wood pile concrete cap

[jwac50]

i have a project to extend the height of an existing saltwater dock. the pile(s) are cresote treated (about 20 yrs old). i want to increase the height (and even up the elevation) by 2 feet for each pile. then i will replace the beams with 8x12 acza pt doug fir. Is it feasible to place drift pins in each pile, seal the top of the pile and then build a form 3 inches larger than the top of the pile around the top foot of the pile , then pour a reinforced concrete pile cap extension of 24 inches on top of the existing pile(s). the dock is a residential dock and the pile(s) are 12 inches across at the top?

 

[gerhardl]

jwac50!

Please be warned that I am not a construction engineer, and have no constructional experience for this type of construction.

I am, however, not convinced that this type of 'interface' between wood and concrete would be the best solution. Especially if seen with regard to different climatic crimping/increasing properties (climatic temperature variatons critical at location?) and corrosion (reinforced steel in concrete?) and concrete perhaps keeping top of wood piles more whet/moist than fortunate, and inner surface of concrete details not open to inspection and repair.

Perhaps a construction with 'cleaner' interface between wood and concrete could be arranged, if you have to use concrete at all?