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ALAMILLO BRIDGETheory of StructuresPRESENTED BY:BACCAY, DAIGO, ESTRADA, LORENZANA, REYES PRESENTED TO:ARCHT. MARK GARCIA

Name:Puente de Alamillo, Alamillo Bridge, Harp Bridge, Designer:Santiago CalatravaLocation:Seville, Andalusia, SpainStructural Type:Asymmetrical Cable-stayed Bridge, Inclined Pylon, No BackstayFunction:Road bridge, Pedestrian and Motor BridgeCrosses:Guadalquivir RiverDuration:1987 - 1992Materials:Cables: SteelsPylon: Reinforced ConcreteDeck: Reinforced ConcreteDimensions:Main Span: 250 m.Pylon Height: 162 m.Pylon Angle: 58

ALAMILLO BRIDGESTRUCTURESPECIFICATION

Santiago Calatrava merges the boundaries between engineering and architecture, art and function. He has gained an international reputation for integrating technology and aesthetics, producing dynamic structural forms that challenge traditional practice in both architecture and engineering.INTRODUCTION

Commissioned for the World Fair, Expo '92, to serve as its main entrance.

This static concept can be traced back to the 1986 sculpture by Calatrava entitled 'Running Torso', in which inclined stacked marble cubes are balanced by a tensioned wire.

The core of the tower contains a service stair to the top.

BRIEFBACKGROUND

Originally consisted of two mirrored bridges to create symmetry.

For political reasons, an asymmetrical solution was decided upon.

This is the only cable-supported bridge that is not backanchored.

The bridge is balanced solely through added weight of inclined pylon.BRIEFBACKGROUND

CONCEPTUAL IDEACalatrava is inspired by natural forms in movement waves undulating, trees bending to the wind, flower petals opening. Especially, he focuses on the human body.

DESIGN CONCEPT

One draws the human body to understand the movement, the gesture. The space, the landscape, the human landscape, and topology are important for me. These will inspire or bring the essence to a project. So, for myself I venerate the human body.

CONCEPTUAL IDEAThe Alamillo Bridge Completedin just thirty-one months for the 1992 Worlds Fair in Seville, Spain, was instantly recognized as a landmark, joining the list of numerous memorable historic structures in this remarkable city.DESIGN CONCEPTIn the case if the Alamillo Bridge, the images a Harp, a ships mast, a swan might come to mind. Deeper reflection, however, onthe structural raison detre of the bridge carrying horizontal weight requires a more robust metaphor.

The simple image of the human body bearing a weight on its back recasts our perception of the bridge by the strong relationship between the cables and the horizontal deck.

STRUCTURALCONCEPTCalatrava tries to express the kinetic movement of the static members in a structure. In the Alamillo Bridge, he shows his intention strongly with the concrete-filled steel pylon inclined at 58 degrees. He had the pylon that is divided with several pieces and accumulated for the structural solution and allowed the weight of the pylon to counterbalance the deck.

He created a new type of cable-stayed bridge. Spanning 200 meters, thirteen pairs of stay cables support a hexagonal, steel bow beam over the Meandro San Jeronimo River.KINETIC VS. STATIC

STRUCTURALCONCEPTINCLINED PYLONIt makes a counter-force and enhances the asymmetry

International geometric arrangement of the return anchorage cables1> ASYMMETRIC CABLE-STAYED BRIDGE

STRUCTURALCONCEPTThe concept design was based on the balanced cantilever method. It was intended to erect segments of the bridge deck and the tower so that they balanced - so as the deck grew outwards from the tower so the tower grew upwards. The construction designers and advisors showed that this was too risky - proper safety levels could not be reached. They realised it was possible to backfill part of the river underneath the bridge and erect temporary supports.

STRUCTURALCONCEPTThe sequence was as follows:Construct the foundations and the lower concrete part of the tower.Backfill part of the riverConstruct temporary piersErect the steel box girder using the temporary suports.Weld into place the steel ribs onto the box Construct the four lower segments of the tower .Continue to erect the tower and tension the cablesThe total construction time was 2 years

STRUCTURAL ANALYSISREACTIONSDISTRIBUTED LOAD OF ROAD DECKCABLE STAYS IN TENSION CONNECT ROAD DECK TO PYLONDISTRIBUTED LOAD OF ANGLED PYLON

ROOF DECKSTRUCTURAL ANALYSISBRIDGE DECK The bridge deck is designed as a metal structure and consists of a central platform and hexagonal anchorages where the cables attach. In this platform, metal ribs leave some 4 meters on both sides, which rests on a slab of concrete that functions as the road; there are two roads of three lanes each.

Mast and bridge deck are embedded in a solid base of concrete, anchored by 54 pillars of 2 m in diameter and 48 m deep. These pillars is compensate for movements experienced by the mast and bridge deck.

The device is made through the corresponding transitions between the concrete and metal

Hexagonal box beamLightweight crossbeams

ROOF DECKSTRUCTURAL ANALYSIS

CABLES The cables are made up of 60 cords of 6 inches in diameter each, except the last couple of 291m in length, consisting of only 45 cords. The cords are protected by epoxy resin, and the cable is surrounded by a sheath of high density polyethylene injected into the anchorages. STRUCTURAL ANALYSISCABLE AND DECK CONNECTION

CONNECTION OF CABLE TO BRIDGE GIRDERThirteen pairs of cables

Compression wedge connectionsSTRUCTURAL ANALYSISCABLE AND DECK CONNECTION

Rigid connectionGusset platesLoads transmitted through drilled piers to soil.STRUCTURAL ANALYSISPYLON - GIRDER CONNECTION

STRUCTURAL ANALYSISARRANGEMENT OF PYLONREINFORCEMENT BARS

Concrete filled steel pylonCentral service core58 degree inclination

STRUCTURAL ANALYSISCABLE AND DECK CONNECTION

STRUCTURAL ANALYSISCABLE AND DECK CONNECTIONCompression wedgeconnectionsEqual tension in all cablesInstalled prior to concrete fill

CONNECTION OF CABLE TO PYLON

TYPICAL NEED FOR BACK SUPPORTS IN ASYMMETRIC BRIDGES

WIND LOADS AND SEISMIC LOAD CONSIDERATIONS

UPLIFT MAY CAUSE POTENTIAL INSTABILITIES

ADDITIONAL DESIGN CONSIDERATIONS

CONCLUSION & STRUCTURALANALYSIS REVIEW"It is phallic, but I was mainly concerned with thelightness of traversing the river," - Santiago Calatrava

The Alamillo Bridge from the south at La Cartuja

As seen from central SevilleVIEWS

VIEWS

close up of deckBridge deck - with transverse steel ribs under and cable supports over

the leaning towerVIEWS

as seen from base of tower - footway on right and east to west traffic on left

VIEWSpedestrian's view

looking up front face of tower

VIEWSlooking back at tower from footway

Bridge deck - with transverse steel ribs under and cable supports over

VIEWScentral box girder with ribs either sidesupport and bearings under deck adjacent to tower

VIEWSwelded junction of ribs to box girderwelded junction of ribs to box girder

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