Nonlinear analysis of prestressed structures with external cables

A nonlinear procedure for the analysis of prestressed structures with external cables is presented. Several methods of Nonlinear Analysis have been developed in recent years to model the complex behaviour of Reinforced and prestressed Concrete Structures,and several level of sophistication can be individuated. A few of these procedures has been adapted to the case of prestressing using external cables. However the use of nonlinear analysis in design of real structures is still limited to very particular cases,despite the fact that simplified methods of Nonlinear Analysis exist today which could be used as "normal" tools of design. To encourage a more widespread use of Nonlinear Analysis, in this paper methods of nonlinear analysis of r.c. structures are first classified according to different parameters of complexity and preformance to identify the procedures more suited in the preliminary phases of design. Secondly a procedure conceived by the author which was used to prepare a nonlinear program which can run efficiently on personal computers is briefly described. Additional considerations are made concerning concrete resistance,ductility and constitutive laws.