Klimatförändringar till följd av ökade utsläpp av växthusgaser är en av dom största utmaningarna som dagens samhälle står inför. Byggsektorn står för en betydande del av alla utsläpp och dessa behöver minska för att skapa ett hållbart samhälle. Syftet med studien är att undersöka om stagning av pelare leder till minskad klimatpåverkan och om effekten skiljer sig mellan olika konstruktionsmaterial. Studien använder en hallbyggnad med VKR-pelare som referensobjekt. Byggnaden dimensioneras även med limträpelare och HEA-pelare med likvärdig utnyttjandegrad för jämförelse av konstruktionsmaterialen. Pelarna dimensioneras för två fall där dom antingen är stagade eller ostagade. Klimatpåverkan beräknas under hela byggnadens livscykel med indikatorn GWP. Resultatet visar att effekten av stagning skiljer sig åt mellan dom olika konstruktionsmaterialen. Stagning av limträpelare leder inte till någon minskad klimatpåverkan, medan stagning av stålpelare minskar påverkan för båda profilerna. VKR-pelarens klimatpåverkan minskar med 4,6 procent och HEA-pelarens med 14,2 procent. Även om stålpelarna stagas är det limträpelaren som har klart lägst klimatpåverkan, och är därmed det konstruktionsmaterial som är att föredra ur ett hållbarhetsperspektiv. HEA-pelaren som är den av stålpelarna med lägst klimatpåverkan har mer än sju gånger så hög klimatpåverkan som pelaren i limträ. VKR-pelaren har i sin tur mer än dubbelt så hög klimatpåverkan som HEA-pelaren vilket belyser att även valet av stålprofil har betydelse. / Climate changes as a result of increased greenhouse gas emissions is one of the biggest challenges facing todays’s society. The construction sector accounts for a significant part of all emissions and these need to be reduced in order to create a sustainable society. The purpose of the study is to investigate whether bracing of columns leads to reduced climate impact and whether the effect differs between different construction materials. The study uses a hall building with VKR-columns as a reference object. The building is also dimensioned with glulam columns and HEA-columns with an equivalent degree of utilization for comparison of the construction materials. The columns are dimensioned for two cases where they are either braced or not. Climate impact is calculated with the indicator GWP during the building's entire life cycle. The results show that the effect of bracing differs between the different construction materials. Bracing of glulam columns does not lead to any reduced climate impact, while bracing of steel columns reduces the impact on both profiles. The climate impact of the VKR-column decreases by 4.6 percent and the HEA-column decreases by 14.2 percent. Even if the steel columns are braced, it is the glulam column that has by far the lowest climate impact and thus it is the construction material that is preferable from a sustainability perspective. The HEA column, which is the steel column with the lowest climate impact, has a climate impact which is more than seven times as high as the glulam column. The VKR columns climate impact is twice as high as the HEA column, which highlights that the choice of steel profile is also important. / <p>2022-06-22</p>

After the collapse of the roof structure in Tarfalahallen 2020, great attention has been focused on instability of sub-tensioned glulam roof trusses. Investigations were launched to find the reason for the collapse and the cause was instability in the roof truss that supported the roof. As a result, several similar glulam roof trusses in Sweden have been investigated and reinforced to avoid the fate of Tarfalahallen.Inexperience with instability, negligent design procedure and faulty assumptions is an underlying issue with this type of structure. Complex structures can be difficult to analyze without suitable assumptions which means sophisticated method must be used. Proper analysis must be done before construction.To perform this sophisticated analysis, an engineer can use the finite element method to perform global stability analysis. Simple and computationally cheap models can produce meaningful insight, but in most cases the user must be experienced to understand the implications of the results that the finite element method can produce. There is therefore a need for a more detailed, realistic model that can capture failure and motion and visualize it for the user. This thesis has created such a model in the FE-software Abaqus/Standard.By using a wide variety of elements and element sizes a detailed geometry of the connection between primary beam and compression stud, the behavior of the structural components has been analyzed throughout the loading period of the structure. The critical buckling mode was identified, and the complex non-linear interaction of the connection was tracked when buckling occurs.The thesis can be used as a guideline of how to create a FE-model that captures the intricate behavior of the connection between primary beam and compression stud and be used as the groundwork for more complex models in the future.

