huangyhg

certify fabrication drawings
from time to time i have been asked to provide steel fabrication drawings with pe certification. i am asking what it means to the engineer that stamps each fab. drawing?? i assume that the engineer looks at each connection and runs calculations to assure that the connection meets the loads provided on the design drawings or meets the min. code loads.
has anyone else been involed with this type of project where the fabrication drawings require a pe stamp???
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if you haven't directly prepared the fabrication drawings or had direct supervision over their preparation, you should not seal these plans as it violates most u.s. state laws.
if someone is asking you to seal them, i would suggest that they don't know what they are asking.
fabrication drawings (i'm thinking these are like steel shop drawings - right?) are prepared by shops who are taking your design drawings and providing plans for use in a shop to fabricate the "pieces" of your structure. these are not engineering documents and should not be sealed.
you should, however, review these plans and indicate on them that you have reviewed them for general conformance to your plans and specifications. this is usually done with a standard stamp that states that you reviewed them and what action you are taking - such as "no exception taken", "exceptions as noted", "revise and resubmit", etc.
if you have delegated engineering design to the fabricator (such as steel connections) you should have stated in your contract documents that those connection design drawings should be prepared by a licensed engineer and so sealed by that engineer.
you can delegate the engineering design task to the fabricator's engineer, but you are still ultimately responsible for the capacity of those connections. however, to seal someone else's design, or to add your seal to an already sealed shop drawing, is not correct.
i agree with everything you say and i think you see my concern. on projects where i am the ser, i review all shop drawings and verify that connections are adequate. when i have bar joists or roof trusses, i request that they be certified by pe.
i guess it makes the ser's job a little less time consuming to have an extra set of eyes looking at the drawings.
thanks for your thoughts.
tankman:
it is my opinion that when an engineer asks for a stamp on a structural steel shop drawing, it is a confession of incompetence. connection design and structural steel shop drawings are not proprietary items.
you are on the right track when you say you design and take responsibility for your own connections. asking a fabricator to get a stamp on his shop drawings is just plain sloppy.
watermelon:
i agree that it is preferrable to design your own connections and include them in your sealed engineering drawings. we do that currently in all our projects.
in the u.s., though, common practice through the years has been to delegate this task (for common shear connections only) to the fabricator. the thinking was that you lose economies if you force fabricators to make connections that are not to their usual standards.
on one of our more famous collapses, the hyatt regency walkway collapse, the engineer did just that...delegate a connection design to a fabricator. the fabricator started the connection design, but then got busy on other projects and let the job out to another fabricator who saw the detail that had already been started and assumed it was complete. the connection was fabricated per the original fabricator's drawing and was built. the eor failed in fully checking the connection but insisted that it was the fabricator's responsibility to correctly design the connection.
the judge ruled that the eor could delegate engineering tasks to others, but the eor could not delegate his responsibility for the entire structural integrity of every part, including the connections.
today, we delegate all sorts of things for others to engineer. steel bar joists, metal deck, prefab wood roof trusses, etc. are all engineered by others. we trust the load tables and specify that they be designed per sji, sdi, etc.
standard, shear-type connections can be considered as no different from bar joists as long as you, the eor, understand that you are still responsible for the connection's adequacy. i'm not sure its "sloppy", but i'd agree that i prefer doing them myself.
so all three of us are in agreement that we'd rather do our own connection design. and it really is no big deal. it's quite easy to make your intentions and requirements known to any reasonably trained detailer.
my point is: many items like wood trusses, core slabs, are proprietary designs. they have been developed and marketed by fabricators over the years. if i had to design my own wood trusses for each and every job, i'd soon be out of business. so of course we delegate the design of those items to specialty suppliers. but where non-proprietary items are involved, then we should be designing them ourselves. i would never ask for a seal on any shop drawing.
having signed and sealed hundreds, perhaps thousands, of shop drawings, i have some fairly strong views on the matter.

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