Load path and bracing layout
One PEMB Model, Different Bracing Systems
Follow a hands-on comparison of X-braced, torsion-braced, tie-back and portal-frame configurations. Justice changes the model and applies hand pushes to show how the response changes.
Follow a hands-on comparison of X-braced, torsion-braced, tie-back and portal-frame configurations. Justice changes the model and applies hand pushes to show how the response changes.
Authored explanation · separate from narration
The concept behind the demonstration
Follow a hands-on comparison of X-braced, torsion-braced, tie-back and portal-frame configurations. Justice changes the model and applies hand pushes to show how the response changes.
Keep the model in context
The stiffness descriptions refer to this model and configuration. This is not an instrumented comparison, a full-size building prediction or a safe erection sequence. Any real bracing or portal-frame arrangement must be designed as part of its complete structural system.
Read the transcript
Transcript checked against the recording.
The reason why I made this model was so that we could show how different bracing systems perform. We can see we've got X-brace and X-brace, and look, it's really stiff. It hardly moves.
Next, what if we make it torsion-braced by removing the bracing on this front side wall?
Oh yeah, you can see how it moves so much more.
We push this way. That's still pretty stiff, but then this side is not stiff. But this side is still stiff.
What if we do tie-back bracing?
We're going to get rid of these.
Stiff, stiff, flexes, flexes, but then it flexes a lot more.
But it pushes all together at once.
Portal X. What if we got rid of the X-bracing and dropped in the portal frame? We can see it's very flexible, but still the same kind of rigidity. Let's take and put these back.
It's stiff, it's stiff, but then it's much stiffer. But what happens if we don't tie in our end walls?
We've got a lot more.
But still stiff.
Bring it into the conversation
Pause. Compare. Explain.
What changes in the model, and what stays the same?
The stiffness descriptions refer to this model and configuration. This is not an instrumented comparison, a full-size building prediction or a safe erection sequence. Any real bracing or portal-frame arrangement must be designed as part of its complete structural system.
A physical point of reference
Bring the explanation to the table.
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