Mine Fan Foundation - Dynamic Analysis

Question

I am designing a foundation to support a 2,000 HP mine fan. This foundation will be designed in accordance with ACI 351.3R-04. In addition to performing manual calculations, I am going to use both Staadpro and Staad Foundation Advanced as computer-based solutions. 
 *Note - I've just downloaded Staad Foundation Advanced, and I'm aware of the machine foundation wizard. However, I've identified one (maybe two) errors with the output, so I'm likely just going to use that wizard output as a general reference. 
 Here are a few input parameters that might be of interest: 
 
 Minimum foundation stiffness = 5,000 k/in 
 Minimum foundation weight = 395,000 lbs 
 Motor/shaft/impeller RPM = 894 
 ISO G2.5 (ew = 0.1 in/s) 
 Rotating weight = impeller (7,845 lbs) + shaft (12,645 lbs) 
 Maximum allowable vibration amplitude = 0.2 in/s 
 
 The foundation block is 37' long x 15' wide x 5' thick. There are also pedestals on top of the block that support the bearings/shaft/impeller and the motor. (I'd like to attach my model, but I'm not seeing that option.) 
 Ok.....so......as for the Staadpro model........is there a way of having Staadpro calculating the vibration amplitudes (in bold above)? I'm familiar with the Modal Analysis approach in Staadpro, but not so much the Time History function. Do either of these give an output of the vibration amplitudes?

Sye · Accepted Answer

Correct. Modal analysis would just give you frequencies and mode shapes. For time history, you will need to input the forces.

Sye · Answer

Yes once you carry out the time history analysis you can go to the Postprocessing > Dynamics page and get time history of the velocities, displacements and accelerations as shown in the screenshot below. If you need the time-history data based on which these graphs are plotted, simply right click on the appropriate diagram and choose Save data in a text file ...

Sye · Answer

Sure. After you read the help documentation it may be useful to take a look at a few examples namely Example 16, 22 and 29 available as part of the help documentation as well. The corresponding STAAD.Pro models can be found within C:\SProV8i SS6\STAAD\Examp\US folder.

Sye · Answer

You can easily get the maximum displacement by looking at the Node Displacements table which basically reports the maximum response out of all instants of time at each node for a time history load case. To get the max/min out of all nodes, you can go to the Summary tab within the Node Displacements table and filter the table data based on the time history load case alone. This can be done by going to the menu option Results > Select Load Case and choosing the time history load case. 
 There is no way, that I can think of, to easily obtain similar data for time-vel or time-acc. You may possibly look at the nodes where the displacements are maximum to get some idea of what the critical locations are in your model. You can then look at the vel or acc time history at such nodes. One can plot the average of the time history responses for a node group if that if that is of any interest to you.