# Need help with trusses

1. Mar 15, 2012

### Joelllllll

Need help with trusses!!

Hey guys
So I'm trying to solve this truss problem and get all the reactions of the trusses
I've done it so many times but my equations never work out and I get crazy answers :\
I've found the reactions at A and B
Ax=-50kN
Ay=72kN
By=128kN
My answers for tryingto solve it are
Pac=-90kN
Pce=6.66kN
Pcd=-177.3kN
Pde=-295.5kN
Pdb=132.4kN
I just can't see where I went wrong?
Can someone help me out here?:(
Thanks

#### Attached Files:

• ###### Untitled.jpg
File size:
9.7 KB
Views:
58
2. Mar 15, 2012

### KyPhyTeach

Re: Need help with trusses!!

I found Ax= -50 too, but I found Ay=96kN and By=104kN.

To find Ay and By I used moments. Taking the moment around A you find the equation.

Ma = 100kN(2.25m) + 100kN(4.25m) - By(6.25m)

When you solve this I get By = 104kN. From their you just take 200kN - 104kN and that gets you Ay=96kN.

I think this should help you get on the right track from here.

3. Mar 15, 2012

### Joelllllll

Re: Need help with trusses!!

What about the 50kN force?
Why didn't you use that in your moment equation?