ECO SEESAW

LOCATION / SEOUL, S.KOREA

PHASE / YANGJAE-GOGAE ECO BRIDGE INTERNATIONAL COMPETITION

PROJECT TEAM / YOUNGSU LEE, BOSUK HUR, SUK LEE, DAVID MATTO, WEJIE ZHENG + JIHOON YUN (LANDSCAPE ARCHITECT)

ECO SEESAW: Connecting “people and the nature” and “the nature and the nature”

Design Concept

Eco See-Saw propose the regeneration of ecological environment as urban intervention and passageway connecting between two mountains and separated by the highway. Our ecological controlled succession design minimize energy usage and maintenance expenditure, restores wildlife habitats, and creates self-sustained ecosystem in urban context.

Eco See-Saw attempts to connect ecological flow and collect its movement through ecological passage way. Considering the terrain slope, we link two separated mountain through our ecological bridge having 20m wide; this ecological bridge connect along the ridges of both mountains. We locate ecological pond at the entry way of bridge for attracting animals and purifying rainwater redirected from bridge. And, in order for the animals to be able to hide, various tree layers were arranged in succession to plan the natural movement of wildlife. In order to prevent collision between the passageway for people and the animal movement from the bridge entrance, we separate these two circulations using the level difference of existing terrain. Visitors can observe ecological habitats through passage way.

Bridge Programs

Eco See-Saw is the example of a public infrastructure that combines ecological systems created by geometric programs. Beyond the function of a simple bridge, it invites wildlife and pedestrians together, and revitalizes the disconnected ecological structure.

Site Plan, Landscape Plan, & Section

Structure / Construction Method

Pre-stressed Concrete (PSC) Segmental Box Girder Structure: Eco See-Saw is broader than a typical traffic bridge and includes landscape and soil surfaces that connect to the natural habitats of both mountains. The bridge type is a PSC box girder having economic (maintenance) benefits and aesthetic aspects. The V-shaped PSC segment was designed for the system with the soil depth and ecosystem required for the habitat.

Span by Span Erection with Launching Gantry: The pre-stressed concrete segments divided by a constant thickness of 2.5 m are fabricated at the fabrication site, and after the fabrication is completed, the upper structure is completed by post-tensioning arrangements.

Landscape + Assemblage

Bioswale: In order to reduce the live load on the bridge during rainfall, it is inclined to be drained from the center of the bridge toward the both entries; rainwater flowing over the bridge during rainfall is slowly filtered by the soil and purified from the roots of the sloping grass layers. Overflow rainfall is purified and then drained to the existing waterway through a drainage pipe located at the bottom of the soil, or sent to the designed ecological pond on the each entries of the bridge through the slope.

Controlled Succession: Initially, plantation of herbaceous plants, shrubs, and seedlings from the entrance of the bridge leads to a natural stabilization process between two separated mountains. Over time, natural communities meet in the middle of the bridge and a stable ecological equilibrium (climax community) is maintained naturally in sequence.