Rte. 3 Over Piankatank River (John Andrew Twigg Bridge) Fender Replacement. Virginia Department of Transportation, Virginia.
In 2009, the Fredericksburg District of the Virginia Department of Transportation (VDOT) approached WRA to perform a study to replace the failing existing timber fenders around the channel span piers with a low-maintenance fender system. WRA prepared a study consisting of generating a record of river traffic, calculating vessel collision energies and forces required to be resisted by the fender system in accordance with the AASHTO Vessel Collision Specification and preparing separate viable fendering design concepts. WRA subsequently designed and prepared construction contract drawings of the Piankatank River fender replacement using the recommended system of rows of plumb glass fiber reinforced polymer piles faced with composite whales. Each line of fenders stretches 170 feet from tip to tip.
WRA engineers generated a record of river traffic traversing under the bridge. Based on the recorded vessels and velocities, WRA calculating vessel collision energies required to be resisted by the fender system in accordance with the AASHTO Vessel Collision Specification.
New fender system consists of rows of plumb GFRP piles faced with composite whales and connected by stainless steel through bolts. The composite piles were spliced together with steel H-piles at their bottoms to permit installation under low bridge deck.