Capitol Blvd. Bridge
Northbound IH5
Photo taken by Royce and Bobette Haley in August 2014
BH Photo #306323
Thanks Michael, asked and answered!
This is a steel arch. I have been under it many times.
A close-up in the street view from underneath does actually seem to suggest a steel arch, painted light gray (looks the same color as concrete)--The upper and lower edges of the arches themselves are flanged, where concrete would be flat without flanges. Also, it looks like the arch is reflecting a little bit of sunlight in the view to the southwest, also suggesting metal. These are just observations; I can't say for sure that this is accurate, however.
Description indicates "steel arch", street view images clearly suggest, concrete arch. Local information needed.
This bridge was originally supported by vertical piers, but widening of I-5 in 1988 necessitated replacing the piers with the arch you see today. I have attached a photo of when the piers were still standing between the arches.