Sorry for the misinformation. Apparently the correct term is "bending" rather than shear. I was referring to the weight placed on the horizontal beams of the gantry cranes pictured earlier. It is the weight of the object suspended from the top beam as well as the load it places on the "legs" by the two columns (verticals) when the legs are on casters. Wood is not particularly strong as a beam (when bent), but does much better in compression (as a column). That was my concern.
Some texts I have reviewed seem to indicate that bending may be a special case of shear, but I am not sure and will leave that to the engineers to clarify. I know that a shock bolt that goes through one support and the shock is called in "single shear" and if it goes through two supports on each side of the shock (or end link) it is called in "double shear". I am not sure why the beams in question are not in "double shear". Again, anyone shedding any light on this would be most welcome.
Thank you for the clarifications.
