I am using STAAD foundation to design foundation for a vertical vessel using the plant mode. This is the error I keep getting even though my loads are substantial.
Not sure how to correct this, please advise.
In this current situation, axial load is less (as the vessel itself is lightly loaded) but the moment is high ( As wind does not depend upon the weight of vessel). Due to this reason, the stress concentration is high and pressure on soil exceeds bearing capacity. Please not that here bearing capacity value is also very less. Here following things can be followed-
1) Put the footing in a deeper lever to increase soil weight
2) Bearing capacity value can be multiplied with some factor (1.15 to 1.25 as per respective code and soil condition) for seismic and wind cases. This is possible if the soil is not sandy soil and soil consultant approves.
3) Increase the plan dimension of the footing.
Thanks. Looks like because of exactly what you noted, it is skipping rebar design, as I am able to see all other calcs. Using min reinforcement should suffice.