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Dodder Bridge Competition, Ballsbridge


Date: August 2008

  • Complete Competition Entry
  • Plan of One Structural Bay and Part Longitudinal Section
  • Black and White Perspective Showing how Bridge Could be Assembled
  • Long Section1to100
  • Plan
  • Perspective South

Result: Competition Entry

Brief:

This competition was held in 2008 and sought a design for a new pedestrian bridge in a busy part of Ballsbridge. The bridge was intended to form a new pedestrian link between the nearby DART train station, and a neighbourhood with many office buildings. It was intended that this would form part of a major development in the locality. The site was a narrow section of a shallow river with a line of mature trees on one bank, and a riverside walk, behind a stone wall on the other bank. The competition requirements said that the bridge should be quickly and easily constructed and should impose minimal disruption to the existing fabric of the site.

DKAD entered this competion because of the design challenge it presented, and the possibility to employ ideas about public space developed in Diarmuid’s final university thesis. DKAD approached this design as the design of a public space, not as the design of a static machine, oblivious to it’s context as many bridges are designed. The precast structure we used was timeless and indestructible, and it created new spaces for people to spend time, and enjoy this small tranquil space in a crowded urban district.

When designing public spaces, an architect must meet a unique challenge: the space must be extremely robust to resist wear and tear, but it must also be welcoming and amenable so that people will chose to spend time there. It must be a space to pass through, but also a place to linger; you must be able to claim a small part of it while you read the paper of make a call, and feel comfortable even though there will be strangers sitting near you. To meet this challenge, DKAD considered the nature of the site, and the need for all urban design to seem as if no one had ever designed it, but that it simply could not exist in any other form.

The obvious choice to meet the functional requirements of the brief was to use a pre- fabricated steel- truss structure. DKAD took the position that Dublin city already had many such structures, of high quality, and that they represented only one approach to bridge design. We used a system of bays prefabricated concrete sections, each one roughly the size of two sheets of plywood. Each formed part of a deep upstand beam, which connected in sections and thickened to create a seat which ran the length of the bridge in bays reminiscent of train compartments.

The underside of the bridge was clad in perforated aluminium sheeting, and the deck had structural glass apertures cast into it. The space between these two surfaces was to be lit by simple sodium lamps. The light would shine upwards from the deck to light the brige for pedestrians, and the undercroft would project a pattern onto the plane of the water.

Complete Competition Entry
Complete Competition Entry

The verbal description offered as part of the entry was as follows:

“Reflections and Surface

The Dodder valley links the amenity spaces of South Dublin. This corridor is bounded by walkways and linear parks for much of its distance; however, the visual plane of the river’s surface is the true amenity. The attraction of watching a body of water is in the tension that exists between the surface and the space above; and the mystery of the depths. In this project I have lit the under croft of a pre- cast concrete girder structure, and made apertures for light to project out from the deck and soffit. This strategy lights the bridge users, and with the same light- source, projects light through a laser- cut aluminium sheet soffit, which creates a shifting image taken from Monet’s Water Lilies series on the water below. This is intended to define the river channel as a series of spaces; some trafficked by pedestrians, and some untouched. The bridge is lined with seating separated into niches at the scale of a conversation which creates the second space, and the banks are defined by concrete cast at the human scale.”

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