Practical question for mechanical/Civil engineers

[CR Haeger]

Ill briefly take a shot at this.

I think you are correct in that the max poured concrete pressure will be at the bottom of the 3m column of concrete (~0.71 bar).

I think you are also correct in assuming that if you fix the top and bottom of the board, then the location of max (unfixed) board deflection will be lower than the 1.5m point, due to the linearly increasing pressure being placed on the board per meter of depth. At 2m, the estimated pressure will be about 0.47 bar.

As to the total force from the wet concrete pressing against the board, it seems you may generate about 21kN total, with the majority being borne by the middle and lower board "fixtures".

I am sure there are experts out there who can check my math and probably give you more detailed advice.

   

PS - Here is a fun link that may help directly Beam Calculator