By U.S. ArmyApril 9, 2019
The Government Bridge, which connects Rock Island Arsenal to Davenport, Iowa, was built in 1896. It is a double-decker bridge with double railroad tracks above and a roadway below with a pedestrian crossing. It was built on the same piers as the third bridge of 1872. Its swing span can rotate 360 degrees for river traffic -- a rare engineering accomplishment. Fort Armstrong Avenue crosses the river from Illinois into Iowa via this bridge, and Rodman Avenue's western terminus is at the southern end of the bridge.
Built on the piers of a bridge constructed in 1872, the current Government Bridge was completed and opened in 1896.
The previous bridge had been constructed of iron, and was the first of the bridges on the island that carried pedestrian traffic into Iowa. The bridge was built further west on the island than the previous bridges due to the establishment of the arsenal. Not long after that bridge was opened, it was determined to be obsolete. The iron construction was not able to withstand the heavier locomotives that were now used by the railroads.
The U.S. Army posed the task of designing a new bridge to Ralph Modjeski. Modjeski over-engineered the bridge to prevent the same issues that troubled the 1872 bridge. Utilizing the same piers, the new Pratt/Baltimore truss bridge was designed with a redundant steel frame. It was constructed by the Phoenix Bridge Company. Modjeski's design for Government Bridge has paid off, as it remains one of the most sound in the region more than 120 years later.
The gear system that turns the bridge is smooth enough that a 35 mile-per-hour wind restriction is placed on the bridge for safety. Most days, the draw is able to open and close without the motor.
Rock Island Arsenal's Joint Manufacturing and Technology Center maintains the parts necessary for maintaining the bridge and the swing span.
Government Bridge Facts
Designer: Ralph Modjeski
Style: Swing Truss Bridge
Constructed: 1872, Piers; 1896, Bridge
Length: About 1,600 feet
Swing Span: 365 feet
Traffic: Trains, motorists, pedestrians / bicycles