Thesis: B.S., Massachusetts Institute of Technology, Department of Building Engineering and Construction, 1949 / by Paul T. Reynolds, Richard W. Warren. / B.S. / B.S. Massachusetts Institute of Technology, Department of Building Engineering and Construction

Thesis: B.S., Massachusetts Institute of Technology, Department of Building Engineering and Construction, 1941 / Includes bibliographical references. / by Douglas Watson, Stanley H. Van Greenby. / B.S. / B.S. Massachusetts Institute of Technology, Department of Building Engineering and Construction

Thesis: B.S., Massachusetts Institute of Technology, Department of Building Engineering and Construction, 1936 / by Angelo M. Tremaglio and John D. Viola. / B.S. / B.S. Massachusetts Institute of Technology, Department of Building Engineering and Construction

<p>Detta examensarbete behandlar området stålfiberarmerad betongplatta. Istället för att använda en traditionellt armerad betongplatta undersöks möjligheten att använda sig av den alternativa tekniken stålfiberarmerad betong. Stålfiberarmerad betong består av vanlig betong med iblandning av stålfibrer vilket ger den unika egenskaper.</p><p>Rapporten utgörs av en jämförelse mellan en traditionellt armerad betongplatta gentemot en stålfiberarmerad betongplatta. I jämförelsen används ett referensobjekt som är den nya Konsumbutiken i Sunne där traditionell grundläggning med nätarmering använts. Detta alternativ jämförs med en teoretisk framtagen konstruktionslösning där fiberbetong används. Studien behandlar aspekterna dimensionering, genomförande, tid, ekonomi och arbetsmiljö. Målet med studien är att se vilket grundläggningsalternativ som hade varit mest fördelaktigt.</p><p>Resultatet som framkommit i denna studie visar att grundläggningsalternativet stålfiberarmerad platta på mark hade varit ett bättre alternativ i det givna fallet. Dimensioneringsmässigt leder den nya lösningen till en slankare konstruktion, enklare genomförande och bättre arbetsmiljö på grund av minskat armeringsarbete. Ekonomiskt blir det stålfiberarmerade alternativet billigare och även tidsbesparande.</p> / <p>This report manages the topic of steel fiber reinforced concrete slab. In this study we examine the possibility to use steel fiber reinforced concrete instead of traditional mesh reinforced concrete for the foundation. Steel fiber reinforced concrete consists of ordinary concrete mixed with steel fibers, which give it unique characteristics.</p><p>The report is based on a comparison between a traditional mesh reinforced concrete slab and a steel fiber reinforced concrete slab. A reference object has been selected for the study. The reference object is a new supermarket named Konsum in Sunne, Sweden, where traditional mesh reinforced concrete has been used for the foundation. This foundation is compared to a theoretically produced steel fiber reinforced concrete slab. The comparison is based on the following subjects: design, implementation, time, economy and working conditions. The purpose of this report is to determine which alternative is the most advantageous.</p><p>The result of this study shows that the steel fiber reinforced concrete alternative would have been a better solution for this foundation. The steel fiber reinforced alternative leads to a slimmer construction, easier implementation and better working conditions due to a smaller amount of reinforcing work. Financially, the steel fiber reinforced alternative is cheaper and leads to a shorter construction time.</p>

<p>The degree thesis is based on an architecture competition where the community had decided on producing residential buildings on the district <em>V</em><em>ä</em><em>stra kajen</em>. The community of Jönköping wanted to build two types of residents; one part was going to have residents with right of tenancy, were the company <em>V</em><em>ä</em><em>tterHem</em> is going to administrate. The other part of the residential was going to be tenant-ownership were the administrator is going to be <em>Riksbyggen</em>. The line of argument in the thesis is the design process of doing a proposal that would meet the requirements of the competition and of the companies'. Other requirements that also had to be considerate on the proposal were the adjustment with the existing environment and that it had to be appealable to society.</p><p>Question that assumes in the thesis and trying to be explained through the reading of the chapters is; "How the area is affected of the external conditions. How a residential yard and construction is going to be designed to get the best possible light- and view-alternative, and to get good internal planning. How the design is on the wining proposal. What are the energy requirement, and the other requirements; what kind of conditions does the area have".