Actually, its not pin joints unless you want the beam to be able to swing in two dirrections. A hinge is more like it, hence the term "hinged joint". Both would be usefull though. This should be an easy one to impliment also. Enjoy. :-)
It'd be nice to have joints that could pivot and bend with out breaking links. Additionally, being able to run the cable through a pully would allow weight on some parts of the bridge to distribute to others.
AFAIK hinges are not usually used in building bridge trusses :-)
A pin joint (such as on a bicycle chain) allows swinging in one direction and offers resistance to the other 2. It takes force in 2 directions, and resists movement along the axis of the pin, but can't take great force in that direction. On brantancan (see www.bridgebuilder-game.com -> links) you can see pictures of pin joints.
Since BB is 2D, you can't try rotating a beam in any other plane than the monitor plane, and applying force in the 3rd direction is out of the question, too, so pin joints is what I call them, though in 2D you can't tell them from hinges :-)
I agree, if there was one feature lost from bb to PFX that I miss, Pivoting links would be it. They allowed for bridges to settle with much less damage.
The word is "pin joints" :-)