Engineered timber dome roof wows in Barcelona

Glulam and Kerto LVL panels have been used to create a timber and glass roof structure over the refurbished Las Arena bullring in Barcelona.

Finnforest supplied the engineered timber and sister company Finnforest Merk employed its timber engineering expertise on the project.

Contractor Dragados selected Finnforest Merk as its engineering partner in order to help it fulfill the challenging roof design specified by Rogers Stirk Harbour & Partners and engineered firstly by Expedition and then BOMA of Barcelona.

The project has transformed a disused bullring into a mixed-use development, with the dynamic roof structure able to provide protection from the weather and enable the building to be used for a wide variety of activities.

The dome structure covers a roof area of 5,100m² and a diameter of nearly 80m. It rises some 9m from the existing facade of the bullring.

“Because of the location of the building the roof had to be fixed in height in order to adhere to local planning restrictions,” said architect James Leathem. “As a result the dome is quite flat in shape and the structural systems have to work much harder because of the large circumference and tolerances required.”

The structural solution Finnforest Merk produced is based on a timber gridshell and metal ring beam. This has been constructed from repetitions of glulam beams that create a pattern of lozenges. The pattern changes at the crown where the structure terminates in a circular ring beam, defining a 30m diameter oculus, itself constructed of a simplified pattern of glulam members.

The wooden superstructure of the dome had to be designed as REI 60 structure based on Eurocode 5 part 2.

Engineered so that the timber members are connected using flitch plates and dowels within the wood, the appearance is one of a continuous timber structure. The beams themselves are then finished with load bearing Kerto Q LVL panels and insulation before the application of a liquid roofing membrane for a weather-proof finish.

For the roof glazing Finnforest Merk used a special variation of its KertoConcept system.

The entire roof sits on a 3m high base, overcoming the possibility of unusable low space at the perimeter of the dome. This comprises 20 boomerang shaped columns supporting the dome’s perimeter beam.