Framework was one of the first tall buildings designed in timber to receive approval for construction in the USA. The project by LEVER Architecture resolved many technical challenges associated with the material.

Most wood buildings are low-rise. Timber, when used in taller buildings, is generally limited to interior fit-outs. The raw material, or products made from it, are often imported from afar.

Framework, however, would be a 12-storey, 40-meter tall structure sited in Portland, Oregon, a place where locally sourced timber is abundant. It would use timber extensively across different elements, including structure.

Framework promised to alter buildings in Portland, Oregon, in terms of how they are built and experienced.
© LEVER Architecture, Holcim Foundation for Sustainable Construction

Framework was supported by a US$1.5 million award from the U.S. Tall Wood Building Prize Competition. This paid for the costs of testing and peer reviews, deemed necessary to undertake research.

The mixed-use design combined retail and public exhibition on the ground floor with five levels of office space and 60 units of affordable housing above.

Framework’s target tenants were corporations seeking high standards of social and environmental performance. The housing segment would serve individuals earning below 60% of the Area Median Income.

The ground floor of Framework, dubbed “Tall Wood Exhibit”, was designed to highlight its connection to nature by showcasing the use of timber.
© LEVER Architecture, Holcim Foundation for Sustainable Construction

The experience of nature continues vertically in the apartments, which have views and natural light.
© LEVER Architecture, Holcim Foundation for Sustainable Construction

Testing the limits of construction

The project’s use of timber included elements of structure and envelope, in addition to interior fit-outs. The sole exception was the foundation, made of concrete.

The building deploys timber across multiple elements including its structural core but excluding the foundation.
© LEVER Architecture, Holcim Foundation for Sustainable Construction

Cross-laminated timber (CLT) was proposed for floor slabs and glue-laminated timber (Glulam) for beams and columns.

Lamination increases the compressive and tensile strength of structural elements such as columns and beams.
© LEVER Architecture, Holcim Foundation for Sustainable Construction

The structural system has a core that can sway during earthquakes and a structural frame that holds together in a seismic event.
© LEVER Architecture, Holcim Foundation for Sustainable Construction

The structure would be made of a 40-meter post-tensioned CLT ‘rocking’ wall core – made from nine-ply CLT – to ensure the building can withstand earthquake damage. This would resist the forces generated during a 2,500-year seismic event. The core was designed to sway, and then re-centre itself with no damage to the primary structural system.

The connections between floor slab, beams and columns had to be designed to bear passive and active loads.
©Holcim Foundation for Sustainable Construction

Extensive fire, structural, seismic and acoustic testings were undertaken to counter risk and address safety concerns. These tests resulted, for instance, in the first two-hour fire-rated cross-laminated timber connection.

A ripple effect on local economies

The project drew attention to local sourcing, advocating support for economies in rural communities by increasing demand. At scale, this could potentially transform regions in North America where timber is abundant and readily available.

Timber buildings have the potential to transform rural economies, such as in the state of Oregon where timber for sustainably managed forests is abundant.
© LEVER Architecture, Holcim Foundation for Sustainable Construction

In the years following Framework, several projects have emerged that rely on lessons learnt. One example, the Ascent in Milwaukee (USA) by the same architecture firm, was certified as the “tallest mass timber building in the world” in 2022.

LEVER Architecture argues that real-world projects offer a research opportunity which, in turn, can alter the wider ecosystem of practice. Tellingly, Framework has already impacted since its inception new and amended codes for mass timber construction, including the 2021 International Building Code (IBC).

The key to innovation is research which is capable to altering how buildings are made, also how codes governing construction are written.
© LEVER Architecture, Holcim Foundation for Sustainable Construction

Across the world today, timber is seeing a renaissance in the construction sector, in part because trees sequester carbon. Buildings that use the material extensively have lower carbon footprints. Timber is also deemed a biophilic material, one that enhances connections between building users and nature.

By solving technical challenges and risks, Framework has made timber a viable option for larger or taller buildings, bringing to these typologies the benefits of carbon mitigation and enhanced human wellness. The project itself, under increased financial strains, had to be put on hold in July 2018, but led the way for Oregon to become the first American state to legalise mass timer high-rises the following month.

For its innovative take on natural building material, Framework won the Acknowledgement Holcim Award 2017-18 in North America. Read more about this project on the Holcim Foundation for Sustainable Construction’s website.

Post sponsored by the Holcim Foundation for Sustainable Construction