Swinerton Mass Timber craft sets a clt panel

A large earthquake is expected by some experts to shake the Pacific Northwest within the next 50 years or so. The new Beaverton Public Safety Center now under construction is being engineered to withstand such a quake and continue operating thereafter.

Ground was broken in September 2018 on the three-story, 72,000-square-foot building on a 3.5-acre site at the junction of Southwest Hall and Allen boulevards. The center is being built by general contractor Skanska USA Building to an “essential facility” standard that calls for immediate occupancy and safe operation following a seismic event. Designers settled on a structural approach combining steel, mass timber and concrete.

“We’re using steel primarily to get our longer spans and reduce the column spacing on the interior,” said John Pete, project architect for FFA Architecture and Interiors.

However, use of cross-laminated timber floor and ceiling panels allowed removal from the design of much of additional steel that otherwise would have been needed. A three-and-a-half-inch concrete deck will be poured atop the CLT.

“The CLT goes in first and actually is the formwork for the concrete to be poured in on top of it,” Pete said. “That provides a lot of our seismic performance and ties our BRB (buckling restrained brace) frames together and provides a lot of the seismic stability.”

While seismically effective, the hybrid approach also increases the complexity of project management, procurement and logistics.

“Anytime you’re interfacing different types of materials,” said Derek Bourque, project manager for Skanska USA Building, “whether it be steel and CLT, steel and CMU, the more materials you mix the more challenging it becomes, in our opinion and experience.”

Currently, ironworkers are erecting structural steel for the building’s second floor. Carpenters from Swinerton Builders have been hired to fly in and install the CLT panels because of their expertise with this methodology.

“Typically when we build a steel structure we go three or four floors and then start decking our way up,” Bourque said. “But on this project we have to go up floor by floor, because we would trap ourselves and not be able to fly the panels in if we framed the structure up. And then just flying 10,000-pound-plus panels 40 feet long and getting them in position and trying to thread them between columns, it’s tough.”

Other building areas – almost exclusively those not facing the public – will feature concrete tilt panels and CMU (concrete masonry unit) wall construction. A slab-on-grade foundation will have an HDPE (high-density polyethylene) liner to keep moisture out.

The building’s interior will hold open office space, holding cells, storage areas, an employee gym, and an open lobby with a stair featuring exposed structural steel and precast treads and landings.

Interior finishes will include exposed CLT ceilings, architecturally exposed structural steel, acoustical paneling, finish carpentry, polished concrete flooring, interior glazing and gypsum assemblies.

The exterior façade will primarily feature masonry veneer with recessed vertical patterns. An aluminum-framed storefront and curtainwall glazing assembly will greet the public with glass and vertical wood slats, while exterior areas featuring tilt panels will also have inset metal panels.

The building is designed to be the new home of not only the Beaverton Police Department, but also the city’s emergency operations management department. To preserve operations after a sizable earthquake, the building must remain upright and functional.

As such, the center will have a 330 kilowatt rooftop photovoltaic array and an emergency diesel generator with underground fuel storage. Also, a micro-grid energy management system is being implemented to coordinate and control various power sources.

The new center will be a vast improvement over the police department’s current digs near Griffith Park, police Capt. Eric Oathes said.

“We’re at the Griffith Building right now, and it’s just a really old building that’s been remodeled time after time,” said Oathes, who is serving as the city’s project manager. “We wanted the open office concept to be able to have free flow throughout the building and bring all the units back together, and especially bringing the emergency management offices into it. They’re (serving) an important role in this as well, so we wanted to make sure that in the event when an emergency comes up and we have to activate the EOC, that we have the room and the facility to be able to meet the needs of the community.”

The building is scheduled for delivery in March 2020.

To view the full article, click here.

As steel, concrete and glass came to dominate cities’ dense cores, wooden construction was largely relegated to single-family houses in the suburbs. But a push for sustainable and aesthetically pleasing construction materials — and some well-timed updates to building codes — could bring wooden construction back downtown.

Buildings constructed with wood were long constrained to a few floors, but in December, the International Code Council voted to ease restrictions on height, allowing construction up to 18 stories with mass timber, an engineered material made of wooden planks bonded and pressed together into immensely strong and lightweight beams. The code updates will go into effect across the nation in 2021. In Oregon and Washington, state governments have already passed their own sets of codes, and construction of large mass timber buildings has been underway. “When you step inside a wood building, it just feels good — it’s a very human product,” said Christopher Evans, an operations manager and head of the mass timber group at Swinerton, one of the nation’s largest contractors. “But there’s a whole host of other reasons the material is making a comeback, from cost and timeline savings to sustainability.” Underlying the boom in mass timber construction is a host of technological advances. While wood framing has been the preferred material in single-family homes for centuries, new materials like cross-laminated timber, or CLT, and glulam, short for glued laminated timber, have recently come to market. In 2018, Swinerton completed the headquarters for First Tech Federal Credit Union in Hillsboro, Oregon; at 156K SF, the building is the largest CLT installation in the nation. Since that project, numerous clients have approached Swinerton asking about mass timber. Evans said the Swinerton team took it upon themselves to become the nation’s experts in wooden construction.
“We decided to do as much research into the feasibility of mass timber as we could,” Evans said. “The company concluded that mass timber is definitely more than a niche technique, that this could be a serious competitor in construction. We’ve been building out the mass timber team since the Hillsboro project. We now have a dedicated group focused on mass timber in the commercial construction market.” Evans noted that a number of catalysts have coincided to bring mass timber into the forefront of the national construction conversation.  First is a push toward sustainable building materials. Though it may seem like cutting down trees would not be the most environmentally friendly way to erect a building, wood is a renewable resource, and mass timber construction has far lower carbon emissions than concrete and steel construction. CLT and glulam construction have become especially attractive for universities and municipalities that want to demonstrate a commitment to sustainability. Next, mass timber construction can significantly reduce the timeline of a project, and consequently, its budget.  “When you use timber, you don’t have nearly as much concrete to set on-site, so most of the work can be prefabricated,” Evans said. “Also, because the building is so much lighter, you’re able to pour smaller foundations. On a decently large project, you can reduce the project schedule by 20% to 25%.” Part of that time is also saved because electrical, plumbing and mechanical work does not have to wait for concrete reshoring, and can happen immediately after the timber goes into place.

Finally, the search for unique office space has pushed tenants, and thereby developers, toward mass timber construction for its aesthetic appeal. The interior of a timber building feels bright and open, as opposed to concrete buildings that can feel cramped or claustrophobic, Evans said. The first wave of progressively minded developers began exploring mass timber as a means to attract higher rents from tenants willing to spring for eco-friendly, bright office space, Evans said. Now, a second wave of developers is getting on the bandwagon because they see their competition filling up their buildings and want to join in. “Timber construction makes sense for where we are in the world, in terms of lowering emissions and making office spaces more productive,” Evans said.  Most of the calls that the Swinerton Mass Timber team fields are from developers who are wondering if timber construction could make sense for their next project. But the cost viability of timber projects is not a simple question. “In some markets, concrete and labor are cheap, and transit costs for timber are high, so a mass timber project just may not make sense,” Evans said. “But in other markets where the costs for steel, concrete and labor are all high, mass timber can be cost-advantageous.”

To read the full story, click here.