12 December 2001
FUNDAMENTALS OF DESIGN. Planning and design procedures for
coastal projects are described in CEM Section V-1. The engineering design steps
related to a specific type of coastal structure can be schematized as follows:
Specification of functional requirements and structure service life time.
Establishment of the statistics of local short-term and long-term sea states
as well as estimation of possible geomorphological changes.
Selection of design levels for the hydraulic response: wave runup,
overtopping, wave transmission, and wave reflection.
Consideration of construction equipment and procedures, and of
availability and durability of materials (e.g., only land based equipment
operational and available at reasonable costs, rock of sufficient size easily
Selection of alternative structure geometries to be further investigated
(e.g., composite caisson structures, rubble structures with and without
Identification of all possible failure modes for the selected structure (e.g.,
armor layer displacement).
Selection of design damage levels for the identified failure modes (e.g.,
50% probability of displacement of 5% of the armor units within 50 years).
Conceptual design of the structural parts based on the chosen design
levels for failure mode damage and hydraulic responses (e.g.,
determination of armor layer block size and crest height for a breakwater).
Evaluation of costs of the alternative structures and selection of preferred
design(s) for more detailed analysis and optimization.
Detailed design including economical optimization and evaluation of the
overall safety of the structure. This stage will involve scale model tests
and/or advanced computational analyses for non-standard and major
DESIGN OF SPECIFIC PROJECT ELEMENTS. The design of specific
coastal project elements is outlined below. For additional information and case studies,
see CEM Section VI-7-1.
Sloping-Front Structures. The types of structures discussed here are
armor units, one-sided shoreline sloping and two-sided sloped structures. Refer to
CEM Part VI-7-2 for further information regarding this subject.