This report investigates the possibilities and difficulties with a courtyard floor in CLT-wood, an alternative to today’s concrete floor. The environmental issue and how to construct a sustainability construction are the main focuses. This report contains data and information from people with competence within this topic that has been collected through literatures and interviews. The main areas that will be looked up is the construction with CLT-wood and moisture damage. Since concrete can tolerate much more load, is an investigation required to find out what factors that need to be modified. A courtyard needs to be kept dry regardless of the material. However, wood doesn´t tolerate that much moisture compared to concrete and the consequences will be much more.Through researches and interviews some solutions with CLT-wood has been made. Several alternatives have been made that has a great potential to match the requirements for this kind of construction. CLT-wood and glulam will be the main focuses.Also, research about CLT-wood through a logistics perspective have been made. All those tasks from transport the material from the manufactures to assemble it on the construction site will be portrayed and then compared with the material concrete. Those tasks that are similar will then be compared through time and cost.

The objective of this research project involves determining a seismic response modification factor for three-hinge glulam Tudor arches. In an attempt to meet this objective, the methods and procedures outlined in FEMA technical document P-695 were implemented on the provided arch designs. Computational models were created using finite elements within OpenSees to accurately depict the behavior of the arch. Incremental dynamic analyses were conducted on each of the provided designs and collapse margin ratios were determined allowing performance groups to be evaluated for each of seven design R-values within two gravity load cases. With the performance groups evaluated, it was determined that only groups within the low gravity load level designs were successfully able to pass, none of the groups designed for high gravity loads passed the evaluations. Within P-695, all performance groups associated with a given design R-value must pass the evaluations for that R-value to be deemed acceptable for use in designs. Because of the implications of this requirement, a seismic response modification factor could not be determined for this type of structural system within the scope of this project. / Master of Science

Timber constructions have during the past two or three decades become more andmore common, mostly due to the easy prefabrication and the cheap, sustainablematerial. For long-span applications it is vital to find design solutions that optimizethe structure from the point of view of material consumption, number of theconnections, structural reliability etc.This thesis focuses on the structural optimization of a long span timber structureearlier developed by a Swedish glulam company for industry buildings and sport hallapplications. The main goal of this study has been the minimization of the volume ofwood required to built the structure, given a set of geometrical restrictions and theassigned loads.The optimal shape of the structure and the arrangement of the different elementshas been investigated by means of theoretical analyses taking into account theprincipal directions of stress which would occurr in similar structures with massivecross sections. The results of this investigations give some guidelines to design newtypes of structures, where both mechanical efficiency and manufacturing issues havebeen taken into consideration.Comparisons of the structural models proposed in this thesis with the originalproposal provided by the Swedish glulam company conclude the work, suggestingsome possible improvements.

