Description

Interview with Jürgen Engel by Sebastian Redecke

Jürgen Engel studied at the TU Braunschweig, ETH Zurich, RWTH Aachen and at MIT, Cambridge, USA. From 1986-89 he was office manager at O.M. Ungers, Frankfurt/Main. Since 2009, he has been the managing partner of KSP Jürgen Engel Architekten GmbH.

The Great Mosque at Algiers will soon reach completion in 2019. What made you apply to take part in the invited competition in 2008? At the time, you had no experience of building in Algeria.

The competition was for general planners and our partner office Krebs + Kiefer asked if we would like to apply. We had not planned any sacred spaces before, but I have always found them a fascinating topic.

Wasn’t that something of a risk?

We saw it more as an opportunity and applied to take part. We had an office in Dubai at the time and travelled from there to Algeria to see the situation first-hand. But when the detailed competition brief arrived, we were surprised by the size and scope of the task.

It seems rather unusual for an office from an entirely different cultural background to take on the challenge of constructing the third largest mosque in the world.

I have been very interested in historical church buildings since my studies, and the idea of designing a sacred space did not feel foreign to me. It is just that to date we haven’t been fortunate enough to undertake any church building projects in Germany.

What were the greatest challenges during the design process?

As general planners, we were initially responsible for everything together with our engineers Krebs + Kiefer, including on-site construction management. We knew from our experiences in China just how important it is to supervise construction to ensure a good quality result.

The French contract that was agreed was not the usual kind of services contract. It contained contractual commitments and procedures that were very bureaucratic and in my opinion was relatively unbalanced, serving mostly the client’s interests. But we adhered to it, and in the end, we fared well with the rather strict contract. The greatest challenge, however, was the sheer number of people involved.

How was the cooperation with the Algerian partners?

I found it an important and enriching experience. What fascinated me most was the language. I speak French well enough but the exuberant, poetic language and the good conversations we had during the process led to some very interesting moments that I learned from personally as well. In general, however, it was difficult to conduct negotiations because the ways of thinking and going about things is frequently very different. My staff on site were particularly exposed to the bureaucratic side of things. The building code in Algeria was not designed for such a large and unusual construction project and regulations were lacking for many things, making it necessary to find new ways of working together with the authorities.

Which client specifications were most important?

Our client at the time, the first general director Mohamed L. Aloui accorded great importance to high quality. He represented the ANARGEMA (Agence Nationale de Réalisation de Gestion de la Mosquée d’Alger) which was part of the Ministry of Construction and Religion. He was the principal official who steered the project in the early period of the project. Over the course of the project, three other general directors came and went. Some were very personally invested in the project while others were just senior administrators who did not deal with the construction project in any depth. Negotiations were conducted verbally and then only what was agreed on was recorded in the minutes. A day later, one would meet again to discuss the next issue … and so on issue for issue. We often had to think very far ahead and when things got too complex, we sometimes had to call in the German government. The German ambassador in Algiers was very open and assisted us from time to time.

What conceptual innovations set the mosque apart from other large mosques?

Every other large mosque I know, for example in Casablanca, was built in an urban context. In our case, despite being in the middle of the Bay of Algiers, the site lies on the outskirts between the city centre and the airport in the Mohammadia district. We saw this an opportunity to define a new urban space that will give direction to future urban development. It was important to create a truly urban place that would be the focal point for future urban quarters. I think it was this approach that set apart our design for the mosque from the competition. Otherwise, we adhered to the fundamental structure of the specifically Maghrebian sacred building tradition.

Did you have a specific model in mind?

I knew the mosque-cathedral of Córdoba. A particularly fascinating detail there is that the visitor enters a garden first, and only then the mosque. Designed as a hall of pillars and arches, it is a space that we only rarely see in Christian churches, for example in the pillared hall-churches of the late Gothic period. Otherwise, such large, pillared spaces seem foreign to us. I found it particularly refreshing not to be faced by a large all-encompassing space that makes the visitor feel small, but instead a hall of columns in all directions as its recurring theme. The visitor feels sheltered but it is still a large space.

How will the area around the mosque develop?

Algiers has already embarked on plans for major urban developments. Les Sablettes along the coast is already developing into a new leisure and recreational area with a park. The urban highway that passes to the north of the mosque will be transformed into a boulevard and several thousand trees have LAO been planted all the way to the city centre.

How did you arrive at the motif of the floral columns and what was the reasoning for the materials that you chose?

