(in Russian, shprengel’), in structural mechanics, a structural element in the form of an open bar system with a triangular or polygonal shape attached to the principal bearing elements of a structure. As geometrically variable systems, strut frames are used mainly in systems that retain their stability after removal of the frames. They may be designed from the start as part of a structure, or they may be used to reinforce existing systems.
Strut frames have various uses: to increase the number of joints in truss chords (for the suspension of crane equipment and to decrease the free length of panels), to increase the bearing capacity and rigidity of flexible structures (trusses, beams, and plates), and to decrease the flexing of columns subject to buckling. Strut frames are calculated according to the general methods used for bar systems.