</p><p>Observation of the location has been carry out where analyzes has been made on wind-, sun-, vegetation-, traffic- and topographic conditions. Some researches has been done on the history of the city which is describe on this thesis and also different point of views of <em>Statsbyggnadvisionen</em>[1] has been explained; which also includes <em>Ramprogrammet</em>¹.</p><p> </p><p>Similar projects have been analyzed to get a bigger perspective on good internal planning and good resolutions on residential buildings with similar conditions. These analyzes have been used and reflected on the design of the project on <em>Västra kajen</em>, which is describe on following chapters. The reference projects have been chosen from three levels which the writers of this thesis choose to name; the community level, the national level and the international level. The objects are <em>Östra kajen</em> in Jönköping, <em>Henriksdalshamnen</em> in the <em>area Hammarbysjöstad</em> in Stockholm and the living area <em>Fyrholm</em> in Kobenhaven, Denmark. The analyses can be found in chapter 4.4.</p><p>After the analyzing phase a proposal on the living space on <em>Västra kajen</em> is designed, this design proposal is illustrated in chapter 4.5, where volume, internal planning, the residential yard and material etc is presented. During the whole design process there was a contact with the company <em>Riksbyggen</em> and Invar Selse that was the functionary of the competition, which also is presented in the chapter. The end of the thesis is base on a description of the winning proposal, where a comparison between the proposal of this thesis and the winning one is done.</p><p> </p><p>[1] Is a document from the community of Jönköping that describe the city planning and future vision of the city</p> / Formgivartävling

<p>Upplands Väsby municipality has a vision that podcars in the future will become an effective alternative in public transport, with reduced car-dependency as a result. The system would also attract new inhabitants and businesses to the municipality.</p><p>This report deals with various issues that podcar stations may face. Also, suggestions for possible track laying at the stations and station design are presented. Two areas are investigated. Eds allé which is a neighborhood that is planned for housing and where the station may be planned into the cityscape from the start. As well as the area around the center, Fyrkanten, where the station needs to interfere with existing buildings and traffic.</p><p>The proposed station in Eds allé is placed over the pavement, about three meters above ground. A station design inspired by nature is proposed, with grass-covered roof and large glass sections. Two platform areas would be enough to cover the station's capacity.</p><p>It is proposed that the Fyrkanten station is situated outside the shopping mall’s west entrance, and built in a contemporary style. Since the station is placed amongst other traffic, it needs to allow approximately 5 meters clearance. Three platforms provide sufficient capacity.</p><p>The station in Eds allé needs to closely attune to nature and environmental design, whereas the station in Fyrkanten can have a tougher design. That is the main difference between the stations in Eds allé and Fyrkanten.</p>

<p>Förstudien är det första steget i projekteringsfasen, där det ges förslag på åtgärder. I Vägverkets arbete med åtgärder tas det fram förstudier, för att se vilka problemen är och vilka åtgärder som kan tänkas vara möjliga. Den här rapporten kommer att granska arbetet med förstudier. Under arbetets gång har vi använt oss av litteraturstudier, intervjuer samt en enkät. Arbetet inleds med att beskriva vad en förstudie är samt hur arbetet går till i teorin. Sedan följer en empirisk del, där berättas det om de intervjuer som gjorts och där presenteras även resultatet av enkäten. Efter det analyseras resultaten från den empiriska delen, och i de sista kapitlen diskuteras problem och förändringar. Först kommer en beskrivning kring hur arbetet med förstudier fungerar idag, och sedan ges förslag på hur arbetet kan förändras. Som ett exempel kan nämnas ett av de problem som finns idag. Det är hur de behandlar ekonomin, i många fall är redovisningen bristfällig. De som läser förstudien får inte veta hur kostnaderna har räknats fram. Den förändring vi kom fram till är att problemet kan lösas om det finns mer dokumentation kring arbetet som görs innan en förstudie påbörjas. Detta skulle öka tydligheten och ge en ökad förståelse.</p>

