangen. Im Verlauf der Arbeit wird auf Besonderheiten hingewiesen, die in der Planungsphase berücksichtig werden müssen, um die Funktionsfähigkeit eines Strohballenhauses sicher zu stellen. Baupraktische Erfahrungen des Autors im Rahmen des dritten Bauvorhabens bilden die Grundlage dieser Arbeit.:Kurzfassung II Abstract II Inhaltsverzeichnis III Abbildungsverzeichnis 1 Tabellenverzeichnis 2 Formelzeichen und Abkürzungen 2 Vorwort 3 1 Einleitung Motivation 4 1.1 Kontextuelle Einordnung des Strohballenbaus 4 1.2 Ziel und Zweck der Arbeit 5 2 Strohballenbauten 5 2.1 Überblick 5 2.1.1 Prinzip Strohballenbau 5 2.1.2 Idee 5 2.1.3 Herausforderungen 6 2.2 Stand der Technik 7 2.3 Ableitung des Ansatzes 7 2.3.1 Bauphilosophie der drei Bauvorhaben 8 2.3.2 Beschreibung der drei Bauvorhaben 10 2.3.3 Eigenleistung 12 3. Vergleich einzelner Konstruktionsdetails der drei Bauvorhaben 14 3.1 Fundament 14 3.2 Sockelbereich 17 3.3 Wandaufbau 23 3.3.1 Holzkonstruktion 23 3.3.2 Strohballenausrichtung 27 3.3.3 Gefachbreiten 28 3.3.4 Dreikantleisten 30 3.4 Baustroh 32 3.4.1 Eigenschaften der Strohballen 32 3.4.2 Kubatur der Strohballen 33 3.4.3 Strohballenvorbereitung 34 3.4.4 Strohballeneinbau 35 3.4.5 Verpressen 36 3.4.6. Verpresstechniken 39 3.4.6.1 Umreifungstechnik 39 3.4.6.2 Kettenzugtechnik 41 3.4.7 Nacharbeiten 43 3.5 Lehm 45 3.6 Wandecken 48 3.7 Fensteranschluss 49 3.8 Befestigungstechnik 53 3.9 Fußbodenaufbau 53 3.10 Leitungsführung 54 3.11 Innenwände 55 3.12 Deckenanschluss 56 3.13 Giebeldreieck 58 3.14 Dach 58 4. Bauteilübergreifende Betrachtung 61 4.1 Wärmeschutz 61 4.1.1 Energieausweis 61 4.1.2 Luftdichtigkeit 62 4.1.3 Sommerlicher Wärmeschutz 66 4.2 Feuchteschutz 68 4.3 Schallschutz 71 4.4 Brandschutz 71 4.5 Baubiologie 72 4.6 Statik 75 4.7 Bautechnologie 77 4.7.1 Maschineneinsatz 77 4.7.2 Materialbeschaffung 79 4.7.3 Lagerung 79 4.8 Bauablaufplan 80 4.9 Eigenleistung 82 4.10 Kosten 84 5 Zusammenfassung und Ausblick 86 5.1 Zielstellung der Arbeit 86 5.2 Ergebnisse der Arbeit 86 5.3 Ausblick 88 Anhang A Berechnungen 89 Anhang B Zeichnungen 117 Glossar 127 Literaturverzeichnis 129 Bildquellenverzeichnis 133 Eidesstattliche Versicherung 137

Building rammed earth structures provides a sustainable alternative to concrete. As a building material, rammed earth exhibits very varied physical and material properties depending on the proportion of constituting soil types. When very sandy soil is used in rammed earth production, the properties are different from when a clayey soil is used. This variability can be seen as a very great advantage in the use of rammed earth as a building material. Builders are able to adjust specific properties by changing mix proportions to obtain a desirable balance in the characteristics of the resulting rammed earth structure. This research work looks at selected mechanical and physical properties of different mixes of rammed earth. It describes typical range of values in density, thermal conductivity, ultrasonic pulse velocity, water ingress and compressive strength. It examines how these factors interrelate in the same soil mixes. Samples were prepared by blending various soil types in specific proportions to ensure that each definition of soil grade is as specific as possible. Unstabilised rammed earth was tested as was cement stabilised rammed earth. Rammed earth was tested at various levels of stabilisation and it was discovered that higher rates of stabilisation was not always beneficial to every material property. The research also looked into the potential disposal of waste materials in rammed earth. As rammed earth is a monolithic material that largely remains undisturbed throughout its life span, it was suggested that waste materials could be stored in an inert form inside of rammed earth rather than dumping it in otherwise agricultural landmass. Pulverised Fuel Ash and Palm Kernel Shells were identified as wastes to be disposed in rammed earth. Pulverised Fuel Ash, a by-product of industrial furnace is found in abundance in developed countries that burn carbonaceous materials in power plants. Disposals have been seen as a problem as only a small proportion of high loss on ignition (LOI) Pulverised Fuel Ash has found application. Palm Kernel Shell is a by-product of the oil palm industry and is currently a menace in many developing countries that need to dispose large quantities of the shell in landfills. At an early stage of the research, experimental trial runs quickly showed that these supposedly waste materials had a positive effect on some of the material properties of the rammed earth walls they were made into. This research effort evolved to look into exploiting these materials to improve the physical and material property of rammed earth and to suggest their effect on stabilised and unstabilised rammed earth. The extent to which these materials could be useful and the level at which diminishing returns set in was also investigated. It was discovered that soil mixes that would otherwise not be considered suitable for use in rammed earth wall production can now be utilised as their characteristics can be improved on simply by adding Pulverised Fuel Ash or Palm Kernel shell in the right proportion. Incorporating Pulverised Fuel Ash in rammed earth resulted in increased compressive strength. Palm Kernel shell improved thermal properties without compromising compressive strength.

