Markarfljót footbridge into the Þórsmörk nature reserve
EFLA, in collaboration with Studio Granda architects, have carried out the design of a footbridge across the Markarfljót river into the Þórsmörk nature reserve in the south of Iceland. The surroundings at the bridge site are mostly untouched by man.
It has therefore presented a challenge to the project team to provide a design that integrates the bridge with the environment. Strong winds in the area were another key criterion in the design process.
About this Project
Client
The Icelandic Road and Coastal Administration; "Friends of Þórsmörk" non-profit organization
Timespan
2014 - 2016
Location
Þórsmörk nature reserve, south of Iceland
Contact
Magnús Arason Manager | Bridges Phone: +354 412 6158 / +354 665 6158 E-mail: magnus.arason@efla.is Reykjavík
The project's objective
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 absence of other manmade intrusions and limited vegetation in the area.
The main bearing elements of the bridge are two locked coil steel cables in a single 158 m span between concrete foundations on the river banks. The foundations are secured with rock anchorages. Locally grown spruce is used for the bridge deck, connected directly to the steel cables. The free width of the deck is 2.5 m. Structural steel tubes and a stainless-steel wire mesh were selected for the hand railing to minimize the wind loading on the structure.
Located beneath the bridge deck, two horizontally aligned additional steel cables increase the structural stability of the system when exposed to wind and pedestrian traffic. A 1:12 scale model of the bridge was constructed and tested in a wind tunnel at the FORCE Technology in Copenhagen, Denmark.
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.
Environmental issues
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.
Service Components
EFLA's role
- 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
The project's long term benefits
Improved access to the Þórsmörk nature reserve.
