Design of prestressed cold-formed steel beams.

Structural design rules for prestressed cold-formed steel beams, considering both the prestressing and imposed vertical loading stages, are presented herein. In the proposed approach, the cold-formed steel member is designed as a beam-column using linear interaction equations in conjunction with the Direct Strength Method (DSM), while the prestressed cable is designed by ensuring that its tensile capacity is not violated during the two loading stages. In the present paper, the design approach and the failure criteria, which define the permissible design zone for the prestressed system, are first introduced. The suitability of the design recommendations is then assessed by comparing a set of parametric finite element (FE) results for several combinations of prestress levels, beam geometries and cable sizes, with the corresponding design predictions. Finally, following reliability analysis, the implementation of the design recommendations is illustrated through a practical worked example. • Design recommendations for prestressed cold-formed steel beams developed. • Linear interaction equations in conjunction with the Direct Strength Method utilised. • Capacities of cold-formed steel beam and cable to be checked for both loading stages. • Design rules assessment through comparisons with parametric finite element results. • Implementation of design rules illustrated through a practical worked example. [ABSTRACT FROM AUTHOR]