Many buildings today primarily serve the purpose of being envelopes that separate theindoor climate from the outdoors, for a large open area. Examples of these buildings arehall buildings of different sorts. In climates where the snow load often exceeds the deadload, like in Sweden, it can be hard to construct a budget-friendly yet strong roof structurefor these halls, especially if a span above 40 m is required. One solution that has gained popularity is the tie rod truss. Oftentimes it is not a real truss,but rather a beam that is equipped with one or more tie rods and one or more compressionstruts. The struts, which connect to the tie rods that run from one end of the roof to theother, support the main beam. This way, the tie rods can decrease the moment load on thebeams by carrying a tensile force. However, this results in an increased compressive loadon the beams. The large compressive forces in conjunction with the often slender beamsections can lead to instability out of the truss plane, and ultimately collapse. This is whathappened to the sports hall Tarfalahallen in 2020 in Kiruna, Sweden. The tie rod truss is an important structure; it is relatively cheap, saves material and is strongin the truss plane. But the instability problems can deter its use. The aim of this study istherefore to explore the different factors that could influence the stability of the structureand to what extent, by studying critical loads and the utilization of all structural elements. The study was performed by analyzing a finite element model of a real tie rod truss thattoday exists in a sports hall in Sweden. The analyses were done for different values of many parameters. The results were then extracted and processed such that the critical load and the utilization were plotted against the tested parameter values. The analysis and results processing were performed in an automated process that the author created himself. The results show that the stability of the model is strongly influenced by (1) the rigidity ofthe joints between beams and struts, (2) the rigidity of the joints between beams and roofing material and (3) the vertical position of potential stabilization systems that actperpendicularly to the truss plane. Pretension of the tie rods had a large effect on themaximum utilization and how it varies along the beams. Any potential reinforcement measure must be cost-effective, and therefore should addressthe three influential properties above. One suggestion is to add sideway bracing as close tothe joints between the struts and beams as possible. / Det finns många hus idag som byggs i syfte att vara klimatskal för en stor, öppen yta. Exempel på sådana hus är hallbyggnader av olika slag. I länder som Sverige, där snölasten många gånger är större än egentyngden, kan ett billigt men hållfast tak vara svårt att konstruera för dessa hallar, särskilt om spännvidder över 40 m krävs. En lösning som blivit populär är den underspända takstolen. I princip är det ett par balkar som skarvats så att de bildar en sadeltakstol eller en lång rak balk (pulpettakstol), och som stöttas av mellanstöd och stållinor (dragband) som löper från den ena balkänden till den andra via mellanstöden. Stållinorna kan då avlasta balkarna från momentbelastning genom att bära en dragkraft. Men samtidigt ökar tryckkraften i balkarna. De stora tryckkrafterna, i samband med att balktvärsnitten ofta görs väldigt slanka, kan leda till instabilitet ut ur takstolsplanet och därmed kollaps. Detta skedde i Tarfalahallen i Kiruna år 2020. Den underspända takstolen är en viktig konstruktion eftersom den är relativt billig,materialbesparande och väldigt hållfast i takstolsplanet. Men instabilitetsfenomenen kanförhindra fortsatt användning av konstruktionen. Därför undersöks i detta arbete vilka faktorer som kan påverka instabiliteten och i vilken grad, genom att studera kritiska laster och utnyttjandegrader. Studien utfördes genom att analysera en finita elementmodell av en verklig underspändtakstol som idag finns i en svensk gymnastikhall. Analyserna gjordes för olika värden på ett stort antal parametrar. Utdata från finita elementprogrammet extraherades därefter och bearbetades så att utnyttjandegraden i alla ingående bärverkselement beräknades. Sedan plottades dessa resultat mot de olika parametervärdena som testats. Analyserna och påföljande bearbetning utfördes i en automatiserad process som författaren själv skapade. Resultaten visar att modellens stabilitet är starkt beroende av (1) styvheten i förbindelsenmellan balk och mellanstöd, (2) styvheten i förbindelsen mellan balk och sekundärbärverkoch (3) det vertikala läget av eventuella stabiliseringssystem som verkar vinkelrätt mottakstolsplanet. Förspänning av stållinorna hade en betydlig inverkan på den maximalautnyttjandegraden och hur denna varierar längs balkarna. Eventuella förstärkningsåtgärder måste vara kostnadseffektiva, och därmed måste dessagälla de tre egenskaperna ovan. En åtgärd som föreslås sidostagning så nära stöttornasinfästningar som det går.

