PARAMETRIC STUDIES ON CABLE SUPPORTED BRIDGES

Abstract

Cable supported bridges are gaining importance world over for bridging long spans. The idea of supporting bridge girders with efficient stays was not new, but the popularity of cable-stayed bridges was delayed due to lack of computational facilities, availability of suitable high strength materials and appropriate construction techniques. The concept of hybrid cable stayed bridges can be efficiently used with spans of 1000m and more. This is possible based on the present high standard theory and calculation methods and additional tendency to use light weight materials including welding techniques as well as high admissible stresses in cables. Elements of suspension and cable stayed bridges can be used together. Hybrid bridges do not require tall towers, and the support capacity lost by using shorter towers is regained by using cable stays at the center of the span. This design also requires somewhat less foundation work than a conventional suspension bridge. In the present study, cable stayed, hybrid cable stayed bridge and cable stayed —cum-suspension bridge with radial, harp, and fan configurations have been studied. The resisting behavior of above bridges is assessed by parametric study which can be used to achieve right and economic answer. The parametric study has been performed varying the height of tower, side to main span ratio, cable sag, and cable area. Analysis has been carried out using ANSYS 5.4 by generating 2D models of the above bridge profiles in radial, harp and fan configurations. Results have been presented in tabular form and x-y plots are drawn with non-dimensional parameters to arrive at appropriate conclusions.