how to describe a good design

huangyhg

how to describe a good design
we have had a problem with a manufacturer providing very poor quality drawings and documentation for a component to be added to a structure we have designed.  it seems that simply stating that the design must meet the 2006 ibc is not good enough to get us a good design.
i am trying to come up with a way of describing a good design that is well documented and detailed so that we can put into writing what we are looking for as far as a submittal.  the problem i am having is that it just seems to be more of a gut feel than an easy definition.
we have even been having difficulty getting the design of the component in one package.  it seems that we have several smaller components of the system designed by their engineers, but no one is reviewing the system as a whole and putting all the smaller components into a single package.  global stability of the component is an issue that they seem to have difficulty understanding.
does anyone have a good description of what comprises a good, complete design?

i think you're skrewed ...i think your vendor has been given a contract "design to 2006 ibc" which is what they've done.
i think you wanted to have design reviews (to have input on the design) and/or design acceptance of the component.  messily you could have said "design with a view to good practices" but that's open to interpretation.
maybe go over their calcs to verify that the design is compliant, maybe there are a bunch of assumptions that you don't like, then (unless you're mgmt are on side) expect a fight.
good luck !
tell them to provide a 20 year warrantee
actually, there was not a clearly defined contract...  i am kind of stuck in the middle here, as you seem to have noticed.  there were many red flags pointed out, but the system was used regardless.  upon (attempt of) installation, the component collapsed on itself - no doubt due to the very same problems i pointed out.
money has been paid for the product and whatever agreements do exist require that this manufacturer must be used for this specific project.  i have the opportunity now to do better with describing the requirements.  any help would be greatly appreciated.  
this is also somewhat of a non-project-specific exercise...  i am interested to know if i live too much in my own ideal world and expect structural designs to meet high standards.
what kind of language did you have in the spec.  we typically have a performance spec for things like that (metal studs, stairs, things that we don't design).  we put language in the spec that we need to see detailed shop drawings, and calculations that show the system can withstand loading per ibc (or a specific load that we want).  the calcs and shops need to be stamped by a pe registered in the state of fill in the blank.  we also specify deflection limits for things like metal studs.
that is exactly what was stated.  what they gave us is a pile of drawings and calculations signed by different engineers for each component going into the final system.  there was not a single engineer taking responsibility for the system as a whole that was purchased as a unit.  because of the lack of coordination (or the lack of an overall coordinator) the system was disjointed (overall stability was not considered) and did not act as a unit.  
because this, theoretically, may not be a problem simply for this project, i want to be able to "fool-proof" our spec a little better.  a good description of what comprises a good design would be helpful.   
"no clearly defined contract" ... either you're completely skrewed if they won't do more work without more money (presumably you don't want to pay them to fix their "obvious" mistakes) or if they're reasonable (and will fix the design) then describe the design the way you think it should be ... you know how it failed, you know what doesn't look right ... how can they modify the design to make it right (even if it looks ugly).
i would send the drawings/calcs back with all of your notes and say that they "have been reviewed for conformance to the design criteria specified in the contract documents, and for compatibility with the design of the primary structure.  with regard to these reviewed items, please see the individual sheets for comments.  these comments should be addressed and resubmitted for subsequent review."  then, in addition to whatever specific comments you have, i would say on the first page of the submittal, "please provide calculations for overal stability/strength of entire assembly.".
they clearly haven't met their responsibility of designing for the specified loading or it wouldn't have failed.
don't know the exact language to use, but i would try to move down the path of requiring a complete design stamped by one engineer.  this will require one individual to take responsibility for all the pieces together.
it sounds similar to a situation i have been involved in.  
i was asked about some modular buildings that had components designed and engineered by different companies/engineers.  each made assumptions in their design and some of the assumptions conflicted with each other.  while each component was engineered adequately (based on their assumptions) the system as a whole did not work.  in the end the contractor had to make retroactive repairs and our recommendation to the client was that in the future they should require one structural engineer of record that takes responsibility for the design as a whole.
enginerding:
if you have e & o insurance, you might contact your carrier or agent and get their spin on the question.   
mike mccann
mmc engineering