VIDEO: Cable barrier goes up on I-94 near Alexandria
There's a new cable barrier system snaking its way along a 10-mile stretch of Interstate 94 through the Alexandria area. The installation started earlier this summer and should wrap up within the next two weeks.
In the meantime, the Minne-sota Department of Transpor-tation (MnDOT) hosted a train-ing session last week for local professionals who may encoun-ter the cable barrier up-close - for repairs or responding to vehicle crashes.
The cable barriers are de-signed to contain and redirect errant vehicles, primarily from crossing a median into oncom-ing traffic.
Cable barrier systems have been in use since the 1960s and provide for less violent impact.
In a classroom setting and out on the interstate, a group of MnDOT workers, tow truck drivers, emergency responders and law enforcement learned more about the high-tension cable barriers and how they work. Here are a few of the training highlights:
--When hit, posts that hold the cables in place are designed to fold over at grade-level.
--Compared to the cost of in-stalling concrete, cable barrier covers 10 times as many miles.
--Cable barriers are placed at a 4:1 slope for the system to be effective.
--The steel wire rope used is 21 strands of 12-gauge wire.
--Temperature affects the tension of the steel cable. Dur-ing installation this summer with daytime temperatures in the 70s, the cable barrier ten-sion is set at about 4,800 pounds and, because steel contracts in cold weather, the cable tension naturally increases to about 8,000 pounds in -10 degrees.
--If a vehicle crashes into the cable barrier, first responders and tow truck crews were ad-vised that cutting the wire should be a last resort. Instead, they were advised to pull the vehicle out the same way it came in and provided tips on other ways to loosen cable ten-sion.
--MnDOT crews received in-formation on maintaining and repairing the cable barrier sys-tems after a vehicle crash.
Next year, there are plans to continue the cable barrier along I-94. A stretch of about 18 miles of barrier will continue west of Garfield to roughly the Ashby exit, according to MnDOT.