FIXED MARINE STRUCTURES By: Cameron Roy

Uses Piers Wharves Bulkheads Quays Dolphins Trestles Catwalks Moles

Pier A pier is a raised walkway over water, supported by widely spread piles or pillars

Bulkhead Coastal bulkheads are most often referred to as seawalls, bulkheading, or riprap revetments. These manmade structures are constructed along shorelines with the purpose of controlling beach erosion.

Trestle A trestle is a rigid frame used as a support, especially referring to a path supported by a number of such braced frames or short spans supported by splayed vertical elements (usually for railroad use).

Marine Engineering Marine Engineering involves the design, construction, installation, operation and support of the systems and equipment which propel and control marine vehicles, and of the systems which make a vehicle or structure habitable for crew, passengers and cargo.

Open Vs. Closed Fill Construction Closed - manufactured in such a way that various portions cannot be readily inspected at the installation site without their disassembly or destruction. Open - manufactured in such a way that all portions can be readily inspected at the installation site without disassembly or destruction.

2 Types of Closed Fill Construction Sheet pile cofferdam structures and Concrete caissons Use weight and gravity as their primary structural components Suited for areas where shallow rock exists Ideal for structures that require resistance to high lateral pressure and overturning Concrete and stone offer great compressive strength

Sheet Pile Cofferdam Structures A watertight structure that encloses an area under water, pumped dry to enable construction work to be carried out. Constructed by driving a series of thin retaining dividers in the form of interconnecting circles or diaphragms and filling the voids with a concrete or stone substrate The system is divided into smaller diaphragms because excessive concrete would cause to much lateral pressure during the curing phase and could cause the supporting sheet piles to give out

Sheet Pile Cofferdam Structures

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Concrete Caissons A caisson is a retaining, watertight structure used, for example, to work on the foundations of a bridge pier, for the construction of a concrete dam, or for the repair of ships. Concrete caissons consist of circular steel or concrete tubes drilled into the ground The tubes are filled with concrete or an equivalent structural material The caisson will be brought down through soft mud until a suitable foundation material is encountered. While bedrock is preferred, a stable, hard mud is sometimes used when bedrock is too deep.

Concrete Caissons

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Pile Supported Construction End Bearing Pile Loads – get strength from the dense soils or rock located below the upper layer of sand Friction Pile Loads – get strength from the surrounding cohesive soil Pile construction is generally used where lateral load is not a huge concern.

Pile Supported Construction

Factor Involved in Determining the Best Type of Structure to Use Subsurface soil conditions Bedrock depth Bearing material Water depth

Subsurface Soil Conditions Subsurface soil can be made up of materials such as sand, stone, clay, silt or any combination of the four Pre-construction involves consulting with a soil engineering firm so the engineers can administer any necessary test involved with designing a safe and sturdy structure

Bedrock Depth/Water Depth Bedrock depth is an important consideration because you need to know how deep you need to drive piles or columns to meet the required live and dead loads Live Load – any projected load the structure will have to support that is not connected to the structure itself (people, equipment, etc) Dead Load – weight bearing or non-weight bearing materials connected to the structure

Bearing Material Important in determining what equipment to use and the means of acquiring it Contractors need to know this when figuring out how to cut costs Local cost and availability of construction materials and labor

Other Factor That May Affect the Choice Between Open and Closed Type Construction The magnitude and nature of loadings Hydraulic conditions such as wave action and currents Fire hazard and safety-related requirements Damage susceptibility and ease of repairs Construction schedule and weather considerations Local construction practices Environmental and regulatory concerns over water circulation and habitat loss

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