By Luke Carothers
As the AEC industry continues to prepare for and respond to the effects of climate change, many firms are turning to alternative building materials that will be a catalyst for building a decarbonized future. One of the firms pushing this view of the near future is DIALOG. A multi-discipline design firm that incorporates architects, urban planners, interior designers, and landscape architects as well as mechanical, structural, and electrical engineers, DIALOG has adopted the AIA 2030 Commitment to make all projects carbon neutral by 2030. As a part of this commitment, DIALOG is in part focusing on how we can achieve the ambitious goal of decarbonization while sustaining the vertical urbanization that is taking place all over the world.
DIALOG has recently developed a Hybrid Timber Flooring System (HTFS) as one measure towards decarbonized vertical expansion. The HTFS is part of DIALOG’s Hybrid Timber Tower Prototype, which is intended to demonstrate that tall buildings can be a catalyst for the future. Crafted by DIALOG’s research and development team, the Hybrid Timber Tower Prototype suggests that building zero-carbon tall buildings is a viable option for the future. Seeing the immediate application of the HTFS for their client base, DIALOG chose to develop this aspect of the tower first and is currently pursuing a patent for the HTFS.
DIALOG’s HTFS combines cross-laminated timber panels with steel and concrete. The HTFS system can also incorporate other smart building technologies such as photovoltaic, algae bioreactors, or other renewable energy solutions, which would allow a tower as tall as 105 stories to achieve carbon neutrality. The HTFS system is made with post-tensioned steel cables encased in concrete bands and embedded into cross laminated timber (CLT) panels. This system allows for a 40 foot column-free span, while standard CLT design systems currently span just three-quarters of that distance.
Starting from the floor up is more than just a phrase. Typically, floor plates comprise approximately 70 percent of building materials used in high rise projects according to Craig Applegath, AIA, a founding partner at DIALOG and one of the project’s key leaders. This means that, when employed, the HTFS can drastically reduce a project’s carbon footprint. When further incorporated with renewable energy solutions, this system significantly reduces the environmental impact of tall building development in high density urban areas.
Traditionally, concrete and steel are used in the construction of tall buildings due to code and safety requirements. However, because of the massive carbon footprint of these materials through the manufacturing and installation processes, there is a drastic need to develop alternative materials for these projects. Studies estimate that buildings in both the US and UK are responsible for up to 40 percent of annual CO2 emissions. Using sustainably harvested wood will drastically reduce these carbon emissions, locking up carbon for decades. Planting young trees to replace those that have been harvested would continue to remove carbon from the atmosphere.
Furthermore, the HTFS system helps developers and builders save money, open more of the calendar year to construction, and reduce safety and environmental risks onsite through prefabrication. Panels up to 10 feet by 40 feet are processed in a controlled environment, which means structural integrity can be tested and verified. CLT is bonded with reinforced concrete and high tensile steel, then the panels are delivered to the construction site ready to install.
In the United States as in the UK, one of the biggest challenges facing the implementation of timber hybrid buildings is code enforcement. In recent years, there has been an increase in small and medium sized buildings using timber, but this has not yet been seen for large, high-rise buildings. These larger and taller buildings are limited in their use of timber due to structural, fire, and cost considerations. Once patented and approved by local authorities, the HFTS offers a potential solution to these problems.
The HTFS is poised to make a significant contribution to the environmental goals of the AEC industry. Recently named one of Fast Company’s 2021 “World Changing Ideas” in the architecture category, HTFS represents a significant building block towards the ultimate goal of carbon neutrality. While the world population continues to grow, these building blocks are foundational to ensuring that we can reduce our carbon footprint while continuing to develop high density urban buildings.
Luke Carothers is the Editor for Civil + Structural Engineer Media. If you want us to cover your project or want to feature your own article, he can be reached at firstname.lastname@example.org.