retug October 03, 2022

One Way Load Distribution In ETABs

I have used ETABs one way load distribution button for a long time and it works great on flat floors and "slightly sloped roof" to distribute load based on tributary area.

Today though, a coworker of mine noticed on a slightly more pitched roof, angle of about 30 degrees, the one way loading was not working as intended (could not see applied loading due to tributary area).

I built a test model to explore the odd behavior.

Slab section properties uses one way distribution:

(3) sample floors are made, each with the same load and beam restraint layout, but you can see, once the floor becomes "too sloped", the load distribution switches from a line load on the frame elements to merely point loads applied at the edge of the membrane

 

The magic slope where this seems to occur is about 20 degrees from horizontal. 

Edit 2024-10-22

It appears that this 20 degree number is in the Set Tolerances button of ETABs, tweak away.



Hopefully this post saves someone in the future the pains of troubleshooting this odd behavior

ETABs

Our Sidebar

You can put any information here you'd like.

  • Latest Comments
  • retug on ETABs Parametric Building -

    @Toni, this post does not discuss the level of mesh refinement required. The focus is on building an ETABS model efficiently. Mesh refinement is typically evaluated within ETABS by studying the parameter of interest and refining the mesh until the results converge to an acceptable tolerance.

    @fpsstructures, I edited your …

  • fpsstructures on ETABs Parametric Building -

    Really impressive work combining Three.js with ETABS for a parametric workflow. The ability to quickly generate and analyze multiple tower forms can be a huge advantage during early-stage design exploration. I also like how the structural logic still feels clean and efficient despite the complex geometry. 

  • Toni on ETABs Parametric Building -

    How do you assess the fineness of the mesh required? More scale or load based?