Showing papers on "Breakwater published in 1977"

Design considerations for a tetrapod breakwater

Abstract: The paper addresses two important considerations in optimizing the cross-section design of a tetrapod breakwater: the shape and weight of the concrete breakwater cap and the related stability of the harbor-side armor units under wave overtopping conditions, the simultaneous selection of the optimum combination of the design wave height, the tetrapod form size, and the concrete density. The breakwater cross-sections discussed have a 4 on 3 seaward slope of concrete tetrapod armor units, a massive concrete cap, and prototype crest heights ranging from + 7.0 to + 9.9 meters above the wave still water line.

Imperial Beach, California design of structures for beach erosion control : hydraulic model investigation

Abstract: : A 1:75-scale (undistorted) hydraulic model, reproducing approximately 26 miles of shoreline and sufficient offshore area to permit generation of the required test waves, was used to investigate the arrangement and design of alternative proposed structures for prevention of erosion of the Imperial Beach shoreline The proposed structures consisted of (a) continuous breakwaters at the -15 ft and -10 ft contours, (b) segmented breakwaters at the -15 ft and -5 ft contours, (c) stepped breakwaters at the -10 ft and -5 ft contours, (d) a system of five groins, and (e) a system of nine groins A 115-ft-long wave generator, crushed coal tracer material, and an automated data acquisition and control system (ADACS) were used during model operation It was concluded from model test results that: Existing conditions are characterized by strong rip currents and longshore currents for most wave conditions with considerable onshore-offshore movement of sand; The original improvement plan for Imperial Beach (ie, the authorized five-groin plan) is ineffective in trapping tracer material, and, in fact, contributes to the offshore movement; The originally proposed breakwater plan (Plan 1) is not adequate for full protection of the beach Of the plans tested, Plans 3A, 4A, 5A, 5B, and 7 provide adequate beach protection