This is what is called a 'bond beam'. It is designed to be stronger than ordinary concrete. The reason is because the crew will use RedHead bolts to anchor the roof structure to this poured-in-place beam. The RedHead bolts are so strong that you could lift an entire block if a crane was attached to these bolts. These special bolts expand like a mushroom where it meets resistance.
The main part of the aluminum roof frame is 1/4 in thick and 4 x 6 material. The legs are 1/4 thick and 4 x 4.
Gary Dennis of Dennis Aluminum in Foley did the fabricating.
Aluminum used for the porches because we knew it wouldn't rot and it resists the elements better than steel. This is the bottom of the Great Room porch. We planned to use Hardiboard for the ceiling because it is resistant to decay and it can be painted. Update: We have changed our minds after finding out about Magnum board from Magnum Building Products.