Workers prepare to install a CSi Bridge Dek on the Jewfish Creek Bridge in Key Largo, Fla.

Options for new or replacement bridge decks continue to expand. In addition to traditional steel-reinforced, cast-in-place concrete with removable forms or precast/prestressed concrete decking, design engineers can now consider composite steel-concrete cast-in-place systems with stay-in-place forms or steel grid systems, either cast-in-place or precast. For lightweight requirements, aluminum or fiber-reinforced polymer (FRP) composite bridge decking are options.

CSi’s Bridge Dek is a fully engineered metal, stay-in-place form system used for concrete bridge decks. According to the company, the designed live load allows the flexibility of workers, supplies, and equipment to reside safely on top of the installed system. The heavy galvanizing on the steel forms results in a no-maintenance system for the life of the bridge, the company said. In environments where corrosion is a significant concern, CSi offers Rhino-Dek, a polymer laminate-coated metal, stay-in-place form system designed for extremely aggressive environments. CSi’s Bridge Dek is compatible with steel and concrete superstructures, and used in new construction, bridge widenings, and redeckings. A variety of profiles and gauges accommodate design spans ranging from 2 feet to 13 feet, 5 inches with no requirement for temporary shoring.

D.S. Brown’s Exodermic Bridge Deck is a modular system comprised of a reinforced concrete slab on top of, and composite with, an unfilled steel grid. According to the company, this maximizes the use of the compressive strength of concrete and the tensile strength of steel. Horizontal shear transfer is developed through the partial embedment in the concrete of the top portion of the main bars, which are punched with 3/4-inch holes. The deck can span 15 feet between supports and weigh as little as 40 pounds per square foot. The concrete component of an Exodermic deck can be precast before the panels are placed on the bridge, or cast-in-place, in which case the steel grid acts as a form that permits elimination of the bottom half of a standard reinforced concrete slab. Exodermic decks are made composite with the steel superstructure by welding headed studs to stringers, floor beams, and main girders as appropriate, and embedding these headed studs in full-depth concrete.

Sapa Industrial Extrusions offers aluminum bridge decking that allows for accelerated construction, including preassembled, “Deployment Ready” designs for rapid bridge deck or whole-bridge replacement. The lightweight decking (25 pounds per square foot) decreases dead load, which the company says facilitates bridge rehabilitation versus replacement by allowing for widening of functionally obsolete bridges using the existing substructure, as well as increasing bridge load rating. Aluminum bridge decking also reduces lifecycle costs because it does not require paint and is recyclable. The modular panels have a proven minimum 12-year wearing surface, the company said.

Martin Marietta Composites’ DuraSpan FRP decks are one-fifth the weight of a comparable concrete deck, the company said, which allows rapid installation using light equipment, reducing construction time and labor costs. According to the company, composite materials have significant advantages over conventional materials (steel, wood, and concrete) in those cases where light weight, corrosion resistance, and rapid installation are important, such as in historic bridges, movable bridges, and in urban environments. The decks are resistant to corrosion and freeze/thaw cycles; and deck surfaces can be topped with skid-resistant overlays. DuraSpan decks are prefabricated in 8- to 10-foot-wide panels. Bridge designers often use DuraSpan to achieve composite bending action with the bridge’s beams, Martin Marietta said, thereby increasing the beams’ ability to resist bending and deflection.

More information:
Metal Dek Group — www.metaldek.com

D.S. Brown — www.exodermic.com

Sapa Industrial Extrusions — www.sapagroup.com/us/industrialextrusions

Martin Marietta Composites — www.martinmariettacomposites.com