Moisture content of shear wall framing members

I am a SE in California, seismic zone 4. I would like to know how other engineers account for the moisture content of framing members in wood panel (plywood or OSB) shear wall framing members. The NDS and UBC code tables are based on framing members with a moisture content of 19 percent or less (S-Dry). What we keep hearing from contractors and suppliers is that other engineers are accepting green lumber (which has a moisture content greater than 19 percent) for residential construction. Dry 2x framing material is available for a significant upcharge, but dry 4x material doesn't seem to be available. We typically use 4x posts for tie downs. For nail design, the NDS gives a reduction factor of 25 percent for green lumber that will be dry in service. Are there load tables or design methods for this situation that anyone knows of?

 

[rlflower]

I am a C. E., also in Zone 4, and I concur with this concern. It is considered unrealistic amoung contractors to require less than 19% moisture content on 2x lumber. It is usually purchased "green" - often can be described as "wet". To add to this query if I may: just how is moisture content measured at the lumber mill, and at the job site? Can there be a visual determination, something like the way lumber is graded?