How to Obtain Reaction of Truss Pinned Connection A, B, and C?

[DavidLee24]

Hey guys,

Sorry for this newbie question, I would to ask how to I obtain the reaction of the pinned connection of A, B, and C (See attachment)? Do I really have to use Force-Method? I actually attempted to use Moment at different places and do simultaneously (Idk if it's the right thing to do) but apparently I got Ay = 38.07kN, By = 37.39kN and Cy = 0, which I think it is wrong, can anybody help?

Thanks.

-DL

 

[PhanthomJay]

The truss is externally statically indeterminate with 6 unknown reaction forces and just 3 equations of equilibrium, so you have to resort to a painstaking indeterminate analysis using a method of your choice.

 

[DavidLee24]

The truss is externally statically indeterminate with 6 unknown reaction forces and just 3 equations of equilibrium, so you have to resort to a painstaking indeterminate analysis using a method of your choice.

Thanks for the reply, Jay! I've been studying stiffness method to solve for this question. But I have several question that I would like to ask, (see attachment)

From the truss, I put them into global coordinate, and named the member (in square), but I would like to ask about the arrow for Near and Far (in Cyan), is there ways to determine or is it assumed by ourselves? Thanks!

 

[zeronem]

nodal analysis is how one would do it but as said if there are too many unknowns than knowns, computational methods may have to be used. I know sometimes with complicated trusses using matrices can be an adequate tool I believe.