huangyhg

beam cambering
i have a wf beam (w40x324)cambering issues for help. we have a 60-ft span beam and will deflect about 1.5" under dead load. it will be expensive to camber this beam to 1.5". the beam will be under l/240" deflection under total load. do i need to camber the beam? any suggestions? thanks.
judging just on span on deflection ratio that looks ok but you also have to consider the application. is there anything that could limit maximum deflection including appearance? if it is an industrial or mining application it should be ok.
what cost was quoted for cambering? my experience has shown it is a small add-on, less than 4% of the total or less than 700 dollars. well worth the cost to approach level with all the dead loads deflecting.
thank you. it is more than 2000 dollars for cambering each 60 span w40x324.
if a flat floor is required other options include increasing the beam size until your camber is less than the camber that is naturally allowed in mill tolerance.
when the shape comes off the mill, it will already have a natural camber to it. given the length of the beam, it's probably already gotten most, if not all of the camber required. the fabrication shop should automatically fabricate the beam "natural camber up" but you may want to call it our on your drawings just in case.
i stand corrected. it looks like half of your required camber would be taken out naturally:
chip b
excellent thread reference, it explains most of the questions.
interesting that the aisc document stated $50 to $75 per beam, but chencfp was quoted $2000 per beam. however, i can see the $2000 per beam easily - if it can even be accomplished. 40 x 324 is a very large beam to camber.
another approach is to build cambered plate box girders. overhead crane box girders are commonly built with camber. this might invoke other problems - but may be worth considering.
lastly, do not count on mill camber to be consistant! beams come in with a huge variety of sweeps & cambers. we have not used w40's, but we see a lot of w36's that are dead straight - and have seen a lot that have 2" in 60 ft as well
if project has already been awarded, they will charge you $3000, but if u specify them before tender, u'll get it in $100. as we checked form fabricators, they charge 2 hours of labour at the rate of $50 per hour with no limitation of span upto 60ft.
but make sure you will never get smooth cambered beam. they will camber in the middle third part of the beam and u might end up with an odd shape at the centre. if it is for roof beam, then it might be fine.
thanks all for sharing so valuable information.

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