Can it be designed to protect against a category 5 storm?
Yes. However, classification of storms by the Staffir-Simpson scale (Category 1-5) is no longer a viable benchmark to determine the forces produced by tidal surge from a storm. Other factors must be incorporated into the design and calculations in order to minimize risks from a major hurricane. Some factors, in addition to wind speed are: storm size, direction, forward movement, and slope.
Can a proper factor of safety be obtained?
The system can be designed to meet or exceed any factor of safety required by the building codes or governmental agencies.
How will you stop sand subsidence?
A geosynthetic layer will be put down.
If built on top of an existing levee subsidence should be very little.
Inspection ports can be in the concrete cap to inspect for subsidence or possibly pump in sand if needed.
It should be noted that a small amount of gap between the sand and cap would be beneficial to aid in impact resistance.
Will the structure subside?
As with any levee, subsidence must be engineered into the height of the structure for specific soil conditions.
Can it withstand the impact of a large boat?
It can be engineered to withstand any boat impact. The wider it is made, the stronger it will be.
How tall can you make it?
The height can be increased by increasing the width of the cap and depth of the piles, engineered to specific soil conditions.
Can you drive an vehicle on it?