We chose the motif after studying the flora and fauna of the country during the competition and design phase. The loadbearing calla columns are distributed throughout the entire project – there are 618 in total. For the stone, we chose a material that bears relation to the country and reflects the changing colour of the desert and the specific quality of light there. 80% of Algeria is desert and we therefore decided on travertine. The first general director was very supportive and helped ensure we could use Italian travertine. For cost reasons, we had to use Turkish travertine for the surrounding buildings.

Was the viewing platform for tourists at the top of the minaret also your idea?

Yes. One can travel all the way to the top in the lift and look down on the city. From there one can truly appreciate the dimension of the mosque. We have also incorporated a museum and research areas for scholars in five segments in the minaret. The various levels of the exhibition can be reached via open stairs from the respective skylobby. Structuring the exhibition in five sections refers to the five pillars of Islam.

What was the reason for glazing the publicly accessible viewing platform at the top of the minaret?

The glass construction is a windbreak. The viewing area can host events, and for this reason it needed to be closed off. The muezzin’s call to prayers is broadcast via loudspeakers, so the minaret no longer needs to be open. Also, as the minaret is 265 metres high, no-one would hear the muezzin from there. It is currently the tallest building in Africa.

Did the client expressly wish to build the tallest building in Africa?

In our competition design, the minaret was lower, but still well over 200 metres. Then the client specified 265 metres.

Earthquake safety was also an important issue. What consequences does that have for a project of this size?

This is something we examined in great detail. The minaret is a composite structure of steel and concrete and stands on a Barrett foundation that extends some 60 metres into the ground. The prayer hall, which measures approx. 150 × 150 metres, rests on seismic isolators, which one can imagine as large shock absorbers that ensure that the structure is cushioned in the event of an earthquake and can shift in all directions. There are wide joints around the entire structure to accommodate such displacement.

How much influence did you have on the details of the design of the prayer hall?

In the mosque, we left considerable room for local and religious expression in the design. We collaborated on details such as the friezes with calligraphy, which are a few kilometres long! We worked together with an Algerian scholar who elaborated the design of the calligraphy, but the friezes were made by machine. The religious ornamentation was undertaken by hand and the resulting relief is magnificent. We also employed the motif of the mashrabiya in several areas. The large mashrabiya along the esplanade are made of fibre-reinforced concrete. In the end, an additional ornament was introduced over which we had no influence.

The prayer hall is crowned by a central dome, which is about 70 metres high at its apex and some 50 metres in diameter at its base. What kind of atmosphere does this create, and how is it constructed?

The dome is a translucent facetted dome. It is covered on the outside with ornamental decorations. The actual steel supporting structure is concealed between the outer shell and the inner dome. A system of mirrors in this intermediate space channels daylight from outside and reflects it upwards into the dome to indirectly illuminate the prayer room with natural light. The large crystal chandelier is lit from above by a ring of spotlights and that too dissipates light diffusely throughout the space.

As part of documenta 14 in 2017, you put on an exhibition of the project in construction at the Centre of Architecture in Kassel. In the accompanying booklet you wrote: “We must learn to question our European ways in order to be adaptable and able to act accordingly.” What do you mean by that?

In Algiers, we had to start from scratch in many respects. For example, the construction company first had to build a concrete plant on site. It then became clear that it wasn’t possible to produce the specified high loadbearing concrete in the high temperatures that prevail in Algiers. We needed ice to cool the fresh concrete. So, an ice machine was brought in. The Chinese building contractor was quite open to experimental solutions. The construction workers had to mediate between our designs drawn up to European standards and the material shortages in Algiers. We saw them draw on their ability to improvise in many places on the large construction site. In our exhibition at the documenta, we wanted to draw attention to this pragmatism as something we can learn from in this country. It is about tackling and solving problems on site with the means at hand. It does, however, also require an effective directing partner in the country who can help make decisions quickly.

How many visitors do you expect?

Up to 120,000 people come together in the Friday Mosque. The prayer hall here is designed for 36,000 worshippers, and many visitors remain outside, in the prayer courtyard (Cour), in the gardens, on the esplanade or in the other areas.

The Grand Mosque is intended to be the catalyst for a new urban development.

Very definitely, and the large number of visitors to the mosque will certainly stimulate development. French urban planners have been working for some time on projects that will gradually weave the mosque into the urban fabric of the city. There are plans for a tram line, and in future visitors may also be able to travel to the mosque by boat. Over the years, there have been many plans for expanding the city along the great bay of Algiers, of which Le Corbusier’s is well-known.

How do you feel now when you see and walk up to the building?

It is quite overwhelming and quite unlike anything else I know. One feels a sense of reverence, and of tranquil solitude which is really rather special.

Originally published in Bauwelt 19.2021, pp. 32-42, abridged and edited for Building Types online, translated by Julian Reisenberger

---