7/26/2011
Reed Hollinshead
ITD Communication
208-334-8881
reed.hollinshead@itd.idaho.gov
UPDATE: Idaho 55 repairs near Marsing will extend into next week
MARSING – The replacement culvert for a washed-out section of Idaho 55 near Marsing will likely not be received until Friday (July 29), extending repair time and subsequent re-opening of the road into early next week.
"The replacement culvert must be a reinforced concrete pipe made specifically for deep installations," said southwest Idaho Operations Engineer Dave Kuisti. This type of pipe material is not readily available and will have to be manufactured. The replacement pipe is coming from a Nampa company.
"A less-expensive metal pipe cannot be used because the composition of the soil would eventually corrode and eat away the metal, causing another failure. Aluminum, in that quantity and shape, is more expensive and difficult to find," he added.
To handle greater water-flow volumes, the new culvert also will be 48 inches in diameter rather than the 36-inch diameter of the corrugated metal culvert that failed Sunday afternoon.
Crews have constructed a gravel-and-dirt “bench” from which to use an excavator. From the bench, ITD will remove the remains of the old pipe and create a diversion channel in order to have a relatively dry area to work while replacing the culvert. The new concrete pipe will then be installed and the joints sealed. The diversion pipe will be removed and the excavation filled to near roadway level. The roadway base will then be graded, compacted and the roadway repaved.
The aging culvert failed, causing the washout of a 20-foot section of highway about a half-mile west of Marsing near the junction with U.S. 95 Sunday between 3:30 p.m. and 4 p.m.
Subsequently, an excavator opened the area above the culvert and removed debris Sunday night to minimize material washing down the channel and to the Snake River, about a mile away. The remaining roadway in that area was trenched through the night to allow water to flow from one side of the road to the other and not interrupt service to irrigators downstream or risk a collapse of the culvert. A collapse would have created a dam and spilled water over the roadway, potentially expanding the area of damage.
Two detour routes are in place. Drivers coming from Oregon on U.S. 95 are being directed to Pershall and Idaho 78, and drivers are directed to Edison and Thompson roads to get to Marsing using Idaho 55. Detour signs are in place to move traffic around the work area. The detours add about two miles to the route.
Repairs are estimated at $22,000. Because the failure was within the highway right-of-way, ITD will pay for the repairs through its maintenance funds.
According to 2010 data, approximately 3,300 vehicles use that section of highway each day, especially agricultural traffic.