Structural Stiffeners Snapping Through Beam Web

[Will.lloydGXGKD]

Hi,

I'm having an issue where I'm placing stiffeners on a beam and they are snapping onto each other through the web. I then can't not separate them. How do I stop this from happening? 

[AEC_Revit_Lab]

Use Place on Face in a shaded or hidden-line section/3D view, not Wireframe. Hover the required web face and press Tab until it highlights; use Space to flip if needed. For paired plates, use the Steel Stiffener connection and set Number of stiffener plates to 2. Hope this helps. If it solves the issue, you’re welcome to mark it as a solution so others can find it more easily.

[jay_colc]

When placing Structural Connection > Stiffeners it asks for a point of placement so ensuring you are in a view what you can accurately place them is imperative.

As regards going through the Web, I am not 100% sure but your does section looks slights off axis/plane and could cause issues?

[Will.lloydGXGKD]

Hi, this wasn't the issue. Might have to try the steel stiffener connection though often I have to use bespoke beam families not the standard ones, which often have limitations with steel connections.

[Will.lloydGXGKD]

Hi, placement isn't the issue, this is a cross beam for a bridge so the I section is not horizontal. The issue is that after they have been placed the space between them is too small (15mm) so they auto connect to one another. This leads to one of them  passing through the web to attach to the end of the other one. After its done this I am unable to separate them. 

I've used structural stiffener family category, but it looks as though you use structural connections which we don't normally use because they don't work well with our bespoke families. I'll have to play around with them more to see if I can get them to work as I want.

[jay_colc]

That makes more sense as regards bespoke families I assumed that were Revit based!

There is no way no way of guessing how they work if they are bespoke and small tolerances in orientation or alignment may cause this to happen so review you families for such discrepancies.

As regards selection can you use the Tab Key to try and cycle through selection of items?

[Emanuel.Nestor]

Hi,

The behavior might very well be related to the definition of the bespoke beam family.

Was it created starting from an existing beam family? Or a completely new one?
Does it follow the requirements for steel fabrication beams:

• Supported Structural Steel Shapes and Families for Steel Fabrication

Hope it helps 🙂
Emy

[AEC_Revit_Lab]

For bespoke beams, model both plates in one paired Structural Stiffener family. Drive their offsets from a Web Thickness parameter (±Web Thickness/2). That preserves the 15 mm gap and removes the adjacent instance ends Revit is snapping together.

[lauri_barnhart]

Greetings, @Will.lloydGXGKD.

Hope you are well. Following up to see if any of the information provided by AEC_Revit_Lab, jay_colc or Emanuel.Nestor helped clarify your question and resolve it. If any reply provided the help needed, please consider clicking on the 'Accept Solution' button on the reply that helped.

Thanks,

[Will.lloydGXGKD]

The issue is that the web thickness of the beam is 15mm so as long as the stiffeners are separate instances they will snap and join together. Without creating a single family for both stiffeners, I don't this parameter solution would work, and I'd prefer to keep the stiffeners as individual anyway. Thank you for the suggestion though.

[Will.lloydGXGKD]

Hi Emmanuel, they aren't structural steel shapes. The issue doesn't seem to be the beam itself but that stiffeners made in the stiffener family category will automatically snap and join together when placed inline and within 15mm gap of one another.

[Will.lloydGXGKD]

I've tried the suggested but they do not work. It seems to be a Revit quirk of not allowing the disabling of stiffeners automatically snapping and joining together. The snapping and joining happens after the placement of the stiffener instance, regardless of if the place I click when placing it isn't touching the other stiffener instance. 

[Emanuel.Nestor]

Hi @Will.lloydGXGKD,

The "Stiffener" is a structural connection (a joint/macro). This connection is designed to work with a structural steel shape: it expects & uses the parameters of the input beam (web thickness, flange thickness, and so on).

This is why I asked about the beam parameters to follow the recommendations for supported steel shapes.

Looking at the image you sent, it seems that the I beam can very well be set up as a supported steel shape.

Is there a particular reason why you cannot make it? Add the necessary parameters?

Is it possible to attach a test model with one of your beams and a stiffener, for investigation?

Best regards

Emy