Santiago CalatravaSUNDIAL BRIDGE

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

Sacramento River

LOCATION PLAN:

SPECIFICATIONS:

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

• Structural Type: Asymmetrical Cable-stayed Bridge

• Function: Pedestrian bridge

• Location: Turtle bay, California,USA

• Crosses: Sacramento River

• Year completed: 2004

• Materials: Cables: SteelPylon: Reinforced ConcreteDeck: Steel truss

• Dimensions & Quantities:Main span: 128 mPylon height: 66 mPylon angle: 42°

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

BACKGROUND:

• Plans for the Sundial Bridge began in the 1990s, when the city of Redding budgeted $3 million for a pedestrian bridge across the river.

• The bridge was completed in 2004, three years later than originally planned , at a cost of $23.5 million, with funding from the Redding-based McConnell Foundation.

• The cable for the bridge totals 4,342 feet and was made in England.

• This is the only cable-supported bridge that is not back anchored.

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

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

• 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 bridge does not balance the forces by using a symmetrical arrangement of cable forces on each side of its support tower; instead, it uses a cantilever tower, set at a 42-degree angle and loaded by cable stays on only one side.

• This design requires that the spar resist bending and torsional forces and that its foundation resists overturning.

• While this leads to a less structurally efficient structure, the architectural statement is dramatic.

DESIGN:

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

STRUCTURAL ANALYSIS: • distributed load of road deck• cable stays in tension, connects road deck

to pylon.• distributed load of pylon• reactions

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

To calculate the maximum bending moment within the deck the overall system must be simplified to a simply supported beam with a pin connection at the South side of the Sacramento River and a fixed connection at the North side (i.e. the inclined pylon).

BENDING MOMENT

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

STRUCTURAL ANALYSIS:

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

• The decks structure consists of a triangular pipe truss system with varying sized chords.

• The lower chord is 360mm in diameter while the two top chords are 280mm in diameter.

• The truss is asymmetrical in cross section allowing the centroid of the truss to become closer to the pylon allowing a smaller cantilever distance for the pylon to cable connections.

• The cables attaching the deck to the pylon are connected to the deck through transverse bulkheads in the truss.

STRUCTURAL ANALYSIS: ROAD DECK

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

CABLE CONNECTION

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

• The 14 cable stays attached to the bridge deck are not centered on the walkway but instead dissect the bridge into a major and minor path. This 2/3 to 1/3 split when looking longitudinally over the deck creates torsional affects resulting in the bridge deck wanting to roll.

• To reduce these effects an asymmetrical truss system below the aqua marine translucent glass uses its varying length members to move the decks center of gravity closer to the connection line of the cables. This reduces the cantilever arm so that the, point center of gravity of the deck produces a smaller torsional effect.

• The diagram below shows the torsional moment diagram caused by pedestrian loading on the 2/3 of the deck.

TORSION DIAGRAM

TORSIONAL BENDING MOMENT OF DECK

TORSION WITHIN THE DECK

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

INCLINED PYLON

• The pylon is 66m tall and is placed on the North South axis acting as a sundial casting its shadow on a plaza below.

• no backstays to withstand some of the bridge decks loading, the pylon is inclined at 42º to use its dead weight to equilibrate the moment induced on the pylon by the deck.

• Due to this lack of backstays the pylon has a foundation 14m deep to resist the bending forces allowing them to be transferred to the ground without causing overturning.

NARSEE MONJEE INSTITUTE OF MANAGEMENT | BALWANT SHETH SCHOOL OF ARCHITECTURE | MUMBAI INDIA

CONSTRUCTION STUDIOPRIYAM MEHTA

SUNDIAL BRIDGE

INCLINED PYLON