I'm building a 12x24 concrete block shed. I would like to build my own 6:12 pitch trusses from 2x3x14ga steel. I know this sounds like a lot of work vs wood but I want something simple that will last forever with no maintenance, so that means no exposed wood eves, i can keep these trusses completely sealed up inside the building and deck over with metal roofing. There is lots of moisture in florida that rots wood over time. The trusses will get concreted into the top lentil blocks of the walls when the cells are filled, and i will weld the trusses to the vertical rebar. Is there any potential for detrimental corrosion over time due to concrete's alkalinity. I know rebar holds up because it forms an oxide layer and is sealed inside the concrete, but this will only be partially sealed since it is at the top.