Cross Laminated Timber (CLT) Analysis

Supervisor: Frank Lam
Researcher: Yue Chen

Introduction

Cross Laminated Timber (CLT), which is made by laminating dimension lumber at right angles, is an innovative high-performance building material that offers many positive attributes including renewability, high structural stability, storage of carbon during the building life, good fire resistance, possibility of material recycling and reuse.  It is conceptually a sustainable and cost effective structural timber solution that can compete with concrete in non-residential and multi-family mid-rise building market.  Therefore, there is a need to understand and quantify the environmental attribute of this building system in the context of North American resources, manufacturing technology, energy constraints, building types, and construction practice.  This study is to compare energy consumption of two building designs using different materials, i.e. CLT and concrete.

Method

The designs are based on a five-storey office building, Discovery Place-Building 12, which is located in Burnaby, British Columbia, at 4200 Canada Way.  The existing building was built with reinforced concrete.  The first step was to redesign the structure using CLT and glulam system in accordance with CSA Standard O86, Engineering Design in Wood.  Embodied energy was calculated based on the total amount of material required for each of the building systems.  Operational energy was calculated using eQUEST, an energy usage modeling software tool.  The environmental impacts of the buildings were evaluated by comparing the total energy consumption through the building life.

Results

CLT has lower non-renewable energy consumption compared to concrete in terms of material acquisition, manufacturing and transportation.  Previous studies show that operational energy accounts for the main amount of total energy use in buildings during their service life.  Hence, the importance of embodied energy increases by reducing operational energy consumption.  CLT has lower embodied energy compared to concrete.  Therefore, the advantage of using CLT as a construction material is becoming greater by designing low energy or passive buildings.

Conclusions

Both embodied and operational energy were calculated for a five-storey office building built with different materials, i.e. CLT and concrete.  Over the building life period, wood embodies and consumes less energy compared to concrete.  This study will provide a deep insight of the environmental advantages of CLT and lay a solid foundation for creating better and more sustainable buildings in the future.

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Comparison of Environmental Performance of a Five-storey Building Built with Cross Laminated Timber and Concrete, Yue Chen 2012