Transcript of Cable Stayed Bridges
Cable Stayed Bridges Where the future is headed! INTRO Cable Stayed Bridges use large columns that have cables attached at different intervals which relieve tension in the bridge span. Tension in the cables holding up the span is transferred to the towers in the form of compression. What is a Cable Stayed Bridge? Why use a Cable Stayed Bridge? Unlike suspension bridges, cable stayed bridges do not require anchors, reducing the amount of material – reducing cost. Cable stayed bridges offer much greater stiffness than suspension bridges, so that decking deformations are greatly reduced when subjected to load combinations. Takes little time to erect the decking since it’s typically made from precast concrete More aesthetically pleasing than suspension bridges or cantilevered bridges Cable Arrangements Cables are arranged in such a manner that they all meet relatively close at the top of the tower That being said, arranging the cables this way places a lot of loading in a small area Fanned Cable Arrangement Harp Arrangement Aesthetically pleasing. Places more compression in the deck and produces bending moments in the tower Comparing the Two Arrangements Cable Stays Locked Coil The core is composed of conventional round steel wires, outer layers have Z-shaped steel wires that interlock together Helical or Spiral Strand Galvanized round steel wires, wrapped in a helical pattern Parallel Wire Strand steel wires wrapped in filament tape and coated in polyethylene (enhances fatigue resistance) Advanced Composites Carbon or Aramid Fiber Reinforced PlasticsFull transcript
Relatively new in bridge construction.
Have an advantage to when related to other materials due to a high tensile strength to weight ratio Towers The tower is the tall pillar to which the cables are attached on the bridge. It’s primary function is to transmit and absorb forces from the anchoring stays, which will control how the pylon is eventually designed Material Considerations Towers can be made out of steel or concrete (primarily concrete) Early designs made from steel, with no real consideration for material cost or artistic design I-280, Toledo, Ohio