A milestone in mass timber construction

Milwaukee's Ascent becomes the tallest mass timber building in the world

Author

Trip Edwards
February 02, 2024

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Ascent at dusk, courtesy of Korb + Associates Architects.

Headline: Milwaukee building breaks records in mass timber construction.

So What: Milwaukee's Ascent, a 25-story mass timber hybrid structure, now stands as the tallest mass timber building in the world at 284 feet, edging past Norway’s Mjøstårnet tower at 18 stories, 280 feet. Overcoming regulatory challenges and leaning on creative problem solving on the structural engineering side, the project showcases the growing influence of mass timber in high-rise construction, setting a precedent for the blossoming, sustainability-conscious material.

Structural schematic, courtesy of Thornton Tomasetti.

Under the Surface: Designed by Korb + Associates Architects and developed by New Land Enterprises, Ascent faced a number of regulatory hurdles that tested the resolve of Thornton Tomasetti’s structural engineers. For starters, the 25-story (originally 18) planned height well surpassed the traditional, code-prescribed maximum timber structure height limit of 5 stories, 85 feet. With structural engineering and testing from Thornton Tomasetti, the Ascent team and other stakeholders found a way to obtain the variances they needed. With a performance-based design approach anchored on the International Building Code’s Section 104.11, the designers were permitted to propose unconventional or unusual systems for approval, provided that they pass relevant testing and intended purpose requirements. After months of research and design and materials testing, including an extensive series of fire-proofing tests, the project successfully navigated the approval process, obtaining multiple variances and a unique fire rating system.

Ascent Build Technical Animation

Technical Animation of the Ascent Build Model Garry Clarke, courtesy of Thornton Tomasetti.

vimeo.com/488603314/b0543cf9eb

Other notable mass timber projects include:

  • Mjøstårnet - completed in 2019 in Brumunddal, Norway. 18 stories, 280 feet tall, mixed use (office, apartments, retail, and a hotel).

  • HoHo Wein - completed in 2019 in Vienna, Austria. 24 stories, 276 feet tall, mixed use (office, apartments, retail, and a hotel).

  • HAUT - completed in 2022 in Amsterdam, Netherlands. 21 stories, 240 feet tall, apartment building.

  • Sara Kulturhus - completed in 2021 in Skellefteå, Sweden. 20 stories, 239 feet tall, currently home to City Library, Anna Nordlander Museum, Västerbotten Regional Theatre, and Skellefteå Art Gallery, as well as The Wood Hotel.

  • C Gerald Lucey Building - completed in 2022 in Brockton, Massachusetts, 3 stories, the first publicly-funded mass timber project of commercial scale.

Machines I wish I owned

Amphibious Sherp takes an ice bath.

Net, Net: Ascent's structural efficiency, optimized through extensive load testing and innovative design, highlights the economic viability of mass timber in high-rise construction. The project's success in overcoming regulatory challenges and its positive impact on construction schedules set a new standard for the potential of mass timber in creating environmentally friendly and commercially viable tall buildings.

Go Deeper with ASCE’s coverage here.

The Industry Scoop

  • A dozen (UK) construction firms going bust every day: Construction in the UK is facing a crisis, with one in six business failures attributed to the industry, totaling 4,370 insolvencies in the year ending November 2023, according to Mazars. Specialized construction activities, including demolition and electrical work, accounted for 58% of failures. The sector's insolvencies have consistently surpassed other industries for three years, reflecting a challenging environment marked by rising costs and delayed payments. (Source: Construction Enquirer)

  • Land in many coastal cities is sinking faster than sea levels are rising: Rising sea levels threaten coastal cities, but land subsidence is exacerbating the problem, with many cities sinking faster than sea levels are rising, according to research by scientists at the University of Rhode Island Graduate School of Oceanography and the U.S. Geological Survey. Cities in South, Southeast, and East Asia are experiencing the most rapid subsidence rates, with Jakarta, Indonesia, sinking due to groundwater extraction, prompting the country to relocate its capital. The study emphasizes the importance of accounting for subsidence in planning for the impacts of rising sea levels. (Source: The Conversation)

  • The best way to manage wastewater debris infiltration and inflow: The study, "Reducing Infiltration and Inflow in Small Collection Systems: Environmental, Economic, and Additional Impacts," conducted by researchers Andrew Hansen, Susan Moussavi, and Bruce Dvorak, uses life-cycle assessment (LCA) to analyze the environmental and economic impacts of infiltration and inflow (I&I) mitigation projects in wastewater treatment facilities. The research, published in the Journal of Environmental Engineering, highlights the benefits of I&I mitigation in reducing environmental impacts, operational energy, and water pollutant emissions, as well as improving wet weather resilience and reducing maintenance for existing facilities serving small communities. (Source: Civil Engineering Source, Technical Notes)

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