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Engineering - Truss Bridge Calculations Help Needed! Watch

1. So I'm coming up to a couple of my engineering exams that are degree extensions of mechanics known as forces in members of a truss bridge.

I'm able to calculate the reaction forces at each base, and the member forces at each base. However I get stuck every single time with the members in the middle of the truss..

Is there an easy way to calculate them ?

so Reaction Force at E is 30 and reaction force at A is 60

I can then work out the Member forces at A using the sums of x/y in equilibrium giving me AB= -69.28 and AG=34.64

(This is done with 60+ABsin(60) = 0 etc)

however at joint B I am literally completely stuck.. Would love some help!
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2. (Original post by iron_lloyd)

however at joint B I am literally completely stuck.. Would love some help!
At B, resolve vertically, and this will give you BG, and then horizontally to get BC,....

The structure is assumed to be pin-jointed, and forces only act along a spar, compression or tension.
3. (Original post by ghostwalker)
At B, resolve vertically, and this will give you BG, and then horizontally to get BC,....

The structure is assumed to be pin-jointed, and forces only act along a spar, compression or tension.
Brilliant! You know that moment when everything suddenly clicks into place, you know the method and now the 'hard' questions become easy? BOOM

Thanks for the help man
4. (Original post by iron_lloyd)
Brilliant! You know that moment when everything suddenly clicks into place, you know the method and now the 'hard' questions become easy? BOOM
Good to hear - understanding!

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