Hydraulic Assisted Bridge

Hydraulic Assisted BridgeIshan Kossambe 13MCD0038IntroductionIncorporates an integrated hydraulic system into the bridge in order to carry more weightSuitable for arch based bridges

How it works

Forces in a lateral/horizontal direction at the supports

Three hinged arch

Loading will cause the arch to spread

Supports

Load causes the three hinged arch to spread out

Piston is held in place via a pined connection

O-rings of the pistonMid-Span of BridgeThe high pressure hydraulic fluid causes another piston to become raised

Counteracting the load

Calibration and calculation is required by changing the diameter of the piston and shafts

Advantages

Little maintenanceQuantity of material required to construct the bridge is reducedIncrease its aesthetic and social impactReversal of hydraulic fluid still results in equilibriumDisadvantagesVertical hydraulic column being required to be located in the center of the archVertical column type hydraulic bridges may never be used in arch bridges required to span gaps which are very high in the context of the altitude of the locale.Failure by very high forceOvercoming the Disadvantages

Eliminating the single vertical hydraulic columnReplacing hydraulic components placed at an angleAdding several, thicker O-rings and gasketsPotential ApplicationsPedestrian FootbridgesWater TransportationVehicular TransportationLight VehiclesFreight VehiclesRailway TransportationMoving BridgesDrawbridgeBascule bridgeCurling bridgeVertical-lift bridgeRetractable bridgeTilt bridgeHydraulic Systems for Movable BridgesObjectivesAbility to handle varying loads Smooth acceleration and decelerationPositive locking in any positionHydraulic CylindersTwo per spanTie rod and weldedIntermediate trunnion and spherical bearing clevis both endsThe national fluid power association (NFPA) established a standard for tie rod type hydraulic cylindersTie rods should be inspected for corrosion damage

Counterbalance ValvesVarying loads, wind makes it unbalanced and causes run awayA counterbalance valve keeps this condition in checkHolding the bridge firmly in any positionActs as a check valve

Proportional ValvesSmooth acceleration and decelerationGradually increasing or decreasing the amount of flow to the cylindersThe use of servo valves for this task is not recommended0 - 9 volts dc/800 milliampsHydraulic PumpVariable volume-bent axis-piston type pumpStrong suction capability and greater dirt tolerance, make them a good choice for movable bridgePumps which require a boost or supercharge only add complexity to the designHorsepower limiterHydraulic FluidsISO GradeViscosityNormal Operating TemperatureAW32Light1O0-150FAW46Medium3O0-160FAW68Heavy4O0-170FCare to be Taken While DesigningPumps and motors should be accessible for workVibration mounts and hoses to isolate pump VIBRATIONThe use of ANSI standard bolt pattern sub plate mounted valvesDrilled manifolds to minimize piping and fittingsFilters which are easy to change with good clogging indicatorsStraight thread "o ring ports and fittingsLarge access covers for reservoirsThe Rolling BridgeCompleted in 2004 as part of theGrand Union Canaloffice & retail development project atPaddington Basin,London.Despite the connotation of its name, it is more accurately described as"curling".Designed by SKM Anthony Hunt with Packman Lucas, and built by Littlehampton Welding Ltd.The Hydraulic design and development was done by Primary Fluid Power Ltd in the North West.In 2005, the bridge won the British Structural Steel Design Award.Referenceshttp://en.wikipedia.org/http://www.designingbuildings.co.uk/wiki/Hydraulic_Assisted_Bridgeswww.youtube.comHydraulic systems for movable bridges by Michael A. Henley