Balance Beam formula
Balance Beam formula
(OP)
Hi folks,
Sorry to have to ask a seemingly simple question. Ive been out of practice for some time, and the "googling" route is not providing me any clarity.
I need to calculate how much weight to put on one side of an asymmetric beam. This is somewhat easy to figure if the loading was balanced, and i had the weight of all materials including the beam.
However Im working with evenly distributed loads on either side of the fulcrum.
my example is thus:
Beam is 20ft long
Fulcrum is at 8ft from left end
I need to figure how much weight (distributed) say over 2ft from extreme left to apply to the beam to create equilibrium across the fulcrum.
I know there is an easy solution to this, but I just cannot put my finger on it.
Can someone advise me on a formula or location of one?
Thanks,
Sam
Sorry to have to ask a seemingly simple question. Ive been out of practice for some time, and the "googling" route is not providing me any clarity.
I need to calculate how much weight to put on one side of an asymmetric beam. This is somewhat easy to figure if the loading was balanced, and i had the weight of all materials including the beam.
However Im working with evenly distributed loads on either side of the fulcrum.
my example is thus:
Beam is 20ft long
Fulcrum is at 8ft from left end
I need to figure how much weight (distributed) say over 2ft from extreme left to apply to the beam to create equilibrium across the fulcrum.
I know there is an easy solution to this, but I just cannot put my finger on it.
Can someone advise me on a formula or location of one?
Thanks,
Sam






RE: Balance Beam formula
W= weight of beam
W1= weight of distributed load 2ft from left
W(12)(12/2) = W(8)(8/2) + W1(2)(7)
RE: Balance Beam formula
LL = span on the left of the fulcrum = 12'
LR = span on the right, 8'
W = weight (per ft) of the beam
WL = weight added on the left side
XL = distance from the fulcrum (of WL)
WR = weight added to the right
XR = where this is
if you're applying a distributed load, apply a concentrated load in the middle of the distributed span (clear as mud)
LHS moments = W*LL*LL/2+WL*XL
RHS moments = W*LR*LR/2+WR*XR
RE: Balance Beam formula
Thanks for your responses.....It didnt even occur to me I could turn the dist. load into a point load. This will help me figure this out. I know that the moment needs to "null" out at the fulcrum to be in equilibrium, I was just having a bear of a time dealing with the loading on the beam (being distributed).
Thanks again for your responses, this made my afternoon.
-Sam
RE: Balance Beam formula
RE: Balance Beam formula
BA
RE: Balance Beam formula
RE: Balance Beam formula
If the additional load on the end of the 8' span is w1, then 2*w1*(8-2/2) or 14w1 is its moment about the fulcrum.
The beam is balanced when those two expressions are equal.
BA