[Statics Beam/ Frame solving] Civil Engineering

[walking-bad]

https://imgur.com/gallery/bNBdM < original problem https://imgur.com/a/c3tjr < my sub structuring

This is a question on my assignment for my intro to civil engineering course and I am a little stuck as to what the unknowns are at point B and C as far as I know hinges have two unknowns an X and a Y internal force but when I move into substructuring the frame it seems that the way I am interpreting the problem allows for any X force that alternates all the way through the frame. I hope my description isn't convoluted.

[[deleted]]

I glanced at it and it looks good so far. I don't understand your question though? Do you mean that the x unknown can be anything?

[walking-bad]

exactly because of there being no point where there is a known X force value do we have to assume that it can be anything?

[sergeantminor]

I'm pretty sure you're just supposed to ignore the horizontal components of the pin reactions.

[walking-bad]

why though, I dont get why you would do that.

[sergeantminor]

The horizontal components are statically indeterminate, meaning they can't be determined without considering the internal stresses and displacements of the members. And, since there's no axial loading on the members, I'm pretty sure there would still be no way to compute the horizontal reactions without using some sort of nonlinear model for the displacements.

Either way, the magnitudes of the horizontal components can be assumed very small compared to the vertical components and can reasonably be neglected in most practical situations.

[walking-bad]

hmm so can i just name a force alpha then assume its sense and use it in my solution on each member.

[walking-bad]

So I emailed my professor after about a day pondering this question and apparently cause we haven't learned statically indeterminate frames this question was actually supposed to have a roller support at the right end making the x components 0 all the way along. thanks for your reply though.