Rating:
3 votes

Nishnabotna River Bridge

Photos 

Photo by Joe Elliott, Summer 1995, for HAER

View photos at Library of Congress

BH Photo #122220

Map 

Historical American Engineering Record Report - 1995 

Taken from the report written by Geoffrey H. Goldberg, Engineer

The availability of steel for domestic purposes like bridge building was severely limited during World War II. Most of the counties of Iowa, including Crawford County, turned to timber to fulfill their short-span bridge construction needs. In May of 1945, however, heavy flooding washed out 27 bridges and culverts throughout the county. It was decided to build replacement spans using steel. The Des Moines Steel Company was hired to design and fabricate the bridges. Forced to economize with material they turned to a bridge form that was popular in the 1860s and 1870s: the bowstring arch-truss. Although lacking the lateral stability of later bridge forms, the bowstring offered outstanding structural efficiency. During the period of the 1860s and 1870s thousands of bowstring arch-trusses were built throughout the nation. In a time of national crisis this once popular bridge form again supplied the solution. The Nishnabotna bridge is an excellent example of this series of bridges built during the war.

Facts 

Overview
Bowstring pony truss bridge over Nishnabotna Creek on 300th Street near Manilla
Location
Manilla, Crawford County, Iowa
Status
Open to traffic
History
Built 1945
Builders
- Des Moines Steel Co. of Des Moines, Iowa
- H. Gene McKeown of Council Bluffs
Design
Bowstring pony truss
Dimensions
Length of largest span: 77.0 ft.
Total length: 121.0 ft.
Deck width: 18.0 ft.
Recognition
Eligible for the National Register of Historic Places
Approximate latitude, longitude
+41.86501, -95.28614   (decimal degrees)
41°51'54" N, 95°17'10" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/310261/4637315 (zone/easting/northing)
Quadrangle map:
Defiance
Inventory numbers
IA 126550 (Iowa bridge number)
BH 37265 (Bridgehunter.com ID)
Inspection (as of 04/2015)
Deck condition rating: Poor (4 out of 9)
Superstructure condition rating: Fair (5 out of 9)
Substructure condition rating: Fair (5 out of 9)
Appraisal: Structurally deficient
Sufficiency rating: 46.4 (out of 100)
Average daily traffic (as of 2012)
45

Update Log 

  • August 8, 2016: New photos from Kevin Skow
  • May 11, 2015: Updated by Nathan Holth: Merged Latest NBI Data... and Updated Bridge... NOT LOST.
  • May 15, 2012: Updated by Luke Harden: Added category "H. Gene McKeown"
  • September 26, 2011: Updated by Jason Smith: This bridge has been replaced.
  • August 22, 2008: Essay added by J.R. Manning

Sources 

Comments 

Nishnabotna River Bridge
Posted May 14, 2015, by Robert Elder (robertelder1 [at] gmail [dot] com)

Finding truss bridges in aerial images is not always that easy. If the bridge is casting a shadow, consider yourself lucky. Most abandoned truss bridges are surrounded by dense foliage, unless you are in the deserts of the Mountain West. I have found plenty of "lost" bridges that were really just hiding in the trees.

Very lightweight trusses, including bowstrings can practically disappear against brown water.

Nishnabotna River Bridge
Posted May 13, 2015, by Elliott Johnson (elliottsgon15 [at] hotmail [dot] com)

even in blurry photos, truss bridges are really easy to spot because of the shadows they cast. well, that and the bright white color of the uceb's that replace them. its still hard to tell sometimes.

Nishnabotna River Bridge
Posted May 12, 2015, by Kevin Skow (weatherbum [at] hotmail [dot] com)

Also, if you're lucky, you can also sometimes even see the new bridge being built in the historical satellite data. I've encountered that a number of times while looking back to figure out when a bridge was replaced.

Nishnabotna River Bridge
Posted May 12, 2015, by Kevin Skow (weatherbum [at] hotmail [dot] com)

Thankfully, satellite imagery is getting better and it is becoming easier to do this kind of pre-reconnaissance before spending the time and money to visit the bridges. I've made it a habit to do a thorough analysis via Google Earth before going out to figure out what bridges are still (hopefully) there and update these pages if I find a discrepancy. The historical imagery function in Google Earth is also a lifesaver, since you can pick out when the bridge might have been replaced much easier (deck style changes, trees surrounding the bridge removed when it was replaced, etc).

Nishnabotna River Bridge
Posted May 12, 2015, by Elliott Johnson (elliottsgon15 [at] hotmail [dot] com)

with poor satellite imagery quality and no street view in rural areas like this, it really is hard to determine whether or not a bridge has actually been replaced or not. Especially when some old bridges have their views blocked by trees. even with street view and good quality imagery, the frequency of updates to these views could mean that the bridge has been replaced without even knowing. ive done some "armchair" visits myself but if the nbi doesnt show a replacement and I havent actually seen it with my own eyes than i dont change the status. just adding my views to the situation here.

Nishnabotna River Bridge
Posted May 12, 2015, by Nathan Holth (webmaster [at] historicbridges [dot] org)

I'm not bickering, just thought it was worth letting people know about this for trip planning purposes. Nothing is more frustrating than making a 3000 mile bridge trip, and not visiting a bridge because you heard it was replaced, then you get home and find out it was still standing and you missed it. I don't recall what the other bridges were, it was a while ago I found them. I did correct the other ones I found, but there may be others I missed which is why I felt the need to mention this. I realize a lot of bridgehunters just do "armchair" visits to bridges using Google, but some of us to field visits to bridges and this is therefore an important issue. Personally, I'd rather air on the side of caution... I'd rather drive to a bridge and find it replaced vs skip a bridge, get home, and find out it was still standing and I blew it.

Nishnabotna River Bridge
Posted May 12, 2015, by Anonymous

Oh, great. Now the constant bickering on the forum pages has gone intercontinental. Please take it private.

Nishnabotna River Bridge
Posted May 12, 2015, by Jason Smith (flensburg [dot] bridgehunter [dot] av [at] googlemail [dot] com)

Au contraire Monseiur Holth, which examples are you referring to? I noticed during my round a while back, using the same program, that there were plenty of concrete on the roadways spanning the ravines.... ;-)

Nishnabotna River Bridge
Posted May 11, 2015, by Nathan Holth (webmaster [at] historicbridges [dot] org)

I know I have found a number of bridges in Iowa on this website that Jason for some reason listed as replaced that aren't replaced...

Nishnabotna River Bridge
Posted May 11, 2015, by Kevin Skow (weatherbum [at] hotmail [dot] com)

Satellite imagery taken in March of this year shows that this bridge still exists. Can anyone else confirm this?