STAAD Foundation Advanced CE do not check eccentric foundation
I was tried to design a isolated foundation with a eccentricity and the program shown a warning message, that the function was unable to perform the design. Does exist any particular reazon to disable this feature? And does exist any date for realese this feature again?
The second point that I notice, at Data Imput Pane the pedestal bar size are block, Does exist any particular reazon to disable this feature? And does exist any date for realese this feature again?
Regards,
I wasn't talking of full uplift. A full uplift is caused by a column reaction force that tries to uproot the foundation. Wind or seismic may cause full uplift.
I was talking about partial uplift. It is not necessary to have full uplift forces to produce loss of contact. A combination of a small vertically downward force on the foundation and a large moment can cause partial uplift.
See the figures below for how to identify a partial uplift condition.
As such there are no forces which are creating huge uplift forces. where can i find if there is partial loss of contact?
If the footing experiences a partial loss of contact for any of the ultimate load cases, the program will calculate the top reinforcement.
Are there any ultimate load cases in your model where there is a partial loss of contact? Doesn't the output show any top reinforcement?
What i have been getting in the calculation sheet for Top reinforcement design requirement is " Top reinforcement needs to be provided because of resultant negative pressure coming from net pressure calculations for bending. Should i calculate the top reinforcement as the SFA has not specified any
Your question:
Will be the footing be designed considering the additional moments that are going to be generated due to the eccentricity.
Answer
Yes
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Will the footing be designed even for the negative base pressure. What i have been seeing in the message is the negative pressures are nullified by the software, how will it actually work practically?
Answer:
Negative pressures are not ignored or nullified. The neutral axis (NA) position is re-evaluated until there are no negative pressures at the base. At this point, the CG of the soil pressure bulb coincides with the CG of the applied load for any given load case. Parts of the footing on one side of the NA will have zero pressures, parts of the other side will have non-zero (upward directed pressures). The CG of the non-zero pressures coincides with the CG of the load at its eccentric position.