Design for demontering og ombruk av trekonstruksjoner

Abstract

This master’s thesis addresses the environmental challenges of the construction industry, which is responsible for approximately 37 % of global energy- and process-related CO2 emissions. The sector also consumes large quantities of non-renewable resources and generates a significant share of national waste. To meet sustainability goals and transition toward a circular economy, there is a growing need for solutions that enable reuse of materials and components in buildings.

The thesis investigates design for deconstruction and reuse (DfDR) in cross laminated timber (CLT) and glued laminated timber (glulam) bearing structures. This study is based on a case study of the Stabbursmoen school project, provided by general contractor Backe. With information from BN3 and Backe, this study provides the research question: How does the implementation of demountable connections affect cost, material usage, and future reuse of CLT and glulam structures compared to conventional design in school buildings?

The theoretical background includes timber properties, engineered wood systems, mechanical fasteners, relevant regulations and standards (TEK17, PBL and ISO 20887), and both traditional and sustainability-focused design criteria. The methodology involves analysis of the existing timber structure and its connection system, followed by a cost evaluation of both conventional and DfDR alternatives. A reuse value analysis is also conducted, assessing material loss due to non-reversible joints and estimating future reuse scenarios.

The results indicate that introducing demountable connections increases the structural cost compared to conventional design. Material usage remains unchanged due to applied assumptions. However, the adoption of demountable connections significantly enhances the potential for disassembly and reuse of timber components in future projects.