Axial behaviour of prestressed high strength steel tubular members

The axial behaviour of high strength steel tubular elements with internal prestress-ing cables, representing the chord members in prestressed trusses, is investigated herein. Ex-periments on tensile and compressive members were carried out, with the key variables exam-ined being the steel grade (S460 and S690), the initial prestress level and the presence of grout. FE models were developed to replicate the experiments and generate parametric results. The presence of cables was shown to enhance the tensile load-carrying capacity of the mem-bers while the application of prestress extended the elastic range. In compression, prestressing was detrimental, and a modified Perry-Robertson design approach was examined

Compressive behaviour and design of prestressed steel elements

© 2015 Elsevier B.V.The tensile performance of the chords of steel trusses can be considerably enhanced through the addition of prestressed cables. However, under compression, which may arise due to wind uplift, the prestressing may have a detrimental effect. The behaviour and design of prestressed steel elements in compression is examined presently. Eight experiments on prestressed elements were carried out, where the key variables examined were the initial prestress level, the presence of grout and the member slenderness. Cross-sectional behaviour and member buckling behaviour are examined analytically, numerically and experimentally, with good correlation achieved between the three approaches. The benefit of adding grout to bond the prestressing steel to the encasing tube is also investigated and design approaches for both non-grouted and grouted prestressed elements are proposed