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Fig. 2: Preparation of the work barge work is not visible, a natural gun finish is speci- fied. Another typical, yet more difficult repair is the total encapsulation of the top of a support pile to a concrete pile cap with shotcrete. The piles have to be recentered underneath the pile cap Fig. 3: Spalls along the outside wall of the Ferry House Platform #2 using a come-along and wedges to secure it in place. After the removal of barnacles and other contaminates, any unsound concrete is removed and welded wire reinforcement is wrapped around the pile cap and the support pile, thus “bridging” or “locking” them together. Expansion anchor bolts are installed to secure the welded wire reinforcement and shotcrete is then applied with a minimum thickness of 6 in. (150 mm). This jacket type of repair is extremely tidal-affected, as the top of the pile and pile caps are often com- pletely submerged during certain high-tide cycles. Ferry Slip Renovations at Liberty State Park Liberty State Park is located on the Upper New York Bay and is one of New Jersey’s most dra- matic and popular parks. This park is the only location in New Jersey with ferry service to Ellis Island and the Statue of Liberty. Passengers board the ferries from loading platform piers adjacent Fig. 4: Triangle-shaped piles and underdeck beams repaired and encased to the Ferry House Building. Ferry House Plat- with shotcrete form #2 is a concrete box structure built on timber piles and supported by large triangle-shaped work because the only access was limited by the concrete pile caps, also supported by timber piles small hatch door. Surprisingly, the inside walls of (Fig. 3 and 4). The only access to the underside the structure were in decent shape, with minor or inside of the structure is through a small hatch spalling but with substantial concrete erosion. The deck door on top of the platform deck. Spalled spalls were chipped, walls pressure-washed, and concrete including severely eroded pile caps galvanized welded wire reinforcement installed below the platform deck and along the length of and supported with expansion anchor bolts the inside and outside walls were repaired with attached to the substrate. Shotcrete was then shotcrete. Various spalls along the outside walls applied to a thickness of 3 in. (75 mm) to fill the were over 9 in. (225 mm) deep and only accessible spalls and add additional coverage over the during a low spring tide elevation, thus allowing existing reinforcement on the eroded sections of only 2 hours of productive work time. Concrete the walls (Fig. 5). underdeck beams were also repaired. The beams ran the width of the pier and were only reachable Safety Concerns by the workforce during neap tide cycles. Narrow, Typically, when there is ship activity, pier lightweight float stages were used to execute this security is very strict. A current Transportation Shotcrete • Summer 2014 25


2014SumShotcreteEMag
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