Office building in Hernani

Building use

Office building

Country/Region

Spain

Overview

The building is the headquarter of the Orona Lift Industry, as well as the central point of a new campus creating a place that is both a flagship and a common home for its more than 4,500 employees and a hub for researchers and students on its vertical transportation, urban mobility, energy and technology branches. The design of the building is made by a hollow cylinder of 90m in diameter and 16m in height. The cylinder is inclined 16° so that it looks like it is emerging from the ground, cantilevering with a surface of 1500m for about 30m above the entrance.

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

Construction date: 2013
Number of stories: 4
Gross floor area: 12,000m2
Adopted design code: Eurocode
Engineer(s): MC2 Ingeniería
Contractor(s): –

Issue and/or innovation

The very unusual shape of the building is created with two circular truss beams. One has a dimeter of 90m and the inner one has a diameter of 4m. Both are formed by trusses made of almost perfectly square modules of 4×4 meters (4m between the uprights and an inter-story height of 4 meters). The trusses are made of straight elements, that create an angle of 5° with the preceding one, creating that overall circular shape. The two trusses are connected by steel beams that act compositely with the concrete slab above.

Reason for composite solution

The composite floor solution is formed by the main steel ribs that connect the inner and outer circle and a collaborative concrete slab. This cast-in place solution prevented the use of very large irregularly cut corrugated steel sheets, while creating at the same a very stiff solution. Timing the deflection of the 20+m long free span of the lower floor.

Specific solution/technical details

The uprights of the inner and outer trusses are connected by a series of ribs made with HEB profiles (240-300mm deep) in S275 steel in addition to a cast-in-place concrete slab with a thickness of 15cm. Every other rib terminates about 5 meters before touching the inner truss, and it is supported by connecting beam that links the two adjoining beams.

Impact or effectiveness

Despite the composite solution used, to reduce the deflection of the floors an layer of internal columns was added forming a circular series of columns with a radius of approximately 52m. To support these columns the thickness of the lower composite floor has been increased, and it is formed by 500 and 600mm beams with a 20cm composite concrete slab.

References / Technical Papers Content

Martinez Calzon J., Ladron De Guevara G. , Rodriguez Munoz D., Bartalotta P., Palacios M., Orona Zero Building, Structural Engineering International Volume 24, 2014 – Issue 1 https://doi.org/10.2749/101686614X13830788505720
Ladron De Guevara G., Rodriguez Munoz D., Orona Zero Building, Hormigon Y Aciero 2015, Volume 66, Issue 276, DOI: 10.1016/j.hya.2015.11.001