Figure 6 simulated crane placement in model and

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Unformatted text preview: conditions, o Two different “slings” and quick release mechanism, o Different toe details. Figure 6 – Simulated Crane Placement in Model and Actual Placement These test results confirmed the ability to place filter stone and armour units during typical swell conditions (including achieving the required placement density for the armour units), and also confirmed the stability of the resulting structure under the design wave conditions. The tests also led to refinements in the toe detail, and to the recommendation to use conservatively sized armour units (to reduce down slope settlement of the armour layer). Regardless, the ability to construct a suitable under layer in the field, and also to achieve good placement of the armour units, remained a significant concern due to the persistent swell wave conditions and the need for divers to verify placement under dangerous conditions. Although a study was planned to address the second issue noted above (i.e. risk of armour unit breakage), this study was not completed, as the breakwater design concept was switched from concrete armour units to a berm design when a suitable source of quarried stone was confirmed. Two berm concepts were considered, including: • Single-class berm breakwater; • Multi-class berm breakwater. 8 Baird developed the single class berm breakwater concept in the early 1980s, based on historical precedents and extensive physical model testing for projects in Iceland and Alaska. The design concept is based on the use of a wide, porous berm of armour stone to dissipate wave energy. This allows the use of smaller armour stone than a conventional design, with better utilization of the quarry, and provides an alternative to concrete armour units for exposed locations, with the potential for significant cost savings. Baird’s most recent application of this concept was for the rehabilitation of a damaged breakwater in the Azores (refer to Scott et al, 2006), where a 30 m wide berm of 5 to 15 tonne stone was utilized to resist a design breaking wave of Hs = 7.5 m. The multi-...
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This note was uploaded on 02/04/2014 for the course HE 8450 taught by Professor Verhagen during the Spring '14 term at Technische Universiteit Delft.

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