Är korslaminerat trä ett bra alternativ för påbyggnader? Studiens syfte är att utreda hur väl påbyggnader i CLT står sig som alternativ i konkurrens med andra metoder att ta fram nya bostäder inom tätort där ett behov av förtätning finns. Studien riktar sig till en eventuell byggherre och i första hand till uppdragsgivaren: AB Gotlandshem. Kvartert Höken 1 är uppfört i början på 1960-talet. De aktuella byggnaderna för en eventuell påbyggnad är tre hus om två våningsplan och källare. Dessa byggnader benämns: B, D och F. Bärande väggar i stommen är uppförda i varierande material. I studien har två väggar valts ut som särkilt intressanta. De undersöks närmare genom statiska beräkningar enligt EKS 9. Studien konstaterar att de har tillräcklig tryckhållfashet för att bära en påbyggnad. Studien undersöker även ekonomiska förutsättningar för en påbyggnad i CLT. Detta görs genom att särkostnader identifieras och jämförs. Givetvis är kostnaden för materialet en särkostnad när valet står mellan två material, men studien identifierar även produktionskostnader för montering av bjälklag och installationer som särkostnader. Den ekonomiska jämförelsen indikerar en möjlighet att göra en besparing vid ett val av CLT-bjälklag. Studien visar att det är möjligt att utföra en påbyggnad av hus B, D och F i kv. Höken 1. Dessutom visar det sig att CLT är ett gott alternativ ur ekonomisk synpunkt. Materialet har fördelar som medför rationell produktion. Det innebär att CLT kan vara en billigare lösning för en påbyggnad. / Is cross laminated timber a suitable building material for adding storeys to a building? The purpose of this study is to examine how good an alternative CLT makes in comparision with other methods of developing new homes in urban areas. This study aims to a property developer and primarily to the client: AB Gotlandshem. The block Höken 1 was built in the beginning of the 1960s. The buildings of current interest are three houses with two stories and basement. These buildings are designated: B, D and F. The load bearing structure is constructed in varying materials. Two walls has been selected as especially interesting. They are examined closer through static analysis accordnig to EKS 9. The study concludes that they are sturdy enough to carry an added storey. The study also examines the ecomonic premises for adding a storey made from CLT. Separate costs are identified and compared. Naturally is the materials cost a separate cost in the choice between two different materials, but the study also identifies costs for mounting subfloor construction and installations as separate costs. The economic comparision indicates a possibility to cut costs by choosing subfloor constructins of CLT. The study shows that it is possible to add a storey to house B, D and F. Furthermore is CLT a good alternative from an economic viewpoint. The material has advantages that results in rational production methods. From this follows that CLT may be a cheaper solution for adding a storey.

No description available.

Cross-laminated timber (CLT) is an emerging engineered wood product in North America. Past research effort to establish the behaviour of CLT under extreme loading conditions has focussed CLT slabs with idealized simply-supported boundary conditions. Connections between the wall and the floor systems above and below are critical to fully describing the overall behaviour of CLT structures when subjected to blast loads. The current study investigates the effects of “realistic” boundary conditions on the behaviour of cross-laminated timber walls when subjected to simulated out-of-plane blast loads. The methodology followed in the current research consists of experimental and analytical components. The experimental component was conducted in the Blast Research Laboratory at the University of Ottawa, where shock waves were applied to the specimens. Configurations with seismic detailing were considered, in order to evaluate whether existing structures that have adequate capacities to resist high seismic loads would also be capable of resisting a blast load with reasonable damage. In addition, typical connections used in construction to resist gravity and lateral loads, as well as connections designed specifically to resist a given blast load were investigated. The results indicate that the detailing of the connections appears to significantly affect the behaviour of the CLT slab. Typical detailing for platform construction where long screws connect the floor slab to the wall in end grain performed poorly and experienced brittle failure through splitting in the perpendicular to grain direction in the CLT. Bearing type connections generally behaved well and yielding in the fasteners and/or angles brackets meant that a significant portion of the energy was dissipated there reducing the energy imparted on the CLT slab significantly. Hence less displacement and thereby damage was observed in the slab. The study also concluded that using simplified tools such as single-degree-of-freedom (SDOF) models together with current available material models for CLT is not sufficient to adequately describe the behaviour and estimate the damage. More testing and development of models with higher fidelity are required in order to develop robust tools for the design of CLT element subjected to blast loading.

