(Roseville, Minn.) — Motorists who regularly travel across the Mississippi River on the Interstate 35 E Lexington bridge just south of downtown St. Paul will have one less worry th is coming winter . Installation of an anti-icing system on the 1,150-foot long bridge deck begins July 11. The system, which sprays potassium acetate onto the bridge surface in inclement weather, will lessen the amount of frost and ice that for m on the bridge deck's surface.
The system also will be installed on 1,250 feet of the northbound approach road in an attempt to keep salt off the bridge. This will help the Minnesota Department of Transportation determine if an anti-icing system can prolong the life of a bridge by using a measured amount of anti-icing liquid on the structure only when it is needed.
W eather stations mounted on the bridge, along with sensors and thermometers in the bridge deck, will monitor weather conditions and temperature as well as register any precipitation amounts. By determining when frost forms or if there is any chance of freezing, spray nozzles in the bridge deck spray potassium acetate onto the bridge surface where the chemical is further distributed by traffic. Potassium acetate is used because of its ability to melt snow and ice at low temperatures and because of its minimal impact on the environment.
An anti-icing system installed in 1999 on the 1,950 foot Interstate 35W bridge just north of downtown Minneapolis has gotten credit for reducing crashes on the structure by nearly two-thirds. The bridge's location above the river near the St. Anthony Falls and nearby power plants made the bridge susceptible to icy conditions and resulting crashes.
The new I-35E Lexington bridge completed last September, spans the Mississippi River between St. Paul and Lilydale. Its location above the river near downtown St. Paul makes it an excellent candidate for the system.
During the installation and testing work, motorists are advised to watch for daily lane closures and intermittent ramp closures and use alternate routes to avoid congestion. Closures will be marked in advance and detour information will be provided. Drivers are advised to watch for workers and equipment along the interstate and they should slow down and drive carefully through work zone.
Weather permitting, the system will be up and operational by the middle of September.
Mn/DOT reminds motorists to SLOW DOWN in the work zone and NEVER enter a roadway that has been blocked with barriers or cones. Please join us in a safety partnership. For statewide traffic, construction and travel information visit www.511mn.org or call 511.