on polcevera, the thompson center, and moral choice in preservation

Several regular correspondents wrote last week to note the controlled demolition of the remaining spans of the Ponte Morandi in Genoa, and to wonder about its replacement.

As noted earlier, the collapse of the bridge last August was largely attributable to lack of maintenance, the inability to easily monitor the health of the embedded steel in its stays, and a design that offered little redundancy. The question of what should replace the span is a provocative one–at the moment a scheme by Renzo Piano for a simple, understated viaduct with none of the heroic towers or muscular stays of the original is planned:

https://www.domusweb.it/en/news/2018/12/18/renzo-piano-selected-to-design-new-bridge-in-genoa–for-free.html

All well and good–the design is understated, seems reasonably efficient, and predominantly in concrete, meaning that it will have the multiple load paths and robustness to weather the lack of attention that infrastructure in Italy (and, for that matter, in the U.S.) receives these days. But a couple of readers, knowing of my fondness for Morandi and this bridge in particular, wonder about the lack of reference to the original, which was a true Genovese landmark. I used the bridge all the time to talk about basic cable stayed principles in classes, since it had a simple, direct form that did a great job of explaining itself.

But. That simplicity clearly came with a price. Piano’s design relies on bending and the hyper static nature of continuous beams–difficult to explain how it carries itself over those piers without some serious math, or at least some complex diagrams showing negative moments canceling one another out, etc. That complexity adds redundancy to the span, though–there are many possible load paths and ways to distribute the loads of the deck among the piers, while in the original viaduct there was a single path, through the diagonal stays and into the A-frame towers. Disrupt that one path and you lose the whole bridge.

That makes for a great teaching example, but–and this is purely hindsight–a dangerous design that relies on the health of a single, largely invisible element–the steel strands encased in concrete that formed the diagonal stays. This is the structural equivalent of putting too many eggs in one basket, and while that basket may be evocative, beautiful, expressive–all the things I look for in a teaching example–it was an approach that came with dire consequences.

Do we memorialize that? It’s hard to imagine residents of Polcevera, the neighborhood underneath the bridge, warming to such a reminder of last August’s disaster, or to the legacy of deferred maintenance (the conscience-salving term of art for ‘negligence’) that has put thousands of miles of viaducts and bridges all over the world at risk for similar collapses. There’s an argument, I think, that if as a society we’re so manifestly unwilling to invest in the upkeep and care of such beautiful–but delicate–structures, then maybe we really shouldn’t build them.

Just to further poke the bear, the current debate over the fate of the James Thompson Center in Chicago strikes me as a related question. The State of Illinois, its longtime occupant, is putting the building up for sale, and most current options involve a wholesale demolition, which has preservationists up in arms about the loss of a controversial, though important, piece of post-modernism. I’m on record as being no fan of the building, but the questions around Piano’s memory-free viaduct resonates with my reasons for being ambivalent about the Thompson Center fight. The Thompson Center was an energy disaster when it opened, requiring 35% more energy to cool it during summer than anticipated, a figure blamed initially on the failure of an ice-making system, but over time resting squarely on its 17-story, southeast-facing, single-glazed atrium. The “$172-million oven” failed to attract much interest when the State initially floated the idea of selling it in 2015 in part because of its high heating and cooling costs.

How energetically do we fight to save a building that promises low energy efficiency, inefficient space planning, and ongoing maintenance issues as its curtain wall continues to leak and granite panels fall off of their supports? As our energy situation gets more and more dire, I’d argue that fighting to save the 1986 Thompson Center will look, to future generations, like restoring a 1986 Jaguar XJS to all of its 13-mpg glory and gifting it to them, along with its five-figure annual garage bills and its dated aesthetics. Yes, it may be seen as a classic someday, but aesthetics are tied to how cars or buildings serve our needs, too. I doubt the XJS is going to garner more fans as gasoline prices go inexorably up, and I doubt that the Thompson Center would, if we lost it, be our generations’ Chicago Stock Exchange–a building whose loss reflects poorly on the architect and developers of the early 1970s.

Chicago Federal Building/Postoffice. Henry Ives Cobb, 1905.

I’m guessing, instead, that the loss of the Thompson Center would be more like our generation’s Federal Building/Postoffice–which Helmut Jahn himself cited as inspiration for the Thompson Center’s atrium. The building was supposed to be Henry Ives Cobb’s masterpiece, but it turned out to be an unmitigated disaster. Cobb had taken a position as Supervising Architect for the Treasury Department after receiving the commission, and in splitting his time between Chicago and Washington he failed to keep in touch with the Postoffice project. It went over budget and several years over its planned schedule, but even worse were the inherent flaws in the design itself. While mail handling and retail operations required vast, open spaces, Cobb insisted on a rigid, Beaux-Arts plan, with a frankly useless dome and a greek-cross layout that divided the full-block site into four quadrants, each of them far too small for the functions that Cobb then crammed into them. The dome itself worked as a giant chimney, drawing air through the public areas that sucked doors shut and scattered paper throughout the building. Worse, the dome’s stack effect pulled foul air from the horse tunnels that brought mail to the structure’s basement, meaning that the entire building stunk of manure, especially on hot summer days. The Postmaster General of the United States began planning for its replacement days after its opening (a more effective structure that was built in two phases and now straddles the Congress Expressway). Cobb never built on this scale again, and took up a second career as a founder and leader of (wait for it) the American Arbitration Society.

