Engg vs. Conventional Construction - residences in Florida
Engg vs. Conventional Construction - residences in Florida
(OP)
I'm interested to hear other engineers' experiences regarding use of conventional construction versus engineered designs for residences -- specifically in Florida.
My experience is as follows: have spent my career doing structural engineering in California (SF Bay area). Building departments here require engineering typically on custom homes, including modifications and additions.
Have recently been working in Florida and discovered that building officials in a particular county with 150 mph wind speeds do not require calculations to be submitted for residential designs. Including large, custom homes. If I'm correct, both the Florida Residential Building Code and IBC Residential both require engineering for lateral loads in areas where wind speeds are in excess of 110 mph.
My experience is as follows: have spent my career doing structural engineering in California (SF Bay area). Building departments here require engineering typically on custom homes, including modifications and additions.
Have recently been working in Florida and discovered that building officials in a particular county with 150 mph wind speeds do not require calculations to be submitted for residential designs. Including large, custom homes. If I'm correct, both the Florida Residential Building Code and IBC Residential both require engineering for lateral loads in areas where wind speeds are in excess of 110 mph.






RE: Engg vs. Conventional Construction - residences in Florida
many state have a peer review process were the owner hires a second engineer to peer review the plans for significant structures.
i would be curious what teh west coast people think of the value in submiting these calcs.
and yes at least BOCA, IBC and UBC codes have a line in it that says "shall submitt details and calculations" i don;t know about the sbc
RE: Engg vs. Conventional Construction - residences in Florida
RE: Engg vs. Conventional Construction - residences in Florida
RE: Engg vs. Conventional Construction - residences in Florida
Look at it this way. This approach cuts out the individual who wants a quick buck and is prepared to kick back and just stamp drawings presented by a non-engineer and it also creates more work for those engineers who truly design.
I have not done any structural design in ages but out here in So. CA, calculation submittals (when I designed) were required for the majority of bldgs except for most typical Group R-3, Type V residential dwellings. Structural plan checkers would go through the calcs thoroughly.
RE: Engg vs. Conventional Construction - residences in Florida
For design of structures that are not in seismic or high wind areas, I concur -- there's no reason to submit calculations, provided that a building is within the limits of conventional construction.
However, for design of structures within high seismic, or high wind areas (we're talking about a jurisdiction within 150 mph wind zone), the design of an engineered structure -- i.e. based on code level lateral forces, will be a wholly different animal from same building built by conventional construction methods. The lateral-load-resisting system will be entirely different, significantly beefier, by the engineered method.
As far as roles go, of course it's the responsibility of the designer to design according to the code. If my interpretation is correct, conventional construction does not apply even to residences in 150 mph wind zones. Does responsibiity apply only to designers? Only the building department has the ability to ENFORCE the code.
Bottom line - by my interpretation, wood framed residences, per the Florida Building Code (or by IBC measure) are required to be engineered where wind speeds are in excess of 110 mph.
One reference in particular is table R602.10.1, "Wall Bracing" of the 2003 IRC covers areas only up to 110 mph.
RE: Engg vs. Conventional Construction - residences in Florida
I completely agree that calculations are required by code for most buildings. I just don't know if i see the value in it. If the person who receives the calculations is qualified to review the calculations; then they should be qualified to do their own calculation if they think something does not work. If they are not qualified to review them, why am I taking the time to make them?
If with my experience, expertise and professional judgment i am completely comfortable designing a structure with no calculations and am willing to stamp it, why should anyone argue with me.... unless is does not work. If it does not work, sue me, discipline me what ever.
RE: Engg vs. Conventional Construction - residences in Florida
RE: Engg vs. Conventional Construction - residences in Florida
Honestly, it seems really weird to hear of you guys submitting plans w/o calculations. Unless it's just an architect asking for a beam size, we always send calcs along with the drawings.
RE: Engg vs. Conventional Construction - residences in Florida
RE: Engg vs. Conventional Construction - residences in Florida
RE: Engg vs. Conventional Construction - residences in Florida
It appears to me that not only are the calcs not being submitted/reviewed, but that they're not being done. The common practice seems to be conventional in Monroe County, Florida, where it should be engineered designs.
I would expect to see SOME level of review by the building official. Enough to determine that a design is engineered where necessary.
RE: Engg vs. Conventional Construction - residences in Florida
RE: Engg vs. Conventional Construction - residences in Florida
I am talking about doing what ever calcs you feel needed to design with competance, putting them in a file and leaving them there until needed.
do i need to write down that 2X10s at 16" o.c. can span 10' in a house to make it ok?
I just think having to take the time to "pretty up" my calcs and send them in eliminates some of my efficieny by having to over document things for little perceived benefit. that being said certain things obviouly require calcs to be done regardless of the submittal required.
RE: Engg vs. Conventional Construction - residences in Florida
However, for lateral-load-resisting system, I'd expect to show: What are the wind forces acting on the building?
What are the shear forces in the diaphragms?
What is the shear load in a given line of shear walls?
What is the uplift on roof framing members? What are the overturning forces in the shear walls?
The basics of an engineered lateral-load-resisting system, where an engineered system is required.
RE: Engg vs. Conventional Construction - residences in Florida
Check these links:
http://www.iasonline.org/PDF/AC/ac251.pdf Sec 5.0 with particular emphasis on Sec 5.4
http
http://www.iccsafe.org/news/nr/2005/0131IAS.html for memorandum of understanding between IAS and ISO
RE: Engg vs. Conventional Construction - residences in Florida
I've also contacted the Florida Structural Engineer's Association to chat with them about code enforcement.
RE: Engg vs. Conventional Construction - residences in Florida
RE: Engg vs. Conventional Construction - residences in Florida
FYI -- I've done some homework. According to the Florida Buildig Code,
a) conventional construction not allowed in zones > 100pmh basic wind speed (Sec. 2308.2)
b) minimum plan review criteria includes submittal of engineering calculations/wind requirements, where calcs are required, per above. (Sec. 106.3.5)
c) "The building official shall examine or cause to be examined the accomanying construction documents and shall ascertain by such examinations whether the construction indicated and described is in accordance with the requirements of this code and other pertinent laws and ordinances." (Sec.106.3)
It's all there in the code. I've written a letter to the building official in the subject city/county with all the above info. Will see how this goes...