topic Re: Revit to Robot. Physical beam position & Overlapping element volume calculated twice. in Robot Structural Analysis Forum

Revit to Robot. Physical beam position & Overlapping element volume calculated twice.

Ryan.sulistian — Mon, 08 Nov 2021 15:30:23 GMT

I made a 2D concrete frame structure (3 stories) in Revit and linked the model to the Robot Structural Analysis.

In Revit, the physical beams are automatically positioned slightly lower so the top face is located according to the story's elevation, at the same elevation as the analytical beam element. (which is correct).

But after I exported it to Robot, the position of the physical beams moved a little higher, so now it's centerline is located according to the story's elevation.

Also during static seismic analysis, the effective seismic weight of overlapped volume of beam & column is automatically calculated twice (I've checked with manual calculations)

1. How can I set the physical beam placement orientation in Robot correspond with Revit?

2. How to avoid doubled calculation weight of overlapping volume of beam & column? (in context of static seismic analysis)

I attach the revit & robot file just in case anyone want to check

Revit ModelRobot Model

Re: Revit to Robot. Physical beam position & Overlapping element volume calculated twice.

TienDat.NGUYEN.Engineer — Tue, 09 Nov 2021 15:06:06 GMT

In fact we have to accept this overlap in mathematical model for the self weight.

But this one is not significant (normally 5-10% sum of self weight, superdead load, live load for the participant mass).

And beside, when you model the slab, the boundary of slab is at beam axis (not the outside edge), so it's the compensation for increase mass (double times at column-beam node) and it's acceptable in pratice.

Re: Revit to Robot. Physical beam position & Overlapping element volume calculated twice.

Ryan.sulistian — Wed, 10 Nov 2021 18:30:18 GMT

It's true. But it is also the case in SAP2000 vs ETABS, where in SAP2000 the overlapping volume calculated twice but not in ETABS.

By the way, is there any settings for each element to be offset? (i.e. beam end being offset to the location of the column face) It would help a lot when showing internal force on offset-end elements. (Just like ETABS when showing internal forces)

Re: Revit to Robot. Physical beam position & Overlapping element volume calculated twice.

TienDat.NGUYEN.Engineer — Wed, 10 Nov 2021 23:59:53 GMT

Hello @Ryan.sulistian , as I know Etabs can consider the internal force at beam/coulm edge. For RSAP it will not show like that.

But in RSAP, you can export the internal force from many points in bar element, you can choose the other points next to the start and end point to use the internal force at these node.

Re: Revit to Robot. Physical beam position & Overlapping element volume calculated twice.

Ryan.sulistian — Thu, 11 Nov 2021 05:13:05 GMT

I've figured that we can use the Offset feature in RSA to adjust them beam-column intersection volume (https://help.autodesk.com/view/RSAPRO/2021/ENU/?guid=GUID-63486561-1D79-4056-A945-890FD7CED7AB).

But I'm still wondering, how do you exactly specify the point/node on that certain point to show the internal forces ?