Zero-force member problem (Statics)

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The discussion focuses on identifying zero-force members in a truss using established rules. The user initially identified six zero-force members but was uncertain about two additional members, BE and IJ, mentioned in the solution. Clarification was sought on how to apply the rules correctly, particularly in relation to the implications of identifying BC as a zero-force member. The conversation emphasizes the importance of understanding the relationships between members at joints to accurately determine zero-force members. Ultimately, the user received confirmation that the reasoning for identifying BE and IJ was valid based on the rules provided.
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Homework Statement


Determine the zero force members in the following truss


Homework Equations



- If only two members meet in an unloaded joint, both are zero-force members.
- If three members meet in an unloaded joint of which two are in a direct line with one another, then the third member is a zero-force member.

- If two members meet in a loaded joint and the line of action of the load coincides with one of the members, the other member is a zero-force member.




The Attempt at a Solution



Ok, I got 6 (there are 8 according to the solution) using the above rules:
HF, HI, OQ, QR, BC, and DE

The solution says that BE and LJ are also zero force members, but I have no clue why...

Any help please?

Thanks in advance!
 

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Not LJ, its IJ, why? If BC is a zero force member, that should tell you something about BE (and DE).
 
Ok, I had thought about IJ before but since the solution didn't mention it I didn't count it...

Now, for BE: since BC is a zero-force member, can we "ignore" it and then consider the other 3 with Rule #2?
 
aero_zeppelin said:
Ok, I had thought about IJ before but since the solution didn't mention it I didn't count it...

Now, for BE: since BC is a zero-force member, can we "ignore" it and then consider the other 3 with Rule #2?
yes.
 
Thank you sir ;)
 
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