Bill Schwab wrote:

You left off the horizontal component of the tension in the "tension
member". I've said that at least three times now. Given the
idealized structure you created, it is simply where Newton takes us.



Whether or not this force is included depends on how you model the
structure. If you look at my diagram of the idealised structure, the
tension member, column and roller support are all connected by the
same pin. In this case the roller support provides a reaction
(transmitted through the pin) against the horizontal component of the
tension, and this force is not seen by the column.


I don't know how else to say it. That is not correct. The tension
member and the support both interact with the beam.

That depends on whether the tension member is connected directly to the
column. In my idealisation it isn't. The tension member is connected to
the pin. The pin is also connected to the support and the column. It
seems like you are disagreeing with my idealisation, which is fine, but
the FBD is consistent with the idealisation. Perhaps someone else can
offer an opinion on this?

Chris