We've been building these things they call "Pai Pai"s. They're pretty much the same thing, with a Polinesian twist.
Anyway, The attachment used was a 1/2" x 8" round plate, with a 12" x 3/4" all thread welded on the bottom. This was epoxed in when setting the post. The plate had 4 holes drilles for 12" x 1/2 lags that went up into the Ohia post.
This passed all the wind and uplift loads requiered, and left no exposed hardware.
Hell of a lot of trouble though.........
Anyway, The attachment used was a 1/2" x 8" round plate, with a 12" x 3/4" all thread welded on the bottom. This was epoxed in when setting the post. The plate had 4 holes drilles for 12" x 1/2 lags that went up into the Ohia post.
This passed all the wind and uplift loads requiered, and left no exposed hardware.
Hell of a lot of trouble though.........