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I work at a museum and we use weighted free standing walls to hang artwork in the center of rooms. Could someone recommend how much weight to use inside our walls to ensure stability with the installation set up described below?

We have two 8-foot wide walls (10 feet high and 20 inches deep) combined (attached with hardware) to make a 16-footwide free-standing wall, and we are looking to install a sculpture that is built into a steel grid on one side of the wall. The grid is 103” wide x 78” tall and attaches to the wall with 6 pieces of hardware that look like posts, offsetting the artwork from the wall by 9”. The sculpture weighs around 100 lbs.(probably closer to 60 lbs. but I’d like to assume it’s more). We don't typically use hardware that extends this far from the wall. Is it safe? How much weight should we use inside the wall to ensure stability?

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    $\begingroup$ the walls you describe sound like a recipe for disaster ... what prevents the walls from falling over? $\endgroup$
    – jsotola
    Commented Jul 8 at 22:56

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I’m going to tak a stab at this more as entertainment. Otherwise an object hanging to a free-standing wall not anchored to floor is a textbook example of what not to do.

Let’s assume you ballast is metal and can be placed at the middle of the bottom of the wall and ignore the weight of the wall. We set the overturning moment equal to zero. We take the moments about the edge of the wall close to the loaded face.

$$\Sigma M =0 100lbs * 10”= W_{ballast}*20/2$$ $$ W_{ballast}=100lbs$$ If we use a factor of safety of 5 we need a ballast of 500lbs placed in a way that its CG falls at the middle of the wall.

I assumed your statue was flat otherwise we need to add the distance from its CG to the face of the wall and plug it in the above equation instead of the 10”.

In this scenario, stability is more important than finding the tipping point. If, by an unforeseen accident, this display is shaken, the balance quickly and irrevocably deteriorates. Because the vertical projection of the imbalance momentum of the cantilever statue at a height of, say, five feet is going to increase rapidly, while the restoring force of the ballast momentum is going to decrease fast.

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  • $\begingroup$ Thanks for this info. It's very common to have free standing walls in a museum or gallery setting, so this surprised me. Based on your comment about stability, does this weight then create enough stability? Any thoughts on how to anchor the wall to the floor? What if we add a "support wall" to make it an "L" shape? $\endgroup$
    – user49384
    Commented Jul 16 at 20:26
  • $\begingroup$ Any arm sticking out of the wall on the floor is going to be helpful. Stability is determined by the fact that the load's distance from the corner of the wall on the floor is greater than the ballast's distance. Balance is achieved when the ballast is heavier than the load. However, if the wall is shaken by an earthquake, this advantage is quickly lost. If you have recently purchased furniture such as bookshelves or chest drawers, you may have noticed that they need to be anchored to the wall. $\endgroup$
    – kamran
    Commented Jul 17 at 0:08
  • $\begingroup$ Thank you so much for your help. We are adding the extra ballast and are planning to adjust our layout so we can anchor the wall to a large platform on the opposite side of the wall. Luckily we are not in an area where earthquakes are a concern $\endgroup$
    – user49384
    Commented Jul 17 at 20:32

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