The European standard Eurocode 5, a design method for timber structures,is currently under revision. In this study the draft for a reviseddesign method for vibrations in timber floors was compared to the currentmethod. The hypothesis of the thesis was that the revised designmethod might force some changes to the present construction practiceand that these changes may carry with them increased costs for the industry.Six common floor structures used in Sweden today were identifiedand for these floors design calculations were made according to the currentand the revised design method. It was checked whether the floorspassed the criteria in the two design methods and a comparison was madefor the only criterion which could be compared between the methods, thepoint load deflection. Floor structures could pass or fail the current designmethod based on two criteria, the point load deflection and the unitimpulse velocity response. All floors passed the current design methodexcept one which had a fundamental frequency below 8 Hz, because ofthe low frequency the current design method was not applicable to thefloor structure. In the revised design method the final result is a responsefactor and based on the response factor floors are given floor performancelevels. The seven step scale for the floor performance level go from I toVII where I is excellent and VII is unacceptable. All floor structures excepttwo achieved an acceptable floor performance level according to therevised design method. The two floors which failed were floors commonlyused in single family houses, they failed for a span length commonly usedtoday. A limited parametric study was performed where it was found thatthe modal mass used had a larger impact on the floor performance levelthan the mass per square meter included. For floors with a fundamentalfrequency above 8 Hz, including a higher mass per square meter resultedin a lower, i.e. better, response factor in all cases except one. For floorswith a fundamental frequency between 4.5 and 8 Hz, a higher mass resultedin a higher, i.e. worse, response factor. The study found that notall floor structures used in Sweden today are acceptable according to therevised design method therefore changes may have to be implemented andthese changes could result in an increased cost.

The purpose of this Master Thesis is to study how the value stream mapping concept can be applied along the construction supply chain for prefabricated massive timber floor elements. Identification and qualification of waste are starting points to propose suggestions on how to reduce and/or eliminate them. In order to use the value stream mapping along the construction supply chain, pertinent data has been collected and analyzed. To conduct the value stream mapping, the first three steps of the lean thinking principles in construction have been followed. The first step aims at defining the customer and his value as well as the value for the delivery team and how it is specified in the product. The second step is based on identifying the value stream and this is done through defining the resources and activities needed to manufacture, deliver and install the floor elements. This is conducted by using the VSMM methodology. In addition the current practice should be standardized and key component suppliers should be defined and located. The third and last step identifies non-value adding activities, in other words waste and suggestions on how to remove and/or reduce waste have been reached. Wastes from product defects, transportation waste and waste of waiting were to be found in the construction supply chain. Propositions to reduce and/or eliminate wastes were to implement a more careful planning of the manufacturing process and production schedule, to apply lean production principles in the manufacturing facility and decrease and or eliminate storage time. The study made has shown that in the supply chain of massive timber floor elements at Limnologen there is a big potential to lower costs and increase customer value as value added-time accounted for only 2% of the total time.

<p>The purpose of this Master Thesis is to study how the value stream mapping concept can be applied along the construction supply chain for prefabricated massive timber floor elements. Identification and qualification of waste are starting points to propose suggestions on how to reduce and/or eliminate them. In order to use the value stream mapping along the construction supply chain, pertinent data has been collected and analyzed. To conduct the value stream mapping, the first three steps of the lean thinking principles in construction have been followed. The first step aims at defining the customer and his value as well as the value for the delivery team and how it is specified in the product. The second step is based on identifying the value stream and this is done through defining the resources and activities needed to manufacture, deliver and install the floor elements. This is conducted by using the VSMM methodology. In addition the current practice should be standardized and key component suppliers should be defined and located. The third and last step identifies non-value adding activities, in other words waste and suggestions on how to remove and/or reduce waste have been reached. Wastes from product defects, transportation waste and waste of waiting were to be found in the construction supply chain. Propositions to reduce and/or eliminate wastes were to implement a more careful planning of the manufacturing process and production schedule, to apply lean production principles in the manufacturing facility and decrease and or eliminate storage time. The study made has shown that in the supply chain of massive timber floor elements at Limnologen there is a big potential to lower costs and increase customer value as value added-time accounted for only 2% of the total time.</p>

Springiness and vibrations of timber floors are familiar to many as a ‘live’ feelwhen walking on them, especially if living in single family housing with timberframework. Since the building regulations in Sweden changed to performancedependentrequirements in 1994 the use of timber in multifamily housing hasincreased. New timber building systems have been developed and increasedbearing capacity of floors has made it possible to build with longer spans. Thelow mass of timber floors makes them more sensitive to dynamic loading byhuman activities, such as walking, running and jumping, compared to heavyfloors e.g. concrete floors. To improve vibration performance it is possible tochange the structural properties of the floors by increasing mass, stiffness ordamping properties. The most practicable solution is to increase the stiffness.Improved damping is also highly effective, but is difficult estimate and designaccurately since it originates from many sources in the finished building. In thepresent thesis the effects on dynamic properties from increased stiffnesstransverse to the load bearing direction of a floor have been assessed from testsin laboratory. The effect on dynamic performance of a timber floor fromelastic/damping interlayers (polyurethane elastomers) installed in the junctionsbetween walls and floors have been assessed in laboratory and in situ. Also thechange in dynamic properties of an in situ floor has been investigated atdifferent stages of construction and compared with results from laboratory tests.The present criteria for design of timber floors with respect to vibrationperformance were developed at a time when timber floors were mainly used insingle-family housing. The traditional timber joist floors differ in structuralbehaviour from the new types of floors developed recently. The experiencedvibration annoyance by residents in single- and multifamily housing differs asthe source of vibration disturbance and those who become disturbed aredifferent. The changed conditions give cause for a review of present designcriteria. A laboratory and field study on vibration performance was conductedwith questionnaires and dynamic performance measurements. The subjectiveand objective results were correlated and indicators for vibration acceptabilityand annoyance were assessed and new vibration performance criteria andvibration performance classes were suggested.

