Locations of compression and tension in footing rebars?

Compression and tension occur in opposite side of the footing relative to position. So, at a spread ftg or pile cap, the top reinforcing will be in tension and the bottom compression. At the midspan, between spread ftgs or pile caps, the tension will occur in the bottom and compression in the top. Rebar lap splices usually occur in the compression points, so bottom lap at spread ftgs and top at midspans. Also, details will typical have additional rebar at the points of maximum tension so at the top over supports and bottom at midspans. This though should be confirmed with the Engineer of Record on any project, as assumptions can change project to project. But this is the general concept.