Kusugibashi Bridge

Location

Japan

Credits

Kengo Kuma

Scope

Digital FabricationWoodInfrastructureBridge

Role

DeveloperCo-designer

Kusugibashi Bridge /

“A bridge in Iwakuni City destroyed by the Western Japan Flood in July 2018, was rebuilt as a wooden bridge that became a new symbol for the community.

Considering the risk of recurring disasters, a RC frame was combined with 105-square cypress balustrades. The arrangement of the cypresses created a gentle curve that echoed the surrounding mountain range, and the use of 105-square members, the most used member-size in Japanese wooden construction, created a bridge with a nostalgic human scale.

By combining Japan’s proud carpentry skills with the modern technology of computational design, a human and soft expression that has never been seen before in conventional civil engineering structures was created.”

©︎Kengo Kuma and associates - Photography ©︎Katsumasa Tanaka

Kusugibashi Bridge /
1. Design Realization Process
2. Pattern Exploration
3. Fabrication Drawings

1. Design Realization Process

The unique design of the bridge was realized through a computational system featuring a series of analytical and geometrical processes for ensuring an agile and reliable streamlined workflow connecting the design exploration, development and fabrication.

1. The four driving curves of the connections to the bridge structure.

3. Generating the separating planes in between the segments.

5. Planarization process for the generated concrete panels to facilitate the local construction process.

7. The wooden units are categorized firstly based on their position and the logic of the pattern.

2. Segmenting the curves based on the angles between the tangent vectors at every two consecutive points.

4. Locating the concrete sections on the separating planes and use them as guides to the precast concrete geometry.

6. The final concrete panels after the planarization and ready to host the wooden units.

8. The wooden units are categorized secondly based on the segments they belong to, so the file-to-production structure for the units would carry both metadata.

The final vision for the bridge including all the parts.

2. Pattern Exploration

Exploring different reciprocal pattern logics for efficient stability, safety and connectivity to the river and the surroundings.

Exploring different reciprocal pattern logics

The section shows the 3 categories of units and the logic for the selected pattern (b-a-b-c) that assures stability, safety and connectivity.

3. Fabrication Drawings

The computational design system was designed to facilitate the file-to-factory approach by automating the creation of the production drawings, bridging the gap between the early-stage design exploration and the production. This resulted in significant time saving, minimizing the risk of human error while maintaining the quality of the fabrication drawings at the industry standard.

Assembly plan - Cars’ side

Fabrication data - 184 units - Cars’ side

Assembly plan - Pedestrians’ side

Fabrication data - 192 units - Pedestrians‘ side

Project Team: Minoru Yokoo, Shun Horiki, Toshiro Ota, Hossam Elbrrashi, Tomohiro Matsunaga

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