Helix Bridge- Architectural & structural innovation

Presentation by,

Akshay GauravGNDEC, Ludhiana

1°17’15.44°N, 103°51’38.15°E

Contents

• Introduction• Architecture

• Material Selection• Design

• Analysis• Fabrication & Erection

• References & Bibliography

Introduction

• Carries – Pedestrian• Crosses – Singapore River

• Location – Queen Elizabeth Walk, Esplanade Mall, Singapore• Official Name – The Helix• Other Name – Double Helix Bridge

• Material – Duplex stainless Steel• Opened – 24 April 2010 ( 18 July 2010 )• Cost at Completion – 82,900 SGD ( 41,45,000 INR / 61,434.26 USD )

• Area – 1379.08 sq.metre• Architect – COX Group Pte Ltd (Australia) & Architects 61 (Singapore) • Consultant – Arup (Civil, Mechanical, Electrical, Lighting), Tierra Design (Landscape), David

Langdon Seah (Cost)• Builder – Sato Kogyo (S) Pte Ltd • Managed & Maintained by – Land Transport Authority

Architecture

• Inspiration – Geometric helicoidal arrangement of DNA

• Team – Cox Group, Arup Engineers & Architect 61• Lighting – Dynamic multi colored light emitting

diode(LED)

• 4 Viewing pods – Panoramic view of Singapore skyline.

• World Architecture Festival Awards 2010 - “World’s

Best Transport Building” • BCA Design & Engineering Safety Excellence

Award 2011 – Building & Construction Authority

(BCA)• Industrial, Transport & Infrastructure Category 11th

Singapore Institute of Architect’s Architectural

Design Awards.• World’s first curved double helix bridge

Material Selection

Duplex stainless steels have a two-phase microstructure of austenite and ferrite grains.

The duplex structure gives this family of stainless steels a combination of attractive properties.

Duplex stainless steels are about twice as strong as regular austenitic or ferritic stainless steels.

• Local planners place noticeable emphasis on quality urban design.

• Designers are encouraged to use sustainable, low maintenance and

aesthetically pleasing materials.

• Environment of Singapore is hot, humid, industrial and coastal.

• Stainless steel give designers a good option.

• Grade 1.4462 of stainless steel provided the requirements of good availability,

cost effectiveness, ease of fabrication and the structural / architectural

requirements.

• It also provides high resistance to stress corrosion cracking.

• Cost of duplex steel was equivalent to potential costs of using carbon steel.

Design

• Selected out of 36 design submissions.• Two set of spirals, one in another

interconnected by tension rods spiraling in different directions.

• Total length – 280m

• Width of deck – 6m• Major helix diameter – 10.8m• Minor helix diameter – 9.4m

• Total length of steel tubes – 2,250m• Total weight – 1700 tonnes• Maximum Capacity – 10,000 people

• Sunshade – Canopies (Fritted glass & perforated steel mesh).

• Computer controlled LED lighting.

Analysis

• Extensive numerical analysis was

completed using structural optimization

software

• Due to complexity of structures, 3D

simulations are used as analysis tool.

• Prior to specifying materials or even

finalizing designs, the bridge was

modelled using 3D software.

• Non-linear analysis was also carried.

• Robustness studies was also important

to carry out.

Fabrication & Erection

• The helix is fabricated from approx. 650 tonnes of Duplex stainless steel & 1000 tonnes of Carbon steel.

• The steel was delivered from the supplier in Europe to Singapore and then fabricated in Johor, Malaysia.

• The bridge components were fabricated to the maximum transportable dimension.

• Average length of components was 11m.• Trial assembly of segments of the bridge was conducted in the

workshop.• Installation began with the lower deck components and completed

at the highest level of the bridge.• Major and minor helices were welded on site and all the light struts

and tension rods were pinned.

References & Bibliography

1) https://www.steel-sci.org

2) http://www.archdaily.com/185400/helix-bridge-cox-architecture-with-architects-61/

3) https://www.youtube.com/watch?v=WHFpZc3nryE

4) https://en.Wikipedia.org/wiki/Arup Group

5) https://en.Wikipedia.org/wiki/Stainless_steel

6) https://en.Wikipedia.org/wiki/Austenitic_stainless_steel

7) https://en.Wikipedia.org/wiki/Helix_Bridge

8) https://en.wikipedia.org/wiki/BS_5950