T3 Minneapolis – 7 storey Mass Timber Office

By Lucas Epp,
Engineering + 3D Manager
Tags:  nlt-panels

Tall Wood

Tall Wood construction in North America has taken a new turn with T3 Minneapolis (timber, technology, transportation). This will be the first modern tall wood building to be built in the USA, led by the developer Hines with their vision for a new type of sustainable construction.

Designed by Michael Green Architecture and DLR Group along with engineer MKA, this new office building's seven stories and 220,000 square feet of mixed retail and office space will have a strong draw on local investors and the tech and creative tenant due to the warmth of wood and the embrace of green construction techniques and materials. The bottom concrete level is set aside for both retail space and a tenant amenity centre which includes fitness, social workspace, and bike parking. Above it is six stories of pure wood office space.

Looking for efficient structural solutions and quick erection times to meet a fall 2016 opening, Hines and Kraus Anderson Construction have engaged StructureCraft to work as design-assist builder for the timber structure. Our love for pushing the edge in timber construction has led us to create new connection ideas, erection methodologies, and carry out full scale testing for this project - in pursuit of creating the most efficient structure possible. We have a vision for perfecting this new system of building with wood and are eager for new opportunities to apply our ideas.

There are many options for mass timber floor systems – CLT, GLT, and NLT panel systems were all candidates for the floor and roof panels which span the glulam post and beam framework. The teams' decision to go with NLT ( nail-laminated timber) was formed on a number of factors including aesthetics, structural advantages, lower cost, and faster procurement times.

Our crews will be on site November 2015.

Tall Wood Technologies

Mass timber construction is a new take on the traditional post-and-beam heavy timber structures built 100 years ago. Using timber in a panel format allows concrete or steel composite slabs to be replaced with prefabricated wood slabs (with concrete topping as applicable).

Why Wood? The question has been posed by many in North America over the last 30 years, and the necessary answers of economy, weight, speed of construction, aesthetics, and sustainability have now been proven on many different projects across the world.

Tall Wood Benefits

Speed of Construction – a 30,000sqft floor plate erected in as little as a week.

Construction Cost – within a few percent of a steel structure, all factors considered (including no fire-proofing necessary for mass wood).

Sustainability – 3200T of carbon sequestered in the timber frame of a building the size of T3.

Aesthetics – the structure of the building can remain exposed, yielding an environment increasingly attractive to modern tenants.

Weight – 30% lighter than an equivalent steel building and 60% lighter than an equivalent P/T concrete building. This reduces foundation size and in particular seismic loads.

Fire – mass timber chars during a fire, forming a natural self-protection layer. Under the heavy timber designation, mass timber panels do not need fire proofing, removing the need for intumescent paint and often dropped ceilings.

Tall Wood Challenges

With initiatives like the USDA's $2M funding for the Tall Wood Building Competition and the similar earlier competition led by the Canadian Wood Council, the impetus for building tall with timber is now well known. However industry unfamiliarity means that well established supply chains are often not in place, and engineers and architects are sometimes less aware of the possibilities of designing with wood. The incorporation of CLT into the 2015 IBC as well as CSA O86-2014 has meant that AHJs across North America are beginning to accept mass timber. NLT has been recognized in building codes since the early 1900s, however is only now being used as part of efficient prefabricated assemblies.

Suppliers now have ICC rated assemblies for penetrations, and much testing has been carried out to establish the fire, acoustic, and thermal performance of mass timber floor and wall buildups.

The Future

We are seeing a new demand for mass timber structures. Our company goal is to help bring these structures to reality across North America. The 19th Century was the age of steel, the 20th of concrete; this century is the new age of timber.

Licensed in numerous states and provinces, our engineers come alongside base building engineers and architects, and assist with designing cost efficient yet beautiful timber structures. Getting involved early in the project development allows us to give input not only on timber engineering and connection design, but also on constructability, erection sequencing, and, if engaged early enough, on product choice. We work with all the different mass timber products (and complimentary materials such as steel and concrete), using the right material in the right place, and have close relationships with Glulam and CLT manufacturers across North America and in Europe. Our field teams are highly skilled timber erectors, having installed nearly 1M sqft of mass timber in the last seven years. We are also well-versed in building systems, and assist architects and building services engineers in understanding implications for the building as a whole.

Our business model allows us to be nimble, serving virtually any jurisdiction by tapping into local material resources, yet organizing all the planning, engineering, and 3D skills necessary to deliver high quality timber structures across the globe.

More Info