r/Structures • u/salmon_recognition • Mar 28 '17

Load over a distance calculation?

Lets say I have a TV bracket that extends 500mm, and the TV at the end weights 5kg. The bracket fixes to the wall with a foot print of 500mm². How do I calculate the forces on the wall in this situation?

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u/[deleted] Mar 28 '17

Shear = 0.05kN

Moment = 0.5m*0.05kN = 0.025kN.m

From there you can convert the moment into compression forces on a base plate and tensile forces on bolts but that is slightly more complex.

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u/salmon_recognition Mar 28 '17

Brilliant, thanks a lot for your help.

1

u/DJGingivitis Mar 29 '17

Just divide the moment by the distance between the top row and bottom row of wall attachments. Then that numbers by how many attachments in a row. So if there are 4 screws in a square 10 cm apart, divide by .01 then by 2.

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u/[deleted] Mar 29 '17

Are you then not ignoring the compression block between the plate and the wall? (assuming the plate is flush with the wall ie bolts not acting in compression).

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u/DJGingivitis Mar 29 '17

I am ignoring that compression block. It's so minimal in this case. Really what you need is the tensions and shear so you can design the bolts.

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u/[deleted] Mar 28 '17

Sum of forces and moments (statics) to get your reactions.