Purpose 

Indicate why modeling a U-bolt (guide support) connected to a beam and wall base plate indicates no torsional moments. This will show how results reports indicates only forces and moments on the beam and no torsion loading, why?

Make a change to modeling approach so that the torsional loads can also be transferred from the pipe to the beam and wall base plate.

Key Information 

• AutoPIPE modeling of wall base plate, cantilever beam, and guide support:

• Analysis results:

• Question:
  • Why are there no torsional moment in the exported beam loads or at the beam/baseplate reaction when a pipe guide support was connected to the end of a cantilevered beam.
• Answer: 
  • First, A guide support resists lateral movements perpendicular to pipe and not torsional / rotational restraint. Next, pushing down on node point End2 (see model image above), would not create a moment on the beam. The guide support would act like an pivot point. 

Making the anchor at End1, very flexible, further proves how a guide support acts like a pivot / fulcrum. Notice how End1 rises up and End2 falls in image below in comparison to the image above. 

• • The only rotational resistance provided by a guide support would be due to friction loading. If the intent is to transfer a rotational load to a beam and ultimately the wall mounted base plate, consider a different modeling approach that maybe should include a Rotational Support and / or Connected Anchor.
  •  
  •  How to model a U-bolt support? Assuming you believe a U-bolt support restrains rotational movement about the axis of the beam, consider inserting a rotational support. 

• • Now the results will clearly show a rotational / torsional load on the beam and wall base plate:

FAQs (if applicable) 

Does an AutoPIPE guide support tied to a beam transfer torsional moment into the beam?

No. guide support does not transfer torsional load because of exactly how a guide support is defined in AutoPIPE. 

What loads can a guide support transfer to the beam in the original modeling approach scenario?

A guide support is described in AutoPIPE help "A guide restricts movement of the pipe normal to the pipe axis, and is the only support type which uses two separate bearing springs (one for up/down, one for left/right). In additional, friction loads can be applied when the pipe is contacting a guide boundary.

How should the model be changed if torsional load transfer is required?

The case specifically notes adding a rotation support to the guide support or replacing the 2 supports with a single connected anchor, both of these modeling techniques would impose torsional loads on the beam and wall baseplate.