Pedestrian bridges have evolved far beyond mere infrastructure to get you from one area to another and over the years have become landmark destinations in their own right. These structures have become even better designed and more ingenious, thanks to architects across the world continuously challenging themselves to enhance their craft.
1. The Twist
Part bridge, part museum and part sculpture, the Twist is three structures in one, primarily acting as a pedestrian bridge connecting two forested riverbanks and creating a new route and art piece in Kistefos Sculpture Park in Jevnaker, Norway. The art bridge, set in Northern Europe’s largest sculpture park, was recently completed by Bjarke Ingels Group (BIG) and won the 2020 LCD Berlin Leading Culture Destinations of the Year Award.
Bjarke Ingels, founding partner at BIG, says a simple twist in the structure’s volume allows the bridge to lift from the lower, forested riverbank in the south and connect with the hillside area in the north, traversing the winding Randselva River. He says the 1 000m² contemporary art bridge, conceived as a beam warped 90 degrees near the middle, creates a sculptural form built around a historical pulp mill.
Inaugurated by royalty
“The Twist was inaugurated with Her Majesty Queen Sonja, His Royal Highness Crown Prince Frederik of Denmark, Prime Minster Erna Solberg of Norway, and Ministers Siv Jensen and Trine Skei Grande in attendance. It reconfigures the sculpture park, turning the journey through the park into a continuous loop, and as a museum connects two distinct spaces of a vertical and a horizontal gallery with panoramic views across the river,” says Ingels.
A third space is created through the translation between the two galleries creating the namesake Twist; and the resultant form becomes another sculpture among the sculptures of Kistefos Sculpture Park. As you approach it, you will notice the museum reflecting the trees, hills and water below, glimmering and changing its appearance in connection with nature.
Curves created with straight lines
According to Ingels, both sides of the structure are the main entrance. From the south entry, visitors cross a 16m aluminium-clad steel bridge to reach the double-height space, with a clear view to the north end, linked with a 9m pedestrian bridge. He says as the bridge connects the two riverbanks, it rotates 90 degrees forming a warped, ruled surface and two pure functional forms united by complex curvature.
“Wherever you look, you see arches and curves, Fibonacci spirals and saddle shapes. When you look closer, you realise everything is created from straight lines, straight sheets of aluminium and straight boards of wood. It is an expressive organic sculpture composed of rational repetitive elements,” says Ingels.
Gallery areas divided by light
David Zahle, a partner at BIG, says the double-curve geometry of the museum is made of straight 40cm wide aluminium panels arranged like a stack of books, shifting slightly in a fanning motion. He says the same principle is used inside, with white-painted 8cm wide fir slats cladding the floor, wall and ceiling as one uniform backdrop for short-term Norwegian and international exhibitions.
“Due to the curved form of the glass windows, the variety of daylight entering the museum creates three distinct galleries. These include a wide, naturally lit gallery with panoramic views on the north side; a tall, dark gallery with artificial lighting on the south side; and in-between, a sculptural space with a twisted sliver of roof light,” says Zahle.
A natural extension of the park
Zahle says a glass stairway leads down to a lower level area on the north river embankment, where the structure’s aluminium underside becomes the ceiling of the basement and restroom area. He says the full-height glass wall brings visitors closer to the river, offering panoramic views of the pulp mill, curving upwards to form a 25cm wide strip of skylight enhancing the experience of being in the woodlands.
“From an array of straight elements, the art bridge is a natural extension to the park and was constructed to reflect its natural surroundings and transform the visitor experience. It has been extremely complex to construct, but after many years of planning and development we’re delighted to open this striking, beautiful new space,” says Ingels.
2. 41st Street Bridge
The 41st Street Bridge in Chicago is an iconic structure, welcoming pedestrians, cyclists, people with disabilities and emergency vehicles, connecting them to the Bronzeville neighbourhood, Williams-Davis Park and Lake Michigan lakefront.
The recently finished bridge by AECOM with Cordogan Clark & Associates is claimed to be the only serpentine double monotruss bridge in the world at the time of design in 2004 and was awarded the Midwest Project of the Year Award in December 2019.
Graceful lines inspired by Olmsted
John Clark, principal at Cordogan Clark & Associates, says they won the design of the bridge through an international competition called “Bridging the Drive” by the City of Chicago and Chicago Department of Transportation.
He says the steel bridge weighs 676 tons, spans 229m over Lake Shore Drive and Metra commuter rail lines, and its height was determined by the rise being sufficient to clear a commuter train and the vehicles on Lake Shore Drive, but still allow a slope gentle enough for wheelchair use.
“A major inspiration for the bridge was the work of Frederick Law Olmsted, who designed Central Park in New York and other beautiful parks throughout the United States of America. He aimed to preserve Chicago’s lakefront, keeping it largely clear of buildings, and opted for gracefully-curved lines and generous spaces in his architecture suggesting leisure, contemplativeness and happiness,” says Clark.
Preassembled prior to shipping to site
The 457,2m long bridge uses double-curved arch monotrusses to form a large, graceful S-curve that echoes the park’s walkways. Structural detailing includes a main dual spine of induction-bent 91cm diameter and 1,2m diameter steel tubes, which curve horizontally and vertically with shop-welded box girders.
