A Parametric Study on Cable-Stayed Bridges by the Limit States Design

Abstract

Cable-stayed bridges with multi-stays have been recently planned and constructed in many countries probably because of aesthetic and economical superiority. It would be generally possible that the girder could become much slender by properly controlled cable prestresses. The system has been designed in this paper by mainly BS 5400, one of the few codes which have introduced the limit states design. The consistently optimised designs have been achieved by Linear Programming in order to compare the various bridge configuration. A simple method has been proposed to estimate the buckling capacity of the girder. The girder stiffness obtained is substantially lower than that of existing bridges. The bridge with multi-cables could have much slender girders than that with few-cables.

Optimum Design System for Steel Cable‐Stayed Bridges Dealing with Shape, Sizing Variables and Cable Prestresses

“…(a) The stress at the main girder element: Vg*(Z, x,, y,, PP) = Oi(Z, x,, y,, Pp) -a,,(Z) 5 0 (i = 1, ..., mg) (6) where a,(Z, X,, Y,. P,): the stress due to design loads and pseudo-loads, (a) cantilever system at erection closing stage (b) continuous girder system at service stage The minimum web plate thicknesses of each element of the main girder and pylon are determined so as to satisfy the composite stress criteria on the web plates.…”