CABLE STAYED BRIDGE

Abstract

The cable-stayed bridge is one of the relatively recent innovate bridge form. It consists of three principal components, namely, girders, tower (pylons) and cable stays. The girder is support elastically at points along its length by inclined cable-stays so that it can span a much longer distance without intermediate piers. The cables are connected to the tower to transmit the load to the foundation. Cable stayed bridges have good stability, optimum use of structural materials, aesthetic, relatively low design and maintenance costs, and efficient structural characteristics. Therefore, this type of bridges are becoming more and more popular and are usually preferred for long span crossings compared to suspension bridges. A cable stayed bridge consists of one or more towers with cables supporting the bridge deck. In terms of cable arrangements, the most common type of cable stayed bridges are fan, harp, and semi fan bridges. Because of their large size and nonlinear structural behavior, the analysis of these types of bridges is more complicated than conventional bridges. In the present study a simple cable-stayed has been considered for examining and comparing the forces generated in pylon and cable forces for different types of deck .Here we have considered one RCC box girder deck and the other composite truss deck. Modern designs adopt thin and lighter decks, inducing savings in the deck, cables, piers and foundations. Field bolted splices provided fast and simple connections between almost identical modules, ensuring maximum repetition of pre-fabricated deck components and construction procedures. These concepts have been applied to the majority of composite cable stayed bridges with main-spans exceeding 200 m, built over the last twenty years by the balanced cantilever construction method. CSI BRIDGE v20 software has been used for analysis purpose.