A support reaction is a force or a moment with which a support or restraint supports a technical object such as a structure . The totality of the support reactions fixes the respective object on the supports.
Examples of this could be: the superstructure of a bridge rests on the abutments, a centrifuge on a foundation, a rail vehicle on the tracks and the bookshelf on the wall; the drill is clamped in the chuck and the tap bar in the masonry.
In technical mechanics, the methodology is such that the supports are removed in the calculation model and replaced by the associated support reactions. One then speaks of support forces and restraint moments .