Had the postoffice survived into the present era, I suspect plans to demolish it would meet with stiff resistance–both for its age and its importance to the daily life of the Loop, it would have made a strong argument for preservation, under today’s criteria. But it still would have been a remarkably lousy building–Cobb’s lack of supervision meant that it was built with largely inferior granite, the subject of lawsuits and accusations of corruption that dogged him and the contractor long after the building’s completion. For better or worse, and I’d argue for better, the building came down in the early 1960s to make way for Mies van der Rohe’s Federal Center:

That’s the replacement postoffice in front–a clear span volume that does the job that Cobb’s building could never do. Is Chicago worse off for having demolished what was, by all accounts, an historic but fatally flawed building? Diehard postmodernists would disagree, but I find it hard to argue that the 1905 Postoffice would have been better for the city than the public plaza and rigorous but subtle architecture of the Mies buildings. Certainly the Post Office is better off.

We can’t save everything, and when the preservation community argues for everything we tend, I think, to dilute any moral authority we have for making the case for buildings worth saving. No, we can’t know what will look like it should have been saved a generation or two from now–this is the Stock Exchange argument. But that doesn’t make it possible to take the fundamentalist position of going to the barricades for every proposed demolition. The fight to preserve, in the Thompson Center’s case, a building whose main argument for preservation is that it’s an exemplar of a particular style seems to me like a ‘moral holiday.’ It’s easy to see the headline, pull out the letter-to-the-editor template, and express outrage at yet another loss to the city’s historic fabric.

The more difficult choice is to acknowledge that there are moral and ethical consequences to preservation, too, and not being absolutely sure of what future generations will value or be able to use doesn’t give us the right to simply throw up our hands. We’re perfectly capable of making a reasonably well-informed decision about a building that in this case, is likely to be as welcome to our children and grandchildren as that Jaguar XJS. What if, instead, we fought hard to make sure that whatever replaces the Thompson Center, or the Polcevera Viaduct, is objectively better–safer, more energy-efficient, more durable? That may not win us many preservation merit badges, but it would be a step toward assuring that the cities around these contested sites evolved in ways that those future generations would still find helpful.

9 thoughts on “on polcevera, the thompson center, and moral choice in preservation

  1. Bravo!
    Rational and well-reasoned, leading to balanced and sensible conclusions. A refreshing change from “let’s save all the old things.”
    Richard A. Miller
    Founder, Landmarks Preservation Council of Illinois and Leader, Campaign to Save the Old Chicago Stock Exchange

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  2. I agree with the thesis. As I am often moved to say, a 1000 yr old church was torn down to build St Peter’s.

    Would like to comment on the structural form of the bridge, though. There is a severe mismatch of stiffness. Those enormous struts beneath are (were) very stiff. the deck is a remarkably deep and stiff section. The stays look too slender even clad in concrete. the concrete cladding is a contrivance. By prestressing it he created a concrete tie which was still just barely stiff enough to provide support. I suspect that the deck was carrying much of the load unsupported for some time. Did anyone even consider looking for hogging steel corrosion in the deck over the struts?

    Once it was blasted there was no going back. No doubt that suits all parties but it is VERY bad for engineering.

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    • I’m going to steal your St. Peter’s comparison…! The forensics on the bridge haven’t been made completely available yet, and I know there are competing theories that point to foundation problems as contributing factors. The struts under the deck were huge, and that definitely suggests that radically different levels of stiffness plagued its design. I’m watching for further reports–while the collapse is terrible for the field, being able to learn anything from it seems important…

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  3. Great post, as always, Tom!

    The most recent issue of Structural Engineering International (May 2019) has a detailed article on the bridge and collapse Calvi et al “Once upon a Time in Italy: The Tale of the Morandi Bridge”

    It is based entirely on publicly available info, so there will be more to learn once (if?) an official report is released.

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    • P.S. Renzo Piano (an architect) selected to design the replacement for a bridge known by its designer’s name, Morandi (an engineer).
      Structural engineers losing the PR contest to architects anew!

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      • Ha! Architects have always had better PR folks, I guess. Engineers could learn a thing or two from Mr. Eiffel…

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  4. Appreciate your comments re Cobb’s post office and government building. Also, how the story of that building relates to today ‘s preservation movement. However, to draw a strong comparison to the Thompson Center is not quite a fit for me. The Thompson Center central atrium space is a unique and grand space. It is not a question of style or preservation of a past style, it is a question regarding our willingness to preserve something special. The building was heralded as an energy responsive building when designed. It was not a Jaguar. The failures have occurred in execution including eliminating the double insulated glass. Are we willing to restore the building and bring it in-line with today’s preservation standards including energy efficiency? There is a moral argument as to how far we are willing to go to preserve and maintain what is something very special to all of us.

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    • Fair points. The question you ask is, I think, the important take-away: are we willing to spend the resources to bring a building like the Thompson Center up to today’s standards? There’s a pretty wide range of views on its atrium, too. While architects and critics have generally appreciated it, the public has had more mixed views. To someone coming in to settle a bureaucratic or legal issue with the State (or even just to renew a driver’s license), it can come across as less ‘thrilling’ and more ‘intimidating.’

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