Nearly every aspect of Portland International Airport is getting a redo as the $2-billion PDX Next project redevelops or expands two concourses, adds parking, updates operations and features a core terminal redevelopment. But the megaproject’s pinnacle piece is an innovative, nine-acre, seismically isolated curved timber roof that uses locally sourced materials.

波特兰港首席项目官Vince Granato说：“ PDX新利18备用网址最大的下一个项目是相互联系的。”“他们团结起来，旨在更新和增强机场并准备在未来几十年中准备PDX。”

PDX Next’s first phase opened in July 2020, with the $215-million Concourse E extension, constructed by Skanska and designed by Hennebery Eddy and Fentress, which added six new gates and seven new shops.

The $100-million Concourse B, a Hoffman Skanska joint venture project designed by ZGF Architects, is scheduled for a fall 2021 opening that includes demolition of Concourse A to nearly double the concourse space while moving the exoskeleton to the outside for energy efficiency.

屋顶是在飞机场建造的。
Photos courtesy Port of Portland

Meanwhile, a $282-million flexible transit hub (under construction by JE Dunn with design by YGH Architects) will host 2,225 close-in parking spots and rental cars on site when it opens in fall 2021. Already, a $67-million quick turnaround facility for rental cars has opened.

But the $1.2-billion T-Core project serves as PDX Next’s prominent piece, a project slated for a 2025 opening. It remakes the footprint of the airport’s core while nearly doubling its size.

The project, designed by ZGF and constructed by Hoffman Skanska, with KPFF as the structural engineer, includes everything from remaking back-of-house operations to a completely new layout for ticketing and the lobby, all while making the space more energy efficient—a ground-source heat pump will reduce energy loads by 50% per sq ft—and done in Pacific Northwest themes. But it’s the new roof that leads every conversation.

The undulating timber roof highlights what Granato hopes will become a focal point of the updated PDX. ZGF architect Gene Sandoval says what makes it all work are the “roots” that not only support the roof but also open and modernize the space inside the terminal.

“You don’t get a roof like that without touching every single part of that building,” says Sharron van der Meulen, ZGF architect. “We had to deal with functional and operational aspects of the future.”

Douglas fir was chosen for its stiffness.
Photos courtesy Port of Portland

Beginnings

完整的T-Core改革消除了八个成矿dings that had been stitched together since 1954 to create the floorplate. Instead of the current 200 columns in a seismically vulnerable design, the team sought to use only 34 columns—half of them new and half that use existing footings—to hold the 18-million-lb, 380,000-sq-ft roof while opening up 100-ft by 125-ft bays between the columns to create more operational flexibility.

The roof uses nearly 400 glulam beams—more than 250 of them are 80 ft long—paired with 40,000 lattice pieces atop 34 Y columns. The columns are about 96,000 lb each, fabricated from 1-in. plate steel and filled with thermal grout for fireproofing.

ZGF和港口官员选择了木材（屋顶为330万英尺的道格拉斯FIR），出于各种原因，包括成本，可建造性，可持续性和庆祝该地区资源的机会。

Timberlab, Swinerton’s mass timber company, is working with Hoffman Skanska to handle the full timber scope, everything from walking local forests with the contractor and architect to select lumber to working with Oregon firms, such as Zip-O and Freres Lumber, to ensure first-use production is attained in the beams and laminates.

Zip-O从未产生的80英尺亮胶梁在单个跨度中具有7.5英尺的深度和16英尺的拱形，从而消除了一半的样条，以通过拆卸钢制硬件来降低成本。该设计在美学上还突出了木材，同时最大程度地减少了金属。

While making the beams, Jared Revay, Swinerton’s chief project manager, says they worked with the manufacturer to create mock-ups. “We wanted to see what would happen to the beam when supporting weight,” he says. “Not having done a test would have been a disaster.”

他说，调整巩固了他们在0.5英寸内创建这些光束的能力。272张80英尺梁的公差，这是项目1,500张纤毛的一部分。Freres Lumber Co.销售副总裁T. Tyler Freres正在采购该项目的贴面，包括Douglas Fir Roof Diaphragm。

The work required tens of thousands of specially cut components that make up the curved glulam sections.
Photo courtesy Port of Portland

Douglas fir was selected for its stiffness and predictability and for an improved bond, while the veneer strengthens the fibers. PDX Next is the first major project for this new-to-market product, using 2-in.-thick panels, each with a bevel for interlocking the unique curvature.

