Rebar.

[Flatlander]

I’m add three more bins to my line of hopper bins. They are a little larger than the last ones and will hold close to 400 tons of wheat each. Pouring a pad 24 inches thick and doing 3/4 rebar two layers and on a foot grid. The last pads we poured were 18 inch thick and I place the rebar evenly. 6 down from top and 6 up from bottom. Any advice on how to position the bars. Kinda of a dumb question I know but would like to get the best possible pad strength. Site has been dug down to sub soil and packed with crushed concrete 10 inches deep.

 

[HatsOff]

Steel closer to the bottom/top is stronger. Minimum 75mm off the bottom and 50mm from the top. But you'd need to bend some steel to make a mini cage to space the bars.

However... 400 t is quite a significant load. You could get an engineer involved for a few hundred quid to provide a proper design. Don't want any sudden failures.