How to calculate tension/compression in a truss bridge (diagram shown)?

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To calculate tension and compression in a truss bridge with a load positioned between two joints, the method of joints should be employed rather than the method of sections. The load can be treated as a moment at the joint connected to the loaded member, ensuring force equilibrium is maintained. It is recommended to start calculations from the supports and work towards the center, focusing on the joints adjacent to the load. If initial assumptions about tension or compression are incorrect, negative values will indicate the actual force direction. Understanding these principles is crucial for accurately determining the forces in truss members.
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In general, in a truss diagram the forces like load, reaction force are act on joints but in this case the load is in the middle of two joints. How can I find forces on members in this case?

9qfdw6.jpg


Your help is really appreciated. Thank you for reading
 
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Since the force is in the center of the spar, you could split it into 2 5N forces at its ends...
 
Mech_Engineer said:
Since the force is in the center of the spar, you could split it into 2 5N forces at its ends...

Could you help me find out what force (tension/compression) do the truss members have please? I have done most of them but the middle section with "X" trusses are making it dificult to calculate the forces the carry...
 
346oy09.jpg

I have done some calculations to find out the forces but i am confused with the middle section. Can someone tell me if figure 2 is correct or not?Thank you
 
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You can just assume one or the other (tension or compresison) and if you guessed wrong, you will get a negative value.
 
enosthapa said:
In general, in a truss diagram the forces like load, reaction force are act on joints but in this case the load is in the middle of two joints. How can I find forces on members in this case?

9qfdw6.jpg


Your help is really appreciated. Thank you for reading

Well, you can't use method of sections for the center... you'd have to use method of joints and treat that "external load" as a moment on the joint you're analyzing that's "connected" to the member that's loaded (as well as in force equilibrium)... seems as if the only two joints you'd concern yourself with with that center load are the ones to the left and right of it. at least that's how id attempt to do it. start at the supports and move your way towards the center.
 
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