Prestressed pin-jointed structures—Flexibility analysis and prestress design

Abstract Two classes of prestressable structures exist. Class I are geometrically rigid and statically indeterminate structures. Class II are statically and kinematically indeterminate structures with infinitesimal mechanisms. In structures of class I, prestress by means of imposed lack of fit can substantially enhance the design, particularly when failure is governed by compression member buckling. Structures of class II depend on prestress for their geometric integrity. A unified algorithm for the analysis and for the design of prestress of pin-jointed structures of both classes, consisting of any combination of bars and cables, is presented. The algorithm is based on the flexibility method of structural analysis, and assumes small displacements. It is capable of identifying states of prestress and mechanisms and optimizing the prestress in compression controlled structures.