vtrc Bridge Deck Anti-Icing System
Bridge on Ramp from Route 7 EBL
to Route 66 EBL
Fairfax County, Virginia		 spray

The State of Virginia experiences numerous freeze-thaw weather cycles during a winter season. These cycles may occur daily as overnight atmospheric temperature drops below freezing and daytime temperature rises above freezing. Humidity levels in the state are usually high which results in moisture forming on surfaces as temperatures drop. The temperature of bridge decks, because they are exposed to the air, usually tracks air temperature more closely than the adjacent roadway pavements. These circumstances can lead to frozen moisture and reduced friction on bridge decks while the adjacent roadway is unaffected. To combat this problem maintenance crews often treat bridge decks with chemicals and abrasives when no action is needed on the adjacent roadway. In the interest of providing motorists with the safest driving conditions possible on its highways and bridges during icy weather, VDOT is evaluating the effectiveness and practicality of automated bridge deck anti-icing spray system technology.

The objectives of the project are to: 1.) Evaluate the durability and effectiveness of the system, 2.) Become familiar with the maintenance and construction problems involved with such a system and 3.) Develop a prototype performance specification for the installation of such systems in Virginia.

The need for this project is driven by VDOT’s plans to widen a number of bridges along Route 95 through the Richmond District and the construction of the Route 95 - Springfield Interchange in the Northern Virginia District, with a number of new structures, both to commence in the year 2000. VDOT desires to investigate new technologies available for keeping frost from developing on these structures.

The initial phase of this effort involved selecting an anti-icing spray system most appropriate for the bridge site. Time constraints due to the design schedule for the Route 95 and Springfield Bypass bridges dictated that the pilot test system be designed and installed during 1998. For this reason a bridge scheduled for deck surface replacement was chosen for the pilot test installation. The bridge is on the ramp from Route 7 EBL to Route 66 EBL in Fairfax County, Virginia. This bridge site is located in an urban area where frost conditions during winter can be quite prevalent.

The anti-icing system is designed and manufactured by Odin Systems International, Inc. of St. Simons Island, Georgia. The system is composed of a reservoir, pump and a network of spray nozzles capable of applying a liquid anti-icing agent on the travel lanes of a bridge deck. The liquid anti-icing agent is magnesium chloride. The system will test three nozzle mounting schemes; parapet mounted, in deck lane edge mounted and in deck centerline mounted. When activated, the system will spray liquid chemical across the deck.

This spray system is automatically activated by a computerized control system developed at the Virginia Transportation Research Council. It utilizes the following combination of input sensors:

The control logic is programmed to activate the system in anticipation of frost or icing road conditions. In addition, the control system allows for custom programming of the starting sequence, including a manual startup.

Click here for details

If you need additional information about this project,
please contact Mr. Daniel Roosevelt or Dr. Edward Hoppe at the
Virginia Transportation Research Council
(434) 293-1900

Updated March 6, 1999