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VIDEO: Cable barrier goes up on I-94 near Alexandria

Out on Interstate 94 last Wednesday, a group of MnDOT workers, tow truck drivers and emergency responders learned more about the recently in-stalled high-tension cable barriers and how they work. Jay Winn (center) rep-resented the cable barrier manufacturer, Gibraltar, and showed the group how the system's posts function and can easily be repaired if struck by a vehicle.(Echo Press photo by Amy Chaffins)1 / 2
A new cable barrier system was recently installed along a 10-mile stretch of Interstate 94 through the Alexandria area. The cable system is intended to contain and redirect errant vehicles, primarily from crossing a median into oncoming traffic. (Echo Press photo by Amy Chaffins)2 / 2

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.

Amy Chaffins

Amy Chaffins is a journalist working for the Echo Press newspaper in Alexandria, Minnesota.

(320) 763-3133
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