T3 Minneapolis Mass Timber Office Building
T3 Minneapolis was the largest modern mass timber building in the USA at completion, and the 180,000 sqft timber superstructure was installed in only 9.5 weeks.With the successful launch of T3 Minneapolis (timber, technology, transportation), tall wood construction in North America continues to reach new heights. Replacing traditional structural systems such as concrete and steel, prefabricated solid wood panels, such as Nail-Laminated Timber panels, create a construction method which is fast, clean, and sustainable–not to mention aesthetically pleasing.
StructureCraft was chosen as timber engineer-builder, for efficient structural solutions, low-cost, and quick erection/delivery time. We were also the Engineer of Record for the timber superstructure.
Mass Timber Design
Designed by Michael Green Architecture and DLR Group, this mass timber building's seven stories and 220,000 square feet of mixed retail and office space has a strong draw on local investors and the tech and creative tenants 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.
NLT was chosen over CLT, GLT, etc. because of structural advantages, lower cost, and faster procurement times
Our Role for This Mass Timber Structure
Looking for efficient structural solutions and quick erection times to meet a fall 2016 opening, Hines and Kraus Anderson Construction engaged StructureCraft to work as engineer-builder for the timber structure. StructureCraft was Engineer of Record for the timber structure, working closely with MKA as the base building EOR.
As engineers, our love for pushing the edge in timber construction 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 mass timber 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.
As builders, our role involved the engineering, procurement, fabrication, and installation of the timber superstructure leading to installation of 180,000sqft of timber in 9.5 weeks.
See the following sections for more details on the fabrication and installation.
Mass Timber System
There were 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 structural advantages, lower cost, and faster procurement times.
In order to maximize the fabrication and erection process, we fabricated the NLT panels in a shop in Winnipeg and shipped them to Minneapolis - several hours to the south.
We arranged with a European supplier to ship the glulam members - CNC'd and ready for the steel connection plates - to Winnipeg. Here, we pre-installed all steel connection members to allow for JIT delivery and immediate erection on site.
Mass Timber Construction (installation)
- Mass timber structures are 30% lighter than steel equivalent; 60% lighter than equivalent post-tensioned concrete building = smaller foundation, lower seismic loads
- Close to cost of steel structure – no extra fireproofing necessary due to the charring performance of heavy timber
- 30,000 sqft floor plates were erected in one week
- Approximately 3,600 cubic metres of wood are used in the structure, which will sequester about 3,200 tonnes of carbon for the life of the building
- Over 1100 8'x20' NLT (Nail-Laminated Timber) panels were used, the equivalent square footage of nine hockey rinks.
We also attached a GoPro to an NLT Panel as it is flying into place.