CompositesWorld
Issue link: https://cw.epubxp.com/i/944580
45 CompositesWorld.com Marine Fender Project PA, US). Trademarked HarborPile, the pilings' design, described by Grimnes and project engineer Nate House, is an interesting example of how composites can be customized for specific project conditions. Optimizing a piling for best material use "Fenders are essentially fence posts that support guard rails, in simple terms," explains Grimnes. New Jersey Department of Trans- portation (NJDOT) authorities wanted to surround the bridge's deepest structural piers with energy-absorbing structures that would prevent damage to them from a large, out-of-control vessel. In this case, NJDOT specified (in US customary, non-metric units) Illustration / Karl Reque Manahawken Bay Bridge Marine Fender Project › Composite pilings allow greater design freedom and easier installation where treated wood has been banned. › Custom design optimizes performance with less material, for lower cost. › Fendering performance is enhanced with concrete fill, which increases allowable piling deflection. an impact load or force of 40.76 kip-ft, which it calculated would be produced by a 200-ton hopper barge, the largest vessel that NJDOT knew would ply the waters beneath the bridge, says House. Unlike a wharf or pier, where pilings must withstand significant axial loads to support the overhead structure, the Manahawkin piles would be fendering piles, which would need to resist lateral loads, explains House. e hollow tubes would be driven down into the sea bed far enough so that the soil friction provides fixity, to hold them in place: "e main purpose of the piles is to absorb energy, so they must deflect if hit by a vessel." NJDOT engineers provided Kenway with design factors for the piles: 1) a maximum allowable deflection of 18.6 inches (from Concrete fill inside 30 cm by 30 cm Barforce HDPE composite timbers w/pultruded composite rebar PLAN VIEW OF FENDER SYSTEM Six-piling "dolphin" Composite piles (angled piles to stop vessels) New bridge pier Old bridge pier Old wooden fenders Total pile length: 18.5m Wall thickness: 9 mm/ diameter: 400 mm Composite fendering pile Barforce composite lumber