SMF Bracing to Wood shear wall lateral system

[Fil_struc]

Hi All E.I.T. so thanks in advance,

I'm designing a moment frame and the plan checker is asking for bracing per Section E2c.
Special Bracing at Plastic Hinge Locations.
"(b) The Required strength of lateral bracing of each flange
provided adjacent to plastic hinges shall be: Pr = 0.06 Ry Fy Z / (α h_o)"

if I have the moment frame below.

Question:
Do I need to provide one bracing for each hinge, so 6 bracing?
If the resistant lateral system for the bracing is a wood shear wall would the force above ( 6 hinges * Pr ), be divided by R= 6.5?

 

[bigester93]

frames don't need braces. Use brace in the other direction.

 

[driftLimiter]

Aisc allows nodal and stability bracing. The seismic provisions require the plastic hinge locations to be braced.

Think about the concept here. Your design says the frame can have plastic capacity due to hinging. In order to plastify the section you need to ensure that there are no instability limit states less than the plastic limit state.

You absolutely need to brace special moment frames at all the expected plastic hinge locations.

Do not divide the stability bracing required force by R factor. If you think conceptually of what R factor is for you should see that it is not applicable to that force, the force is based off only the sectional strength and doesn't include any terms regarding spectral acceleration or displacement.

These concepts are very important for good seismic performance and safety.