Two different asphalt concrete systems were examined in this research study. The existing system, consistent with current timber bridge construction practice, uses a preformed waterproofing membrane placed on a preservative treated wood deck overlaid with a bituminous concrete wearing surface. The second system consists of a treated wood deck overlaid with a base course of bituminous concrete, a waterproofing membrane, and a bituminous concrete wearing surface. The testing regime used in this research to evaluate watertightness and bond performance incorporated three parameters: three waterproofing membranes, two wood preservative treatments, and two environmental degradation conditions induced by temperature cycling in a moisture saturated condition. Control groups were evaluated for each study parameter and duplicate specimens were prepared and tested for each of the study parameters. A total of 160 specimens were constructed and tested. Watertightness of each system was determined by measuring the electrical impedance across a test specimen perpendicular to the direction of bond orientation in the pavement. The bond strength between each material of the paving systems was assessed using a shear test apparatus designed and built for this study. In addition to the laboratory constructed specimens, three drilled cores were taken from a bridge located on Creekside Drive in East Pennsboro Township, Pennsylvania. The deck was constructed using the new design proposed in this research and each core was tested for watertightness and bond strength. Results of watertightness testing indicated that low temperature environments appear to be most detrimental to system integrity in both the existing and proposed paving system configurations examined in this research. In general, each membrane appeared to perform equally well in the proposed paving system configuration as well as with all of the wood preservative treatments used in the existing pavement system. Bond strength between asphalt and wood with no membrane was observed to be nonexistent whether or not any preservative treatment was present. The placement of a membrane between these two layers did, however, result in a significant increase in bond strength because each membrane tested was able to adhere to the wood base better than the asphalt overlay. This gain is strength was significantly offset when petroleum solvent based preservative treatments were present in the wood substrate. Protectowrap M400 membrane performed slightly better than the other membranes when used with untreated wood, but all of the membranes performed equally when preservative treatments were present. The highest interlayer bond strengths (asphalt/asphalt or asphalt/wood) observed in this research occurred when asphalt concrete surface material was placed directly on top of asphalt concrete base material, however the addition of a membrane between the asphalt lifts consistently reduced this strength. The results of bond testing indicate that the proposed system will perform better in terms of shoving in the pavement overlay. Based on bond test results of cores taken from the Creekside Drive bridge, it appears that a shear strength greater than 25 psi after 200 low temperature exposure cycles will provide acceptable paving system performance in a low temperature (0-40ºF) environment. / Master of Science

This thesis studies the relationship between the internal characteristics of the site, based on an existing set of artifacts, abandoned concrete railroad trestles, and external views of them. The project establishes orthogonal and non-orthogonal geometries in re-developing this urban site creating buildings that relate to the site, surroundings, and themselves. The physical, structural connections and spatial relationships reconcile the superimposition of geometries. Ultimately every decision in the project returns to the analysis of the site allowing for different buildings, people, and environments to interact as a single entity. / Master of Architecture

O objetivo do presente trabalho foi encontrar novas espécies para o segmento de Madeira Laminada Colada e substituir adesivos tradicionais que emitem compostos voláteis tidos na literatura como não amigáveis ao meio ambiente. Foram caracterizadas as espécies Hevea brasiliensis (Seringueira), C. maculata (Maculata) e C. lusitanica (Cupressus) e sintetizado um poliuretano à base de óleo de mamona, sem solventes e aditivos, que foi utilizado na fabricação de corpos de prova para ensaios de cisalhamento. A resistência ao cisalhamento paralela às fibras foi a variável trabalhada para caracterizar as espécies e validar o poliuretano. O processo de produção desse poliuretano iniciou-se com as sementes de mamona produzidas, seguiu na extração à frio do óleo que foi comparado com um óleo comercial e culminou na síntese do poliuretano. O óleo comercial possibilitou a obtenção do melhor poliuretano devido a sua pureza. Não foram encontradas diferenças na aplicação do poliuretano quando aplicados em uma ou nas duas faces de contato a serem unidas nos corpos de prova das três espécies, vantagem do poliuretano que representa redução de custo na MLC. O poliuretano de mamona produzido em laboratório com óleo comercial superou o adesivo resorcinolformaldeído no que se refere à resistência ao cisalhamento da madeira de Cupressus e foi similar quando comparado à Seringueira. Seringueira e Cupressus mostraram-se aptas para a produção de madeira laminada colada, superando o Maculata em termos de qualidade mecânica. / The aim of this study was to indentify new species for the segment of glued laminated timber (glulam) and replace traditional adhesives that emit volatile compounds, reported in literature taken as unfriendly to the environment. We characterized species Hevea brasiliensis (Rubberwood), C. maculata (Maculata) and C. lusitanica (Cupressus). We synthesized castor oil-based polyurethane without additives and solvents, used in shear strength tests. The shear strength parallel to grain was the worked variable to characterize and validate the polyurethane species. The manufacturing process of polyurethane started with the production of castor oil seeds, followed by cold extraction of oil, which was compared with commercial oil, and the process culminated with the polyurethane synthesis. The commercial oil provided better polyurethane due to its purity. There were no differences in the polyurethane application in one or two of the contact faces to be joined in the manufacture process for wood test specimens of the three species, one advantage of polyurethane is cost reduction of the glulam. The castor oil-based polyurethane produced in the laboratory outperformed the commercial resorcinol-formaldehyde adhesive in terms of wood shear strength tests for Cupressus and was similar when in Rubberwood. Rubberwood and Cupressus proved suitable for the production of glulam, surpassing Maculata in terms of mechanical quality.

