Chicago Loop Bridges

We were very interested in the many bridges in Chicago. They are called “Trunnion Bascule Bridges”; they rotate vertically about trunnions (axles) on the river bank and bascule describes a family of draw bridges that use counterweights to assist in the vertical movement of bridge leaf. You can see the huge concrete counterweight on the left in the above picture. The clear protective barrier under the bridge (to prevent anything from falling on pedestrians) is called an”eyelash”.

The bridges are opened twice a week in May and October to let people with tall-masted boats bring them to the lake since the river freezes in the winter. While many people think this is a bothersome disruption, the bridges, some of them 100 years old, used to be opened on demand.

After 1910, involvement from the Chicago Plan Commission and architect Edward Bennett improved the bridges’ architectural elements, including bridge houses. These houses represent many major architectural styles, including Art Deco, Beaux-Arts and Modernism. The modern building on the left was built around the bridge house.