Base pressure in SAP2000

[maestri]

For a raft modeled using thick-shell elements in SAP2000, with supports specified as area springs or Joint springs; how does one compute the base pressure?

More specifically is there a direction option to get base pressure values like in STAAD.pro
or do I have to calculate effective contributory area at each node and then divide this with joint reactions?

Also, in the user form for Display Joint reactions there is an option "show soil pressure"
can anyone please explain what SAP does when this option is enabled? I see a contour which is displayed is this is Base Pressure contour?

Thanks in advance.

 

[Guest262653]

There is no option for "show soil pressure" in SAP2000. But you defined the spring constants yourself, right? So, what is keeping you from calculating the pressures directly from the displacements?

 

[maestri]

Hello avscorreia!

I am using SAP ver 16, in which there is an option of "show soil pressure". It can be accessed by Display> Show forces stresses> Joints. which opens a user form with the mentioned option.

I have clarified my original query with CSI and they replied saying that the contours shown are indeed base pressure values, but one cannot extract the exact numerical value in SAP. The exact reply by CSI is as follows

"On the basis of color codes you can get a good idea about the average pressure at a location. Values of base reactions at a point can be seen in tabular form using Display>Show Table command. Once these forces are divided by the tributary area of a joint then pressure at a point can be obtained. Alternatively you can use SAFE software where this is handled with great ease and efficiency. Export of model and its results from SAP2000 to SAFE are available.

regards"