Scotland’s vernacular earth-built heritage has received inadequate recognition over a number of decades, being the reserve of a small group of academic, architectural and conservation practitioners, with negative perceptions of the structures and their inhabitants having been developed over the long-term. This has ultimately contributed to the loss of a wide number of earth building traditions previously widespread across Scotland. Heritage custodians have invested in the restoration and maintenance of a select few sites, but wider recognition of the significance of extant structures, including the intangible aspects of inherited traditions, remains limited. This thesis therefore seeks in the first instance to promote improved understandings of Scotland’s earth-built heritage through historical appraisals that underline its wider heritage value within global, regional and local contexts, whilst demonstrating the limitations of survey evidence hitherto relied upon. Heritage policies and management procedures are increasingly driven in response to the climate changes projected for the remainder of the twenty-first century, partly informed by the impacts of changes that have already been observed. As a result of this, new fields of research such as heritage climatology have developed with a view to offering bases from which to develop longer term mitigation and management strategies that recognise potential changes to the causes and processes of deterioration in the historic environment. Alongside the development of academic interest in climate and heritage has been an ever-increasing accessibility to advanced analysis methods through technical apparatus (often portable) that can be used to create improved evidence repositories based on processes-led approaches to investigation. Scotland’s earth-built heritage is susceptible to a range of climate-related phenomena that are likely to manifest in different ways over coming decades. Conservation strategies have continued to rely, however, upon the empirical observations and the experience of very few individuals since the latter-twentieth century. Consequently, the ad hoc approaches to the management of Scotland’s earth-built heritage and lack of strategic planning that have been typical to this point require amendment. This interdisciplinary thesis therefore seeks to contribute to addressing the issues outlined above through the exploration and application of portable scientific sampling apparatus that allow for in situ, rapid and non-intrusive insights to be gained at various scales of interest. These, together with other minimally intrusive approaches to assessing performance in earth building materials, allow for the development of processes-led strategies to extending the evidence base beyond that presently relied upon. Amongst the key outcomes of this are the generation of a locally-focused dataset of climate projections that are used to develop understandings of future climate conditions in the Carse of Gowrie, Perthshire, and in turn garner insights as to how these will impact in relation to the earth-built heritage for which this region is noted. Temperature and humidity monitoring evidence gathered from within the walls of extant structures over the course of fourteen months from March 2012 to April 2013 are set against contemporary external weather conditions and alongside measurements of moisture ingress. These serve to highlight both aspects of inherent resilience and points of particular risk to the future integrity of earth-built structures. An extended benefit of this work is the demonstration that the novel procedures used are easily replicated and could be employed in a variety of local contexts to develop suites of intra-site data across Scotland, with the potential for offering evidence-based inferences relevant to management procedures and policy discussion. The utility of the understandings and methods of investigation long established in the field of soil science but conspicuously overlooked in earth buildings research is also addressed, with insights into micro-scale processes offered using micromorphological and micromorphometric methods and the results being directly related to macro-scale observations.

Les techniques de l'éco-construction répondent au besoin de réduire l'empreinte environnementale du secteur de la construction grâce à l'utilisation de ressources de proximité (filières courtes), sans transformation énergivore et grâce à la capacité de régulation thermo-hydrique des parois. La terre crue seule ou associée à de la paille fait office de symbole. Mais ses caractéristiques variables selon son origine, le long temps de séchage, et de faibles résistances mécaniques sont des freins à son utilisation. L'association de la terre avec des adjuvants biosourcés, tel que l'amidon déjà utilisé dans la fabrication de plaque de plâtre, représente une voie intéressante d'amélioration des performances. La thèse a pour objectif d'étudier l'influence de l'amidon sur le comportement physico-mécanique de la terre seule ou mélangée à de la paille. L'application envisagée des formules est la préfabrication de produits de construction non-porteurs. Les formulations incluent des fines argilo-calcaires (FAC), de la chènevotte ou des anas de lin, et différents amidons. La première partie de la thèse porte sur les mélanges terre-amidon. Des essais au viscosimètre ont défini le comportement rhéologique des mélanges de type Bingham modifié et ont montré une augmentation de la thixotropie. A l'état durci, les résistances mécaniques ont été meilleures avec l'amidon. La deuxième partie porte sur des mélanges terre-paille-amidon. L'amidon améliore l'ouvrabilité et les résistances mécaniques mesurées selon différentes conditions de stockage. A l'échelle d'un carreau, les performances mécaniques, thermiques, et acoustiques de certaines formules sont comparables à celles de carreaux de plâtre. / The eco-construction responds to the need to reduce the environmental footprint in the sector of construction through the use of proximity resources (e.g. earth, straw, etc.), without energy-intensive transformation and through the thermohydric regulation capacity of walls. Raw earth alone or in association with straw is a symbol. But variable characteristics according to its origin, a long drying time and low mechanical strengths are brakes to its use. Earth material in association with biosourced admixtures such as starch, already used in the manufacturing of plasterboard, represents an interesting way to improve its performances.The thesis aims to study the influence of starch on the physico-mechanical behavior of the earth alone or with straw. The intended application of the study is the prefabrication of non-load-bearing construction products. The designed mixes include quarry fines (QF), hemp or flax straw and various starches.The first part of this work deals with earth-starch mixes. Viscometer tests were defined modified Bingham as the rheological behavior of mixes and showed an increase in thixotropy. In hardened state, the mechanical strengths are better with starch.The second part deals with earth-straw-starch mixes. Starch improves the workability and the mechanical strengths measured under different storage conditions. At the scale of a block, the mechanical, thermal and acoustic performances of some mixes are comparable to those of plaster blocks.