# Need help with statics problem -- Structure to hold 1300 pounds

#### Noah332

Summary
Trying to build a structure but not sure if i am doing it correctly

So given a force F that is at r1/2, distances y, r1,r2,and r3. What is x?

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#### berkeman

Mentor
What is the context of your question? Is this for schoolwork?

#### Noah332

Im trying to build a structure that can hold a 1300 lb supersack full of walnuts for work.

#### phinds

Gold Member
What is x?
Since you have given us no idea what constrains you want to put on x, how could we know? What is it you are trying to achieve?

#### Noah332

Does x need to have a constraint? Its a statics problem. I figured you sum up the forces in the x direction, sum up the forces in the y direction and sum of the moments and solve for x. Seems pretty straight forward im just trying to check if i did it right so i want to see how someone who knows what they are doing, does it? The one thing i realized i left out is the angle of those angled beams. They should be 45 degrees.

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#### phinds

Gold Member
Does x need to have a constraint? Its a statics problem. I figured u sum up the forces in the x direction, sum up the forces in the y direction and sum of the moments and solve for x. Seems pretty straight forward im just trying to check if i did it right so i want to see how someone who knows what they are doing, does it? The one thing i realized i left out is the angle of those angled beams. They should be 45 degrees.
??? x is a DISTANCE, not a force, at least the way you have it drawn.

#### Noah332

Yes exactly. Its a distance. I need to figure out how long that beam should be so thing thing doesnt fall over from the weight.

#### davenn

Science Advisor
Gold Member
Yes exactly. Its a distance. I need to figure out how long that beam should be so thing thing doesnt fall over from the weight.
and what are you wanting to build the structure from ?
anything less than very strong and it will buckle long before it topples over

#### phinds

Gold Member
Yes exactly. Its a distance. I need to figure out how long that beam should be so thing thing doesnt fall over from the weight.
Well, that's trivial. x has be be a minimum of r1/2 + r2 - r3. In practice you'll want it a bit longer. Personally, I'd go with x = r1 + r2 - r3

#### jrmichler

Science Advisor
You want to hold a 1300 load, but don't know how to keep it from tipping over. I strongly suggest talking to a real engineer.

BTW, those angle braces do exactly nothing for the strength of the vertical column. Can you explain why?

Well, that's trivial. x has be be a minimum of r1/2 + r2 - r3. In practice you'll want it a bit longer. Personally, I'd go with x = r1 + r2 - r3
If it was my job, I would want the front support at least 2 feet past the center of gravity of the 1300 lb load. Preferably a little more, or a lot more depending on the height. And anchor it to the floor.

#### phinds

Gold Member
You want to hold a 1300 load, but don't know how to keep it from tipping over. I strongly suggest talking to a real engineer.

BTW, those angle braces do exactly nothing for the strength of the vertical column. Can you explain why?

If it was my job, I would want the front support at least 2 feet past the center of gravity of the 1300 lb load. Preferably a little more, or a lot more depending on the height. And anchor it to the floor.
Sure, but he gave a very simplistic problem and I gave him a simplistic answer.

#### sandy stone

You want to hold a 1300 load, but don't know how to keep it from tipping over.
As far as that goes, what keeps it from tipping over sideways?

#### Noah332

and what are you wanting to build the structure from ?
anything less than very strong and it will buckle long before it topples over
Its being built out of steel

#### Noah332

As far as that goes, what keeps it from tipping over sideways?
Well it will have two of those side frames about 4 ft apart with connected cross beams

#### Noah332

Well it will have two of those side frames about 4 ft apart with connected cross beams
One at each corner

#### Noah332

We need to be able to drive a forklift to be able to rest straps from the supersack on the top bars sticking out

#### Noah332

Sure, but he gave a very simplistic problem and I gave him a simplistic answer.
I wanted to see how you would use statics. Like sum the forces and the moments. I wanted to see how its done

#### berkeman

Mentor
Thread closed temporarily for Moderation (safety issues).

Because if the inexperience of the OP and the heavy loads involved, this thread will remain closed. Thanks to all who responded.

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