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86th Street Overpass

Photos 

The 86th Street Overpass remains an important milestone in civil engineering history: it was the first welded aluminum bridge in the world.

Photo taken by Historic American Engineering Record

View photos at Library of Congress

BH Photo #123891

Map 

Facts 

Overview
Lost Aluminum Bridge over Over I-35 & I-80 on 86th Street in Urbandale
Location
Urbandale, Polk County, Iowa
Status
Replaced by new bridge
History
Built 1958; Replaced 1994
Builder
- Ned L. Ashton of Iowa City, Iowa (Engineer)
Design
Built as part of the earliest construction on America's interstate highway system, the 86th Street Overpass represents a formative exercise in welded aluminum construction. It was designed by noted Iowa engineer Ned Ashton, under contract with the Iowa State Highway Commission, as an alternative to steel for bridge construction. The bridge's serendipitous merger of structural aluminum and electric arc welding was unprecedented. Never before had one structure combined such novel materials and techniques as this 220-foot-long overpass in Urbandale. Aluminum soon fell into disfavor among structural engineers, however, rendering the 86th Street Overpass an engineering anomaly. The lightweight metal may never have caught on for bridge construction, but the 86th Street Overpass remains an important milestone in civil engineering history: the first welded aluminum bridge in the world.
Approximate latitude, longitude
+41.65278, -93.73889   (decimal degrees)
41°39'10" N, 93°44'20" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/438475/4611489 (zone/easting/northing)
Quadrangle map:
Des Moines NW
Inventory number
BH 37422 (Bridgehunter.com ID)

Update Log 

  • December 12, 2015: Updated by Clark Vance: Added category "First of its kind"
  • May 10, 2012: Updated by Luke Harden: Added category "HAER documented"
  • September 13, 2008: Added by J.R. Manning

Sources 

  • J.R. Manning - thekitchenguy [at] sbcglobal [dot] net
  • HAER IA-42 - 86th Street Overpass, Spanning Interstate 35 & 80 at Northwest Eighty-sixth Street, Urbandale, Polk County, IA