Football Stadium in Bilbao

IDOM Consulting Engineering Architecture – Spain

Building use

Other

Country/Region

Spain

Overview

The building is the new stadium for the San Mames, Bilbao. The challenge was to substitute the pre-existing stadium on the lot, without interrupting the football season and creating a UEFA 5 class stadium. The construction project therefore divided in two lots. The first lot (2011-2013) was built on the site of the parking space of the original stadium, while sport activities continued in the old structure. Then, matches were moved in the new partly-finished stadium with a seating capacity of 36.000 people and demolition of the old stadium started. The second lot (2013-2014) allowed the completion of the new stadium to its full capacity of 53,229 seats.

Basic information (construction date, number of stories, gross floor area, adopted design code, engineer(s), Contractor(s), etc.)

Construction date: 2011-2014
Number of stories: 37 meters from ground level
Gross floor area: 38,280m2
Adopted design code: CTE (Código Técnico de la Edificiación) Eurocodes1,2,3 & 4
Engineer(s): IDOM
Contractor(s): UTE Estructuras San Mames : Acciona, Inbisa, Altuna y Uría, Murias

Issue and/or innovation

The main issue of the new stadium is its roof that is cantilevering out up to 55 meters. These large cantilevers lay on a frame system that is partially made in reinforced concrete and partly – in the tensed portions – in composite construction. Also, the frames of the stadium, below the seats, have a varied geometry and in some circumstances s few vertical elements/columns in a row disappear to make space, for instance, for a swimming pool. These irregular elements are also realized with a composite steel/concrete solution.

Reason for composite solution

In the frames that hold the 55 meter cantilever a composite steel-concrete solution was adopted to cope both with moment acting on the portal frame and with the façade geometry that, at that height, creates a 7 meter deep cantilever projecting the perimeter of the stadium outside its footprint. The system developed allowed the creation of self-standing roof elements that made possible the 2-stage construction sequence.
Additionally, some portions of the concrete frame are substituted by composite portals, to cope with a varied geometry and the insertion of some heavy elements (ie: a swimming pool)

Specific solution/technical details

The composite portion of the frame is located in the under-tension portions, where the moment generated by the roof cantilever creates a tension component in the frame, is made of hot-rolled steel profiles. These are encased in concrete and act compositely by means of shear studs. This solution not only increases the structural capacity but it also allows a more diaphanous structure that what could have been obtained with a simple concrete structure.

Impact or effectiveness

The solution allowed the erection of the stadium in two lots, that were built independently thanks to the self-sustained structure created for the roof. The great capacity obtained thanks to the use of the composite elements allowed a further extension of the roof structure toward the center of the pitch. This was created in 2016 thanks to the installation of a cable-tensioned EFTE membrane that further increased the span of the cantilever structure for an additional 13-23 meters.

References / Technical Papers Content

Llarena J., Castro N., Bilbao A., San Memes New Football Stadium. Design and Construction, Proceedings of the 19th IABSE Congress, Stockholm, 21-23 September 2016