<p>En av orsakerna till att det inte byggs fler passivhus i Sverige är de ökade kostnaderna. I detta examensarbete genomförs en grundlig jämförelse mellan fyra olika passivhusprojekt och konventionella projekt. Jämförelsen görs kring de olika processerna i projektet: projektering, byggande och förvaltning. Den största vikten är lagd kring byggandet där byggnadsdelarna, grund, vägg och tak, jämförs med konventionellt byggande, för att få fram särkostnader för passivhus. Denna information ska förhoppningsvis underlätta för beställaren.</p><p>I den teorietiska bakgrunden ges en grundläggande presentation av litteraturstudierna om passivhus, dess historia, krav, kostnader, m.m. Den största delen av examensarbetet bygger på intervjuer med plastchefer och arbetsledare från fyra olika passivhusprojekt. Detta presenteras i fyra olika praktikfall där informationen från intervjun indelas i projektering, byggande och förvaltning samt en kostnadsdel som har stor vikt i examensarbetet. Programmet BidCon användes för att få fram uppgifter om tid, material- och totalkostnader kring klimatskalet i praktikfallen. Detta sammanställdes i en modell som skapades för att ge en överskådlig bild över praktikfallen.</p><p>Dessa praktikfall analyserades och sammanställdes till en modell med samma syfte som de övriga i varje praktikfall. Resultatet blev att ett antal slutsatser kunde dras utifrån särkostnader kring projektering och byggande men några rimliga slutsatser kunde inte dras vid förvaltning.</p>

<h1>Sammanfattning</h1><p> </p><p>Byggbranschen som sådan har över lång tid visat sig vara en mycket konservativ bransch. Gamla beprövade metoder och konstruktionslösningar tenderar att väljas före det som kan anses som nytt och oprövat. Under senare år har dock ett stigande energipris samt den globala uppvärmningen drivit utvecklingen i en riktning där energieffektiva byggnader efterfrågas i allt större omfattning. Detta medför en efterfrågan för nya material och byggnadssätt som kan ersätta eller komplettera de mer traditionella.</p><p> </p><p>Ett för i Sverige förhållandevis nytt byggnadssätt är att uppföra byggnader med Structural Insulated Panels SIPS. Dessa är konstruktionselement som används för både väggar och tak. De består av en yttre beklädnad av OSB-skivor mellan vilka det finns ett isolermaterial, vanligen bestående av någon typ av cellplast eller liknade. Vägg- och takblocken saknar således de stående reglar och takstolar som finns i traditionella konstruktioner utan bärförmågan utgörs av materialens samverkan sinsemellan.</p><p> </p><p>Ursprungligen kommer denna byggnadsteknik från USA där de första försöken att använda denna teknik startade redan på 1930-talet. Det är dock först under senare år som SIPS fått ett större genomslag på marknaden i USA. I Sverige används än så länge tekniken ej i någon större omfattning. SIPS förtillverkas vanligen i fabrik och levereras sedan färdiga för montering till byggplatsen.</p><p> </p><p>Det som undersöks i denna rapport är SIPS-elementens lastupptagande förmåga då de används på tak. Frågeställningen är då hur mycket last de kan uppta per m² utan att den nedböjning som då sker skall bli för stor. De metoder som använts för att undersöka detta är huvudsakligen enklare deformationsberäkningar samt jämförelser mellan framräknade resultat och de laster som kan tänkas förekomma på ett tak i form av egentyngder och snölast. Resultaten visar att spännvidder upp till 5-6 m kan anses vara rimliga att använda, beroende av elementens tjocklek, takets form och var byggnaden är belägen.</p><p> </p><p>Det utförs även i rapporten en utredning om vad för slags brandteknisk klass dessa SIPS-element kan tänkas tillhöra. Detta utförs utan någon som helst provning vilket bör påpekas måste utföras av ackrediterad instans för att resultaten skall vara giltiga. Resultaten och diskussionerna kring SIPS-elementens brandklass är mer en jämförelse mellan traditionella konstruktioner med generella godkännanden och ett teoretiskt resonemang kring hur resultatet bör bli om ett brandprov genomförs. Metoden för att utreda detta har till största del varit litteraturstudier, då främst Boverkets skrifter BBR, BKR samt byggvägledningar. Även de olika materialens egenskaper har undersökts, främst genom studier av olika tillverkares hemsidor. Resultaten visar att klassen REI 15 kan ett SIPS-element antas ha om det är isolerat med polyuretanskum. Denna brandtekniska klass uppfyller de krav som ställs i BBR när det gäller småhus. När det gäller flerbostad hus och liknande byggnader där kraven ställs högre kan det anses svårare att uppfylla kraven.