BY BRIAN LIBBY
It is still 15 months away from opening, but Portland's new bridge, the Tilikum Crossing, is now close enough to completion that its primary forms have been finished. That was clear at last week's connection ceremony, in which local dignitaries and press walked from both sides of the bridge to meet in the middle. And with the 1,720-foot span's signature towers, deck and cables in place, we can start to consider its place on the skyline and on the river.
My first impression of Tilikum Crossing, a cable-stay bridge designed by Bay Area firm MacDonald Architects (in partnership with engineering firm HNTB and others ), is a good one. Whether it's the shape of the towers or how the bridge span itself juts out in the middle, there is a unifying language of angles here that gives the bridge up close a sense of movement. The striking white cables coming down to its surface from two towers mimic the angle of Mt. Hood, and the entire bridge possesses a compelling kinetic energy.
As one walks or bikes onto the bridge, as a group of us did for the connection ceremony last week, Tilikum Crossing's sense of proportion and balance becomes apparent. The span itself, thin and elegant, has a gentle slope that goes high enough to provide clearance for boats and ships, but maintains no more than about a four to five-percent grade. Standing in the middle, the bridge's pedestrian and bike path juts out -- a belvedere, it's called -- in a way that prompts one to focus on views of the river, treeline and skyline. Jutting out like that also reduces wind by diverting its flow.
It's not a stretch to predict that Tilikum Crossing could become a primary visual symbol for Portland. As a friend told me recently, one could easily imagine some future Portland logo in which Mt. Hood is bookended by the bridge's two towers, with its cables parallel to the slopes of the mountain. And after more than 40 years, it's exciting to see our so-called Bridge City add another span to its connection.
Furthermore, I think the Tilikum Crossing designers got the contextual proportions right. MacDonald and the rest of the design and engineering team (including HNTB) labored to get the size of the towers down, even employing a unique type of cable-stay bridge to do so. In most cable-stay bridges, the cables are connected from the deck to the tower columns at the center and are independent of each other as they go down to the other side of the deck. Tilikum Crossing is a saddle type in which the cable goes from the deck, up through the tower and down to the other side. That allowed for a shorter, narrower tower.
All that said, the one complicating factor with regard to evaluating Tilikum Crossing could arguably be the proposed bridge by another designer earlier-on in the process. Boston-based designer Miguel Rosales and his firm, Rosales + Partners, were hired as a design consultant in the late 2000s and in 2009 proposed a one-of-a-kind hybrid bridge that combined the cable-stay and suspension bridge types. "I’m excited about this,” bridge advisory committee member Guenevere Millius, who now chairs the city's Design Commission, told Portland Monthly when the hybrid design was introduced. “[Rosales is] finding a great solution given the constraints.”
Some bridge designers, including MacDonald, who eventually got the job over Rosales, argued that a suspension bridge wasn't right for this span, that true suspension bridges such as the Golden Gate or the local Saint Johns Bridge are intended for longer spans. Yet the Rosales hybrid bridge design found strong favor with the local design community. The Rosales design probably would have cost more, but it also was an exceptionally elegant-looking bridge, at least in renderings. Yet Tri-Met instead decided to go with a more conventional cable-stay bridge and hired MacDonald over Rosales to make it happen.
"We're not taking advantage of an opportunity to do something great," Lloyd Lindley, a former Design Commission chair, told The Oregonian after the selection. "We're doing something that's an oatmeal, plain-Jane solution: We know it works and it fits our budget."
But make no mistake: both Donald MacDonald and Miguel Rosales rank among the nation's most prominent and acclaimed bridge designers. MacDonald's portfolio includes iconic projects like the east and west spans of the Bay Bridge, for example. MacDonald is a major talent with an impressive track record.
Was the Rosales hybrid prettier than MacDonald's cable-stay bridge? It's hard to say for sure. It's a comparison between a rendering and a finished bridge. That means MacDonald's design had to be subject to cost-cutting measures as well as changes from a wide spectrum of stakeholders. Rosales's rendering was never subject to that kind of scrutiny.
I found the bridge in Rosales's rendering to be a little more clean-lined and slender than the MacDonald bridge I walked across last week. But I also found the real-life Tilikum Crossing to be a better-looking bridge than I felt like I saw in the renderings. And MacDonald's design, with its angularity, arguably has more energy than the Rosales design. I like its zigzagging geometry. Would I trade it for the hybrid? Maybe, but it also may be a bit of a false choice. While cable-stay bridges are ubiquitous in America and no one has ever built a hybrid cable-stay/suspension bridge, that's not something likely to resonate strongly with the general public. (Although Rosales's nod to the St. Johns might have.) There was never an obligation for Portland and Tri-Met to choose a one-of-a-kind bridge type, and uniqueness of type is not necessarily the most important yardstick.
And besides, it's really about what kind of finished Tilikum Crossing we are getting, not how it compares to past iterations. Luckily, there's a lot to like here, and this bridge seems likely to find great favor and popularity as the years go by. I'm looking forward to taking another walk across its span.