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Cities, counties and public agencies in the Pacific Northwest are jumping on the mass-timber bandwagon. The city of Hillsboro, for example, has hired Swinerton to construct the Hidden Creek Community Center. The two-story, 51,500-square-foot facility will feature a mix of structural elements that include glulam beams and cross-laminated timber panels as well as concrete tilt-up panels and shear walls.

The $37 million building, designed by Opsis Architecture, is expected to serve as an example of how mass timber can be integrated into public works. Meanwhile, Washington County and the cities of Milwaukie, Hillsboro, Oregon City, Lincoln City and others are pursuing mass-timber projects.

鈥淲e now have more and more public entities in multiple states that we’re in plans for,鈥� said Tym, a superintendent with Swinerton’s mass timber subsidiary who goes by a single name. 鈥淭he success of our private partnerships showed us there’s a big learning curve, but we’re turning that into something that is predictable and cost-effective.鈥�

The in Hillsboro also was constructed by Swinerton. That five-story, 156,000-square-foot structure was designed by Hacker and completed in 2018. Swinerton still regularly fields inquiries about how the project came together, Tym said.

鈥淭hat was my first interaction with mass timber and CLT,鈥� he said. 鈥淎nd those partnerships have really driven the idea of a sustainable, really aesthetically pleasing product into the mainstream of public works projects.鈥�

The Hidden Creek Community Center is becoming one. It will feature a two-court gymnasium, with 90-foot-long glulam beams supporting CLT ceiling panels.

The building also will hold cardio聽and weight rooms, two exercise or dance rooms, community meeting rooms and more 鈥� all inside an open shell comprised largely of wood. The facility is being built on 20 acres of city-owned land across the street from 53rd Avenue Community Park.

Swinerton’s general contracting team has worked with its mass timber division as well as concrete and carpentry self-perform units. KPFF Consulting Engineers performed structural engineering. Calvert Co. of Southwest Washington fabricated the beams and columns, with one exception: The glulam beams used in the gymnasium were fabricated in Drain by American Laminators.

Finally, Austrian firm KLH Massivholz GmbH manufactured the five-ply cross-laminated timber panels used in the building’s ceilings and roof.

鈥淢ass timber is really hot right now,鈥� Swinerton project manager Greg Byrnes said. 鈥淪chedule-wise, the local (fabricators) are all filled up.鈥�

One of the biggest challenges for the construction team, Byrnes said, was connecting the gym’s concrete walls with its massive long-span roof beams, as well as sealing the building envelope around them. Each glulam beam weighs 13,700 pounds. A NessCampbell Crane + Rigging crew flew them in.

鈥淭he insulation layer on the tilts connected with carbon fiber pins, and to stitch the whole thing together 鈥� those were a challenge,鈥� Tym said. 鈥淚’ve never done the large beams and the clear story on top of it with compounding sloping elements (33 inches) on top of that. It has tapered column lines, and making sure everything was sound while we put it together was phenomenal.鈥�

For Swinerton Mass Timber, each project presents something new.

鈥淚t’s evolving every day,鈥� Tym said. 鈥淚 have weekly, daily meetings about how the timber is going to interface with other mediums, how we’re making these connections and still sustaining the viability and technical ratings we require for these building types.

鈥淲e’re learning more and more that six, eight months out we have a heavy-loaded front end because of the planning and design work, but also for procurement and fabrication. All that work that comes on the front end is then dependent on having a good logistics and erection plan from the craft superintendent side.鈥�

The connections and fasteners for each material are different and the plans are different, even down to the moisture barrier around those connections, Tym added.

鈥淓very element we’re able to work with comes with new challenges,鈥� he said. 鈥淏ut with the challenges we’re able to archive and make predictable these things for future projects.鈥�

Because Swinerton operates nationally, it has a good handle on regional market trends. And those trends suggest mass timber is steadily rising in popularity.

鈥淭he market is absolutely exploding in California,鈥� Tym said. 鈥淲e are putting these projects up all over the country, but because this is an emerging market there are still constraints on who can provide, manufacture and deliver. Those supply chains are a critical element in deciding factors during pre-con.鈥�

But as the market matures, he continued, companies are branching out into more specialized aspects of mass-timber construction.

鈥淧eople might see it as niche right now, but what we’re seeing is that it’s going to be much more commonplace,鈥� he said, driven in part by public-private partnerships like the one used for the Hidden Creek Community Center.

鈥淚f there’s a desire and growth in the market, new businesses are going to spawn from it,鈥� Tym said. 鈥淭he whole world is trying to go tall wood. We want high-rises and we want big stuff. There’s a lot of math by engineers to make these things behave properly, but we have great aspirations to make this mainstream enough and utilize these efficiencies so we can continue to grow bigger and make things look really beautiful.鈥