At 284ft and 25 storeys, Ascent is the tallest mass timber building in the world.

As the forest product state’s biggest city, Milwaukee was the perfect location to showcase tall-timber innovation. Ascent now leads awareness in the US of the fire safety and viability of mass timber structures. It provides 410,000 ft2 of residential, retail and amenity spaces, with concrete construction for the first six floors and 19 floors of mass timber construction. The aesthetic appeal of mass timber, coupled with its low-carbon footprint, has been driving steady traction in the US market.

Arup provided façade engineering and fire safety engineering consulting services for the building. The lack of building code for mass timber buildings over six floors in Milwaukee presented a clear obstacle for Ascent. We worked closely with the Department of Neighbourhood Services’ commercial-building code variance committee to drive the project forward through an unprecedented approvals process.

Our extensive analysis demonstrated that the tower would comply with safety requirements and provided the client with strategies to mitigate fire-related risks. We are a recognised leader in mass timber design and construction, and Ascent demonstrates our commitment to forging pathways to a more sustainable future.

Navigating the mass timber approvals process

Our fire safety expertise with mass timber construction design, modelling and detailing was key to obtaining the city’s approval. Our analysis method proved the safety of the partly exposed mass timber structure. The building design was supported by three-hour fire resistance tests for glulam columns, which historically are only tested for two-hour ratings.

For the building façade, we carried out in-depth condensation studies to develop effective strategies for the building’s owners to manage the challenge of condensation in cold-climate residential buildings.