Fire Resistance Test of Cross Laminated Timber Joints

• Main Author: Cato, Oliver
• Format: Bachelor Thesis
• Language: English
• Published: Luleå tekniska universitet, Byggkonstruktion och brand 2022
• Subjects: CLT; Joints; Fire; resistance; Korslaminerat; trä; skarvar; Brand; motstånd; Construction Management; Byggproduktion; Luleå
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-93666

The increased popularity of timber buildings has heightened the demand for more knowledge on how tomake these buildings safer. In many cases, parts of wooden constructions are prebuilt in factories that later are delivered to the building site. Transportation by road limits the sizes of the parts. When the structural timber parts arrive on site, they are ultimately assembled into the building. Some of these smaller parts, specifically cross-laminated timber (CLT) floor boards, create joints when connected together. The EI criteria of these joints will be examined in this bachelor thesis. The purpose is to show the requirements to satisfy the EI criteria for CLT joints and evaluate different types of joints with the help of screening tests using the fire furnace at Luleå tekniska universitet (LTU). While doing so also collect more information and become more familiar with the material and engineering methods used. Previous evaluations of joints have shown that it is essential that they are fully airtight for them to meet the EI criterion. However, this was with different types of structural timber, combined with different core joints and thicknesses of floor boards. Results have shown various viable CLT joints, airtight and semi-airtight, that met the EI-90 criteria and other non-viable joints that explored non-airtight solutions with a twist. The method, results and other observations during testing were analysed and discussed to assess their feasibility and the impact some error sources may have had. The conclusion is that all joints met the EI-criteria. While straight joints have a lot of smoke emissions, the temperature at the top of the joint do not exceed critical temperatures for the gap sizes in this thesis.