</p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p>Det som i första hand avgör SIPS-elementens brandtekniska klasstillhörighet är dess förmåga att bibehålla sin bärförmåga då de utsätts för brand. Denna beror till största del av vid vilken temperatur materialen i konstruktionen inte längre kan anses vara sammanbundna med varandra. Det vill säga när den vidhäftning som finns mellan isolermaterialet och OSB-skivorna upphör att existera. Det är således inte i det avseendet av störst betydelse huruvida isolermaterialet är brännbart eller ej utan vilken temperaturbeständighet det har. Enligt detta resonemang kan eventuellt SIPS-elementet skyddas genom att det bekläds med ett antal lager gipsskivor. En sådan åtgärd kan enligt fört resonemang om möjligt placera konstruktionen i klass REI 30 vilket då innebär att konstruktionen i fråga kan användas i vissa byggnader där kraven enligt BBR ställs högre beträffande brandteknisk klass.</p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><h1> </h1><h1> </h1><h1> </h1> / <h1>Abstract</h1><p> </p><p>The construction industry as it is has for a long time proven itself to be a very conservative trade. Proven methods and materials from the past have a tendency to be chosen instead of those who can be referred to as new and unproven. However, during the last few years the increased cost for energy and the global warming have pushed the acceptance of new construction materials and solutions when more energy efficient buildings are requested. This brings out an increased need for new materials and ways to construct buildings, which can replace or complement the more traditional ways to build.</p><p> </p><p>One for in Sweden relatively new construction method is to construct buildings with Structural Insulated Panels SIPS. These elements of construction which can be used for constructing both walls and roofs are made out of an outer skin of OSB-boards which are in between isolated by a core of cellular plastic of some sort. The wall and roof panels do not have those joists that a traditional framework has. The result is that the amount of heat leakage through wooden lumber are minimized compared to a traditional construction.</p><p> </p><p>This building technique has its origin in the USA where the first basic tries to use the SIPS-technique begun in the 1930s. However it's not until recent years that SIPS has made a bigger breakthrough on the market in the USA. The SIPS are usually prefabricated and delivered ready for assembly to the construction site.</p><p> </p><p>What is to be investigated in this report is the SIPS ability to withstand load when they are used as roof-elements. In this case it is the amount of load (kN/m²) the element can withstand before the deflection gets to big. The methods being used for this is mainly simple calculations of deflection and comparisons between calculated results and those loads that in theory could work on a roof in shape of dead load and load caused by snow. The results show that spans between 5-6 meters could be considered reasonably to use, though slightly depending on thickness of the SIPS-element, shape of roof and where the building is located, taking into account the  potential load caused by snow.</p><p> </p><p>In the report an investigation of which rating of fire performance these SIPS could belong to is also made. This is performed without any technical fire tests which should be pointed out must be carried out by a certified test laboratory to make the results valid. The results and discussions concerning the SIPS should be regarded as a comparison between traditional constructions that have a general approval and a theoretical reasoning about the outcome of a full scale fire test performed on SIPS. The method being used for this has mainly been studies of literature, mainly the regulations and recommendations that can be found in the documents produced by the Swedish Board of Construction (Boverket), The characteristics of the included materials in SIPS has been investigated mainly by visiting the manufactures web pages. Results show that a rating of fire performance could be claimed to be REI 15 for a SIPS which have an isolating core consisting of polyurethane foam. This rating fulfils the fire resistance standards according to single family homes and such. Although where standards are set higher, such as for apartment buildings and similar the standards could be considered tougher to meet.</p><p> </p><p> </p><p> </p><p>What mainly decides what type of fire resistance rating SIPS could be given is its ability to keep its load bearing capacity when exposed to fire. This ability mainly depends on at which temperature the materials in the SIPS-element no longer can be expected to be bound together. It is of less importance by these means if the isolation material could burn or not, it's more a question of at which temperature the element will delaminate and then lose its load bearing capacity. According to this a possible way of protecting the SIPS from heat could be to apply a number of gypsum boards to the inside of the element. This could possibly raise the rating up to REI 30. This enables that the SIPS could possibly be used in some buildings where standards according to Swedish building regulations are set slightly higher than those set for single family homes.</p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p>

