Consulting engineer Buro Happold has provided the structural engineering design for the spectacular Palace of Peace and Reconciliation which was officially opened on 1 September, in Astana, the capital of Kazakhstan. The president of Kazakhstan opened the building which was completed in time for the triennial Congress of Leaders of the World and Traditional Religions, a regular meeting of leaders of all the major faiths intended to promote religious tolerance.

The Congress was first held in September 2003 on the initiative of the president who, encouraged by the event’s success, decided it should be repeated triennially. As a result, the project has had an unusually fast design and construction time, of less than two years.

As well as providing an impressive meeting space for the Congress, the pyramid hosts a 1,500-seat opera house, conference facilities, part of the local university and a national centre for Kazakhstan’s various ethnic and geographical groups. These various spaces have been built around a central atrium, above which is a reception area lined with vegetation, dubbed the Hanging Gardens of Astana.

Buro Happold has been involved with the project from the outset, collaborating with world renowned architect Foster and Partners to develop a design that integrates architecture and structure in a way that is both practical and dramatic, while meeting the exceptionally tight deadline and working around the extreme climate of Astana.

The pyramid is 62m high, with a 62m by 62m base and has been designed in two parts: a concrete base building and the steel superstructure. The base, which is partly below ground level, provides firm foundations and an enclosure for the opera house. The superstructure is made from prefabricated steel tubes arranged into inner and outer triangulated plates. The inherent stiffness of these makes the structure very robust and they will be connected to each other with cross members in the floor planes.

The structure is based on 12m-wide triangles, with five at the base, reducing to one at the top. At the base level, the steel creates stable, four-sided pyramids that transfer lateral loads and vertical loads to the basement and foundations. Above this level, the main accommodation floors are carried on steel floor beams spanning between primary beams which link the inner and outer plates.

George Keliris, project principal for Buro Happold, says: “One of the crucial aspects of the engineering of a steel pyramid was dealing with the expansion of the building under the huge variations of temperature in Kazakhstan. In winter it can fall to -30ºC and in summer exceed 30ºC.

“This will result in expansion of the steelwork by up to 30cm across the width of the building. We decided to float the pyramid on bearings so that it can expand and contract freely on the concrete base. But to stop it sliding off its base we secured the steelwork at one point on each face, in a way that let these points slide in and out while preventing them moving in line with the face. This was just enough to hold the pyramid still while letting it ‘breathe.”

The inner and outer plates converge to create a stiff ring close to the top of the pyramid. This supports the uppermost glazed pyramid, which is made of smaller diameter tubular steel to give a more delicate appearance. The stained glass summit of the pyramid, which surrounds the meeting space, has been designed by renowned stained glass artist Brian Clarke and will create a unique light for the Congress.

“The end result is a truly spectacular building and a great example of our innovative engineering – in meeting both the structural challenges and in designing a construction programme that worked around the harsh climate while meeting a particularly tough deadline,” says Mike Cook of Buro Happold who was responsible for the project.

The structural design, as submitted by Buro Happold, was developed in accordance with British Standards and all steel has been treated or clad to obtain the necessary fire rating.