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.
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