definition of work poin

huangyhg

definition of "work point"
hi everyone,
can anyone provide a clear and concise definition of "work point" as far as its use in structural steel drawings is concerned?  i see it frequently in structural steel details - drawn as a dot with the initials w.p. - showing for instance, where the centerlines of two adjacent steel members would meet?  is it only to show where two enterlines of steel members meet?  how often is it used, and where must it always be specified?  does it need to be provided with dimensions?  what are its usefulness to contractors or other engineers?
thanks, y'all.

i'm guessing (from your description, "where 2 cls cross") that this is used to define the theoretic structure for calc's, so everyone uses the same dimensions in their analysis.
i use it in details to construct a dimensional control point where the geometry and dimensions are based upon.  it is usually some convenient point that is easily determined and can serve as a base point for other elements in the detail.  
one example - in wood framed construction, in a sedction through the eave of a roof, we use the intersection of the exterior wall face and the plane of the bottom of roof sheathing as a work point.
this allows us to set a vertical dimension from the top of wall to the roof plane which sets the height of the roof.  the work point is usually selected to also be tied in with plan dimensions as well.
it may also show where centerlines intersect with the edge of a member, showing the detailer how to layout the   
the place i specify work points is when i have a diagonal braced steel frame. i want the fabricator to know where the centerline of the diagonal brace intersects the column. usually this is at the intersection of the centerline of the beam and centerline of column at the high end and at the centerline of the column and 6" above the baseplate at the low end.
they are for the fabricator so he can design the connections to have the center lines of   
it is often lines through the center-of-gravity of members, which is where axial forces act.  this may or may not coincide with the geometrical center lines.