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RE: Details

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Dave,
This is partly an issue of regional practice. I have been a detailer in my earlier life on projects all over the US, and since 1980, I design projects across the US and throughout the world. The bottom line is that the integrity of the design is the sole responsibility of the engineer of record. Now if he chooses to allow a guy on the street with a sign that says "Will detail for food" to do his steel design, that is his prerogative. But he is NOT relieved of the responsibility for the design.

On the US West Coast, the practice is for the engineer to design practically everything and show it on the contract drawings. It goes more to a performance spec for common connection details as you move to the east. But the engineer remains responsible.

The engineer was ultimately held responsible for the connections of the Hyatt walkways. The engineer of record lost his license to practice in the State of Missouri... forever. The detailer just kept on detailing steel. The board for professional licensure and the disciplinary hearing judge made the correct call.

Complicating the matter is that the stability of the connection is a function of the size of the framing members. I could envision increasing the framing member sizes to preclude stiffeners, and this is often cost effective. This is the function of the engineer of record, or those subordinates working for him.

Bottom line.. I do all of the design for stiffeners, and show it on the drawings. I also do the economic analysis to see if it is cheaper to use full height, fitted stiffeners or increase the member size to preclude the use of stiffeners. I will even cost out and design for partial height stiffeners, because they are more economical than full height fitted stiffeners. The engineer of record needs to do the work for a complete structural design.

What other critical structural elements would become the domain of the detailer. Anchor bolts, doubler plates, diaphragm connections, etc.? Where does it end?

Regards,
Harold Sprague

From: "dave lowen" <jatech(--nospam--at)kwic.com>
Reply-To: <seaint(--nospam--at)seaint.org>
To: <seaint(--nospam--at)seaint.org>
Subject: Details
Date: Fri, 30 Dec 2005 21:00:26 -0500

Comments, please.



When designing 'big box' buildings, engineers sometimes (at least in this
area of North America) do not indicate that web stiffeners are required for
beams that cantilever over columns. In many cases, stiffeners are not
required but the fabricator and detailer have no way of knowing this. Some
fabricators and detailers share the view that if you didn't 'call for it',
they will not 'quote it' and you will not 'get it'. Beam and column
stiffeners are a high priced item and can make or break a bid.

In discussion with a local engineer, I find his position on the matter is
"it is the fabricators responsibility to determine if stiffeners are
required and supply them, if needed". His position on this matter is similar
to beam/column moment connections; the design of column flange and web
stiffeners is also the fabricators responsibility. His thinking is that this
area falls under the scope of connection design.

If the engineering drawings provided loads, I would be inclined to agree
with this position but most engineers don't supply them so it is impossible
to any calcs. Also, the majority of engineers around here will not provide
any loads when asked. I think their insurance providers tell them not to.

In many states, connection design must accompany the contract documents but
for those jurisdictions that do not, what are your views? Do you leave these
tasks up to the bidder or fabricator?

Regards,
Dave Lowen

V 519 587 5797

F 519 587 5138

E jatech(--nospam--at)kwic.com




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