The bridges over the Chicago River are an engineering masterpiece.
We were fortunate to be in downtown Chicago on one of the spring Saturdays when the 18 bridges which span the Chicago River are opened to let the sailboats pass through from their winter storage out onto Lake Michigan.
The bridges are opened in the spring and fall to allow the sailboats with their tall masts to pass along the Chicago River to and from Lake Michigan.
I had a hard time to choose from the over 100 photos which I took that morning, which is why this will be my longest blog ever.
When I told my husband that they open to let the sailboats out onto Lake Michigan and he did not believe me. "All of the bridges?"
There are 18 bridges which must be opened along the Chicago River in order for the boats to pass. This occurs over approximately two hours on a Saturday morning.
My husband said: “There is no way those bridges open! Just look at the shape they're in: they are full of rust and corrosion. I don't believe it, especially not those heavy double-decker ones – certainly they don't open in the middle!”
For those of you who follow my blog will know by now that husband has a very good understanding of mechanics.
The opening mechanism is powered by two or more 125 horsepower motors.
These massive steel structures have to withstand enormous temperature variations from minus 30 degrees Celsius (-30C/F) in the winter to 40 degrees Celsius (40C/100F) in the summer. In the summer they have to be cooled with water in order prevent expansion.
The fact that they have been in daily operation for an average of 84 years without an incident is a tribute to the civil engineers who maintain them.
Several of the the Chicago River bridges have two levels. Sometimes it is two levels of for cars, other times there's one level for the elevated train (refer to my blogpost L is for the L) and the another for vehicles. The heaviest leaf of one of the bridges weighs 6420 tons.
To give you some perspective of the sizes, what follows is a series for the DuSable Bridge. First I zoomed in on the bridge engineers standing on the lower level. Then I zoomed out to show the sailboat passing. Finally I end the DuSable series with the bridge closed.
The DuSable Bridge raises only on one leaf, whereas many bridges raise both leaves. In the next photo look to the left side to see the engineers on the lower level and you will appreciate how large the bridges are.
The DuSable bridge allows for traffic in both directions (vehicles) on both levels. The opening and closing of one bridge only takes about 10 minutes.
The opening and closing of the bridge is accompanied by the sounds of a bell and horn as well as blinking red traffic lights for the cars.
Its hard to describe in words the constant cacophony of these loud bells and horns over two hours.
The mast of the sailboat is almost as tall as the flagpoles on top of the bridge.
Despite the cold, cloudy and rainy weather, thousands of people came out to watch the bridge event. Since the weather was not good, the colors in this series are not so brillant, so I'm going to close out this blog with some Chicago River bridge photos taken on another day in the evening with perfect lighting.
If you are interested in visiting Chicago in spring or fall for the opening of the bridges refer to the schedule.
Source: The bridges have their own website: http://chicagoloopbridges.com/index.html