Þórsmörk is a nature reserve at the confluence of two glacial rivers, Krossá and Markarfljót. Its only access is by foot over highland passes or by crossing Krossá in a specially equipped 4x4. The disruption caused by the volcanic eruption in Eyjafjallajökull in 2011 made clear that a secure walking route into Þórsmörk was necessary. The considerable increase in tourism since then has heightened the need still further.
The design for the new Markarfljót bridge was selected by competition between three shortlisted teams following an open selection process. The winning team was Studio Granda with EFLA engineers.
The site for the bridge is between a lava shelf on the northern bank of Markarfljót and dramatic cliffs on the Þórsmörk side. It is overshadowed by the blue-white bulk of Eyjafjallajökull and is visible from afar. The presence of man is insignificant.
The design seeks to intrude as little as possible on the grand scale and purity of this landscape by keeping the height and mass of all elements to an absolute minimum. It has a single span of 158m with a principal structure of two locked-coil steel cables that span between rock-anchored foundations on each bank. The deck of locally sourced spruce is clamped directly to the cables with a handrail of minimal section to minimise wind-load. Gaps between the deck planks drain rainwater and snow as well as heightening the experience of crossing the raging water. Below the bridge two secondary locked-coil cables increase stability.
The bridge has a maximum gradient of less than 8% making it wheelchair, bicycle and equestrian friendly. It is also sufficiently substantial to carry a fully laden mountain rescue truck.
Client : Friends of Þórsmörk & Public Roads Administration
Architects : Studio Granda
Engineers : Efla
Windtunnel consultants : FORCE Technology