From an email from Dave Hansen posted unedited with permission:
Kal & Grace,
FYI – The “Temporary Bulkhead” as shown in the permit application and on the current design plans, is designed with steel sheeting with a tie-back system and a concrete cap. The length is approx 400 LF.
Timber is great for residential bulkheads, but it is not adequate for a commercial/industrial application like this.
Timber would not hold up for the construction duration. The cap would require cleats to tie-off and a timber cap would not provide an adequate anchor for loaded barges, boats, etc., to tie off.
The concrete cap provides more structural stability for the bulkhead design.
This concrete cap bulkhead design is more of a standard section that contractors are used to building.
As an alternate, a more expensive steel cap could be used, but in either scenario (steel or concrete) the cap needs to be more durable than timber.
As promised in my many briefings to your respective organizations we will visit this discussion just past the 50% construction stage to see how we are co-existing with our boating public. Regards, Dave
Deputy City Manager
City of Virginia Beach