Office building in Madrid

Building use

Office building

Country/Region

Spain

Overview

The building is an office tower part of a 4-tower development in a prominent area of Madrid. The building has a distinctive shape, with a square basis that progressively unveils the tower main structure shaped as an ellipse. The structure of the building is composed of a central core and a layer of main columns one the perimeter of the ellipse. These columns run from the foundations to the top floor, with varying heights. On the lower square-shaped part of the building there are additional perimetral column that prevent what otherwise would have be a very long cantilever of the floor slabs

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

Construction date: 2004-2008
Number of stories: 56
Gross floor area: 67,800m2
Adopted design code: –
Engineer(s): MC2 Estudio de Ingenieria
Contractor(s): Obrascón Huarte Lain

Issue and/or innovation

The perimeter columns of the central part of the building are interrupted at the lobby level and transferred by huge truss beams. These columns are composite (steel encased profile) to limit their cross size. Also the truss beam these columns are supported by acts compositely with the concrete slabs above and below.

Reason for composite solution

The promoter and owner of the project, Villar Mir Group, set out some rules that influenced the design, such as the use of concrete for the main parts of the building. Despite this decision, some parts had to rely on the properties of steel to simplify the size of the load bearing elements. Among these, the steel trusses supporting the lateral columns above the lobby and the composite elements in the mid rise area of the columns. In the latter case, a composite solution was used. Also the steel truss beams act compositely with the floor slab above and below, by means of steel cables dissipating the stresses through the slabs. A detailed description of this is provided in the referenced study.

Specific solution/technical details

Composite columns with a total diameter of 1000mm, formed by Ha-70 concrete with a 4% rebar, reinforced with one HEM 500 profile further reinforces by two steel plates 390x50mm welded on the HEM web.

Impact or effectiveness

The size of the concrete composite columns was kept to a manageable 1m diameter in the mid rise portion of the tower. The very strong capacity of these columns contributed, thanks to the belt truss created at 2/3 of the height, a rigid building able to cope with design or extraordinary lateral loads.