Modeling the hybrid Willamette bridge

Beginning today at City Hall at 6PM, a new model of the proposed Willamette River Crossing, the new span connecting MAX light rail and pedestrians that is planned for a space between the Ross Island and Marquam bridges, will be on display.

Sponsored by the Architecture Foundation of Oregon, the Portland chapter of the American Institute of Architects, and Portland Spaces magazine, a reception this evening will include not only the scale model's unveiling, but a lecture at 7PM by the bridge's designer, architect Miguel Rosales of Boston-based Rosales + Partners.

The model will be on display at City Hall through April and then move to other to-be-determined locations for public viewing.

I was given a brief sneak preview of the model yesterday by one of the engineers involved, Philipp Wenger of Stuttgart, Germany-based Schlaich Bergermann und Partner. And compared to the previous renderings we've seen of this suspension/cable-stay bridge hybrid, the bridge now looks undeniably better. When the hybrid and the wave protoypes were first unveiled in renderings, the wave's design had been more refined because Trimet and the advisory committee involved had more questions, and because the hybrid concept was introduced at a later date. So to see a more refined version of the hybrid definitely does the look of this concept justice.

The hybrid is a much better bridge for this site than the off-the-shelf options it draws from. A cable-stayed bridge would require much taller towers rising to over 250 feet, which would be out of scale with the site. (It's equivalent to the height of the tallest South Waterfront condo.) The hybrid option, however, brings that height down to something more reasonable: about 180 feet. The towers are also noticeably more slender.

Even so, a variety of people with knowledge and passion about design, including Portland Spaces editor Randy Gragg, whose magazine is co-sponsoring tonight's event, believe there is still a danger that Trimet will push forward a more conservative option in the off-the-shelf cable-stay bridge. This is a time for the design community to get behind the hybrid as a better, more unique option for Portland.

At the same time, while the wave-bridge concept seems close to dead now, I continue to have serious reservations about how that concept was discarded based on misinformation.

Trimet's case for going against the wave was said to be based on cost and extra difficulty doing such a unique bridge - the wave would be the first of its kind. "You don't want to give a false bridge type and say we think a wave frame is a great type of bridge here but we can't afford it," David Unsworth, project development manager for TriMet, told The Oregonian's Dylan Rivera in a March 4 article. "Do you want a popularity contest on something we can't afford?"

But many of the costs and challenges have been unfairly exaggerated. The wave has been said to require high-performance steel produced by only one company in the United States, for example, which was a major strike against the concept. But according to Wenger, those details could easily have been overcome to make the wave competitive on price and with more common types of steel.

"It was stated by the client that only one source in the US could supply high performance steel with 4-inch plate thickness," Wenger explains. "High performance steel is available in Portland rolled up to approximately 3.5" thickness. The plate thickness could easily been overcome during the ongoing design phase, in order to comply with local supply and a wider choice of sources."

We're at a stage where all the bridge prototypes would need a lot of these details worked out. So to say the wave would cost vastly more is misleading.

I can't help but feel Trimet's conservativism and over-attention to budget are the Achilles' heel of this bridge design process. Isn't Portland supposed to have a trail-blazing, pioneering spirit and a progressive character that favors innovation? So why are we acting like Topeka when it comes to the wave?

That said, at tonight's reception, I plan to strongly support Rosales and the notion of a hybrid bridge instead of the off-the-shelf cable-stay option that is clearly very wrong for this site. In fact, at this point, the most politically advantageous position would likely be to argue solely for the hybrid as the pragmatic choice. It's not as innovative or appropriate as the wave, but it's not as bad as the cookie-cutter option that conservative Trimet seems to be pushing for.

But I can't yet commit fully to the idea that the wave should be dropped. In my heart of hearts, I see Portland missing out on the best bridge out of fear and naivete. It's been 35 years since Portland built a bridge. We don't have the institutional expertise in Trimet or other parts of city government to push for strong design from the get-go. If Trimet had a bridge-design expert on staff, or there were someone else at the city pushing for strong design at the start, perhaps a design competition or other tweaked process could have created a better set of conditions for getting the right bridge.

As things stand now, we have a good bridge designer (Rosales) and engineer (Schlaich Bergermann), but maybe Portland is not the right bold, confident client to go forward with the weave. It's too bad, because our identity is supposed to be that of an innovative, progressive city. And yet the best bridge option out leaders seem willing to commit to is the one that's the second best, patting ourselves on the back for not choosing the cheapest and the worst.

Regardless, I do have great confidence in Rosales and his design team partners. After all, they've explicitly said the wave seems best but that they like the hybrid a lot, which seems about right. What's more, if the city goes forward with the hybrid option, we'll be getting a very nice bridge. Go see for yourself at City Hall tonight or in the days ahead.

Comments

[val]

Can we please call it the Cesar Chavez Bridge and stop this ridiculous street renaming process?

