If alien invaders wanted to bring Chicago’s transport system to its knees, what would be the quickest way?
If you answered boot all the cars, you’re a cynic. If you answered block off all the expressways, you’re a suburbanite.
If you answered disable all the bridges, you are right.
There is a legend, perhaps apocryphal, that the late Michael J. “Umbrella Mike” Boyle, longtime boss of Local 134 of the International Brotherhood of Electrical Workers, once threatened to tie up all of the city’s bridges in a dispute over a five-day workweek for bridge tenders, whom his union represented.
When the city called his hand, Boyle, whose nickname came from the alleged propensity of acquaintances to drop wads of cash into the upturned umbrella he kept near him at all times, ordered all the bridges in Chicago raised so no traffic could get through.
Within minutes, legend has it, the city acquiesced to his demands.
Chicago is a city of bridges, no less than Venice or Paris, though we seldom stop to think about it. Other great cities have more romantic or historic bridges–Florence has its Ponte Vecchio, St. Petersburg its Bankovsky Most, Lake Havasu City, Ariz., its London Bridge. But Chicago is unique.
It is the home of the movable bridge, that obsequious form of waterway concourse that parts to make way for the barges of commerce and tall-masted luxury craft.
Chicago has 51 movable bridges, more than any other city in the world. Thirty-seven are operable, according to Stan Kaderbek, the city’s chief bridge engineer, who adds that most of the rest “haven’t moved in so long they couldn’t move if you wanted them to.” (A few, however, could be brought up to speed if so requested by the U.S. Coast Guard or Department of Defense.)
There is a great deal to know about Chicago bridges. Here is a sample:
– Our town is the birthplace of the modern double-leaf trunnion bascule bridge, which, in essence, is a drawbridge whose halves swing up and down on a pair of horizontal shafts called trunnions. “Bascule,” you will be interested to know, is French for–what else?–“seesaw.”
– The second-longest bascule bridge in the world is the Columbus Drive Bridge, which was opened in 1982 and is 269 feet long. Only the 295-foot bascule bridge that spans Spain’s Bay of Cadiz, near the city of the same name, is longer at 295 feet.
– The most active bridge in Chicago is at Kinzie Street on the North Branch of the Chicago River. The bridge rose and fell nearly 5,000 times in 1996. It gets this much use because it has a very low clearance–only 12 feet–and must be opened not only for the large number of pleasure craft that navigate the North Branch but also for barges carrying bulk goods such as salt, oil, sand and gasoline. Barges slip easily underneath nearly all the other bridges in town, though the Cermak Road Bridge is also only 12 feet high.
– The next most active bridges are those on the Far South Side that span the Calumet River. Each rises and falls some 2,000 times per year.
– You probably thought that the Michigan Avenue Bridge was among the busiest because when it isn’t being repaired (which is often), it always seems to be up–especially when you have an appointment on the other side of the river. Yet the bridge is far down the list of the busiest. In 1996, it opened only some 200 times, about par for the course for Chicago River bridges (as opposed to Calumet River bridges).
– A few eminently operable bridges are never raised, including ones where Halsted Street, Division Street and Ogden Avenue come together with the North Branch Canal. Of bridges that are opened periodically, the least active is the Ashland Avenue bridge on the South Branch, though most of the structures south of Damen Avenue and north of Division Street get little use.
Chicago’s dependence on bridges is, given the city’s hustler reputation, fittingly rooted in the profit motive. The first bridge built here was constructed in 1831 as a sort of bridge over ribald waters. Its purpose: To allow dwellers on the west bank of the North Branch to cross to the east side to patronize a certain saloon of questionable repute.
At the time, there was much resistance in the young settlement to building bridges. Shipping interests wanted nothing in the way of their boats. The question became how to get pedestrians and vehicles across the river without impeding shipping.
The answer? A bridge that could move.
In 1834, three years before the city incorporated, work began on Chicago’s first movable bridge, a crude 10-foot drawbridge at the foot of Dearborn Street that could be parted with chains to grant 60 feet of passage to cargo vessels.
But the bridge kept getting stuck and legend has it that the citizenry chopped it up for firewood in 1839.
