Mile Load Road Bridge
Photos
Side view, facing west
The deck truss is almost impossible to see from the deck.
Photo taken by Fmiser in July 2012
License: Creative Commons Attribution-Share-Alike (CC BY-SA)
Facts
- Overview
- Deck truss bridge over the BNSF Railroad on Mile Load Road (TR 42)
- Location
- Fulton County, Illinois
- Status
- Open to traffic, one lane, 10 ton weight limit
- Design
- Pin connected pratt deck truss with timber floor beams and deck. North approach stringer is 70 ft long. South approach stringer is 40 ft long
- Dimensions
-
Length of largest span: 100.0 ft.
Total length: 213.8 ft.
Deck width: 16.0 ft.
- Approximate latitude, longitude
- +40.35724, -90.22081 (decimal degrees)
40°21'26" N, 90°13'15" W (degrees°minutes'seconds") - Approximate UTM coordinates
- 15/736005/4471116 (zone/easting/northing)
- Land survey
- T. 4 N., R. 2 E., Sec. 1
- USGS topographic map
- Duncan Mills
- Inventory numbers
- IL 029-9908 (Illinois bridge number)
BH 15247 (Bridgehunter.com ID) - Inspection (as of 11/2011)
- Deck condition rating: Fair (5 out of 9)
Superstructure condition rating: Fair (5 out of 9)
Substructure condition rating: Fair (5 out of 9)
Appraisal: Functionally obsolete
Sufficiency rating: 35.7 (out of 100) - Average daily traffic (as of 2010)
- 100
Update Log
- July 7, 2012: Updated by Fmiser: Update design
- July 7, 2012: Updated by Luke Harden: Edited map and bridge. Was improperly categorized as a pony truss
Comments
I walked across the bridge twice and took a bunch of photos before I finally spotted evidence of a truss. And then it was a glimps through the trees. So I hiked down and around to get a view of the side and underside.
This is an odd bridge for automobiles. It feels more like a railroad bridge - so it makes sense it was built by the railroad.
Things I found odd about it:
- Narrow deck truss
- Timber bents and timber cribs substructure
- Timber floor beams
- Timber deck _without_ runners
- The approach spans are not in line with the main span. The south approach is pretty close, but the north approach is definitely not resulting in a curved appearance.
The deck has a very noticable dip in both approach spans. With it's listing as a truss, these dips made me very nervous! But the truss span is straight and level. It appears the bents under the approach spans have settled causing the dips.
The truss is pin connected, with 4 to 6 upset eye bars per panel. This seems heavy duty - but then the distance from the bottom chord to the top chord is only about 8 ft. (2.5 m) I think the short verticals means more tension on the bottom chord...
For future visitors, there is a road off of Mile Load Rd a bit south-east of the bridge that has a grade-level crossing of the railroad tracks. And keep an eye out, there's a lot of poison ivy.
Photos taken 11-4-09.
This page's URL is http://bridgehunter.com/il/fulton/29990807206/