Sylvan Island Bridge
Facts
- Overview
- Pratt through truss bridge over Sylvan Slough on 2nd Street
- Location
- Moline, Rock Island County, Illinois
- Status
- Intact but closed to all traffic
- History
- Built 1901; Bearing plate repaired 1945, Timber deck replaced by concrete 1953; Floor system repaired 1964; Closed 1969; Converted to pedestrian usage in 1995; Closed 2013, Demolished 2017
- Design
- 1 89' six panel pin-connected Pratt truss
1 110' seven panel pin-connected Pratt truss. - Dimensions
-
Length of largest span: 110.0 ft.
Total length: 200.0 ft.
- Also called
- Sylvan Island Wagon Bridge
2nd Street Sylvan Island Bridge - Approximate latitude, longitude
- +41.51097, -90.53599 (decimal degrees)
41°30'39" N, 90°32'10" W (degrees°minutes'seconds") - Approximate UTM coordinates
- 15/705625/4598413 (zone/easting/northing)
- Quadrangle map:
- Davenport East
- Inventory number
- BH 48242 (Bridgehunter.com ID)
Update Log
- November 25, 2017: Updated by John Marvig: Bridge has Been Replaced
- September 12, 2013: New Street View added by Dave King
- April 30, 2013: Updated by John Marvig: Bridge is now closed
- December 29, 2012: New photos from John Marvig
- December 28, 2012: Updated by John Marvig: Added information
- June 4, 2011: Updated by Luke Harden: Added photograph
- February 24, 2011: Added by Nathan Holth
Sources
- Nathan Holth
- John Weeks Highways, Byways, And Bridge Photography
- Luke
- John Marvig - marvigj27 [at] gmail [dot] com
- Dave King - DKinghawkfan [at] hotmail [dot] com
- City of Moline - Bridge Inspection Report
Comments
This confirms what the newspapers said... a quote from the report: "The entire superstructure vibrates under the loading of two men walking. A single man jumping up and down on the deck creates noticeable vibrations throughout the truss."
This is true for any pin-connected truss! Its how they function! This is not a rigid-connected truss bridge... it is pin connected!
If you want to read the bridge inspection report it can be found here (lots of good photos at the end): http://www.moline.il.us/DocumentCenter/View/2047
Major section loss in a few of the lower truss chord members seems to be the main reason for closing the bridge. A few other serious problems were found with the deck support beams, deck, and some of the joints.
They sure as hell better bring in that railroad span then!
That's just dumb! Where the hell did they get the figures from anyway? I think there should be a better way to preserve the bridge rather than demolish it. But I guess the politicians just don't get it, do they?
I don't know who they hired, but Moline obviously hired someone with no experience whatsoever in rehabilitation of historic truss bridges since they now think its cheaper to demolish and replace this bridge rather than preserve it.
http://www.whbf.com/story/23304831/future-bright-for-sylvan-...
Phoenix column Whipple railroad truss. Walleye tournament in October 2012.
Is there any longer public access to Sylvan Island? The road bridge is closed and the RR bridge appears to be shut off from trails.
"Too much bounce?" Seriously? Whoever inspected this bridge does realize this is a PIN CONNECTED truss bridge, right? Obviously, these bridges do flex noticeably under load. Does this person not know this? The only situation where "bounce" would be of concern is if an underlying issue caused excess flex, and if so, it is the underlying issues that should be described, such as section loss, sinking abutments, etc.
OK, I think I have the two Sylvan Island Bridges represented correctly on this website. This is the highway bridge. Some websites say this bridge was built in 1872 by Baltimore Bridge Company, and "strengthened in 1901". However, the truss spans do not look even remotely like something built in 1872. I strongly believe that the bridge was replaced in 1901 with the spans seen today. The former substructure from 1872 may have been reused, which may be why there is this confusion. Given these observations, I listed the construction date as 1901 and the builder as unknown.
Note that the other bridge to this island is a nationally significant (but little known) Phoenix column Whipple railroad truss.
This page's URL is http://bridgehunter.com/il/rock-island/bh48242/
Replacement in place, scheduled to open in December. Man, that is one very ugly MOB! No historic value!!! http://qctimes.com/lifestyles/recreation/long-awaited-bridge...