<p>Slipforming is a construction method that has been used in several decades for production of concrete structures. It is a wide range of different structures that are slipformed, but typical are vertical structures such as towers, bridge columns and offshore platforms. Slipforming are not only used for straight vertical concrete structures, but also on structures where the geometry of the structure and the wall thickness is changed. Slipforming is normally a continuous working operation (24 hours a day), which require a well-planned supply of materials. Problems that occur during this process needs to be solved instantly. Slipforming is a rather complicated operation compared to other construction techniques. The requirements to the materials, personnel and the execution of the work are therefore accordingly higher.</p><p>Slipforming of concrete structures has in most cases been carried out successfully with no or only minor supplementary work. However, in some cases, surface damages have occurred during slipforming. Typical surface damages are lifting cracks and vertical lined damages caused by lumps formed on the slipform panel. These problems have during recent years caused discussion and partly also scepticism to slipforming as a reliable construction technique. The Norwegian Public Roads Administration has recommended in Publication 77 that some concrete structures should not be slipformed depending on the environmental impact at the location, geometric degree of difficulties of the concrete structure and the type of concrete. Also in other countries there are scepticism to slipforming as a construction technique.</p><p>The prime objective of the research program is to improve the understanding of the slipform technique as a construction method in order to ensure high quality concrete structures. The objective is to identify the parameters affecting the net lifting stress (friction) that occur during lifting of the slipform panel. Focus is given to the importance of the concrete properties that will influence the forces that occur between the slipform panel and the concrete. Also any connection between the friction level and the surface damages is investigated. Based on the result it should be possible to define requirements for materials, mix composition and method of execution to ensure that the specified quality in the structure is obtained.</p><p>The lifting stress can be divided in static lifting stress and sliding lifting stress, where the static lifting stress represents the friction that has to be overcome in order to start sliding and the sliding lifting stress is the minimum friction that occurs during sliding. The difference between the static and sliding lifting stress is caused by the decreasing effective pressure during lifting at the sliding zone and the adhesion that occurs because of no movement of the slipform panel between two lifts. Both static and sliding lifting stress are closely related, but the static lifting stress can be extremely large compared to the sliding lifting stress.</p><p>The friction law can be used to describe the correlation between the net lifting stress and the effective pressure. This correlation is almost linear and applicable for both the net static and sliding lifting stress. The effective pressure, which represents the pressure between the solid particles and the slipform panel, is the difference between the normal pressure (concrete pressure against the slipform panel) and the pore water pressure. It is primarily the pressure in the pore water that is responsible for most of the variation in the effective pressure during the plastic phase and the transition period, which means that it is mainly the variation in the pore water pressure that controls the level of the lifting stress. The pore water pressure is decreasing slightly in early phase because of the settlement in the concrete. During the elastic phase, the pore water pressure start to decrease faster as an effect of the chemical shrinkage that occurs because of the cement reaction.