huangyhg

pet peeve about column lines and drawings
pet peeve on contract drawings ! ! !
i understand that the structural guys often have to follow the column lines used by the architect on his drawings. but i am working on a job right now that has a big foundation wall that in many parts is outside of the building footprint specifically where the new building joins with three (yes 3) other existing buildings. none of these walls, piles, pile caps, continuous wall footings, etc are on actual column lines and they jog around all over the place. this means it’s a very hard to write soil bearing capacity reports, reinforcing steel placement inspection reports, and concrete placement inspection reports that have descriptive, coherent locations of the day’s work.
why do they do this?
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they should not. and there is an easy solution - assign "fractional" column lines, such "3.4" (which is located between column lines "3" and "4" - the "3.4" column line is shown, and it's location dimensioned on the drawings. there is no reasonable limit to the number of "fractional" column lines - in addition to the "3.4" (in this example) could also have, say "3.1", "3.6", 3.9", etc.
works in the other direction too, such as column line "b.3" or "h.7"
this approach is taken all the time on the complicated layout of electrical power stations.
or get a copy of the floor plan and add your own matrix grid over the plan - and attach your grid plan to each of your reports as a reference for location descriptions.
i agree whole heartedly with your gripe.
column lines go on the *&#$% columns. not on the outside face of drywall, or wherever else some guy thinks they should go.
this is something that, in my own opinion, we as structural engineers do not reinforce as strongly as we need to.
they are column lines, columns are structural. tell the architects, developers, contractors, whoever - where they should go.
"we as structural engineers do not reinforce as strongly as we need to"
no pun intended, right?
i've never had any problem with column lines being at some location other than the centerline of columns. a column line is simply a line with a bubble on it that is used as a reference. in industrial plants, i run into columns that are off column grids all the time. they can be referred to by dimensions from column grids or as slideruleera has noted.
in a metal building, the outermost columns are usually on the outside face of the (structural)girts. that's how they do it. there is a logical reason for that: it's how the metal wall panels are laid out and how the building dimensions are defined. also, many people have trouble with tapered cols in metal buildings, and i've never understood the confusion. the column line is just a reference line with a bubble and a number/letter in it. it doesn't have to be at the center of anything.
i admit, putting a col line on one face of drywall seems a bit off-the-wall, but i guess it can work. for your reports, can you not just refer to grid lines with some approx. dimensions away, in whichever direction you need?
regards,
chichuck

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