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- Thread starter Alpha[X]²
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- #2

radou

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Alpha[X]²;1286900 said:

Depends on the geometry and the loads applied to your bridge. If would be great if you posted a pic.

Basically, all you have to do is apply the equations of equilibrium to your system. I can't be any more specific with the given data.

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- #4

Pyrrhus

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Well, a picture and your attempt will be a good start.

- #5

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I don't have anything because I don't know how to calculate the forces.

- #6

radou

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- #7

radou

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- #8

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How did it come up with those calculations though?

- #9

radou

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Alpha[X]²;1288812 said:How did it come up with those calculations though?

Which calculations? Do you mean, the calculation of the reaction forces at the supports?

- #10

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Yes, the numbers on the members in the diagram.

- #11

radou

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Alpha[X]²;1288819 said:Yes, the numbers on the members in the diagram.

I assume the numbers represent the forces in the members, and the colors represent compression/tension. As I said, you can calculate every force by looking at every node separately. Imagine you "cut out" the leftmost node. You have two unknown and forces and one familiar force. Set up two equations of equilibrium, one for the "y-direction", and one for the "x-direction". You can calculate the forces in the members from these equations.

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But, that looks like an equilateral triangle, why is there different calculations?

- #13

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Also, I the program used a matrix to solve the forces, what would the matrix calculation formula be?

- #14

radou

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The calculations seem wrong. For example, I got ~28.87 for the leftmost blue truss element.

- #15

AlephZero

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The answers are correct (to 2sf) for the shape as it is drawn. I get 30.05 for the force in the leftmost blue truss.

- #16

radou

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The answers are correct (to 2sf) for the shape as it is drawn. I get 30.05 for the force in the leftmost blue truss.

Of course, for some reason, I totally ignored the mesh. :uhh:

Alpha[X]^2, sorry for causing eventual confusion.

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