Diaphragm Explanation for Beaver County School District

Kendrick and Daniel, two engineers with Jones & DeMille Engineering, explain a potentially catastrophic deficiency of two gymnasiums in Beaver County School District and what it would take to fix them.

[@RostonMathias]

Very well demonstrated

[@amit95gupta]

good explained.thank you

[@soum9645]

Thank you sir

[@jirachai064]

thank so much

[@benjaminisation]

Thanks for the demonstration, however, one thing I didn't quite understand was about the second model. I understood the discussion about the diaphragm, but why the walls also showed to be separated? wasn't it just the diaphragm that was not connected well to the walls (due to the tilt-up construction)?
Also, regarding the retrofitting method, so basically, you guys just used the same method of the 1970s, just with carbon fiber fabric?

[@rolandalphs7022]

I've been searching for an explanation for the difference between rigid and semi-rigid diaphragms and how it affects our analysis. Can anyone here help explain?

[@Jonesanddemille]

No diaphragm is 100% rigid or 100% flexible. However, when the diaphragm is much more flexible than the shear walls, engineers simplify the analysis by assuming that the diaphragm is 100% flexible. Similarly, when the diaphragm is very rigid compared to the shear walls, we simplify the analysis by assuming that the diaphragm is 100% rigid. However, when the diaphragm has similar rigidity to the shear walls, it's not appropriate to assume that the diaphragm is 100% rigid or 100% flexible, so we have to do a semi-rigid analysis. When you're analyzing a semi-rigid diaphragm, you can't use the simplifying assumptions of the rigid or flexible analysis and you have to do a complex analysis that considers the stiffness of both the diaphragm and the shear walls. This is typically finite element or something similar.

[@marcrogue5268]

I don’t know that your analysis is correct, I would like to see what’s in these walls and how they are connected to the foundation

[@isla2974]

Hopefully, the walls are built as shear walls. Else you will have to redo the walls too.

[@jacksoncamilo3624]

InstaBlaster.

[@Forgemno]

Thanks so much. Books aren't the best at times

[@sharmarkeabdirahman7323]

Very well demonstrated