As Chicago grew into a center of industry and commerce in the late 19th century, numerous fixed-span crossings were replaced by center-pier swing bridges, the most common type of bridge that allowed pedestrians and wagons to cross the Chicago River while also periodically allowing ship traffic below.
During the period of rapid growth in the late 19th century, as Chicago became a prominent commercial hub, many stationary bridges spanning the river were exchanged for center-pier swing bridges, which enabled people and carts to cross while allowing ships to pass underneath at regular intervals.