LIGHTWEIGHT BRIDGE DECKS CAN HAVE A RELATIVELY SHORT SERVICE LIFE, SOMETIMES AS SHORT AS 10 YEARS. TIMBER DECKING WILL ROT. STEEL DECKING RUSTS QUICKLY AND OFTEN DEVELOPS CRACKS DUE TO FATIGUE. OPEN STEEL GRATING ALSO ALLOWS WATER, DIRT, AND SALT TO GET ON THE PRIMARY STRUCTURAL MEMBERS AND CAUSE ADDITIONAL SERIOUS DETERIORATION. BRIDGE OWNERS HAVE EXPRESSED THE NEED FOR A LONG LASTING, CORROSION-RESISTANT, LIGHT-WEIGHT, SOLID SURFACE DECK FOR RAPID INSTALLATION. THIS TYPE OF DECK CAN ALLEVIATE WEIGHT RESTRICTIONS, SAVE HISTORIC BRIDGES THAT HAVE BEEN COMPROMISED OVER TIME, OR REPLACE LIGHTWEIGHT DECKS ON BRIDGES THAT WERE NOT DESIGNED TO SUPPORT A HEAVY CONCRETE DECK. ADVANCED COMPOSITE MATERIALS ARE COMMON IN AEROSPACE APPLICATIONS BUT ARE ALSO IDEAL FOR THESE SITUATIONS BECAUSE THEY HAVE A HIGH STRENGTH TO WEIGHT RATIO AND ARE RESISTANT TO CORROSION AND FATIGUE.
COMPOSITE DECKING IS MODULAR SO IT CAN BE INSTALLED QUICKLY. DESPITE THE BENEFITS, THESE DECKS HAVE NOT BEEN ADOPTED ON A WIDESPREAD BASIS BECAUSE THE MATERIAL COST IS HIGH. THERE HAVE ALSO BEEN PROBLEMS WITH THE BOND OF THE WEARING SURFACE THAT RESULTED IN UNEXPECTED MAINTENANCE WHICH DISCOURAGED OWNERS. THE FEDERAL HIGHWAY ADMINISTRATION AWARDED A TECHNOLOGY PARTNERSHIPS GRANT TO BRIDGECOMPOSITES, LLC TO REFINE THE MATERIALS AND FABRICATION METHODS USED TO PRODUCE A COMPOSITE BRIDGE DECK DEVELOPED BY THE NEW YORK DEPARTMENT OF TRANSPORTATION. THE PROGRAM DEMONSTRATED THAT A HIGH QUALITY STRUCTURAL SECTION COULD BE PRODUCED AND BE COST COMPETITIVE WITH OTHER ALTERNATIVES. REFINED ANALYSIS AND TESTING LED TO THE DEVELOPMENT OF AN EFFICIENT TRAPEZOID-SHAPED SECTION THAT IS USED AS A BUILDING BLOCK FOR A PANELIZED DECKING SYSTEM.
BY TAILORING MANUFACTURING PROCESSES, THE PROJECT TEAM DECREASED PRODUCTION TIME FOR DECK COMPONENTS AND PRODUCED A STRONGER, STIFFER, INTEGRATED PRODUCT. PULTRUDED TUBES ARE BOUND TOGETHER TO FORM STIFF STRUCTURAL PANELS READY FOR USE IN TYPICAL SITUATIONS BUT CAN ALSO BE TAILORED FOR SPECIFIC PROJECT DESIGNS AND TRANSPORT REQUIREMENTS. EXTENSIVE LABORATORY COMPONENT TESTING WAS PERFORMED AND FULL-SCALE PANELS WERE PROOF-TESTED TO DEMONSTRATE THE CAPABILITIES OF THE DECK IN FATIGUE AND EVEN FIRE. CONSTRUCTABILITY OF THE DECKING SYSTEM WAS DEMONSTRATED ON A 40′ LONG BRIDGE IN ALLEGANY COUNTY, NEW YORK. THE PROOF-OF-CONCEPT INSTALLATION DEMONSTRATED EXACTLY HOW THE DETAILS OF THE PROJECT SUCCESSFULLY COME TOGETHER.
STAINLESS STEEL CONNECTIONS, FIELD JOINTS, RAILING, AND THE WEARING SURFACE ARE ALL IMPORTANT COMPONENTS OF THIS DECK THAT IS EXPECTED TO OUTLIVE THE LIFE OF THE BRIDGE ITSELF. THE TWO-COURSE WEARING SURFACE APPLICATION INSURES A GOOD BOND, SEALS AND PROTECTS THE SURFACE, AND GIVES SKID RESISTANCE FOR SAFE DRIVING. A BRIDGE RAIL CAN BE ATTACHED DIRECTLY TO THE DECK, BUT IS EQUALLY SUITED FOR USE ON TRUSSES THAT HAVE A RAILING MOUNTED ON THE STRUCTURE SEPARATE FROM THE DECK. COMPOSITE BRIDGE DECKING OFFERS A NUMBER OF BENEFITS. IT IS MODULAR SO IT CAN BE INSTALLED QUICKLY, THE SOLID SURFACE PROTECTS THE STRUCTURAL STEEL, AND IT PROVIDES A QUIET RIDE AND GOOD SKID RESISTANCE.
IN MOST CASES, IT WILL OUTLIVE THE REST OF THE BRIDGE, BECAUSE IT DOESN’T CORRODE OR SUFFER FROM FATIGUE. THE USE OF MODULAR COMPONENTS, FABRICATED AWAY FROM THE PROJECT SITE, ALSO REDUCES EXPOSURE TIME DURING INSTALLATION. THIS INCREASES WORKER AND MOTORIST SAFETY AND REDUCES TRAFFIC CONGESTION AND DELAY. THE FINAL PROJECT REPORT, INCLUDING DETAILED MANUFACTURING SPECIFICATIONS, SHOP DRAWINGS AND CONNECTION DETAILS WILL BE AVAILABLE ONLINE IN FEBRUARY 2013. FOR MORE INFORMATION ON THE COMPOSITE BRIDGE DECKING PROJECT AND THE HIGHWAYS FOR LIFE TECHNOLOGY PARTNERSHIPS PROGRAM VISIT THEIR WEBSITE.