In spring 2023, two engineering students from Jönköping University collaborated with GBJ Bygg Jönköping to investigate the impact of moisture on cross-laminated timber (CLT) and its drying process. The study aimed to identify potential issues, damages, and propose mitigation methods. Through measurements and investigations, this study generated in-depth knowledge of moisture effects on CLT, ensuring proper material handling to avoid long-term negative consequences.The methodology involved quantitative investigations to obtain credible results. Experiments simulated the application of wet macadam on a CLT floor slab in a natural environment to measure time to reach an acceptable moisture content. Collaboration with GBJ Bygg provided access to information, materials, and simulation facilities. Two tests were conducted: immediate construction after placing washed macadam and a 9-day drying period before reconstruction. Results showed that direct macadam application led to high timber moisture content, while drying according to industry recommendations resulted in low moisture content without negative consequences. The drying process varied depending on reconstruction timing, and methods like extending macadam drying time were proposed to reduce damages and shorten the drying period.The discussion of results demonstrated data relevance with limited room for misinterpretation. However, the study's time frame limited complete results, and the lack of prior research on timber drying affected connections to previous studies. The clearest answer came from the 9-day drying test, showing a decrease in moisture content. Some measured values deviated, possibly due to measurement errors. Facility climate and construction execution posed potential error sources. Despite limitations, the experiment effectively addressed the study's purpose and research questions.

Denna rapport utreder möjligheterna att använda restprodukter som ljudisolering i lägenhetsskiljande mellanbjälklag av trä med spännvidd 6 m. Ett steg mot att uppfylla Sveriges byggindustris nollvision för koldioxidutsläpp är att bygga mer i trä och att återanvända/återvinna restprodukter. Det svenska entreprenadföretaget Skanska har vid sina krossanläggningar ett överskott av material i form av bergkross 0 - 0,2 mm och krossad restbetong. I denna rapport har en prototyp av ett träbjälklag tagits fram med influenser från byggtekniken från sekelskiftet 1800–1900 med avseende på nyttjandet av tung fyllningsmassa som ljudisolering i träbjälklag. Den framtagna bjälklagsprototypen uppfyller de krav som ställts i BBR efter dimensionering enligt Eurokoderna med hänsyn till brand, hållfasthet, svikt och nedböjning. Enligt en simulering i SEAWood, ett verktyg för akustiksimulering som är under utveckling vid RISE Research Institutes of Sweden, uppfylls även kraven på ljudisolering, detta stöds av de analyser som gjorts av mätresultat från liknande bjälklag. Fyllningsmaterialets höga vikt medför att prototypen är ett lågfrekvent bjälklag, detta kombinerat med att simuleringen endast är en indikation på ljudisoleringsegenskaper gör att det kommer krävas praktiska tester för att fastställa prototypens ljudisolerande och dynamiska egenskaper. Den framtagna bjälklagsprototypen är lämplig att prefabricera tack vare en konstruktion med få ingående delar. Att prefabricera bjälklaget har utöver de ekonomiska fördelar det medför stora fördelar ur ett arbetsmiljöperspektiv och är även fördelaktigt ur fuktsynpunkt. För att uppskatta bjälklagets miljöpåverkan gjordes en enklare jämförelse med ett prefabricerat betongbjälklag som visade att utsläppen av koldioxidekvivalenter fram till bruksfasen var mer än dubbelt så stor för betongbjälklaget än för prototypbjälklaget. / This report investigates the possibilities of using residual products as sound insulation in apartment separating timber floors with a span of 6 m. One step towards meeting the Swedish construction industry's zero vision for carbon dioxide emissions is to build more using timber and to reuse/recycle residual products. The Swedish building contractor Skanska has at its quarries a surplus of material in the form of crushed rock of the 0 - 0.2 mm fraction and crushed residual concrete. In this report, a prototype of a timber floor has been produced with influences of construction technology from the turn of the 19 th century regarding the use of heavy filling as sound insulation in timber floors. The developed floor prototype complies with the requirements set in BBR after dimensioning according the Eurocodes regarding fire safety, strength, sagging and deflection. According to a simulation in SEAWood, a tool for acoustic simulation which is under development at RISE Research Institutes of Sweden the requirements for sound insulation are also met, which is supported by analyzes made by comparing with data on similar timber floors. The high mass of the filling material implies that the prototype is a low frequency floor, this in conjunction with the simulation only being an indication of sound insulation properties, it will require practical tests to determine the prototypes sound insulating and dynamic properties. The developed floor prototype is suitable for prefabrication thanks to a design with few components. Prefabrication of the floor has in addition to the economic benefits it brings great benefits from a working environment perspective and is also beneficial from a moisture point of view. To estimate the environmental impact of the timber flooring, a simple comparison was made with a prefabricated concrete floor which showed that carbon dioxide emissions up to the using phase were more than twice that of the concrete floor than for the prototype floor.