[joe]

I respect the opinions to build a unique and attractive bridge (don't get me wrong I certain want that too) but lets not forget that the whole point of building this bridge in the first place is to get MAX trains across the Willamette River. This bridge is not being built "to push the boundaries" of bridge construction as many who have clearly spent too much time in architecture crits think. TriMet's sole goal is to run an efficient transit system, everything else is just fluff.

I dont blame TriMet for wanting to go "safe" on the design of the bridge. Already designing a bridge for non-auto use is seen as radical by a certain part of the population (esp. the Lars crowd), particularly those who think anything they can't drive their car on is waste. "Safe" would also be a basic viaduct bridge, so I think we are also lucky they're willing to go for something much better than that.

I'd rather not TriMet lose all its political capital building a single risky bridge that has a good chance of being riddled with structural problems and cost overruns. And don't tell me you can build the first of its kind large scale bridge and not expect problems or cost overruns. A showy yet costly problematic bridge won't exactly go over well with taxpayers, or riders facing service cutbacks and will be seen as a symbol of misplaced priorities.

[Scott]

I think the hybrid is a very handsome bridge...not the most exciting bridge ever, but it seems like a good fit...i think alot of people (myself included) have a very positive visceral response to suspension-type bridges. Honestly, i would have been ok with the cable-stay...even if not unique in the world, would still have been unique for pdx. lastly, i was never a fan of the wave-form, it may be a first-ever of it's type...but that doesn't make it inherently superior...i thought it was a bit uninspiring.

[Brian Libby]

I completely respect the point of view of those who favor the look of the hybrid or even a cable-stay to the wave.

But my larger point was that the wave may not have had an even playing field to be considered fairly if its costs were being over-stated. I'm not trying to vilify anyone, because I can understand an institution like Trimet's need to be cautious given their inexperience with a major bridge project and not wanting to have under-estimated the cost like happened with the aerial tram.

My other point was that, regardless of what you and I think, the committee seemed to be excited about the wave. So if they'd had the sense that the wave could be built for roughly the same cost, what might have they have recommended?

[Scott]

I agree...that is a good point...they shouldn't have made a decision without really looking at the data...it seems there was a lot of false info thrown about

[ka]

welcome to the "real" world as a designer - it is called price gouging.

[John Russell]

This is definitely an improvement over the cable-stayed design. While I would love to have the wave bridge design, I can't find any other reason to not like this one. Absent the wave design, this would easily be my first choice.

[MarkDaMan]

"A cable-stayed bridge would require much taller towers rising to over 250 feet, which would be out of scale with the site. (It's equivalent to the height of the tallest South Waterfront condo.)"

The tallest condo tower in the South Waterfront is actually 325'. John Ross, Ardea, and the under construction Mirabella will all rise to 325'. And IMHO, the towers in the South Waterfront should rise taller, but with a smaller floor plate.

I just don't understand "out of scale with the site". The Marquam Bridge is of pretty hefty scale. There was a proposal for the Portland Storage towers to rise quite high (much taller than 250') on the east side.

We are building a bridge that will probably be around for hundreds of years. I can't imagine how the built form of the city will change, again and again, during that time. I do know we should build the best and most attractive bridge, regardless of height or very objective 'scale' within the budget.

Frankly, I hate the new poles holding up the cable. I didn't much like the original cable stayed bridge's paper clip pole, but I'd take that over these four non-aspirational sticks.

[Matthew Stadler]

I also prefer the wave bridge. Philipp Wenger's claims seem to warrant reopening the discussion of that option. Those are very significant claims, the sort that could reverse a verdict if this were a court trial. Would someone with a deeper knowledge of the client and the decision-making process please tell us if there are any productive ways to reopen discussion of the wave design, at this point? If Wenger is right, there is every reason to bring it back onto the table.

[Double J]

I'm with Matt, I still prefer the wave... though the hybrid is handsome it seems like some kind of hedge against the "off the shelf" cable stays.

Why has Trimet structured this so the only cable stay options are off the shelf "generic" designs that the architect isn't invested in? Good cable stay bridges are elegant, daring and airy... good for a pedestrian/bycicle/mass transit bridge... yet we havnt seen anything but the most generic designs. This is a major symbol for prorland and likely Trimet's most public symbol. If a cable stay does get picked Portland should demand whatever architect is involved propose an improved design from the off the shelf varieties.

I don't buy the scale arguments at all... the massive/ugly Marquam and the towers downtown and SoWa are large scale and they sit well with anything proposed in the cable stay designs.

Still, the Wave gets my vote because of the way it echoes the west hills and other bridges (it sets up a civic/natural environment rhythm)... yet that design is still merely OK.

Major lesson learned here to be applied for the I-5 crossing... simply limiting the discussion to engineering and cost leaves everyone with underwhelming to ok design. We seem to be demanding better and it's a critique of the process.

[Modeling]

This serves like a good design for modeling the bridges of tomorrow... far beyond the bridge to nowhere scenario.