Henderson waves bridge

Henderson Waves Bridge is a 274-metre (900 ft) pedestrian bridge. At 36 meters (120 ft) above Henderson Road, it is the highest pedestrian bridge in Singapore and also the largest manmade structure of its kind in Asia.

The project, which took two years to complete from 2006 to 2008, cost 25.5 million USD and links Mount Faber Park (one of the oldest parks in Singapore) to Telok Blangah Hill Park that forms part of the Southern Ridges. The two parks then join forces with Hort Park, Kent Ridge Park and West Coast Park to form a corridor of green spaces known as the Southern Ridges of Singapore.img

The completion of this  toll free pedestrian bridge (with a life span of 50 years) by the Urban Redevelopment Authority (URA) brings to reality the earlier plans of URA to seamlessly connect all the hill parks and transform the Southern Ridges into a new recreational playground amidst nature.

The Southern Ridges offer breathtaking views of the Telok Blangah area, and also provides an up-close-and- personal experience of nature as the trails cut through lush greenery. Apart from the bridge, the Southern Ridges now also boast the Forest Walk, a 1.3km-long elevated walkway that cuts through secondary forest at Telok Blangah Hill Park; and Marang Trail, which links Harbour Front MRT to Mount Faber. Forest Walk is Southeast Asia’s first one-stop gardening and lifestyle hub. It brings together gardening-related recreational, educational, research and retail activities under one roof in a park setting.

The bridge has a wave-form made up of seven undulating curved steel ribs that alternately rise over and under its deck. The curved ribs form alcoves that function as shelters with seats within. Slats of yellow balau wood, an all-weather timber found in South-East Asia, were used in the decking. The wave-forms are lit with LED light at night from 7pm to 2am daily.

CONSTRUCTION

The Southern Ridges’ Henderson Waves is a one-of-a-kind pedestrian bridge like no other.
Four barges were built to move steel beams into position. The bridge took an interesting 3D surface form that assembled undulating waves generated by a mathematical equation. The form was realised by curved steel I-ribs spaced at 500 meters. Main structural elements were fabricated with curved steel boxes ranging from 300 meters to 800 meters, supporting secondary members, timber deck and timber seating. The severe winter caused construction delays: workmen toiled day and night chopping channels to keep the ice clear for the barges to pass so that work could continue on the superstructure.  The bridge’s wave-like design was by British architects IJP Corporation and Singapore’s RSP Architects Planners and Engineers, who found this bridge the answer to many of their temporary bridging needs.IJP Corporation won the bid to design it in a competition which saw landscaping surrounding the bridge being redesigned by landscape architect Terry Guen.

The bridge spans are 24.0 meters, with steel structures weighing about 50.0 tonnes. Its longest span is at 57.0 meters and weighs about 250.0 tonnes. This span was constructed above a temporary platform across Henderson Road and was then lifted up about 30.0 meters to its position.

The steel structural modules were fabricated outside Singapore and transported to site for assembling and lifting to its final position.

The bridge consists of convex, concave and radius areas stretching the total length of both sides of the bridge, to 1,728 feet (526.7 meters). Because a specific horizontal line had to be maintained throughout the bridge, CMF (the sheet metal contractor) made 4,400 field-fabricated custom panels. The sheet metal constructor used 57,000 square feet (5,300 metres) of materials, and built special heated enclosures so that work could continue throughout the winter. They also designed, fabricated and installed a custom number 4 brush stainless steel parapet to serve in the place of handrails on the bridge. Honey locusts, ash and maple trees were removed and replaced with three varieties of magnolia, which had more than two dozen ornamental and canopy trees along the eastern foot of the bridge. 

The project also used 22-gauge stainless steel with an angel hair finish and a flat interlocking panel process. Stainless steel type 316 is known for its excellent welding characteristics, as well as for its resistance to pitting. The sheet metal work totaled to 5,900 field hours over a six-month period. Fabricating the 10,400 trapezoidal stainless steel panels took 1,000 shop hours and was done in 17 different shops. Other preliminary works for the bridge included setting reinforcing rods for the bridge in the concrete roof deck of the parking garage located under the park. All materials used inclusive of the timber were creative and cost-effective solutions.

“While the substructure was being constructed, the erection period was accelerated making the time required to gain strength in the concrete be removed from the critical path. As a result of the maturity of the concrete at the time of erection, effects of concrete creep and shrinkage were also reduced. The match cast joint method of pre-casting concrete segments proved to be the most versatile and reliable way for a footbridge to fabricate pre-cast segmental bridges. With proper geometry control, this method was ideal for building structures with complex geometry.” stated Mathew Rowland the director of public relations of RSP architects.

The MC3D geometry control program was used to monitor the casting operations and establish “as-cast” curves step-by-step to verify that the actual superstructure geometry is in close agreement with the geometry described in the design documents.
MC3D Geometry Control Program allows the following:

According to Mathew input of a “casting-set” (a cantilever or a span), includes a number of segments, segment definition, joint definition and camber (final deflections at the end of construction with time effects).Match-cast setup is based on already cast geometry (as-cast),survey of match-cast and wet-cast markers, in order to compute coordinates print-out of as-cast coordinates –with MS-Excel Exports

The  Henderson waves used stock components for a light, versatile, and easy to assemble pedestrian bridge utilising a standard 2.44 meters wide deck with clear spans of up to 40 meters.

Conclusion

Bridge analysts say this is one of the most spectacular bridges around the world because of its colour, colorful design and the amazing color palette it creates with its natural surroundings.
Professional team

  • Commissioned by – Urban redevelopment Authority (URS)
  • Landscape Architect-Terry Guen

Architect&Designers – RSP Architects&Ijp corporation

Sheet metal contractor – Custom Metal Fabricators Inc.