After sizing a footing for bearing, sliding and overturning due to service loads, the next step is to design the steel reinforcing of the footing based on ultimate (factored) loads. Once I increase the loads from service to factored (based on the factored load combinations) the software wants to resize the footing to a larger size to compensate for the increased factored loads or else the design function produces an error and does not provide any output. How can the program be used to avoid checking for sliding and overturning so the reinforcing can be designed for ultimate loads?
If the footing size is increased to account for factored loads for bearing then the foundations will be unnecessarily too large.
Thanks for any input.