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Cow Creek Bridge

Photos 

Cow Creek Bridge

February 29, 2008

Photo taken by Michael Goff in February 2008

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BH Photo #117532

Map 

Facts 

Overview
Pony/through girder bridge over Cow Creek on CR 39
Location
Douglas County, Oregon
Status
Open to traffic
History
Built 1954
Builder
- West Coast Steel Works
Design
Pony/through girder
Dimensions
Length of largest span: 128.9 ft.
Total length: 246.1 ft.
Deck width: 24.0 ft.
Approximate latitude, longitude
+42.92444, -123.42194   (decimal degrees)
42°55'28" N, 123°25'19" W   (degrees°minutes'seconds")
Approximate UTM coordinates
10/465565/4752510 (zone/easting/northing)
Quadrangle map:
Nickel Mountain
Inventory numbers
ORNBI 19C215003900352 (Oregon bridge number on the National Bridge Inventory)
BH 36876 (Bridgehunter.com ID)
Inspection (as of 06/2015)
Deck condition rating: Satisfactory (6 out of 9)
Superstructure condition rating: Satisfactory (6 out of 9)
Substructure condition rating: Fair (5 out of 9)
Sufficiency rating: 48.9 (out of 100)
Average daily traffic (as of 2010)
762

Update Log 

  • July 17, 2008: Added by Michael Goff

Sources 

  • Mike Goff - michael [dot] goff [at] hotmail [dot] com

Comments 

Cow Creek Bridge
Posted March 18, 2009, by Michael Goff (michael [dot] goff [at] odot [dot] state [dot] or [dot] us)

When I first came across the Cow Creek Bridge I had a thought or two about classifying the bridge as a Vierendeel Truss. However, after further investigation I decided that this bridge is a pony or through girder bridge and not a Vierendell Truss.

Here is my reasoning. The short definition of a Vierendeel Truss is, a truss where the members are not triangulated but form rectangular openings, and is a frame with fixed joints that are capable of transferring and resisting bending moments.

While at first glance the Cow Creek Bridge may fit this definitions I noticed one key factor that swayed my vote on this one. The Vierendell Truss requires members to be rigidly connected. The Cow Creek Bridge has no individual members, just one giant plate with rather large holes cut into it. Had the bridge had a top chord, bottom chord, and connecting members that were welded or riveted together then this defiantly would be a Vierendell Truss.

Essentially the engineer designed a railroad style plate girder bridge and then cut holes in the girder to provide a more structurally efficient bridge. The reinforced holes and the large vertical stiffeners do give the appearance of a Vierendell Truss, but in my opinion this bridge is a unique plate girder bridge.

Again this is my opinion and reasoning on this subject and would love to hear what others might think, this could be an interesting discussion.

Thanks, Mike

Cow Creek Bridge
Posted March 17, 2009, by Ian Anderson (macsignals [at] gmail [dot] com)

This bridge looks like it could actually be a Vierendeel Truss:

http://en.wikipedia.org/wiki/Vierendeel_bridge

Just a thought though.