Beam question.

simonmln

I have a long beam. I need to know if i pick it up in the middle how much the ends will deflect by.

There are no fixings. Its just a long uniform beam (same shape as a ruler). Anyone?

CatFromHue

I could well be wrong on this but is this not similar to a simply supported centre loaded beam except upside down.

You wouldn't be getting the deflection of the free ends of the beam but of the deflection of the centre where the force applied is the weight of the beam plus gravity.

aujopimur

Your question a bit vague, but for safety reasons slinging a beam in one position is not a good idea.

breadmonkey

If you pick it up in the middle then I guess it will be acting like two cantilevers, fixed at the lifting point (under its own self weight only). In that case, the maximum deflection at the ends will be

d = wl^4/8EI

where:
w is the self-weight expressed as a UDL
l is the length of half of the beam
E is the Young's modulus of the material
I is the second moment of area about the appropriate bending axis

Bri_Dunne

breadmonkey wrote: »

If you pick it up in the middle then I guess it will be acting like two cantilevers, fixed at the lifting point (under its own self weight only). In that case, the maximum deflection at the ends will be

d = wl^4/8EI

where:
w is the self-weight expressed as a UDL
l is the length of half of the beam
E is the Young's modulus of the material
I is the second moment of area about the appropriate bending axis

Yeah im pretty sure if u lift it in the middle and it is in equilibrium, the the upward force of the wire holding it (mg) would cancel with the mg force acting down. thus its a simple cantilever.
deflection on one side = deflection on opposite side. so only the need to work out one side.

godtabh

I wont advise picking it up in the middle unless doing so with lifting lugs.

It will be very prone to slippage and would be much less stable. Deflection, in this case, would not be your main concern. It will not be a controlled lift

Gileadi

I presume that the OP is asking due to a college question and is not intending on actually performing the lift on site... if he is, i hope he has insurance (both health and public liability)!