The 80 M Street SE (80 M) is the first commercial office building in Washington DC to feature a vertical extension constructed using mass timber. The 108,000ft2 addition, designed by Hickok Cole and Arup, adds three full floors to the existing 7-story concrete building, including a penthouse level with additional office and amenity spaces and a rooftop terrace. Arup provided a full suite of design services for the project, located in DC’s Navy Yard neighborhood, across from the Metro station.
While there has been a renaissance in tall timber construction throughout Europe and the UK over the past decade, high-rise mass timber has been slower to take off in the US, partly due to restrictive code requirements. Versions of the International Building Code (IBC) adopted in most US jurisdictions, including DC, cap the height of timber buildings at 85 feet—a height exceeded by 80 M.
To gain approval for 80 M’s exposed mass timber overbuild, Arup’s integrated team of mass timber experts worked closely with Hickok Cole and the DC code authority to demonstrate that our proposed solutions fulfilled current fire and life safety code requirements and aligned with the standards of the 2021 IBC, which will allow mass timber buildings of up to 12 stories.
Opened in September 2022, the project is the first high-rise overbuild timber structure in North America.
1st tall timber office addition in Washington DC
108,000ft²addition to existing building
Sustainable biophilic design: The advantages of mass timber
Mass timber is steadily gaining traction in the US market as more developers and designers recognize the cache and commercial potential of sustainably sourced and built projects and more states and municipalities seek new ways to cut carbon emissions in the building sector. As a renewable material, timber carries a significantly lower carbon footprint than conventional building materials, like concrete and steel. There is also a growing consumer demand for biophilic-inspired designs that take health and wellness into consideration by maximizing the occupant’s connection to nature.
Columbia Property Trust, the developer behind 80 M, was quick to embrace the mass timber solution proposed by Hickok Cole and Arup. Both highly sustainable and aesthetically appealing, the exposed mass timber design differentiates 80 M from standard Class A office buildings in the competitive Navy Yard commercial area. Moreover, mass timber’s lighter weight enabled the client to maximize the vertical build while minimizing structural strengthening interventions to areas outside of tenant spaces, saving capital and allowing the building to remain fully operational during construction.
Modernizing mass timber code requirements
Arup is a recognized leader in mass timber design and construction. Our experts are collaborating with fire research institutes across the world to improve our understanding of how the new generation of multi-story timber buildings will behave in a real fire, so that designers and regulators can identify risks and devise solutions that meet or, in many cases, exceed existing code requirements. We also advise suppliers on testing procedures to ensure certified solutions, and undertake fire testing for project-specific solutions, including on 80 M.
Featuring mass timber
As the first mass timber structure in Washington DC to exceed 85ft, Hickok Cole’s design had to be carefully vetted by the DC code authority before earning approval. The structure’s connections were a critical focus. Due to the lack of fire-tested connections on the market, Arup’s structural and fire engineers developed new concepts for 80 M’s two-hour rated exposed timber connections. These connection concepts were further designed and tested by Katerra, the timber design-assist partner, with help from the Arup team. Once it was clear that the connections and redundant systems proposed for the building delivered a high level of safety, Arup demonstrated the design’s viability and safety to the code authority, ultimately helping 80M to win approval.
Mass timber’s appeal lays not just in its unparalleled sustainability, but also in its beauty. Thanks to the local DC authority’s willingness to work with us to review and approve robust solutions outside of prescriptive requirements for tall timber buildings, 80 M is the first building in Washington DC to feature exposed timber above 85 feet. We are proud to have worked with Hickok Cole on a project that showcases mass timber’s many benefits. ” Lauren Wingo Senior Structural Engineer
Solar photovoltaic (PV) array: Cost/benefit analysis and procurement strategy
As part of the project review process, the building owner chose to include a solar photovoltaic (PV) array on the roof of 80 M, in alignment with the ambitions of the local zoning board. Arup was able to help the client fulfill this request by rapidly performing a feasibility study, including a cost benefit analysis. The analysis found that the savings garnered through local and federal tax incentives, the solar renewable energy credit, and utility cost savings, brought the time horizon for return on investment down from 16 years to four years. Our engineers and consultants also leveraged their knowledge of the local market and permitting department, available technology, and procurement timelines to help Columbia Property Trust develop an owner request for proposal and to evaluate bids.
The Arup Journal 2022 Issue 2
Learn more about this project in the Arup Journal. Applying a gender lens to sustainable transport system design, mass timber construction in the USA, and mitigating the impact of climate change on coastal areas – discover more in the Arup Journal.Download