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|Title:||Proposed jetty-head repair sections, Humboldt Bay, California : hydraulic model investigation|
|Authors:||United States. Army. Corps of Engineers. San Francisco District.|
Davidson, D. Donald.
|Publisher:||Hydraulics Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Technical report (U.S. Army Engineer Waterways Experiment Station) ; H-71-8.|
Abstract: Tests were conducted on a 1:50-scale model of the north jetty at Humboldt Bay, Calif., to determine information from which economical and stable repair sections can be designed to stop deterioration caused by wave action of the seaward ends of the north and south jetties at Humboldt Bay. Tests of the south jetty head were not conducted since results of the study of the north jetty head will be applicable to future repairs on the south jetty. Design of a satisfactory repair section is made difficult because of the large waves and day-to-day sea conditions that prohibit the use of floating plant for construction, the limited lifting capacity and horizontal reach of available land-based construction equipment, and the necessity of placing the armor unit toe protection on the existing underwater rubble mound. The study included the investigation of (a.) the waves that can attack the proposed structure, (b.) the effects on stability of linking the armor units, and (c.) the optimum shape of armor unit and repair section that would be stable for the selected design-wave conditions. Initially, repair sections were tested using cube-shaped blocks, tetrapods, tribars, and tri-longs; tests using dolosse were conducted near the end of the study when it was concluded that the size of tribar necessary to ensure stability for the design-wave conditions could not be placed at the required toe distance. Significant conclusions of the study were that (a.) 40- and 31-ft design waves vrere selected for the north jetty at still-water levels of +7 and 0.0 ft mllw, respectively; (b.) for similar repair sections and armor units, the use of a linking medium will increase the stability of a repair section relative to that obtained with unlinked armor units; (c.) a 44-ton tribar section was considered the optimum linked repair section for rehabilitation of the jetty head; (d.) the optimum unlinked tribar repair section consists of 65-ton tribars; and (e.) although the dolos repair section proposed by the San Francisco District will prevent major damage from occurring to the ends of the Humboldt Bay jetty during a storm of the selected wave conditions, it is believed that a repair section with a minimum armor toe distance of 2.15 ft from the radius point of the monolith and 43-ton dolos armor units made of 160-pcf concrete, random-placed over the entire repair section, would provide a more satisfactory and lasting design. NOTE: This file is large. Allow your browser several minutes to download the file.
|Appears in Collections:||Technical Report|