The next year, a new bridge was built at Clark Street, a floating device hinged to the bank and supported by a pontoon at the other end. It could be opened and closed with chains wound around capstans. But in 1848, a fearsome spring flood, wielding ice floes, destroyed the bridge and several others like it.
Over the next 50 years, the city was to experiment with a number of bridge designs. First came the swing bridge, which rotated on a turntable in the middle of the river so craft could pass on either side. The idea received a blow in 1862, when a swing bridge at Rush Street and the river was destroyed by a herd of cattle which, spooked by a boat whistle, stampeded to one end of the bridge and collapsed it.
A more inherent problem with swing bridges was that the central support pier took up too much room in the waterway, leaving insufficient space for large ships to go around it.
Another attempted solution was the jackknife bridge, whose leaves were hinged at two places like a Japanese screen. But it operated as clumsily as a folding chair.
Then there were vertical lift bridges, which were hoisted up and out of the way by elevators on either bank. Two working vertical bridges still exist.
One, owned and operated by Amtrak, stands near Canal and 18th Streets. The other is at Torrence Avenue. But such bridges have the drawback of being truly ugly.
An improved design arrived in the form of the rolling-lift bridge, conceived by William Scherzer. It consisted of two leaves, which rocked back and forth on what resembled rocking chair runners.
The leaves, when retracted, disappeared into the ground, leaving unobstructed passage for ships. But they were unstable when opened. The Cermak Road Bridge, built in 1906, is the sole example of the genre left in the city.
An exhaustive study by city engineers concluded that the best design was the double-leaf trunnion bascule type. The beauty of this kind of bridge is that the two leaves are precisely balanced by stacks of iron or concrete counterweights sunk into a pit below street level. The weight of this ballast is matched so carefully to that of the leaves that only a small motor, about the size of a Volkswagen Beetle engine, is needed to raise thousands of tons. Yet the bridge can be raised to its full height in less than a minute.
Beginning with the Cortland Street Bridge on the city’s North Side, completed in 1902, all but one of the surviving movable bridges built by Chicago’s Division of Bridges and Viaducts have been of the trunnion bascule type. It has become known as the “Chicago style,” not to be confused with deep-dish pizza.
The most beautiful of these bridges remains the Michigan Avenue Bridge. Built in 1920, it was the work of architect Edward Bennett, a colleague of Daniel Burnham. But the most impressive span is the Columbus Drive Bridge, which cost $33 million to build, is 111 feet wide to accommodate six lanes of traffic and is set back from the water’s edge by several feet so pedestrians can stroll along the city’s riverwalk.
All told, Chicago has about 300 bridges, including those that are part of the Skyway. Not all of these go over water, of course. The number that do that is 85, which coincidentally happens to be the number of bridgetenders remaining in Chicago.
There used to be more bridgetenders, but the city was a pioneer in downsizing. Only the Kinzie Street Bridge still has permanent bridgetenders. The rest are manned by “rovers”–bridgetenders who are expected to play a game of leapfrog in the path of oncoming vessels.
They travel in two packs of four each. The first crew raises a bridge and the second crew raises the next bridge down river, the first crew piles into a car and drives ahead to the third bridge, and so on.
This downsizing reflects a trend. With each passing year there are fewer and fewer bridge openings. In 1982, there were 30,845. By 1987, there were 27,855. By 1997, the number was little more than 20,000.
That number will drop substantially in 1999, when the Kinzie Street Bridge is elevated five feet. That will make it unnecessary to raise its leaves except for tall-masted sailing vessels.
“When that happens, it will be the end of an era,” says Kaderbek. “It will mark the first time in something like 150 years of tended bridges in Chicago that we don’t have full-time, permanent bridgetenders. But it will no longer make financial sense to staff any bridges full time. Sailboats run through on a schedule. We know in advance when the bridges need to be raised.”
Chicago can take pride in its bridges, but the price of maintaining them is steep. Kaderbek says that half of the city’s bridges have undergone major repairs in the last few years, which, at $10 million to $15 million apiece, brings the cost to about $150 million to $200 million.
“Bridges need minor work every 25 years and major work every 50. Plus they have to be painted every three years,” says Kaderbek.
On the other hand, what other city can claim to be the capital of the movable bridge?
“I haven’t heard anyone refute that yet,” says Kaderbek. “Not even New York.”
