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Re: plan dimension standards

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Richard Lewis wrote:
> seaoc(--nospam--at),Internet writes:
> I usually refer all dimension to the architectural plan, except for say,
> major column line to line dimension, top of steel elevations.  Why, we
> all know that architect always change dimension before we even notice
> it.  Just have to update our drawings every so often. I don't see any
> choice.  I also incorporate a note in my General note requiring the
> contractor to coordinate dimensions in all drawings and bring to my
> attention of any discrepencies before proceeding to construction.
> That's my back-up insurance in case I miss something.
> I understand your position (and the position of a large part of the list
> server), but I can't agree with it.  Please don't take this personal, I only
> singled out your letter because it made some comments I think lots of people
> agree with, so nothing personal here.
> As the design professional, we are responsible for coordinating our
> dimensions.  We should not put this responsibility on the contractor.  If
> there are discrepancies between the structural drawings and the architectural
> drawings it is a breakdown in communication and coordination between the
> architect and the engineer and it is not up to the contractor to straighten
> us out!!

I didn't say we don't have to coordinate dimensions. If you read my
note, it say:  we have to update every so often and check the dimension
by our draftperson and engineer. Thanks for the CAD technology, checking
dimensions are a lot easier.   The only way to avoid error is NOT to
have two or three disciplines showing the same things.  Of couse, the
structural design will still be based on the latest architectural

The general note for discrepencies is a provision to try to find out any
dimension conflict before construction. Even after a round of
coordination by the Architect-engineers.  Let's face it, sometime the
contractor know his business better than the designers.  It will be a
great asset to get the contractor involved before hand. Human do make
mistakes, so the more people get involved in checking the plan, the less
mistakes there will be. It is not a perfect word in construction.

> I prefer to include all dimensions on my drawing that are important to the
> structure and the design.  I want everyone who looks at my drawings to know
> what I designed it for.  If my dimensions do not match the architects
> drawings and the contractor points that out then I do one of two things;

That's good. My drawings also shown dimensions relevant to the structure
such as colume line dimensions, steel elevations, top of foundation etc.

>    1.  I go back to the Architect and the Owner and apologize for having poor
> drawings and tell them I will do whatever I need to to straighten them out.
>     2.  I chew out the architect for changing the dimensions and not telling
> me.  It is his responsibility to coordinate any changes he makes with the
> consultants.

Don't count on the architect to coordinate dimensions. Quite often, we
have to coordinate dimensions and tell the architect about the conflict.

> If the architect changes dimensions and as a result my design is insufficient
> because the span was enlarged, shear increased, etc. and a structural failure
> begins to occur, I can point back to my drawing and say "Hey, it was not
> designed for that.  Here is the dimension it was designed for".  If I never
> included the dimension on the plan and the architect changed it then how is
> anybody to know that the design was inadequate?  And how can I justify, in
> court if need be, that I designed it correctly?

If you include the column line dimensions, the beam design should be
accounted for.

> I realize this is an ideal world situation where the architect and the
> consultants fully coordinate their drawings.  But isn't that what the Owner
> is paying for?  Do we write clauses in our contracts that state coordination
> of all dimensions is the Owners and Contractors responsibility?  NO!
> Therefore lets do the job we are paid to due.  If an architect continually
> makes changes on you without telling you then write it in to your contract
> about extra service billing for making these changes.  If he still does it
> then maybe you shouldn't be working for him because they are a disaster
> waiting to happen!  The hardest thing is to turn down work, but if working
> for them compromises your integrity as an engineer then maybe you should not

I don't think we should exclude the contractor from the design team.
After all he(she) is the person who is going to build it.  The architect
will always continue to make changes and we, engineers will always have
to eat it without extra compensation.  Let's face it, it is the real

Yes, we are paid to do a perfect plan, how often does it happen? In some
jobs, I got involved in construction more often than design with or
without compensation.  Why, it is the only way to improve my next design
and get rid of the typical details that won't work.  Most of my clients
are owners, not architects.  So I don't have that middle man(woman)

Tom Chiu, SE
Thomas Engineering