Architects test mass timber systems for high-rise construction

Dive Brief:

Architecture firm Skidmore, Owings & Merrill (SOM) and Oregon State University released two new studies Monday evaluating a mass-timber composite and a cross-laminated timber (CLT) and concrete floor system that could be supported by structural steel, Architect Magazine reported.
According to one study, the floor system was able to function with the weight of up to seven times its design service load. Researchers found that the structure's strength would not be a limiting factor unless the wood had been charred to meet fire ratings.
The second study revealed that prefabrication could speed up construction of a steel-supported CLT building. The team notes that using a hybrid of steel, timber and concrete on projects can often be less expensive and more sustainable.

Dive Insight:

Designers of mass-timber structures in the U.S. have made inroads recently. Still, the building material has struggled to gain popularity there due to perceptions of mass-timber being flammable — and dangerous — among other things.

Supply-side challenges, for one, have made it more difficult for the mass-timber products to gain popularity in the U.S. Mill owners have expressed little interest in producing the product until there is a steady demand, but demand is unlikely to grow until material prices drop and local codes recognize the new material.

Mass-timber advocates argue that the material is resistant to fire because it chars rather than burns, protecting and preserving the strength of the underlying layers. This results in the retention of up to 90% of the wood's original strength and also gives occupants time to evacuate in case of a fire.

Most recently, the University of Arkansas started construction on the country's first mass timber residence hall, a $78 million, two-building complex that will feature exposed structural wood, along with the standard amenities of a modern student housing project. The Stadium Drive Residence Halls will offer students more than 700 beds, as well as a living-learning environment, with study, performance and maker spaces.

The world's tallest mass timber building, the University of British Columbia's (UBC) $39 million Brock Commons Tallwood House, is also a residence hall, which opened to students in July 2017. UBC officials reported that one of the biggest advantages of the building's prefabricated, mass-timber design was that the wood components were able to be assembled on the steel and concrete cores within 70 days of delivery.