DESIGN AND CONSTRUCTION OF BERTH IV MARGINAL WHARF AT SEAGIRT MARINE TERMINAL

摘要

The Seagirt Marine Terminal (SMT) area was originally constructed in 1980 to serve as the placement site for the material excavated to construct the I-95 Ft. McHenry Tunnel under Baltimore harbor. Cellular steel cofferdams were constructed to serve as the seaside retention structure. Over the past 30 years, the Maryland Port Administration (MPA) has been developing SMT as its premier container handling facility. Berths 1, 2, and 3 were constructed in the late 1980's to serve Panamax class vessels. Realizing the critical importance of providing a berth capable of handling 'New Panamax' class ships with 50 ft. (15.2 m) dredge depth, MPA entered into a public-private partnership with Ports America Chesapeake (PAC) to develop such a facility. In turn, PAC initiated a rapidly paced design-build venture to design and construct the berth. The new Berth IV is 1225 ft. (373 m) long and 154 ft. (47 m) wide with a 262-ft. (80-m) long sheetpile toewall on the Berth 3 end, and outboard mooring dolphin on the other end. Four state-of-the art 100-ft. (31-m) gage Supermax container cranes now traverse the new wharf structure. Significant design challenges were imposed by very poor soil conditions, cofferdam cell displacements, and heavy design load demand from ship docking and the Supermax cranes. The resulting wharf structure design featured ballasted precast slab panels founded on 24-in. (61-cm) square prestressed piles. The two crane rails are supported by cast-in-place concrete girders founded on 30-in. (76-cm) square prestressed piles. From the environmental perspective, the construction of the wharf required removal of some existing stormwater management controls that served a portion of the container yard. This necessitated the design of a 190-ft. (58-m) long by 29-ft. (9-m) wide underground stormwater vault.