Office building in Barcelona

Building use

Office building

Country/Region

Spain

Overview

The complex is a mix of multiple office buildings, some for the use of the owner, Gas Natural, some for rental. The two main features of the complex are a vertical tower of 22 floors and a lower, longer building characterized by a huge cantilever of about 40 meters elevated some 20 meters above the ground floor plaza.

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

Construction date: 2008
Number of stories: 22
Gross floor area: 5,800m2
Adopted design code: Eurocode
Engineer(s): MC2 – Estudio de Ingeniería
Contractor(s): Dragados + Intemac

Issue and/or innovation

The shape of this building, called, “aircraft-carrier” created unique structural conditions. The building is supported vertically by two concrete cores: a central one and one on the opposite side of the plaza. The central core acts as the hinge of the whole structure, characterized by a 20 meter tall Pratt truss that is balanced on one side by the second concrete core. The whole structure is composed of metal elements while the node (suspension system) above the central concrete core is made of composite steel-concrete structure.

Reason for composite solution

The powerful short composite structure is formed by a large box section of variable depth and width in order to ensure that its two webs are coincide in the central area parallel to the sides of the concrete shaft and produce a perfect transfer of actions from one system to the other.

Specific solution/technical details

The two composite elements in this assembly form the cap above the central concrete core. They are formed by S460M steel plates, up to 80mm in thickness. And act compositely with the concrete by means of shear studs and more robust steel flanges. They are curved to ease the connection with the Pratt trusses. A 40cm thick reinforced concrete slabs connects the two elements and it is heavily prestressed to form a unique assembly that can take up and transfer to the core any type of transversal forces due to unbalanced loads, wind etc.

Impact or effectiveness

The overall cantilever structure is completely balanced for dead loads by the truss and core system on the other side of the central core. The composite solution is capable of transferring to the core any unbalancing force due to live loads or accidental loads.