Anchor Bolts/Sill Plates

[JKENGR]

Anyone knows why the code is asking for 5/8" dia. anchor bolts for seismic zone 4? Does it mean I cannot use anything smaller than 5/8" dia for zone 4 even it calcs. out?

Also, why shearwalls over 640plf require a 3x p.t. sill plate? Why 3x sill plate is not required when the shearwall is not sitting on the foundation directly?

Appreciate for your help.

 

[dik]

I don't know why, but 5/8 are significantly stronger and not much more expensive. They have greater strength, bearing area against wood, can be tightened so that the wood will crush prior to the bolt snapping, slightly greater ductility... all around a whole lot better.

Dik

 

[JAE]

dik - you're up kinda late on a Sunday aren't you?

 

[dik]

typically get about 5 hours sleep a day... have for 30 years...

Dik

 

[SperlingPE]

3x sill plate - high uplift or compression with the high load walls. Check crushing at the end posts of your walls.

 

[JKENGR]

I haven't checked, but I beleive wood crushing may not be the concern, otherwise, 3x sill plate would not only be required on the first floor but also the floors above.

 

[shepherd]

The 3x sill plate (or any other boundary member) is required when edge nailing gets close. This will help prevent splitting of the member due to the close nailing.