Pushing limits of architecture

“I am delighted to be building the Grand Theatre in Rabat”, said superstar architect Zaha Hadid in 2010. “Morocco’s unique musical traditions and rich cultural history in the performing arts are renowned throughout the world. I am honored to be part of the cultural development of the nation’s capital.” The
Iraqi lady with a British passport was known as the queen of curves. When she passed away in Miami, Florida in March 2016, the world of the architecture held its breath.

 

A monumental theater by Zaha Hadid Architects for whole Morocco

The monumental theater for the whole country, a cultural highlight with first-rate amenities – this has been the vision of the country’s leaders. Zaha Hadid was commissioned to draw up an avant-garde design.

 

A smoothly-formed monolithic concrete wrap

The 27,000 m² structure is sited on a floodplain site in the center of the city, which is currently undergoing major residential, commercial and leisure regeneration. Hadid’s design is based around the idea of a smoothly-formed monolithic concrete wrap, wound around a set of auditorium spaces within. The areas between the auditoria and the external envelope form zones for circulation. These extend out onto the site to create a vast new public landscape, including an outdoor amphitheater with a 7,000-seat capacity.

 

High waterproofing requirements because of flooding risks

Flooding is a fundamental concern, and the site has been raised up to 5m above the river level accordingly. Despite this, the required basement depth means that levels below the flood plain are unavoidable: large-scale tanking measures are being adopted to deal with this. This nearby river has created special challenges for the waterproofing concept for the building foundations. Although the theater site has been raised to a level five meters above the river, some parts of the building are still permanently below the water level. Hence there are exceptionally high requirements for reliable waterproofing systems.

 

Seismic activities in the surroundings

The Bou Regreg valley is subject to seismic activity, and the saturated fine-grained soils mean that liquefaction occurs during seismic episodes. The theater is thus supported on large-diameter piles which can withstand seismically induced lateral loads by acting as cantilevers 12-15m long, supported by the stiffer soils below.

 

Standing on 325 piles

The building shell features a combination of steel framing and concrete. The overall structure stands on 325 piles connected to a slab-on-grade, which, due to structural requirements, is one meter thick. The construction is complicated additionally by the geometry of the walls, which are curved in both horizontal and vertical planes. Further demands are imposed by the size and weight of the steel roof framing.

 

Structural separation for an optimal acoustic experience

To the west of the theater is a bridge which is heavily used by private vehicles and streetcars. This traffic poses acoustic problems, but excellent solutions have been found for the acoustic inside the theatre. In the main structure, acoustic quality is thus paramount; structural separation is adopted throughout, with the steel roof sandwiched between two thin concrete shells. This sits on concrete perimeter walls, separated by isolation bearings. These steelwork trusses span up to 60 m to create a column-free internal void for the theatre itself. The floors also feature metal decking covered in concrete to create the requisite acoustic mass. Together these create an impressive and complex form reflective of, and indeed reflected in, the adjacent waters of the Bou Regreg.

 

Sheet membrane system for waterproofing

SikaProof® A fully bonded composite sheet membrane system was chosen to waterproof the foundations – the first time this product has been used in North
Africa. Sika® ViscoCrete® was added to the concrete, while other products such as SikaSwell® were also used in this special project. The wholehearted
support provided by Sika’s experts in Morocco was very much appreciated, while
the on-the-spot training for applicators, provided by Sika representatives sent
specially from Switzerland to Morocco, served as further proof to all that the
right decision had been made.

 

Watch the film on You Tube

Read more about the project in online magazine archdaily

Read more about the project in online magazine dezeen

More about Zaha Hadid Architects

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