6 votes

Arsenal Bridge



Iowa shore looking south

Photo taken by Nathan Morton in Sept. 07



Street Views 


This double-deck through truss bridge carries road traffic on its lower level, and rail traffic on its upper level. The swing span can rotate 360 degrees, which shortens the time the road and railroad are closed to allow a boat to pass, compared to a bridge that only swings 90 degrees and then swings back. After an opening, what was the north end of the swing span will be at the south end and vice-versa. See the animated gif under Photos to watch it operate. Support for overhead wires mounted atop swing span, over bridgetender's house, rotates opposite the swing span itself, in exact synchronization; it remains stationary relative to the ground while the structure beneath it, on which it is mounted, rotates.


Baltimore through truss bridge over Mississippi River on 2 lanes of traffic and 2 rail lines in Davenport
Davenport, Scott County, Iowa, and Rock Island County, Illinois
Open to traffic
Built 1896, Rehabilitated 1983 & 1997
- Phoenix Bridge Co. of Phoenixville, Pennsylvania
- Ralph Modjeski of Bochnia, Poland (Engineer)
- U.S. Army of Washington, D.C. (Ordnance Department)
- Chicago, Rock Island & Pacific Railroad (RI; CRIP; ROCK)
- Iowa Interstate Railroad (IAIS)
- Streetcar
- Tri-City Railway & Light Co. (TCR&L)
- United Light & Railways (UL&R)
Baltimore through truss swing bridge with pratt truss and steel beam approaches.
Length of largest span: 370.1 ft.
Total length: 1,854.0 ft.
Deck width: 25.3 ft.
Vertical clearance above deck: 11.0 ft.
Posted to the National Register of Historic Places
Also called
Government Bridge
Rock Island Bridge
Approximate latitude, longitude
+41.51917, -90.56694   (decimal degrees)
41°31'09" N, 90°34'01" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/703017/4599250 (zone/easting/northing)
Quadrangle map:
Davenport East
Inventory numbers
IL 000-0008 (Illinois bridge number)
IA 699340 (Iowa bridge number)
IA 2910 (Iowa bridge number)
BH 38082 (Bridgehunter.com ID)
Inspection (as of 09/2002)
Deck condition rating: Good (7 out of 9)
Superstructure condition rating: Good (7 out of 9)
Substructure condition rating: Satisfactory (6 out of 9)
Appraisal: Functionally obsolete
Sufficiency rating: 44.5 (out of 100)
Average daily traffic (as of 2014)

Update Log 

  • April 16, 2017: New photos from David Sebben
  • September 15, 2016: Updated by Christopher Finigan: Added category "Riveted"
  • September 14, 2016: Updated by Roger Deschner: Added category ""Truck Eating""
  • December 1, 2015: New Street View added by Douglas Butler
  • August 19, 2015: Updated by Luke: Added categories "IA 7", "IL 7", "US 32", "US 6"
  • April 26, 2015: New photo from Paul Hamby
  • March 27, 2015: New photo from Luke
  • January 10, 2015: Updated by Luke: Added categories "Tri-City Railway & Light Co.", "United Light & Railways", "Streetcar".
  • June 29, 2014: New Street View added by Ralph Demars
  • May 4, 2014: Updated by Roger Deschner: Added category "Lattice Railing"
  • January 19, 2014: New Street View added by Luke Harden
  • July 15, 2013: Updated by Roger Deschner: Add description, photos including animated gif of swing span operating
  • March 22, 2013: Updated by Luke Harden: Added category "HAER documented"
  • January 10, 2013: New photos from John Marvig
  • December 28, 2012: Updated by John Marvig: corrected total length-this bridge isn't 11,000 feet long
  • October 4, 2012: Updated by John Marvig: Added category "Center Pivot Swing Span"
  • August 18, 2012: Updated by Luke Harden: Added builder
  • May 24, 2012: Updated by Luke Harden: Added category "Navigable waterway"
  • May 11, 2012: Updated by Luke Harden: Added builder, US Army was the primary builder according to the plaque.
  • April 19, 2012: Updated by Luke Harden: Changed name to the name most often used by the locals
  • October 8, 2011: Photo imported by Luke Harden
  • July 25, 2011: New photos from Luke Harden
  • June 14, 2011: New photo from Bob Morgan
  • February 24, 2011: Updated by Nathan Holth: Merged NBI Data.
  • April 16, 2010: New Street View added by James Baughn
  • November 14, 2008: New photo from Nathan Morton
  • November 13, 2008: Added by Nathan Morton

Related Bridges 



Government Bridge
Posted April 19, 2012, by Nathan Holth (form3 [at] historicbridges [dot] org)

Another copy of the report on this bridge shows a bunch of photos at the end: http://books.google.com/books?id=UY8dAQAAIAAJ&dq=Rock%20Isla...

Government Bridge
Posted February 24, 2011, by Nathan Holth (form3 [at] historicbridges [dot] org)

I added Ralph Modjeski as builder for this bridge. This was the first bridge in which the famous engineer was Chief Engineer on.