Ontario's Transportation Technology Transfer Digest · December 2000 ·  Vol 6    Issue 4

 

New Bridge Technology

Anti-icing Hits the Deck

 

U NDER CERTAIN COLD weather conditions, bridges freeze first. This creates potentially haz­ardous driving situations for motorists who may not be expecting a change of condition from road to bridge sur­face. The ministry is testing a new technolo­gy this year to prevent bridge icing by using an automated system for chemically treating bridge decks.

The technology is actually quite simple. Four sensors, which are linked with a Road Weather Information System (RWIS), are placed in the road surface on and off the bridge. The RWIS link and sensors feed a computer with information on moisture, air temperature, humidity, precipitation and pavement conditions. When freezing is antic­ipated, the computer automatically triggers, or alerts personnel to trigger, a pump deliv­ering the anti-icing agent to the bridge deck. The anti-icing agent is pumped up to the deck surface through a system of pipes and nozzles placed along the structure and in the deck.  The anti-icing agent, potassium acetate, is environmentally friendly and non-corrosive; it does not attack the concrete and steel in the structure. Hence, use of this method may extend structure life and poten­tially reduce rehabilitation costs.

Because this is the first tie any such technology has been implemented on a high­way in Canada, it will be tried at one site ini­tially. The test site is at the junction of Hwy 401 and Hwy 416. This structure is a super-elevated high-speed freeway-to-freeway ramp in an area currently serviced through an Area Maintenance Contractor, who has agreed to participate in the testing. A "Boschung” system has been chosen for installation and will be operational by the middle of October.

Ministry staff have also gathered input from other jurisdictions already familiar with this technology. Maryland and Pennsylvania Departments of Transportation assisted the ministry by sharing their knowledge and experi­ence using automated bridge spraying tech­niques. They have generally experienced excellent results to date with respect to operation and reduction of collisions and are considering expanded use of bridge anti-icing.

 

For further information, contact

Todd Comfort at 613-545-4789 or

Todd.Comfort@mto.gov.on.ca, and

Mike Griff at 613-545-4763, or

Mike.Giriff®rtto.gov.on.ca,

Maintenance Office, Eastern Region.