definition of structurally sound

huangyhg

definition of "structurally sound"
a client has requested that we provide a letter stating a certain structure is considered "structurally sound".  the structure is older, but in good condition.  the design is governed by wind loads but the current building code in the area has much more substantial requirements than the code under which the structure was originally permitted.
for this case, since no modifications whatsoever are being made to this structure, i would consider it to be structurally sound if it complies with the building code under which it was originally permitted.
this leaves me with a few questions:
1. is it possible to call something structurally sound without referencing a specific building code or standard?
2. is it possible to call something structurally sound by evaluating condition only, provided that the structure had been previously designed and built according to the current building code at the time?  (this question assumes that orignial drawings are accessible)
3. is it possible to call something structurally sound by evaluating condition only if drawings do not exist, and no calculations are performed?
additionally, does someone have a good definition of "structurally sound"?
find a job or post a job opening
in my opinion, just because it complies with the building code at the time of construction does not make it "sound".  i would think a significant amount of your effort should be in inspection of the building to observe any signs of structural distress which might indicate whether it is sound or not.  some attempt should be made to determine what the underlying structure is and then depending upon the importance, size, cost etc. some analysis should be done to determine it's ability to withstand normal forces such as wind, snow, seismic.
in any report such as this i would avoid the term "structurally sound" as it is way to vague and general and could be totally mis-construed.
for an older structure there will most always be areas where:
1.  the original design doesn't meet the current applicable code and
2.  the current condition of the structure has been deteriorated, changed, or damaged in some fashion to also reduce the load capacities and serviceabilities of the   
to me 'structurally sound ' means that the original structure has not substantially deteriorated or been modified so that it cannot perform as it did when originally built.
my answers are:
1. yes
2. yes
3. probably depends on structure type. eg. a historic building can be classed as structurally sound if it has stood the test of time and it is in good condition without doing calculations. in your case it may be obvious that no modifications have been done so drawings are not required.
i wouldn't state that it complies with a past code unless  the original calculations have been checked, or recalculated, and it's been confirmed that the structure was built as designed.
i just want to reiterate the most important point, made by jae.
"but foremost, you as an engineer, can only state what you know.  and you can only know what you can determine either visually, by tests, by calculations, by research, etc."
this is the crux of the matter, before you take on the work you need to manage client expectations. you need to state to them exactly what you intend to do and the extent to which you are willing to 'certify' the building.
be prepared to let the job go if they are not happy with your response.
you should also talk to your insurance company to see if there are any policy limitations on what you are allowed to say in this letter and still be covered.
regards
craig dolby
     be specific: this building is designed for x.x mph wind.  the floors are designed for 50 psf live loads and the framing for 30 psf live loads.  the seismic capability is 80% of required by 2003 ibc.
     phrases like "structurally sound" have no meaning in an engineering context.  all structures can be overloaded and good judgement is normally expressed by code requirements.
i would throw in with the answer given by apsix on this one.  structural soundness is what you assess in a structural condition report, and is not the same as determining the strength of the structure by analysis.  a structurally sound building is one which has not decayed, deteriorated, or been damaged.  of course, if the building had inherently built in faults those too affect the structural soundness.  i especially disagree with trying to put numbers on percentages of compliance with some modern code.  you don't have to use the words "structurally sound", and you should stipulate that the building is not built to current standards, but that doesn't stop you from giving an honest opinion as to the structural condition of the building.
just to clarify, i absolutely do agree that you need to know exactly why your client wants your report.  for instance, a report for a potential purchaser would be presented in a different manner from a report to be used for preventative maintenance.
i don't think that i've ever used the term 'structurally sound' unless i'm able to do the sums and then it is usually to provide a capacity and possibly a comparison to current standards.  for forensic stuff, depending on the jurisdiction, i may state that it is in conformance with the code in effect at the time (many areas have a grandfathering clause).  most of the reports i've done state that no signs of structural distress were observed (assuming none).  i also caution about latent defects as well as changes in use and occupancy... eg, higher humidities and sealing of historic masonry can have a serious effect.  like jae... also fairly specific about what was reviewed and make sure i get the scope clear at the beginning and caution the client that almost anything can be reviewed if he has the financial resources to do it... i like to put the onus on him as to the scope and often offer the service... such and such is beyond the scope of this report and can, however, be undertaken should we be instructed...
dik
an excellent book to guide you in preparation of a structural assessment report is asce 11-99 guideline for structural assessment of existing buildings.   
if there are no visible signs of structural distress or deterioration and the loads are not different from what it has been carrying historically, then i have no problem stating the building is "structurally sound". as other posters have correctly pointed out, you need to clearly state your basis for this determination (visual observation, nondestructive or destructive materials testing, detailed structural analysis, proof loading, etc.)  
most clients are ok with a visual inspection and do not want to spend the fee $$$ to do a serious formal assessment.  get this clear in writing up front with your client and a limitation of liability clause is not a bad idea.  your small fee does not constitute an insurance policy that the structure is 100% ok if all the client paid for was a visual inspection/observation.     
i include the following cya paragraph on simple letters with a visual inspection and go into significantly more detail (i.e. similar to asce 11-99) for more serious assessments.
per your request, on when we visited the what located in durango, colorado.  the purpose of this visit was to observe the what and render a professional opinion regarding its current condition and recommend any repair schemes.  this observation consisted of a visual survey only, made solely to evaluate the structural integrity of the building at this time.  the observation was not intended to cover any architectural, electrical or mechanical items or features, nor was it intended to uncover or evaluate any hidden or latent structural defects in the what building.  in addition, it should be understood that this observation was not a guarantee or certification that the original construction and/or design of this buildings was without defect or deficiency or that the structure complies with the requirements set forth in the latest edition of the international building code.  
hokie66 makes a good point.
you could put in some words to the effect of:
" the building has been checked for any signs of deterioration such as decay,cracking e.t.c. that may be of structural concern. compliance of the structure to current codes and to the original building codes has not been checked as this is considered beyond the scope of this report."