The two new pedestrian and cycle bridges across Elliðaár estuary are an example of the present emphasis on sustainable transport in Iceland. Those who cycle or walk along the new route will experience new and interesting sights on Geirsnef, the peninsula between the two river streams. In the future the plan is to set up a rest area with a viewing point at the end of Geirsnef peninsula. Strong contrasts feature in the surroundings, the delicate ecosystem of the estuary of Elliðaár and the rough industrial area. The new pedestrian and cycle bridges present a positive change in form of transport, but simultaneously by choice of materials, colour and the shape of the bridge structure, they have clear reference to the surroundings and the history of the site.
The concept for the bridges is based on the three rules of sustainable development; ecological, social and economic sustainability. The two bridges are identical in shape but mirrored and their appearance varies from different angles. In the design process the goal was to minimize the use of material by giving the bridges a basic shape that also becomes their identity. The stable basic structural systems allows material usage and construction cost to be minimized. The bridges are designed in the shape of a tetrahedron. Three columns, one long and two shorter, connected at the top and rest on pile foundations on the river banks.
New landfillings are made by the west bridge which reduces the span and standardize the two bridges across Elliðaárósa. The 36m long bridge deck is held up by steel tension rods that are connected to the top of the pyramid. The deck between custom made steel beams is made of hollow core slab with concrete topping. The surface of the bridge deck slopes towards drainage on each side. Railing posts are bolted on top of the edge steel beams. Between posts railing is made of a vertical wire wrapped around ø 20 steel pipes that are fixed to steel plates on ø 50 stainless steel pipes at the top and bottom.
The pedestrian and cycle paths are joined on the bridges but are otherwise separated with a narrow grass stip. Turning radius of the cycle path does not go below 40m to allow cyclist to keep steady pace. Existing path along Geirsnef peninsula is adapted to the new pathway.
It was important to preserve existing vegetation as much as possible. Where it was necessary existing birch trees were moved and replanted. Existing pathway on north edge of Geirsnef peninsula is discarded. Areas are covered with turf where needed otherwise grass seed sowed.
Elliðaár river is Reykjavík ́s angling treasure therefore the lighting concept for the bridges and adjacent paths was to minimize the light pollution into the river. By preventing the light to illuminate the river the fragile state of the seasonal salmon run and smolt in the river is not disturbed. The tetrahedron structure is illuminated with six projectors with LED as the light source. LED light fixtures are recessed in the handrail and emit light on to the bridge floor, bollards with metal halide lamps light up the path between the bridges. Light sources use minimum amount of electricity, have long lifespan and low maintenance.