| Summary: | 碩士 === 國立海洋大學 === 河海工程學系 === 88 === In recent years, several port breakwaters in the northeastern coastal regions were damaged by several typhoons. For example, Pa-chi-Men breakwater of Port of Keelung was consecutively damaged by typhoons Herb. Zane and Winnie in 1996 and 1997 the parapets of outskirt breakwaters of both Port of Hualien and Port of Suao were damaged by typhoon Tim in 1994. It is found that the failures were due to spring tide, high storm surge and large storm waves and extreme high water levels during typhoon periods cause waves to break closer to the structures and attacked the structure at higher positions.
In this paper the typhoon data and water level data from tidal stations of Keelung, Yanlian, Kenfang, Suao, and Hualien were collected and analyzed. Results from harmonic analysis illustrate that the main tidal components are M2, K1, O1 and S2 and their annual changes were rather steady at each station except the tidal component of SA. The storm surge heights were studied according to the categorized roads and the associated intensity and wind velocity of typhoons. The results show that typhoon-induced surges in some stations, such as Yanlian were extremely large due to local geographical conditions.
The highest water levels and largest storm surge heights for all the studied periods analyzed statistically by using Gumbel method. The resulting periods of the return periods for each tidal station were derived as reference for practical coastal engineering design and constructions in the northeastern coastal zones.
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