Rating:
1 vote

Silver Creek Bridge

Map 

Street View 

Facts 

Overview
Through truss bridge over Silver Creek on Dogwood Road
Location
Pottawattamie County, Iowa
Status
Open to traffic
History
Built ca. 1930; rehabilitated 1983
Builder
- Iowa State Highway Commission of Ames, Iowa
Design
Pratt through truss
Dimensions
Length of largest span: 120.1 ft.
Total length: 165.0 ft.
Deck width: 17.1 ft.
Vertical clearance above deck: 11.9 ft.
Approximate latitude, longitude
+41.26026, -95.53191   (decimal degrees)
41°15'37" N, 95°31'55" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/287893/4570740 (zone/easting/northing)
Quadrangle map:
Taylor
Land survey
T. 75 N., R. 41 W., Sec. 35
Inventory numbers
IA 286410 (Iowa bridge number)
BH 14300 (Bridgehunter.com ID)
Inspection (as of 05/2014)
Deck condition rating: Serious (3 out of 9)
Superstructure condition rating: Serious (3 out of 9)
Substructure condition rating: Fair (5 out of 9)
Appraisal: Structurally deficient
Sufficiency rating: 17.2 (out of 100)
Average daily traffic (as of 2012)
30

Update Log 

  • May 25, 2016: New Street View added by Nathan Holth
  • January 26, 2012: Updated by Jason Smith: This bridge is a Pratt through truss bridge

Sources 

  • Jason Smith - flensburg [dot] bridgehunter [dot] av [at] googlemail [dot] com
  • Nathan Holth

Comments 

Silver Creek Bridge
Posted May 25, 2016, by Nathan Holth (nathan [at] historicbridges [dot] org)

Pat,

I can reassure you by noting that you are misunderstanding the meaning of the Federal Highway Administration's bridge rating system. Unsafe bridges are closed to traffic. This bridge is open to traffic and is therefore safe for use, provided you obey any posted weight and height restrictions. The 17 rating you refer to is a "sufficiency rating" and takes into account of broad range of factors to determine whether the bridge should be eligible for federal funding for repair or replacement. Structure condition is only one of the factors that go into producing a sufficiency rating. This bridge's 17 foot roadway is much more narrower than modern AASHTO guidelines for roadway width... this would lower the sufficiency rating, but does not make the bridge unsafe as long as you are a safe driver and don't swerve while crossing the bridge, or attempt to cross with opposing traffic on the bridge. The Serious rating you refer to indicates that the bridge has deteriorated from its original new condition. However, this deterioration has been taken into account by the owner of the bridge and if engineers find that this deterioration has reduced the bridge's load capacity, the posted weight limit will be adjusted accordingly. Again as long as you are obeying the posted weight limit it is safe to use this bridge. In the United States, unsafe bridges are always closed to traffic, regardless of sufficiency rating. It is possible for a safe bridge to have a 3% sufficiency rating, while alternatively a bridge might have a 60% sufficiency rating but if it develops a problem that makes it unsafe, it will be closed to traffic.

Silver Creek Bridge
Posted May 25, 2016, by Pat Gerdes (ptpkhll3 [at] aol [dot] com)

May 25, 2016

We live on Dogwood Rd. at 34546. We use this bridge daily as do our chidren, grandchildren, a school bus, and farmers with equipment. When is this bridge to be rebuilt to guarantee our safety since it has been deemed serious with a score of 17 out of 100? This is of great concern for our welfare.

Thank you for a quick response.

Pat Gerdes