the front sidewall open
Justice's post describes the model with the front sidewall open and longitudinal X-bracing on the back wall. A force at the front eave takes a route through the roof system to reach the braced line.
Load path and bracing layout
Open bays and lateral load paths in metal buildings
An opening is a design choice with structural consequences. A clear sidewall changes where the model can send lateral force.
Follow the load from the open front sidewall, across the roof and into the X-bracing on the back wall. Justice traces the members involved, then shows the flexible response of this physical model.
Authored explanation · separate from narration
The concept behind the demonstration
Doors, windows and open wall bays are reasonable building needs. Their location can also affect the space available for the intended bracing system.
the structural tradeoff
Use the model to discuss the structural tradeoff alongside the architectural request. The alternative route can be part of an engineered design, but the model does not establish its adequacy or make every longer path equivalent.
Keep the model in context
This qualitative model demonstration explains a load-path concept. It does not measure full-size deflection or provide a bracing design or erection sequence. Clear openings and their complete lateral system must be designed together.
Read the transcript
Transcript checked against the recording.
Here's a thought-provoking question. Where does the load go on this building if I push it here? As you can see, this is a torsion-braced building with one single X-brace on the backside wall, which it has a very flexible response, which you'll be able to see as we track the load path. As we track the load coming in from here, we'll see that the direct load path will push on the eave strut, engage this brace in tension, engage this purlin line, which will cause this brace to come into tension, and then this eave strut carries the load down, carries the load down, and then eventually we get into this X-brace. It's a similar story for all of the load that comes through this eave strut, carries down, over, down, back.
Because it has such a long load path, that contributes to the flexibility of the system.
Bring it into the conversation
Pause. Compare. Explain.
Where does the force have to travel when the nearby sidewall bay stays open?
No opening size, bay layout or bracing alteration is approved by the model.
A physical point of reference
Bring the explanation to the table.
Explore the model used for these teaching and customer conversations.
Explore the Training Model