agricultural structure-engineered design

huangyhg

agricultural structure-engineered design
when does an agricultural building/structure need to be reviewed and signed off by a licensed engineer.  i am reviewing a grossly underdesigned farmers grain recieving and storage facility which is clearly structurally unsafe.  140'+ distribution tower on next to nothing footings.  
these once small farm facilities are now large operations.  i does not appear the code seperates these facilities.
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i don't think there are any exceptions in the building codes for agricultural structures.  as a matter of fact, there are some sections that address the design of such structures, which implies to me that they need to be designed and sealed. local codes might override this.
the building code doesn't always say which buildings need to meet its provisions.  usually that is under the control of the actual community, city, county or state (in the us).
depending on where the project is located, you would want to contact the appropriate government entity.  if it is out in a country setting, then county or state rules would probably apply.
i worked on a large horse breeding project several years ago.  i had to design several barns and out-buildings.  there was no local jurisdiction (city or county) and the state fire marshal would not provide any guidance other than "use your judgement".  i classified the main horse/breeding barns and maintenance building as category ii buildings and the remaining buildings (hay barns, loafing sheds, equipment storage) as category i.  i designed the structural framing as any other building.  
it is county jurisdiction which states "farms are exempt from the building code".  however this has turned into a legal case between the farmer and contractor.  i have checked and found nearly everything underdesigned, not by 5 to 10% but by 200 to 300%.  example: 140,000 lb unloading bin 15' in the air with no lateral bracing... 300+% underdesigned without p-delta because the model locks up.
this is life safety and i have told him to not to use and restrict access under this bin.  how is this ok because it is on farm.   
because it's on a farm and it's how people have done it for years.
jchi,
you really have two issues here.
first, you, as an engineer, have a duty to protect the public safety and welfare.  in this case, you need to firmly, in writing, notify the farmer and the contractor that there is a significant safety issue involved.    this is an ethical (the right thing to do) and legal (as an engineer you have specific laws on your behavior here) issue all rolled into one.   
this first issue has nothing to do with whether a building code is legally applicable.
you might also seek guidance from the state board as to what you should do under your state's standard of care rules.
second, in legal, technical terms, if the county doesn't have any jurisdiction in construction, then you may just need to back away from the project as you would eventually be tied into any legal actions if something fell or someone were hurt.  i'd hate to do this as i've always tried to resolve things as much as possible.
the owner (the farmer?) would most certainly care if the thing wasn't stable, but maybe depends on the person and how influential the contractor is.  keep hammering away at them and even suggest a second opinion from another engineer.  

jae - i agree with you.  i am an expert witness on the farmers side stating the inadequacy of all these structures.  he has quite using the facility and the court battle has begun.  
i am now reviewing expert reports from the other side's engineers stating this is a farm, thus it is code exempt.  i am trying to find a resource stating that just because it is code exempt that does not mean it does not need to meet some sort of minimal design standards.  if there are none, our code needs to be rewritten with respect to farms.  farms are no more small buildings and livestock sheds.  they are multi-million dollar grain handeling and 1000+ head livestock facilities.  some of the these farms are empolying 4-5 full time employees.
does anyone have a resource or paper calling out the distinction between a "farm" and "commercial operation".  there are 4-5 full time employees hired by this farmer to help run his grain handeling faciility.  can i classify this as a commercial structure?

this might help.  if you have a copy of asce 7-05, the commentary section c1.5 gives examples of agricultural structures falling under category i (low hazard to human life because they have small number of occupants...) classification:  "farm storage structures used exclusively for storage of farm machinery and equipment, grain bins, corn cribs, and general purpose barns for the temporary feeding of livestock."  fema technical bulletin 7-93 is listed as the reference for that description.   
based on my experience, category i classification reduces the lateral loads somewhat compared to category ii.  regardless of the classification, the structural system must be designed to adequately resist the loads imposed by gravity and lateral loads.  if the building is unstable no matter how it is classified, then it is unstable.
archeng59-thanks, two very good points for referance!