Design and form-finding of compression structures with prestressing tendons

Compression only structures such as domes and vaults can be modelled as pin jointed networks whose equilibrium configuration is obtained using well-known form-findings methods such as the Force Density Method. As all the members of the network are in compression, its corresponding force density or force:length ratio matrix is non-singular and the final shape is obtained directly from the equilibrium equations. The introduction of prestressing tendons (members in tension) in compression structures allows for the design of more creative forms, showing an exceptional versatility in the design of new structures. However, because tension and compression members exist, the force density matrix can be singular or ill-conditioned and the solution of the equilibrium equations is not quite as simple as in the case of compression-only structures. In this work, a procedure for the design of compression structures with prestressing tendons along with several examples are presented.