What it took to make

ELIA


Technical description

Form of the sculpture

The shape of the sculpture can be seen from the cross-section above.

The external curved surface is shaped as a spherical cap, where the diameter of the sphere is 88m. The diameter of the cap at ground level is 60m. Staircases 10m wide are built into the spherical cap facing each of the four corners of the globe. The staircases have very large steps (about twice the size of a normal staircase). The staircases end in a platform about 11m over ground level. The interior of the sculpture can be viewed through an opening in the spherical cap measuring 10m x 10m.

Four pillars are placed at the corners between the staircases. The pillars rise about 30 m above ground level and are topped with red domes, illuminated from below and equipped with spires to attract lightning.

The base of the sculpture is constructed as the spherical cap, where the sphere has a diameter of 220m. Consequently, the centre of the base is 4m below ground level.

The floor of the sculpture is finished with an asphalt coating.

The external spherical cap, the staircases and the four pillars are constructed of steel. All visible surfaces are finished with black paint. A fifth pillar is placed in the middle of the four pillars. A gas burner is located in the fifth pillar, about two meters under the viewing platform.

At random intervals, the gas burner shoots a pillar of flame about one meter wide and 8.4m high up between the pillars. The gas flame is ignited by a sensor-controlled computer - once within an 18-day period. Each time, the flame burns for about 25 seconds.

The pillars are earthed so that they can function as lightning attractors. In the event of a lightning strike, there will be a powerful resonant sound effect in the interior of the sculpture.

Measurements and quantities

Dimensions

  • Diameter at ground level

    60,00 m

  • Height above ground level (pillars)

    32,00 m

  • Height to upper platform

    11,22 m

  • Radius in the steel dome

    42,00 m

  • Radius at bottom

    110,80 m

  • Staricases: Width

    10,00 m

  • Tread of steps

    0,60 m

  • Rise of steps

    0,34 m

  • Opening in dome

    10x10 m

  • Pillar diameter, lower steel pillar

    2,0 m

  • Pillar diameter, upper steel pillar

    1,60 m

Overview of Materials

  • Steel sheeting

    270 t

  • Structural steel

    80 t

  • Steel pillars

    30 t

  • Concrete

    250 m3

  • Asphalt

    300 t

  • Reinforcing

    15 t

  • Shingle (drainage layer under base)

    420 m3

  • Shingle (drainage along the circomference)

    50 m3

  • Volume of earth excavated

    7.000 m3

  • Treated steel surface

    7.000 m2

  • 90/160 mm diameter drainage pipes

    250 m

  • 200 mm diameter PVC sewage pipes

    100 m

  • Gas burner, installed

    1 stk.

  • Computer controlled flame control

    1 stk.

  • Lightning conductor with common earth

    4 stk.

  • Coloured glass domes with illumination

    4 stk.

Surface treatment

Steel surfaces

The individual steel units have been sandblasted and then treated with a rust prevention coating of 15-20 µ zinc primer. After assembly of the units in the engineering workshop, the pre-treatment was repaired along all seams.

When the steel construction had been assembled and all seams completed, there were further repairs to the pre-treatment prior to the final treatment. The final treatment consists of at least 30 µ epoxy-polyurethane or acrylic, three coats being applied to all exterior and interior surfaces. The steel columns were similarily treated prior to being erected.

The surface treatment has a maximum lifespan of 15-20 years, provided that any damage is repaired completely and promptly.

Gas flame

The technical specifications for the gas flame are contained in the report from Naturgas Midt-Nord, which has made technical calculations in respect of gas and safety.

Description of parts of the structure

Excavation

The base of the sculpture is formed as the inner side of a spherical cap, the sphere having a diameter of 110.8 metres. Thus, on the basis of a level building site, about 7,000m3 of earth had to be excavated. About 14,000 m3 of filling had to be added.

Steel pillars

The pillars were prefabricated in a factory. Each pillar has a diameter of 2m at the base and 1.6m at the top. The steel pillars are topped with red glass domes with internal illumination.

Drainage Installation

A damp course has been formed under the asphalt base by laying down a 15cm layer of shingles. The drain pipe system is constructed as a percolation drain, which is led to the municipal rainwater system.

The construction of the drain pipe system has been based on the soil and ground water situation at the site. Drainage from the exterior of the dome is through a rock filling along the circumference of the sculpture with the rainwater being drained off to the public rainwater system.

Concrete construction

The steel dome is supported partly by four steel pillars and partly by the circular continuous footing. The foundations for the pillars and the continuous footing are cast on site in excavations to frost-free depth.


The width of the continuous footing varies from 0.8 to 1.0 metres, depending upon the bearing capacity of the soil. The foundations for the pillars and continuous footing were cast in situ in shuttering.

Lightning Conductors

Each of the four pillars has a lightning conductor. The lightning conductors are connected to a common earth which is integrated into the foundations of the pillars and the continuous footing.

Gas Installation

A hollow pillar is situated in the middle of the dome. This pillar contains the machine room for the gas installation. A gas burner is located on top of the pillar, approximately 2 m under the top of the steel dome.

Steel Construction

The curved surface of the sculpture is fabricated from 5-6mm sheet steel which is stiffened with rolled IPE 360 profiles (radial) and HE 140 A profiles (circular). The staircase is also constructed of 5-6 mm sheet steel.


All fabrication of sheets and profiles, and of the components of the sculpture (stringers and steel pillars) was carried out in engineering workshops. All components were fabricated in the maximum size suitable for transportation. The assembly of these components to form the completed sculpture was undertaken on site with the assistance of mobile cranes.
All seams between the steel sheets are welded and the joints between the sheets sealed with weld beads prior to surface treatment.


The steel construction is secured to the continuous footing by fittings cast in the concrete. Likewise, there is a solid connection to the four steel pillars. Other than these connections, the steel construction is self-bearing.
The total amount of steel used is about 400 tonnes.

WARNING

In order to avoid any misunderstandings, it must be emphasised that it is extremely dangerous - and may have fatal consequences - to be on or near the sculpture during thundery weather conditions.

Photos of ELIA by Christina Capetillo
Photos of the creation by Gunnar Merrild

Copyright © 2018 ELIA