Bridgehunter.com | 86th Street Overpass

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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

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
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)
USGS topographic map: Des Moines NW
Inventory number: BH 37422 (Bridgehunter.com ID)

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