Sheet1Comparison between a Cable Stayed & an Extradosed BridgeCable Stayed BridgeExtradosed Bridge1) Structural ActionSuperstructure is freely supported via bearings over Pylon and the cables from a highted tower intersect with deck at near to vertical angles, so that the vertical load of bridge deck gets transferred as tension in cables without inducing much horizontal compression component in bridge deck.Superstructure is integral with Pylon for continuous action and cables from a lower tower intersect with the deck only further at a lower angle, so that their tension acts more to compress the bridge deck horizontally than to support it vertically.( Cables--> act as external Prestress)More than 90 % of the vertical force of superstructure transfers through Cables.Only 20 to 50 % vertical force of superstructure transfers through Cables and remaining is taken care by stiff superstructurePylon is Stiff and superstructure is comparatively flexible.Superstructure is Stiff and pylon is comparatively flexible.

2) SuitabilitySuitable for main spans between 200-600mSuitable for main spans between 100-200m

3) Geometry Constraints

4)General AspectsRestriction of maximum permissible forces in cables is .45 fpu because of governing fatigue considerations.Restriction of maximum permissible forces in cables is .6 fpu due to not so dominant fatigue effect on cables.

Tension Adjustment is needed in the external cables at the end of construction stages (Cable force tuning)Tension adjustment need not be done for the external cables and only one time stressing may suffice.

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Sheet3