O objetivo do presente trabalho foi encontrar novas espécies para o segmento de Madeira Laminada Colada e substituir adesivos tradicionais que emitem compostos voláteis tidos na literatura como não amigáveis ao meio ambiente. Foram caracterizadas as espécies Hevea brasiliensis (Seringueira), C. maculata (Maculata) e C. lusitanica (Cupressus) e sintetizado um poliuretano à base de óleo de mamona, sem solventes e aditivos, que foi utilizado na fabricação de corpos de prova para ensaios de cisalhamento. A resistência ao cisalhamento paralela às fibras foi a variável trabalhada para caracterizar as espécies e validar o poliuretano. O processo de produção desse poliuretano iniciou-se com as sementes de mamona produzidas, seguiu na extração à frio do óleo que foi comparado com um óleo comercial e culminou na síntese do poliuretano. O óleo comercial possibilitou a obtenção do melhor poliuretano devido a sua pureza. Não foram encontradas diferenças na aplicação do poliuretano quando aplicados em uma ou nas duas faces de contato a serem unidas nos corpos de prova das três espécies, vantagem do poliuretano que representa redução de custo na MLC. O poliuretano de mamona produzido em laboratório com óleo comercial superou o adesivo resorcinolformaldeído no que se refere à resistência ao cisalhamento da madeira de Cupressus e foi similar quando comparado à Seringueira. Seringueira e Cupressus mostraram-se aptas para a produção de madeira laminada colada, superando o Maculata em termos de qualidade mecânica. / The aim of this study was to indentify new species for the segment of glued laminated timber (glulam) and replace traditional adhesives that emit volatile compounds, reported in literature taken as unfriendly to the environment. We characterized species Hevea brasiliensis (Rubberwood), C. maculata (Maculata) and C. lusitanica (Cupressus). We synthesized castor oil-based polyurethane without additives and solvents, used in shear strength tests. The shear strength parallel to grain was the worked variable to characterize and validate the polyurethane species. The manufacturing process of polyurethane started with the production of castor oil seeds, followed by cold extraction of oil, which was compared with commercial oil, and the process culminated with the polyurethane synthesis. The commercial oil provided better polyurethane due to its purity. There were no differences in the polyurethane application in one or two of the contact faces to be joined in the manufacture process for wood test specimens of the three species, one advantage of polyurethane is cost reduction of the glulam. The castor oil-based polyurethane produced in the laboratory outperformed the commercial resorcinol-formaldehyde adhesive in terms of wood shear strength tests for Cupressus and was similar when in Rubberwood. Rubberwood and Cupressus proved suitable for the production of glulam, surpassing Maculata in terms of mechanical quality.