Seesaws for giants
Chasing Chicago’s movable bridges
by Marcin Wichary
Chicago is a city of bridges but, more importantly for that one weekend day in April 2011, Chicago is a city of movable bridges.
Every spring, a few times a week, twenty-seven bridges open in sequence to allow the boats to get to the lake… and every fall that sequence is reversed.
I flew to Chicago for the weekend so that my local friend Jen and I could chase those bridges as they opened and closed.
Here’s a map. We started in the south-western corner with Ashland Avenue Bridge:
It was amazing; we were looking at structures weighing thousands of tons moving up and down without little apparent effort.
As I found out, it wasn’t entirely an illusion. Most of the bridges match their road decks with carefully balanced counterweights — either visible above or hidden below the ground — and the motor is required only to tip it gently one way or the other.
This type of bridge is called a bascule bridge — French for “balance scale” which operates the same way. Here’s one example with a visible counterweight although this particular bridge, at Cermak Road, works a bit more like a rocking chair than a seesaw:
It’s even more incredible if you consider many of those were built over a hundred years ago.
We were following the same route four different teams of operators did, leapfrogging each other in vans for maximum efficiency.
What happened as a result was the most beautiful mechanical ballet:
The only exception to bascule bridges was the Amtrak rail bridge of a more traditional lift design.
Its slanted appearance is not an illusion — it really is built this way. Here it is in normal, and raised state:
The old control booth in the middle is no longer in use.
As we moved closer to downtown, the bridges got more and more impressive.
(By the way, if you haven’t yet thought of The Blues Brothers, you should watch The Blues Brothers more often.)
The operators were watching the bridges carefully and I wish I had a video to convey the crazy assortment of bells and lights that accompanied every rise and fall (this YouTube clip might give you an idea).
Seeing some construction on the closed Washington Boulevard Bridge (which only opened its one leaf) reminded us of this fantastical accident from twenty years ago. As a friend quipped later, “as you remember from childhood, see-saws also make good catapults”:
On Sunday, September 20th, 1992, the Michigan Avenue Bridge, while under repair to install a new roadway, became a gargantuan catapult hurling equipment and debris hundreds of feet across Wacker Drive. The bridge suddenly sprung upward, sending a forty-ton-capacity crane parked on the end of the southeast bridge leaf tumbling into the counterweight pit. The crane then crashed into lower Wacker Drive and was crushed between the bridge deck and the roadway. (…) Several vehicles were damaged and, most frighteningly, the crane’s 285-pound iron ball bounced off Wacker Drive and landed in the back seat of Jesus Lopez’s Ford Escort.
By the way, did I mention that my awesome friend Jen works at Chicago Architecture Foundation? I think I should because that meant one thing.
Oh, yes, you know it.
We went inside one bridge as it was opening and closing.
Imagine this: seeing a road shoot up into the sky while we were standing right next to it.
For another bridge, we got to go into the control tower and meet a guy who has possibly the best job ever in the history of mankind.
Here I am, tapping on my little 4-inch touch screen, and this person gets to move a bridge for living. (Sigh.)
If you are ever in Chicago in spring or fall, you should consult the bridge lift schedule and see a few of them in action. It’s a humbling and awesome experience — “awesome” as in both “inspiring awe,” and “dude, it was mad awesome!”
I mean, the above photo is only some 13,000 tons of steel moved by a motor weaker than the engine of a Fiat 500.
Lastly, while you’re in Chicago, I’d love for you to make sure to check out my favourite bridge there.
Oddly enough, it’s none of the twenty-seven bridges that go up and down with Swiss regularity.
It’s Kinzie Street railroad bridge, and it was used by Chicago Sun-Times for their paper deliveries. However, following the downturn and moving the printing facility to the suburbs, it was left permanently open in 2000.
Can you feel sympathy for a bridge? Because I think I do. It might no longer be useful, but this bridge alone holds so many stories and will share them if you know how to ask.
I hope you’ll try.