This paper examines the installation of cable stays which are made up of individual parallel strands. For cables that are erected using a strand-by-strand or isotension method, a simple procedure is outlined for computing the installation forces, taking into account the flexibilities of the cable and the structure, and allowing for changes in loading and thermal effects. The procedure is also extended to compute the top-up forces in a two-stage stressing procedure in which the results of the first stage are utilised to predict an improved final force without the need for extensive and laborious geometric monitoring of the anchorages’ displacements.
Comparison of the theorectical results is finally made with measured data from the recently completed Flintshire Bridge in North Wales where the technique has been successfully employed by the author. The formulations presented in this paper are equally applicable to cable stays which are made of parallel wires or bars.
H. Al-Qarra, BSc (Hons), PhD, CEng, MICE, Chief Structural Engineer, DIWI Consult International GmbH, Essen, Germany (formerly Gifford and Partners, Southampton, UK)