Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Out of the blue

Alexandria Library

Floating just in front of the library building is a giant black ball. Seen together, the two structures create the impression of a planet orbiting the sun. This is appropriate, because the smaller building is a planetarium.

It is already the most popular part of the development with locals, largely because of the bright blue strip lights which illuminate it at night.

'It is a sort of advertisement, ' says project architect Christoph Kapeller. 'Here it is colour the people love. By day it is black and at night it is bright blue. We decided not to put any colour in the main library because dark material stores heat. So as a contrast to the light building we put a dark building in the foreground.'

Heat was a worry for French contractor Laubeuf, which had the £2M contract to fabricate and erect the 18m diameter sphere. Its shape means that the sun will always be at an angle of 90¦ to the cladding and during the summer the polished black surface is expected to reach a temperature of more than 80¦ Celsius.

'To ensure that the 18mm thick glass reinforced plastic panels would not be damaged by thermal cracking, trial panels were tested in an oven and cooled before microscope examination, ' explains Laubeuf project manager Frederic Figuet.

The sphere's six tubular steel truss ribs were fabricated in France and shipped to Egypt where they were welded together and lifted into place using a 150t capacity crane.

The trusses were made in three segments so the heaviest lift was 6t. The steel skeleton is fitted with an air and watertight skin and then clad with the black GRP panels.

'The cladding was originally designed as precast concrete panels, ' explains Figuet. 'But they were too heavy so the weight was reduced by using 18mm thick GRP panels.'

A feature of the shell is the hidden drainage channels that run around the whole structure. These were adapted from a system designed by the French contractor, which has worked on projects such as the European Parliament building in Brussels and the Stade de France in Paris.

'It is a speciality of Laubeuf, ' says Figuet proudly. 'The company has patented the system.'

The sphere is suspended above a 24m by 24m concrete basin on two simply supported steel lattice bridges.

The void will be lined with a sloping glass curtain wall through which the supporting structure for the sphere will penetrate. This area below the sphere will be used as a museum to display the artefacts uncovered during the construction process.

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.