See a time-lapse progression of this GRS-IBS bridge – HERE.

This project is administered by the Local Highway Technical Assistance Council.

Project Description: The project is located on Turner Road, a farm to market road approximately 0.2 miles west of Grace, Idaho. The Turner Road Penstock Bridge carries Turner Road over eleven foot diameter wooden penstock enclosed pipe that feeds a PacifiCorp owned power generation plant. The penstock is four and one half miles long beginning at the Grace Dam Complex on the Bear River and ending at the Grace Power Plant.

The Turner Road Penstock Bridge was closed to all traffic due to structural deficiencies. The bridge consisted of two arch pipes founded on concrete and pile foundations with concrete wing walls containing the roadway fill over the arch pipes. The concrete wing walls were severely deteriorated with large open, working cracks and pushed out of alignment. Should a large portion of the wings break off and land on the wooden penstock, it is expected the penstock would crush. The result of this damage would be a total loss of the entire penstock.

This project consisted of reconstructing Turner Road Penstock Bridge with geosynthetic reinforced soil integrated bridge system (GRS-IBS) technology.

Status: The project is currently in construction and about 90% complete. The anticipated completion date is spring 2016.

Project Manager: Matt Koster – mkoster@lhtac.org

Sponsor: Caribou County Road and Bridge Department

Key Number: 13563