seismic restraint of non structural component - adhered veneer (light masonry)

[NorthCivil]

On a wood framed single family home I am doing, there is a wood framed chimney flue structure that is to be clad with masonry veneer.

Its a rainscreen application, with
3/4" vertical strapping at 16"OC
wire mesh screen stapled to the strapping
a layer of fabric will be applied (to keep the mortar out of the rainscreen cavity)
mortar will be applied to the fabric
2" thick cultured stone will be applied with mortar.

the building inspector is requiring sign-off on the veneer. I'm in a high seismic area. All the reading I've done on this is showing lots of failures of masonry veneer (mostly Northridge 1994).

There is lots of methods of seismically restraining 4" masonry veneer (red brick), that is self supported with a shelf angle, and with brick ties back to the main structure.

anyone have a clue how to accommodate a heavy, brittle rainscreen like this? I'm leaning towards telling the contractor we cant sign off on it and they will need to alter their exterior cladding to suit (the local authority requires sign off on masonry over 10feet above grade - the contractor might be limited to this lower height)

 

[jdgengineer]

See Chapter 6 (Veneers) of ACI 530 (assuming you are in US) This chapter has prescriptive requirements for masonry veneer that is adhered. There are limitations to the size, thickness, and weight of the veneer. In our area we do not commonly use rain screens behind stucco. The stucco is applied directly to a double layer of grade D building paper. I'm not sure if the rain screen space violates the prescriptive requirements of the adhered veneer. I don't like it from a structural perspective as the stucco is essentially open stud construction and seems to be more prone to cracking. You'll have to dig around a little to see if it is technically allowed.

I'm not confident the veneer will perform stellar during an earthquake but it's a common installation procedure in our area for residential construction and is allowed in the building code for high seismic.