</p><p>The pore water pressure development can be characterised by the decrease rate of the pore water pressure and the minimum pore water pressure. The minimum pore water pressure is defined as the pore water pressure at the time of maximum lifting stress. The minimum pore water pressure occurs just before the pressure is increasing at the sliding zone close to the slipform panel. It is primarily the level of the minimum pore water pressure that will decide the maximum level of the static and sliding lifting stress. The pore water pressure decrease rate and the minimum pore water pressure depends on the particle concentration and particle size distribution for the finer particles and also the air content in the concrete. Higher particle concentration and finer particle size distribution will both result in a faster pore water pressure decrease rate and a lower minimum pore water pressure. A higher air content will reduce the effect from the chemical shrinkage because the existing air volume will act as a pressure release volume, resulting in a lower pore water pressure decrease rate and a higher minimum pore water pressure.</p><p>Also the compaction method will have an impact on the decrease rate of the pore water pressure and the minimum pore water pressure, because the air content will be reduced with prolonged vibration time. Prolonged vibration will in general result in a higher lifting stress, depending on the response on the concrete during vibration. When lightweight aggregate is used in the concrete, the entrapped air in the lightweight aggregate will increase the pore water pressure and result in a lower lifting stress. Porous lightweight aggregate will have larger impact on the pore water pressure than denser lightweight aggregate.</p><p>Pressure gradients that occur between two concrete layers will affect the decrease rate of the pore water pressure. Water will “flow” from layers with younger concrete without any negative pressure to concrete layers with lower pore water pressure. This will reduce the decrease rate in the concrete layer that receives the water. In later stage the same concrete that supplied the concrete layer below with water will receive water from the concrete layer above. The pressure gradient at the joint (between two concrete layers) will be more even as a result of the water communications between the concrete layers. Evaporation of water from a fresh concrete surface will result in a faster decrease rate and a lower minimum pore water pressure because of the drying process will form menisci near the surface. The water communication is in general good in the concrete in this phase.</p><p>The time at which the minimum pore water pressure occurs will also have an impact on the minimum pressure level. A shorter period of time from the minimum pore water pressure occur to the time of initial set will result in a relatively higher minimum pore water pressure and a lower lifting stress. The minimum pore water pressure has occurred earlier when water has evaporated from an exposed concrete surface. Also when very rough slipform panel is used, the incipient vacuum between the slipform panel and the concrete is punctured early (collapse of the capillary system at the sliding zone) because of the rough panel surface and will result in a relative low lifting stress.</p><p>Both the lifting frequency and the lifting height has a considerable effect on the static lifting stress. Lower lifting height or decreased lifting frequency will both result in a lower pore water pressure and a higher static lifting stress. This is probably because the interface zone is disturbed each time the slipform panel is lifted. Less disturbance of the interface will result in a lower minimum pore water pressure. The lifting stress is decreasing during lifting as an effect of the decreasing effective pressure at the sliding zone and the reduced adhesion. The effective pressure at the sliding zone is probably at minimum and the adhesion is completely broken when the lifting stress is stabilized on a minimum level. The sliding lifting stress is also affected of the lifting frequency and the lifting height if not the minimum level is reached during the lift.</p><p>Surface damages caused by high lifting stress are not demonstrated in the vertical slipform rig. However, similar concrete mix design that has been used in a field project, where surface damages occurred, has been tested in the vertical slipform rig. The concrete mix in this field project was replaced with a new concrete mix, where no or only minor surface damages occurred after the replacement. Both concrete mixes is tested in the vertical slipform rig and the result show a considerable higher static and sliding lifting stress for the concrete mix that was used when surface damages occurred. This indicates that there are a connection between high lifting stress and risk for surface damages. This means also that concrete mixes that obtains high lifting stress in the vertical slipform rig is more exposed to surface damages than concrete mixes that has obtained lower lifting stress.</p>