question about determinacy

[Alamri.A]

in the picture attached. a two story frame with two fixed supports and a hinge at the midpoint of the first story. is this structure determinate, indeterminate or unstable ?

 

[KootK]

Indeterminate, by several degrees.

 

[Luceid]

Does this hinge actually give you an additional equation? Since it's still hooked up at the top....

 

[rb1957]

if all the other joints are fixed, then indeterminate. The hinge looks pretty irrelevant to me.

 

[GregLocock]

Imagine we cut through the lower beam at the pn joint, and I am assuming all the other joints are fixed. So we have a set of goalposts and a couple of cantilevers. if we apply a load to one of the cantilvers we have to do something or other that has to be calculated to bring te other tip into alignment. As it happens this structure seems to be symmetrical so that is not a hard calculation.

I've got to ask since i've got caught by this in another problem, why aren't people stating the degree of fixity of joints properly?

Again if we take our trusty hacksaw and chop the right hand post neear the ground, the thing stays up. So yes it is indeterminate and stable.