I've been asked to run an analysis of an existing piping system that includes a pump. The pump baseplate is supported by six spring cans - one at each corner and two in the middle. The baseplate is fabricated from typical structural steel shapes (channels mainly). I'd like to use the structural steel modeller and include it with the pipe model to create one model but can't figure out how to get the spring cans in. Any suggestions?

Insert them as any other restraint in the piping input (even it is not on the current element). I mean in the piping model.

One comment: I think is not necessary to model as chanels, it is enough as rigid without weight, will be no major difference.

Regards,

Thanks Dan. You are right about the rigids. I had done that already but some of the folks don't believe the support distribution that CAESAR is coming up with - I'm doing this as a way of putting the thing to rest.

I've modelled this system - deciding to model the entire pump/moto/baseplate assembly as a single W shape (I-Beam) with a force applied on the W flange at the pump CG and Motor CG. I still have three sets of springs - one on the pump end, one on the motor end, and one in the middle. For some reason CAESAR won't make a selection for the ones in the middle - it states that a constant spring is required but shows a load of 0. I've attached a screen shot of the model for information. I would think the middle set should be assigned a selection similar to the end sets. Any thoughts?

Chances are, if I have three double-acting Y supports under a loaded beam, one of them will see a positive load. In your case, it's that center support.

I might suggest sizing a single hanger location (the middle) but say you want 6 springs at that point. Then run a second model with two at each of your three positions (providing spring rate and theoretical cold load) to confirm operation.

Thanks Dave

I think that you can also do as follow:

Run the pump model only with rests instead spring cans, obtain the loads and then replace the rests with spring cans having the previous loads.

Regards,