Vertical Turbine Pump Sesimic Calculation

[boze]

Need to calculate seismic conditions for a Vertical turbine pump, 75 hp, mounted on concrete pad. with shell extending 40' into soil.

Soil can provide restraint of shell column (casing) dependent on mass of soil, and will assume there is no horizontal shell casing movement relative to the pad. Expect that this column weight against the soil can be excluded from the equipment seismic calculation.

For weight calculation to determine seismic forces Fp and Fpv, will use full equipment load above grade. Will also
include a percentage (20%?) of the pump shaft assembly weight extending down to the pump impeller.

Determining center of gravity for force calculation will depend on the (20%)length of the below grade shaft assembly weight.

Would appreciate comments, information, tips for selecting the equipment weight, including the above ground weight, along with some of the pump shaft and enclosure assembly.

Thread 487-59047 provided some assistance.

 

[wannabeSE]

Assuming that there is no structural connection between the casing and the pump component anchored to the concrete pad, the seismic mass depends on how and where the shaft is supported and restrained. If there is no intermediate support (bearings) in the casing and the shaft is laterally restrained at the top and bottom, one might assume that half of the shaft mass is used to calculate horizontal forces at the concrete pad. Similarly, the mass used to calculate the vertical forces depends on where the shaft is restrained vertically. The load path needs to be examined.