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This research is inserted in the topic of timber buildings. Many construction systems are available for building using timber, with the two main systems in residential ambit being Cross Laminated Timber and Light Timber Frame. Both systems reckon on the presence of shear walls to bear the effects of horizontal loads like seismic events or wind. This thesis deals with timber shear walls, and is divided into two parts: the first part is related to the ultimate and serviceability limit states rules to be included in upcoming versions of the building codes, while the second part presents a novel use of CLT walls as seismic renovation for existing buildings, as part of a European project. The first part of the thesis, which is presented in three papers, is closely related to the process of producing new building codes, and aims at an easier integration between research and codification. The initial focus is the behaviour of Cross Laminated Timber subjected to in-plane loading. Eurocode 5 currently lacks a part concerning this product and the discussion is still ongoing regarding the methods for stresses evaluation and on the strength values to adopt for safety verifications. The first paper tackles this problem by analysing different calculation methods currently available for the evaluation of the in-plane shear stresses, a common notation is introduced in order to have a meaningful comparison between methods proposed by different authors. All methods are then applied to a real case of existing experimental data regarding a four point bending test of CLT beams. Stiffness and strength of CLT are essential parameters for the definition of models to be adopted in codes regarding timber buildings, in particular for the calculation of shear walls. Another very common timber construction system is called Light Timber Frame: an assembly comprising a timber frame and an external sheathing layer mechanically joined to the frame. Consequently LTF walls are considered, the study is directed towards shear wall models for the evaluation of deformations. The second paper focuses on the evaluation of the displacement at the top of LTF walls subjected to horizontal loads. This is a key aspect for designers, since the limitation of deformations ensures that the building retains a satisfactory performance at serviceability limit states. The displacement is due to many different contributions, with the sheathing-to-framing deformation being one of the major ones. The paper presents a comparison between two of the proposed methods to calculate the sheathing-to-framing deformation of LTF shear walls. The influence of the nail slip contribution on the overall displacement of the top of the wall is studied also with parametric analyses, by varying both mechanical properties and geometrical dimensions. Comparison with existing experimental data is also provided. The study on shear walls regards also their lateral capacity, as well as the comparison between LTF and CLT walls of equal aspect ratio and similar restraining. In the third paper, existing cyclic test data on LTF and CLT walls were used to study the different displacement contributions and estimate the influence of the hold-down on the lateral response of the walls. A simplified capacity model is proposed for the walls, based solely on the hold-down forces. The second part of the thesis deals with the use of CLT shear walls as a mean for the retrofit of existing buildings. The need for sustainable renovation solutions and improvement of the performance of existing buildings is at the base of the European project e-Safe. The project presents a multidisciplinary approach on building renovation, from mechanical, energetic, technological and architectural point of view. In this thesis the focus is on the seismic retrofit system called e-CLT: a CLT panel is attached to the outside of existing buildings with a novel connector that acts as a friction dissipation device, thus offering additional energy dissipation in case of strong earthquakes. The fourth paper presents the first experimental campaign on this novel friction connector. Different geometries for the connector are studied and optimised, before being tested under cyclic protocol. The connector is tested on a steel setup, in order to isolate the friction behaviour and study the stability of the hysteresis loops. The results permitted to acquire new information useful for further developments on the system. The fifth paper presents a subsequent experimental campaign on the friction connector. The shape is changed and improved in light of the previous results. The setup is improved and includes also a screw connection between friction connector and CLT panel. The goal is to study the influence of the timber connection on the friction dissipative performance. An analytical model is proposed, fitted on the experimental data.

