Title : CABLE STAYED AND SUSPENSION BRIDGES - PROBLEMS AND THEIR SOLUTION
Authors : Satander Kumar, V V Arora
Publication : 8 - 10, October 2015
Volume : 1
Pages :
Price : 250
Abstract : A cable-stayed bridge, one of the most modern bridges, consists of a continuous strong beam (girder) with one or more pylons or towers in the middle. Cables are stretched diagonally between these pylons or towers and the beam. These cables support the beam. The cables are anchored in the tower. Extra-dosed bridge is a medium span, hybrid bridge with more substantial bridge deck, stiffer and stronger, allows the cables to be omitted close to the tower/pylon and height of the towers are lower in proportion to the span. The suspension bridge requires two cables strung across high towers on each side of the area to be bridged. The roadway is then hung on vertical suspenders attached to these suspension cables. The support towers support the weight of the suspension cable, which in turn supports the weight of the vertical suspenders and the bridge traffic. These cable bridges are usually of large span (as compared to conventional pre-stressed bridges of span 30-40 m), under severe geological, environmental, and local problems. These are prone to instability caused by heavy rain & wind. These structures must be monitored systematically and protected through appropriate design considerations. The risk of corrosion, loosening of anchors and vibration increases with the large cable-stay length. Short cable stay bridges (span less than 80 m) generally involve no risk, and provision for dampers on short cable stays is not proposed. For long cable stays (more than 80 m in length), dampers must be installed to resist high vibration. The cable stays are checked for the corrosion effects and their protection measures during design and construction. To ensure that users feel safe, the amplitude of cable-stay vibration is limited to 100 mm. This paper highlights the problems, their solution and specifications of cable bridges viz. cable stayed bridges, extra-dosed bridges and suspension bridges.