The paper describes the pluming, design, and construction of an artificial island transshipping terminal in the Atlantic Ocean, 8 miles rom the coast of Brazil. At a connecting open-sea berth built along a 55-ft-deep natural hannel, salt and other granular materials can be loaded into 100,000 dead-weight ton (DWT) bulk carriers. Feeder vessels of 2,000 DWT can be unloaded on the sheltered side of the island. Up to 150,000 tons of salt can be accumulated in the storage area.
Soros Associates established the feasibility of building and maintaining an artificial island in this equatorial part. of the Atlantic Ocean on the basis of extensive investigations of wind and wave data, tidal movements, currents, and bottom conditions. Seismic surveys and soil borings were carried out before the final design of the island and of the pile-supported structures connected with it. The solutions of technical problems encountered during the design and construction provide useful information for the planning of future artificial islands and offshore terminals.
An artificial island was recently built 8 miles off the coast of Brazil, near Areia Branca, for TERMISA (Terminais Salineiros do Rio do Norte, S.A.) (Fig. 1). The island was designed for the transshipment of solar salt destined for markets located several thousand miles away. The decision to build this island was based on a detailed study of the region's salt producing industry, its markets, and the traditional methods of handling and transporting the product.
The new terminal with its sophisticated bulk handling system replaces the antiquated method of hoisting hand-filled buckets from lighters on board of ships riding at anchor. Before selecting the artificial island as the most desirable solution, Soros Asso. investigated several alternate systems, including self unloading barges, floating storage facilities, long-distance conveyors, and aerial cableways. These investigations established that an offshore transshipping terminal would be the most desirable arrangement, provided that a barge-unloading wharf, a storage area, and a ship loading pier can be built at the right location, approximately latitude 040 49' South, longitude 370 02' West (Fig. 2).
Special studies carried out by Sorts Assad., based on available statistical data and special surveys by the Hydrographic Dept. of the Brazilian Navy, indicated that in the open sea off AreiaBranca the frequency of wave height exceeding 5 ft is 10 percent, 7 ft is 2 percent, and the average wave is 3 ft high with a period of 4 to 5 seconds (Fig. 3).
The area is under the general influence of the southeasterly trade winds, subject to seasonal variations in accordance with the movements of the Inter-Tropical Convergence Zone, located immediately to the north. Winds and waves are generally from the easterly quarter (Fig. 4). Prevailing wind velocity is 15 Impost.
On the basis of statistical data, it was concluded that the ships can be loaded at an open-sea berth, but the barge unloading operation requires a wharf sheltered from prevailing waves.
