DOME-SHAPED SPACE-TRUSSES FORMED BY MEANS OF POSTTENSIONING

Dome-shaped space trusses can be derived from a fiat configuration by means of posttensioning. The structure considered here is devised to b e a near mechanism initially and during the posttensioning operation. It is a near mechanism as only the flexural stiffness of the continuou s top chords provides any resistance to deformation. Therefore, no app reciable force is induced in the members of the structure during the s hape formation process, The results of experimental and theoretical wo rk on the shape formation of a dome-shaped space truss by means of pos ttensioning are presented herein. An analytical procedure that include s both geometric and material nonlinearities is developed to determine the final shape of the dome-shaped space truss, using commercially av ailable finite-element software. The ultimate aim is to lead to signif icant economies in the construction of large-span lightweight structur es by eliminating or minimizing the need for scaffolding and heavy cra nes in the Shaping and erection of such structures.