Laminated veneer lumber floor : An evaluation of performance

Sammanfattning: The ongoing climate change has become a very discussed and accurate topic. A fifth of the Swedishemissions of greenhouse gases originate from buildings (Boverket, n.d). According to the SwedishChancellery of Wood Buildings (Sveriges Träbyggnadskansli, 2020), the environmental impact fromthe production phase of a building built in wood is significantly lower than from a similar building,but with a construction built of concrete or steel. To increase knowledge and usage of woodstructures even further than today, research and development are required. Building multiple-storedwellings with wood structures mean challenges, not least acoustic challenges - airborne soundinsulation and impact sound insulation are two parameters for slender wood structures that arecurrently limiting the building possibilities.Because of the above mentioned research and development possibilities within the field of lightweighted wood structures, this thesis aims to propose optimised dimensions of the cross-section fortwo different versions of an LVL floor element for varying span lengths. The optimisation will includeboth bearing capacity evaluations, and investigations of acoustic properties and environmentalassessment of the proposed dimensions.A literature study has been performed to address what is known today within the research field andaddress the current gaps in knowledge and identify what is important to investigate further. Thestudy shows that there is a difference in the calculated and measured acoustical performance, andexperienced acoustical performance of a wooden floor element. Further research is required to beable to match these.Furthermore, a numerical model is built, composed using the program PTC Mathcad Prime 6.0. Thebuilt model calculates the LVL floor element’s strength parameters and utilisation for differentcross-sectional dimensions where three optimised cross-sections are presented for each elementspan-length. These calculations are both performed in the ultimate limit state, ULS, and theserviceability limit state, SLS according to the Swedish and European Standard, Eurocode (EC).Also, a static energy analysis (SEA) has been performed to analyse the acoustic performances of twochosen floor elements. These analyses were performed with the program SEAWOOD whichcalculates values of impact sound insulation and airborne sound insulation of the modelled floorelement, which then is compared to the Swedish standard and sound classification. Results showthat the sound level difference between spaces fulfils class B requirements, but impact sound8insulation fulfils class C. The analysis presented is performed on an individual floor element, but tobe able to draw a conclusion about a whole building's performance, further development andanalyses of the element's joints needs to be performed.Last, an environmental assessment is performed, by summarising the values of global warmingpotential, GWP for each component of the floor element the total impact of the element iscalculated. The GWP result presented is a negative value, which is caused by the contribution of theembodied carbon in wood. This result should be seen as a good reason to pursue further research onwood constructions.