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shims vs. leveling pls below steel baseplates
my office typically specifies temporary shims to be used below column baseplates during erection. i like shims because it is easier to correct and adjust column heights earlier in the project than with leveling plates. with leveling plates, if a mistake in elevation has been made, the plate and grout below it has to be taken out and redone.
what is the practice in other offices? are there other advantages to either method that i don't know about? i am noticing on most jobs that contractors ask to use leveling plates.
hi sam damon:
i used to level base plates, a nut welded beside each 90 degree bolt hole , say a nut at 12, 3, 6, 9 hour relative as old war pilot sayd.
at that nut a bolt is threaded so you can control the level and height, onece done we grout the sapce between tha base plate and the column footh.
samdamon---you have got it right. on columns with baseplates that range into the tons, leveling bolts or other devices must be used but, for the small stuff, stick to the shim packs---much easier and cheaper to erect, level and, plumb in the field. leveling nuts can be used to good effect when the base plate contains a locating device such as a key, but plates preset and grouted are a pain in the arse.
rod
my practice (as a structural engineer) is to leave the decision of whether to use leveling plates, nuts, shims, etc. up to the contractor/erector. they know their preferred method best and may submit change order requests if a different method is forced upon them. i simply specify the erection tolerances that must be met and it is up to the contractor/erector to determine how to satisfy the tolerances. |
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