Environmental
Crucial to early momentum for the 80 M project, Toth highlights the willingness of the contractor to explore a newer to market building material at that time—working diligently to price and source materials, adapt the construction schedule and process, and collaborating with structural engineers—as the start of what would become a groundbreaking process. Also crucial to this process was gaining regulatory approval for the building’s exposed mass timber elements. The version of the International Building Code (IBC) adopted in most US jurisdictions including Washington DC caps the height of timber buildings at 85-feet, a height they hoped to exceed with the 80 M project and limits the amount of timber that can remain exposed within the interior. To gain approval for the project, Arup’s integrated team of mass timber experts, working closely with Hickok Cole and the DC permitting agency, had to demonstrate that the proposed solutions fulfilled current fire and life safety code requirements as well as aligned with the standards of the 2021 IBC to allow mass timber buildings of up to 12-stories. Both before and after the successful design and completion of the 80 M project, Arup has been involved in advocating for mass timber as a sustainable design material while actively pushing it throughout the region. Their teams have been involved with not only the design of mass timber structures, but also around the research and testing that enables the expansion of building codes. However, while mass timber is a great sustainable option that provides an aesthetic appeal that helps attract clients to its use, Farnsworth points out that it isn’t the ultimate solution for all buildings. He believes there also needs to be significant progress in using other materials more sustainably, such as steel and concrete. Pointing to an abundance of steel from scrap and recycled sources throughout the developed world, recycled steel could be a strong
sustainable building material as we develop things like electric arc furnaces powered by renewable energy resources. However, when it comes to developing sustainable building materials for the future, Farnsworth believes concrete should be the highest priority. This means a focus on things like developing low carbon concrete and working to get higher cement replacement ratios built into owner’s requirements. Farnsworth points to a number of different client organizations, particularly in the federal sector, that still have high cement content requirements, and that this needs to change as solutions around low carbon concrete are studied and deployed. Even industry standard solutions, which many engineers just take for granted, should be questioned. For example, lightweight concrete on metal decks is a standard solution in the US for office projects given perceived benefits for fire rating and reduced weight. Most engineers don’t yet realize that lightweight concrete has a significantly higher carbon footprint than normal weight concrete and more optimal solutions are possible from a carbon perspective. Arup has recently focused efforts on studies to assess the impact on embodied carbon of various slabs on metal deck options to challenge the status quo once carbon is part of the equation. While there is an almost unanimous sentiment across the AEC industry that we should be pushing forward in all aspects of sustainability—as well as no shortage of carbon neutrality agreements and pledges—there is, perhaps understandably, little consensus on how change should be best enacted. Change is often a piecemeal process, but the act of committing to enacting it is the first step in solving the challenges of the future. As the AEC industry looks to continue shaping the built environment in a way that answers the challenges of climate change, firms like Arup are exemplary of this commitment to change.
34 Fall 2024
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