It’s concrete (if you got suckered in watching “Baywatch”, the marina scenes were filmed in our home marina).
When Matthew came through, the dock got up to within 18 inches of the top of the pilings. Other docks failed, but, we were good.
Good, down here docks with wooden pilings pull out of the ground when the water rises, then when it goes down, they look like a bunch of twisted ladders, because some of the planks get ripped away...................................