Hillsdale Fabricators fabricated and preassembled the bridge at their shop in five groups, with the longest of this five preassemblies being 74m in length to ensure fit-up could be duplicated in the field. The largest pieces of the bridge weigh about 40 tons, with a width of 7m and a length of 18m, and the bridge was shipped to the jobsite in 28 large, built-up pieces.
Arch spans on reverse curves
Clark says the work of Robert Maillart, a 20th century Swiss bridge engineer who created bridges blending with the landscape, was another inspiration for this project. They wanted the 41st Street Bridge to blend into Williams-Davis Park, becoming an extension of the landscape. He says instead of tall masts with tension cables, they created a low muscular bridge that “hunkers down” into the landscape rather than rises far above it.
The bridge projects outwards with plate sections creating grand concrete decks at midspan, becoming viewing platforms offering spectacular views of the city skyline and beach, inviting you to take a break. Unlike typical arch bridges which are symmetric in horizontal and vertical directions, the bridge arch spans are on reverse curves, with a long crest curve rising 2,13m higher between the arches than at the outside ends of the arch at the approaches.
Creating memorable and fun experiences
According to Clark, aesthetic enhancements included form liners on the piers and mechanically stabilised earth walls, decorative handrails, accent lighting and radiused railings to raise the bridge’s curves vertically, reinforcing its dynamic sculptural form. He says the bridge has ramps and stairs at both ends to be fully accessible, and the ramps are supported on a rusticated concrete base that tapers into the landscape.
“Unique bridge designs make the experience of using the bridge more fun and pleasurable; and the 41st Street Bridge has become a destination for visitors to create memorable experiences. The curving features are smooth and seamless; and the quality and dedication to details by all who worked on this bridge are evident, with the finished product which appears flawless,” says Clark.
3. The Lucky Knot Bridge
The Lucky Knot Bridge, a pedestrian bridge recently completed in the public space of the Dragon King Harbour River theme park area in Changsha, China, has been designed to connect, entertain and become illuminated. The bright red steel bridge which twists and knots, spans the river and was designed considering the recreational, ecological and tourism activities in the area.
Inspired by knots symbolising luck
John van de Water, a partner at NEXT Architects in Beijing, says the bridge which is 185m long and 24m high offers spectacular views of the Dragon King Harbour River, Meixi Lake, Changsha and the surrounding mountain range. He says the design of the bridge, which engages the local context, is becoming iconic as one of the most spectacular bridges that breaks the mould.
“The Lucky Knot Bridge had to function as a link connecting multiple levels at different heights including river banks, the road, the higher theme park and interconnections with the shape inspired by the Möbius ring and Chinese knotting art, where the knot symbolises luck and prosperity.
“The streams of people passing different heights from one side of the river to the other overlap and intertwine; and the shape of the bridge results from literally knotting and connecting the different routes,” says Van de Water.
Illuminated by special light art
According to Van de Water, as part of the entertainment at the river theme park, the Lucky Knot Bridge integrates a light show with LED lights, where tour boats can stop at the bridge and enjoy the light art. He says the Changsha municipality developed the lightshow especially for the bridge, and the side and bottom of the bridge are entirely cladded with steel mesh that has enough openings for the light to go through.
NEXT Architects won the international competition by Changsha Meixi Lake Industrial to design the bridge over the Dragon King Harbour River in November 2013; and their teams in Amsterdam and Beijing came up with the winning design. The Dutch team’s experience in bridges and water management was combined with the Beijing team’s knowledge of the local context to develop the Lucky Knot Bridge.
Going deeper accessing successful projects
Michel Schreinemachers, a partner at NEXT Architects in Amsterdam, says the point of departure for all their designs is the context and needs of a location, so they place a great deal of importance in open dialogue with their client and collaborators. He says it is only by analysing and digging into the programme of requests that they can discover what is needed but has not yet explicitly been formulated.
“A second step is to survey the world’s well-known bridges to discover what features make them successful. From there we start developing our own models and storylines to create the concept behind a bridge’s design.
“For the Lucky Knot, we developed 16 different storylines, which is equal to 16 different shapes and underlying concepts. Together with representatives of the client, we went through all of them, selecting the most appropriate ones,” says Schreinemachers.
Connecting to the environment
According to Schreinemachers, the mobius-strip model lying at the basis of the final Lucky Knot Bridge was not initially among the storylines selected. Only after they started producing renders for several models, they felt it was the right direction.
He says when they design a bridge or any structure, they look further than what is asked of them – as they are interested in architecture’s role in the broader social, cultural, ecological and historical context.
“Bridges are more than a mere crossing where you build the shortest route from point A to point B, but are part of the landscape. Our bridges are always curving, undulating and knotting with the environment, so they connect and work in a cross-disciplinary manner.
“The design of the Lucky Knot Bridge, its relationship with its surroundings and the way it enhances a rapidly changing city inspiring passers-by, is what makes this bridge so special,” says Schreinemachers.
Acknowledgement and thanks go to AECOM, Bjarke Ingels Group, Cordogan Clark & Associates and NEXT Architects for the information contained in this article.