This project aims to investigate a sustainable approach to housing construction by utilizing CLT (Cross-Laminated Timber) as a fundamental structural element. Emphasizing the significance of pedestrian and bicycle accessibility, this aspect was integrated into the design proposal. The housing units are designed to cater to the varying needs of prospective residents, offering 1, 2, and 4 rok options. As Slakthusområdet undergoes a transformation into a vibrant district within the city, the proposal places great emphasis on sustainability and promoting a healthy lifestyle. The overall design and shape of the proposed buildings were heavily influenced by both the existing and planned architectural fabric of the surrounding structures.

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Det har av olika anledningar blivit mer populärt att bygga flervåningshus i trä vilket har lett till en utveckling av material i trä. Korslimmat trä även kallat KL-trä är en konsekvens av denna utveckling i Sverige och precis som för andra stommaterial används datorprogram för att rita hus i KL-trä. Syftet med denna rapport är att få lärdom om KL-trä samt undersöka hur programmet FEM-Design kan användas för att dimensionera ett flervåningshus i KL-trä. Därtill, har FEM-Design också använts för att räkna materialmängden för att kunna göra en klimatdeklaration, för båda materialen betong och trä. Resultatet av klimatdeklarationen visar att träbyggnaden får ett lägre utsläpp i byggskedet jämfört med betongbyggnaden i byggskedet, men Boverkets databas som har använts i denna rapport är något konservativ. Värdena i Boverkets databas i framför allt skede A1-A3 avviker något jämfört med EPD:er (miljövarudeklaration) från olika företag inom betongindustrin. KL-träbyggnaden är lättare än betongbyggnaden vilket gör att betongfundamenten till träbyggnaden borde kunna göras mindre för att klara av lasterna jämfört med betong. Däremot får träbyggnaden något tjockare bjälklag för att klara av ljud-, brand- och brukskraven som då medför en lägre rumshöjd om inte förändring görs av den totala byggnadshöjden. För att uppnå samma rumshöjd på 2,6 m i betongbyggnaden skulle det krävas att träbyggnaden byggs 1,2 m högre vilket leder till större materialåtgång. / For various reasons, it has become more popular to build multi-storey houses in wood, which has led to the development of materials in wood. Cross laminated timber also called CLT is a consequence of this development in Sweden and just like other frame materials, computer programs are used to draw houses in CLT. The aim of this report is to get knowledge of CLT and investigate how the software FEM-Design can be used to design a multi-storey building in CLT. In addition, FEM-Design has also been used to calculate the amount of material necessary to make a climate declaration, for both materials concrete and wood. The result based on the climate declaration shows that the wooden building has a lower emission in the construction phase compared with the concrete building, but the National Board of Housing, Building and Planning's database that has been used in this report is somewhat conservative. The values in the National Board of Housing, Building and Planning's database, primarily in stages A1-A3, differ slightly compared with EPDs (environmental product declaration) from different companies in the concrete industry. The CLT building is lighter than the concrete building, which means that the concrete foundations for the wooden building may be made smaller to handle the loads compared to concrete. On the other hand, the wooden building gets a slightly thicker floor to cope with the sound, fire and use requirements, which then results in a lower room height if the total height of the building still is the same. In order to achieve the same room height of 2.6 m in the concrete building, it would be required that the wooden building be built 1.2 m higher, which leads to greater material consumption.

From the inception of high rise construction concrete and steel have been the foundation both literally and figuratively of the construction process. As we, a society, become more aware and conscious of the environmental impacts of our built environment we must ask ourselves, are our current construction practices the best or are there ways that we can not only become more environmentally cognizant, but also more efficient in our construction of buildings. This project is an investigation of how a joint can help to improve the construction process and manifest itself into creating the tectonic nature of a project by using timber in high rise construction. / Master of Architecture