Diaphragm Deflections

 

Morton Arboretum Partners with NASA to Understand Why Trees Fail

 

 

Equation

IBC section 2305.2.2

total deflection = bending + shear + nail slip + chord splice slip < ???

 

SDPWS section 4.2.2

total deflection = bending + (shear + nail slip) + chord splice slip < ???

 

• Wood Shear Wall and Diaphragm Deflection - spreadsheet
• Wood Truss Gable End Frames
• textbook section 16.10  (advanced topics)

 

Partial failure due to inadequate shear structure at garage level.
Damage in San Francisco due to the Loma Prieta event.  source

link - see pony wall, link

 

 

Rule of Thumb

diaphragm span-to-width ratio = L/b < limit

assumes deflection will be okay as long as diaphragm proportions are reasonable

 

IBC

 

Deflection Of Wood Diaphragms