CMU Design in Florida HVWZ

[JedClampett]

In the 2007 Florida Building Code, Section 2121 requires concrete tie beams and columns at openings, corners, etc. Section 2122 pretty much says if the CMU walls are designed to what I consider very routine requirements, concrete tie beams and columns aren't required.
I've always taken the position that better to be safe, than fight with a code reviewer after I've designed the structure, and provided the concrete tie beams and columns. Am I being too concervative by always putting them in?

 

[Ron]

JC...the difference is that 2121 is prescriptive and contains the minimum construction requirements. 2122 requires special inspection, thereby negating some the the prescriptive requirements, since it is considered that the structure will be better built with that level of inspection required.

 

[ron9876]

Like Ron said. Reinforced masonry is typically the most cost effective. But certainly not both.

 

[JedClampett]

OK, but I have one small problem. Even though Chapter 17, Special Inspection is part of the code, all the specific language on implementation, verification, reporting, etc. in 1704 has been removed. So 2122 requires Special Inspection, yet there is no definition nor criteria for Special Inspection.
Now there is a section on threshhold inspection, but that is a different animal altogether.

 

[Ron]

JC...implicit in the wording of 2122.4 is that the inspection be at the Threshold Level, since the requirement is for a licensed Architect or licensed Engineer. That requirement does not exist under the Special Inspector criteria of Chapter 17, which in the FBC remains undefined. Florida has not yet adopted the "Special Inspection" process as defined under the IBC, but has long had the "Special Inspector/Threshold Inspector" law in place (since 1984), which pre-dates the UBC/IBC requirements.

There has been a lot of confusion over the term in Florida, particular for those who practice a lot in IBC areas. I hope the Department of Community Affairs/Building Code group will get this straightened out in the 2010 code...but I'm not overly optimistic.

 

[spats]

Good post Ron. You enlightened me!(I'm in Florida)

In response to JC's question, I'm beginning to realize myself (don't tell anybody) that horizontal reinforcing in CMU walls is largely ignored, except by experienced seismic designers. A beam (a shear wall segment is a vertical beam) may requires shear reinforcement at d/2 max. The rule is d/3 max for "special reinforced masonry shear walls" with seismic.

Not trying to hijack the post... just an observation from a related perspective. Conservative is in the eye of the beholder.

 

[ron9876]

FBC requires joint reinforcing at 16" c/c.

For better or worse the inspections that are required are normally provided by the cheapest testing lab.