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原文传递 DESIGN, CONSTRUCTION & MAINTENANCE OF LARGE NAVIGATION STRUCTURES IN NORTHERN AUSTRALIA

题名：	DESIGN, CONSTRUCTION & MAINTENANCE OF LARGE NAVIGATION STRUCTURES IN NORTHERN AUSTRALIA
作者：	J. IMRIE; P. CUMMINGS
关键词：	DESIGN; CONSTRUCTION ; MAINTENANCE ; LARGE NAVIGATION STRUCTURES
摘要：	Introduction. This paper examines some of the primary design and construction problems associated with navigation beacons and lighthouses in the remote regions of North Australia. Past and present solutions are described, and the anticipated future trends are predicted. Design and Construction Problems The problems most commonly encountered in the design and construction of navigation beacons at remote locations are identified as difficult access, lack of survey, no geotechnical information, difficult design and construction conditions, and the need for high reliability. Early Design Solutions The use of stone in the first lighthouses, and subsequent early alternatives, including fully bolted mild steel lattice towers [Cape Hotham (1919)]; concrete towers [Cape Don (1920)] and free standing steel tube towers [New Year Island (1960s)] are discussed. Current Techniques The development of the most common style of modern offshore beacon is described. These beacons comprise of a tubular steel pile base, a stainless steel lattice superstructure, and a glass fibre reinforced (GFRP) lantern house. With appropriate care, this design can provide 15 years of maintenance free service in submerged offshore reef locations. Recent examples Typical details are provided for the recently installed beacon at Megaera Reef. Other recently installed piled beacons include Acker’s Shoal, Caldbeck Reef, North Hixon (Swain) Reefs, Megaera Reef, Maxwell Reef, Iris Reef and Lihou Reef. Future trends The advent of accurate GPS has revolutionised navigation, to the extent that it would be theoretically possible to replace the present system of beacons with a limited number of strategically located GPS stations. However in practice, many of the beacons will remain, as ship’s masters and pilots will continue to need visual/radar confirmation of their position. Conclusions Despite recent advancements in GPS technology, it is believed that the need for beacons and lighthouses will continue, as will the challenge for engineers to arrive at low cost, maintenance free, structures for progressively harsher marine environments.
总页数：	Proceedings of the 30th PIANC-AIPCN Congress. Sydney Australia. 22-26 Sept. 2002. pp11
报告类型：	科技报告