Prime contractor Carter and Company will pour new concrete decks on the twin Interstate 5 bridges spanning Crowson Road south of Ashland.
The $2.5 million rehabilitation project will occur during daylight hours and should take about three months to complete. The work requires a traffic crossover, allowing the contractor to close one bridge while removing, rebuilding and pouring a new deck with a new concrete wearing surface.
The Crowson Road bridges, which are located near the Siskiyou Summit chain up area, date back to mid-1960s when I-5 first opened. The decks are old and in poor shape with significant concrete spalling. The use of deicer chemicals and salt for winter maintenance leads to the premature deterioration of concrete bridge decks through corrosion of the reinforcing steel. Once the rebar starts to corrode they in turn cause the concrete to spall and deteriorate.
“Hydroblasting will remove where the concrete is poor,” said ODOT Lead Bridge Engineer Bob Grubbs.
Hydroblasting utilizes high-pressure water to remove deteriorated concrete, providing an excellent bonding surface for repair material and new coating applications. Unlike jackhammers, hydroblasting does not produce vibrations throughout a structure and therefore does not introduce micro fractures.
“About half the depth of the concrete deck will be removed,” said Grubbs. “Once repairs are made, the bridge will receive a new concrete deck.”
Preacher Slide is a historic, chronic slide located on the Old Siskiyou Highway (Oregon 273), just east of the Southern Oregon landmark, Callahan’s Mountain Lodge. Several temporary fixes over the past seven years managed to hold back the slide at milepost 6 and repeatedly reopen the highway until ODOT could schedule a permanent repair.
This summer’s $2.2 million slide repair project will build a rock buttress designed to hold the slide in place as well as a slope drainage system that will divert water away.
“Unfortunately, the construction work necessitates a full closure of Old Siskiyou Highway for roughly a month,” said ODOT Project Information Specialist Gary Leaming. The detour will require travelers to use Oregon 66 or I-5 during the slide repair work. “That’s a longer detour for residents, the delivery drivers who travel it daily, and summer tourists.”
Last summer, ODOT wrapped up a slide repair project on another perennial headache, locally known as the “Crack of Doom,” on the historic Greensprings Highway near the Cascade summit. That slide repair also involved installing a large rock buttress and a new drainage system.
“Our agency’s regional slide budget is focused heavily on U.S. 101 in Curry and Coos counties,” said ODOT District Manager Jerry Marmon. “We’re pleased to finally schedule permanent fixes for the slide on Greensprings Highway and, now, the Preacher Slide on Old Siskiyou Highway. Our Ashland maintenance crew returned to these two locations each spring and summer to begin repairs only to see the slides break away again the following winter.”