Influence lines (concentrated load system)(with the problem this time)

[mohamadh95]

I started by getting the equation for the reaction(which is really simple). I'm a bit confused here, they're asking for the absolute maximum moment, but they're not locating the location of where the maximum moment will occur, should I assume it's happening on the middle of the beam? And another question, how can I find the value of this maximum moment, I'm normally accustomed to a concentrated load, or a uniformally distributed load, but not a system of concentrated forces. Thank you.

https://www.dropbox.com/s/5rngrqme4fv929y/2013-08-15 17.52.30.jpg

 

[SteamKing]

I'm a bit confused here, they're asking for the absolute maximum moment, but they're not locating the location of where the maximum moment will occur, should I assume it's happening on the middle of the beam?

No, the location of the maximum moment probably will not be in the center of the beam. The beam is not loaded symmetrically.

And another question, how can I find the value of this maximum moment, I'm normally accustomed to a concentrated load, or a uniformally distributed load, but not a system of concentrated forces.

You are forgetting one critically aspect of analyzing beams. Multiple loads can be treated using the principle of superposition, i.e., find the effect of one load at a time on the beam, and then add up the effects of a series of single loads to find the total effect of ALL the loads on the beam.

The superposition principle also works with influence lines.

 

[mohamadh95]

No, the location of the maximum moment probably will not be in the center of the beam. The beam is not loaded symmetrically.
You are forgetting one critically aspect of analyzing beams. Multiple loads can be treated using the principle of superposition, i.e., find the effect of one load at a time on the beam, and then add up the effects of a series of single loads to find the total effect of ALL the loads on the beam.

The superposition principle also works with influence lines.

Could you provide some more information? Because I don't know where I should take the cut on the beam.
Ohh and something else should I find the center of gravity of the load system(Gx)? Is the location where maximum moment occur equal to Gx?

 

[SteamKing]

The following should help you with your influence line calculation:
http://www.mm.anadolu.edu.tr/insaat/icerik/dersnotlari/ins313/influencelines.pdf

 

[mohamadh95]

The following should help you with your influence line calculation:
http://www.mm.anadolu.edu.tr/insaat/icerik/dersnotlari/ins313/influencelines.pdf

Thank you, this was helpful.