Environmental Life-Cycle Assessment and Life-Cycle Cost Analysis of a High-Rise Mass Timber Building: A Case Study in Pacific Northwestern United States
Global construction industry has a huge influence on world primary energy consumption, spending, and greenhouse gas (GHGs) emissions. To better understand these factors for mass timber construction, this work quantified the life cycle environmental and economic performances of a high-rise mass timber building in U.S. Pacific Northwest region through the use of life-cycle assessment (LCA) and life-cycle cost analysis (LCCA). Using the TRACI impact category method, the cradle-to-grave LCA results showed better environmental performances for the mass timber building relative to conventional concrete building, with 3153 kg CO2-eq per m2 floor area compared to 3203 CO2-eq per m2 floor area, respectively. Over 90% of GHGs emissions occur at the operational stage with a 60-year study period. The end-of-life recycling of mass timber could provide carbon offset of 364 kg CO2-eq per m2 floor that lowers the GHG emissions of the mass timber building to a total 12% lower GHGs emissions than concrete building. The LCCA results showed that mass timber building had total life cycle cost of $3976 per m2 floor area that was 9.6% higher than concrete building, driven mainly by upfront construction costs related to the mass timber material. Uncertainty analysis of mass timber product pricing provided a pathway for builders to make mass timber buildings cost competitive. The integration of LCA and LCCA on mass timber building study can contribute more information to the decision makers such as building developers and policymakers.
Project contact is Luca Sorelli at Université Laval
Summary
This project aims to develop a new prefabricated wood / concrete floor system that is innovative and competitive in multi-storey wood buildings. The design of the floor will be carried out through a multidisciplinary approach that considers the composite action of the precast floor, the integration of sound insulation, vibrations, the weight of the structure, construction time and environmental impact. Among other things, the construction method and the use of ultra high performance green composite concretes with CLT slabs or GLULAM beams will be considered. The methodology includes digital analysis tools and a new method for the design of mixed structures as well as the life cycle tool. The laboratory proof of concept will assess the performance of the optimized floor system and compare it to existing floors.
As the state of Oregon begins to introduce a new cap and trade program to reduce the effects of its greenhouse gas emissions, the state has opted not to incorporate its largest greenhouse gas emitter; the timber industry. The decline of the timber industry after the 1980’s had lasting effects on disadvantaged communities, and state politicians have battled the cap and trade bill in fear of further deterioration of the timber industry. In this paper I aim to take an in depth look at the potential that CLT has in Oregon, how it can be promoted by the government, and what the environmental effects of it are. I found that, with the rise of mass timber construction and promotion of green building, the state has the opportunity to use revenues from its cap and trade program to economically incentivize CLT construction that can provide relief to economically stressed rural logging communities, all whole bolstering its efforts to better the environmental impact of an ever expanding construction industry.
The aim of this study is to investigate the economic, environmental and technological challenges, as well as the environmental potential, of prolonging the life cycle of construction materials with focus on structural timber in Finland. To achieve this, a literature review was conducted along with interviews with actors pertinent to timber construction. Moreover, a case study of life cycle environmental impact assessment was conducted to quantify the potential of reusing timber to abate global warming and other environmental burden. The literature review highlighted the possibility of reusing structural timber, but pointed to the need for efficient and standardized assessment criteria. The interviews indicated interest towards the concept of circular economy applied to construction and demolition wood material, although this appears to be driven more by policy and regulation rather than for business reasons. Therefore, a reconfigured conceptual framework to achieve circularity for wood is proposed, where material brokers would be used to connect different actors along the value chain. The paper concludes with a case study showing that reusing structural timber components can result in a significant reduction of the environmental burden.
Project contact is Luca Sorelli at Université Laval
Summary
To minimize the built-in energy of the floor, we need to replace the current system with lighter solutions that retain the key features for robustness and maintenance, and are cost-effective and easy to build (Spadea et al., 2015). This project aims to explore innovative flooring solutions that make up a light wood load-bearing structure reinforced underneath by naturally occurring polymeric fibers (FRP) (Bencardino and Condello 2016), which work well in tension, and above an Ultra-Thin Ultra High Performance Concrete Slab (UHPC) that works exceptionally well in compression. Considering the application of very large floors in multi-storey buildings, the following key questions will be addressed: 1) what form should such a system have, 2) how will this be analyzed, and what mode of failure will be desirable? (3) what practical limitations would be imposed by constructability, (4) what would be the gain on economic cost and environmental impact from a life cycle analysis point of view, and (5) is possible to use biosourced epoxy for connections. The methodology consists of: (i) systems analysis and shape optimization using finite element numerical techniques, (ii) connection shear tests, and (iii) proof of concept on a beam prototype.
