Utah's Bridges: I-15 Buckhorn Overcrossing in Iron County

May 2006 (38.008 Degrees, -112.724 Degrees) I-15 Buckhorn OC

From the Paria River, State Route 87 jogs back and forth and then connects to I-15 for the long drive north to Salt Lake City. I don't know if it was the early morning light, the newly paved highway, or some quality of the hills or of the bridge, but I thought this was a pretty photo.

These two span overcrossings on I-15 (with their haunched girders) reminded me of the four-span haunched girder overcrossings in Michigan. For some reason I-15 has both two and four span overcrossings.

Buckhorn Overcrossing is part of a diamond interchange where the on and off ramps are on embankments and the bridge carries you across the freeway. However, the fourth side of the diamond is Buckhorn Road, which takes you away from the freeway. I originally thought this bridge was concrete, but the National Bridge Inventory says its a 292 ft long continuous steel girder bridge. Perhaps the use of haunched steel girders explains why it can go over both the northbound and southbound lanes using only two spans.

The bridge sits on a multicolumn bent in the median and on seat type abutments at the two ends. UglyBridges says it was built in 1979, it has a sufficiency rating of 92.7, and it only carries 32 vehicles a day. I remember the Utah DOT recently retrofitted the bridges on I-15 for earthquakes. I wonder if they retrofitted this bridge even though it carries so little traffic?

Utah's Bridges: I-15 Buckhorn Overcrossing in Iron County by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.