I used galvanized lag screws to attach the beams to the square posts and used galvanized nails to attach the galvanized joist hangers. For attaching 2x4 cross braces to the posts and attaching the outer joists to the beams I used 5/16 x 3 1/8 RSS structural screws. http://www.grkfasteners.com/en/RSS_1_2_information.htm. The structural screws work better than regular screws or lag bolts for me; they drill their own hole, and they installed easily without splitting using a battery drill. I could not find the structural screws at the local home centers, but was able to order them through my local Fastenal dealer. The project was described at http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=185709#Post185709