Markarfljót Footbridge into the Þórsmörk nature reserveMarkarfljót Footbridge into the Þórsmörk nature reserve

In 2014, EFLA, in collaboration with Studio Granda Architects, won a design competition for a new footbridge across the great glacial river Markarfljót into the Þórsmörk nature reserve. The bridge crosses the river from a lava field on the northern bank over to the magnificent cliffs of the nature reserve. The bridge will be visible from a distance due to the absence of other manmade intrusions and limited vegetation in the area. The surroundings at the bridge site are mostly untouched by man. Therefore, the project team was challenged to provide a design that integrates the bridge with the environment. Strong winds in the area were another key criterion in the design process.

The bridge's main bearing elements are two locked coil steel cables in a single 158 m span between concrete foundations on the river banks. These foundations are secured with rock anchorages. In a nod to sustainability and local resources, the bridge deck is made of locally grown spruce, directly connected to the steel cables. The deck has a free width of 2.5 m. To minimize wind loading on the structure, structural steel tubes and a stainless-steel wire mesh were selected for the hand railing.

To ensure the bridge's structural stability when exposed to wind and pedestrian traffic, two horizontally aligned additional steel cables are located beneath the bridge deck. A 1:12 scale model of the bridge was meticulously constructed and rigorously tested in a wind tunnel at FORCE Technology in Copenhagen, Denmark, providing concrete evidence of the bridge's safety and reliability.

The longitudinal slope of the bridge deck is limited to 8% to enable access for the handicapped, cyclists and horses. The bridge was designed to allow for the crossing of a fully equipped search and rescue truck.

The design and tender documents are fully completed, and construction work is expected to commence within a few years.

A key factor in the design was to minimize the visual effect of a footbridge in the otherwise untouched nature of the area. The bridge deck is made of timber grown in Iceland.

• Choosing a feasible design in collaboration with architects from Studio Granda
• Design of a cable supported footbridge crossing the Markarfljót river
• Wind tunnel testing of a 1:12 scaled model of the bridge due to the structure's lightness and low stiffness
• Producing tender documents

Improved access to the Þórsmörk nature reserve.