Since the Korean government introduced the regulation for Air Quality Index (AQI) in 2002, anthropogenic emissions have been substantially reduced and the creation of green areas in the cities has been drastically increased. Particular focus was placed in the metropolitan area of the City of Seoul, where a policy for greening the city was introduced through the implementation of public parks, green corridors and vegetation, in an effort to reduce air pollutants and thermal entrapment. With this goal, our proposal for Seun Sangga aims to contribute to the greening policy of Seoul city by creating a new green corridor for downtown Seoul, amongst a series of opportunities to transform linear obsolete infrastructures into a network of dense green spaces.
The Seun Sangga is reconceived here as a linear park, associated to the elevated walkway which never was, but that is now being retrieved from Kim Swoo Geun original project. Because of its volumetric specificity, the Seun Sangga opens an alternative green corridor typology: the green linear block, developing a three-dimensional green envelope where the existing buildings are transformed into an environmental filter, contributing to reduce pollution and carbon monoxide. The green corridor will not only serve as an urban promenade and a carbon trap, but enhance plant pollination and fauna across the city center of Seoul. The surfaces of the walkway will be provided with linear planters, carrying organic matter through the walkway.
The new ecological envelopes that are proposed for Seun Sangga, will also contribute to reduce the energy loads in buildings. The vertical planting with deciduous plants will project shadows on the building surfaces in summer while enabling the access of direct sunlight to the facades in winter. The creepers will behave as organic brise-soleils for exterior and interior microclimate mediation.
The Seun Sangga building was aimed at the provision of an elevated walkway reaching from Nam-San to the Jeong-Myo Royal Shrine, but because it was developed by individual agents, block by block, the mechanisms to bring public to the platform did not have the scale nor the significance to bring large amounts of public to the platform: a series of narrow and steep stairs with a building rather than an infrastructural scale.
But most importantly, the rapidly aging population in South Korea and the fast development of unipersonal transport in contemporary cities (cycling, Segway, electric scooters, tricycles, quadbikes…) require that the changes in level become negotiable by small wheeled vehicles, including wheelchairs. It is crucial to provide several opportunities along the Seun Sangga promenade to have distributed ramped access. Ramped access will be able to produce bio-diverse continuity to the ground, turning the walkway into a continuum with the natural ground.
– Jong-ro: the Monumental Steps
– Cheonggyecheon-ro: the Liquid Vortex
– Eulji-ro: The Threaded Underground
– Mareunnare-gil: A Monumental Slope
– Toegye-ro: The Twin Helix
Our scheme for the renovation of the existing reinforced concrete structure of the Seun Sangga arcade includes selective remodeling of the lower ground floor with the addition of a new link bridge across the open space between walkways and the addition of a network of stainless steel cables and structural steel props across the length of the structure.
Cable net structure : A new cable net structure is to be hung from the highest level of the structure to the level of the current walkway. This will be a simple pattern of stainless steel Macalloy type cables attached to the existing structure with a simple bolted plate connection. The cables are intended to support only vegetation and some limited people loads hence the reaction forces from each cable are relatively small.
At the edges of the walkway the cables extend outwards to create a naturally shaded canopy. These are supported with a simple structural steel raking column, a steel prop and triangulated stainless steel cables in a simple strut and tie frame, the configuration of which takes up as little space as possible.