弗雷雷斯说：“上面几乎没有正方形或矩形碎片。”“坦率地说，我不知道他们在现实世界中将如何做。我们可以将它们放在更大的元素中，因此您没有那么多的作品可以使用。”

The roof will be fully created at the airfield, including skylights, insulation, mechanical components and finishes. With the jigsaw puzzle-like roof being so complicated, the project was broken into 18 “cassettes,” each about 120 ft by 110 ft. In all, each cassette has about 120 individual pieces, totaling around 2,200 pieces for the roof, with some individual pieces as large as 12 ft by 30 ft. Once completed, crews will place them atop the existing terminal and onto the columns using Mammoet rollers.

The roof will go up in four months in early 2022, but pre-assembly on the airfield is already happening. “If you were to fly in today, you would see the PDX factory right on the airfield, where all of these components are being put together,” van der Meulen says.

Working at an operating airport required prefabrication but also demands intricate planning both from tolerances and from the ability to place roof pieces overnight during a six-hour window when no passenger traffic is occurring below. “It has to be set so passengers can walk under it the next day,” says Dave Garske, vice president of Hoffman Construction, speaking for Hoffman Skanska.

根据项目团队的说法，这没有时间在最终站点上进行修补，这是一个项目的棘手时间框架，该项目的特色是弯曲的木材，从未在这种规模上创建。Garske说，基础的基础进入了建筑物的内部和外部建筑物，因此“当它进入适当的位置时，必须是完美的”。“我们有一个专门针对调查顺序的团队。”

模型至关重要。Revay说：“当您将其剪裁平整，然后在三个维度上弯曲时，您不知道它将如何行动。”“您必须属于3/8英寸。关节公差。我们对此进行了模拟过程。”

Three rounds of mock-ups included working with specialty CAD experts from Canada to drill the dimensions down. The first cassette was constructed satisfactorily, even after all the challenges.

“We weren’t sleeping for a couple weeks before,” Revay says. With tens of thousands of unique pieces needing to be cut to specific dimensions and go onto curved glulam pieces even before assembling the cassettes, Revay says crews cut, code and track each piece so they know exactly where it needs to be at all times, a logistical management process unlike anything he’s ever been a part of before.

Skanska客户经理兼高级副总裁乔·施耐德（Joe Schneider）说：“我们已经进行了胶合连接的模型，木与钢连接，木材与附件连接的模型 - 被嘲笑并进行了测试。”“这是查看负载挑战的唯一方法，我们对我们建造的挑战进行了调整，现在它进展顺利了。”

Along with the wood, the steel columns and supports were also mocked up.

Freres says that not only will the roof produce a regional feel but will signify a true local product. The entire PDX Next’s wood is sourced no farther than from 250 miles away, targeted from specific types of forests that include tribal and forest-restoration stands.

The Port of Portland had a progressive goal for the wood to be as local as possible, sending the mill, contractors and architects into the forests to pick out timber and then track it every step of the way until the finished product. “That way,” Granato says,” we can ensure the lumber is traceable back to those sustainably managed forests.”

With the price of timber increasing, the port says they expect cost increases of potentially $2 million across the entire project. Revay says the port believed that the economic investment into the local mill towns, some heavily impacted by the Oregon wildfires of 2020, was worth the extra costs to procure locally, especially with Zip-O and Freres, among other subcontractors, “bending over backward” to make the project work. “Nobody else would make these glulams,” he says, “and we would be dead in the water.”

Freres admits they could have switched out materials to fit to the budget instead of sticking to the original agreement and taking a financial hit, but that would have hampered the final aesthetic.

“这是一个标志性的项目，”弗雷斯说。“有很多人走过建筑物，他们会感觉到它，我们无法想象比我们自己的专利产品更好的广告。”

屋顶不仅在视觉上是唯一的，而且在地震上也不同。该设计允许屋顶移动到22英寸。沿任何方向和窗帘壁系统移动。为了实现这一目标，霍夫曼·斯坎斯卡（Hoffman Skanska）将隔离器转移到了钢柱的顶部。在运动过程中不会破裂的窗帘墙有铰接的连接，因此它可以与屋顶一起移动，而与粉底无关。施耐德说，他们花了多年的时间来提出一个可以处理地震要求的系统。内部机械系统还旨在破坏并保持“关闭”位置以确保安全。