AQSO arquitectos office, this twisted tower becomes a landmark. The glass facade made of louvers reflect the morning sun

This tower housing the Zain headquarters in the Sudanese capital rises above the city, cutting a slender symbolic figure over the skyline. The monolithic structure gradually twists as it grows in a distinct gesture contrasting with the surrounding cityscape. Like a watchtower, the building domains the horizon expressing its communicative nature and becoming an urban landmark.

Luis Aguirre
Razvan Brezoianu
Diego Linares
Jesús Ramos
Andrés Fernández

Location: Khartoum, Sudan
GFA: 4990 sqm
Client: Zain Sudan
AoR: Iskan

AQSO arquitectos office, the Zain flagship store features a double height space. The entrance is marked through a series of louvers facing a public space.

The Zain tower is located on the 15th street of the Al Amarat district, a renowned residential area in central Khartoum close to the airport, surrounded by restaurants, hotels and number of embassies.

The building breaks the regular rhythm of the urban fabric, arranged in a fixed grid, by introducing a diagonal cut to the corner of the plot and providing space for a public plaza. This welcoming gesture at ground floor level generates an upward movement that defines the shape of the building, twisted to re-align itself with the urban fabric at the top.
The resulting form defines a generous podium at the bottom for the telecommunications company flagship store and twelve floors of offices above for its headquarters, which enjoy extraordinary city views.

AQSO arquitectos office. This axonometric drawing shows the different parts of the tower and the uses of each floor.

The typical floorplan of the tower is a simple square of twenty by twenty meters intersected only by the central core containing the lifts and the staircase, circumscribed in the centre of each rotated slab. The open plan allows a versatile distribution of the space, enclosed by the orthogonal facade glass walls.

AQSO arquitectos office. Low angle of the tower where the rotation of the storeys create a twisted figure.
AQSO arquitectos office, technical drawing of the elevation and section of the building, showing the levels, heights and facade design.

The building facade is defined by the prominent floor slabs, extending over the glazing envelope to become protective brise-soleils. A series of semi-transparent laminated glass louvres offer a second layer of protection, enhancing the dynamism of the tower when the sun hits this multifaceted skin.

AQSO arquitectos office, close up view of the glass facade, the external louvers are placed between protruding GRC slabs, protecting the interior glazing

This multilayered facade system protects the building from the hot semi-arid climate of Khartoum. The envelope offers a transparent appearance but responds adequately to intense sunlight, high temperatures and frequent sandstorms.

AQSO arquitectos office. Glass vertical louvers to control the external shading. Custom-made supporting system on GRC panels.
AQSO arquitectos office. Set of typical floor plans of the tower. With respect to the fixed position of the centra core, the plant rotates on each level.

The slab edge is protected with a series of modular glass-fibre reinforced concrete pieces with a subtle warm aggregate finish. The fixed glass louvres are arranged at the correct angles and distances to provide the best thermal performance of the envelope. To increase their efficiency, each piece count with a decorative brass mesh with delicate arabesque motifs sandwiched between the two layers of glass, also including a protective solar coating.

AQSO arquitectos office. The facade brise-soleil made of sun-shading concrete awnings and vertical glass louvers.
AQSO arquitectos office. Laminated glass slats with metal mesh with arabesque motifs seen from inside the offices.

The interior finishes provide a luminous and minimalistic design featuring white textured walls, polished concrete floors and a plastered suspended ceiling with soft edges.

AQSO arquitectos office. Inside the typical plant, the central core is dressed with vertical ceramic panels. The floor is made of polished concrete.
AQSO arquitectos office, night view of the illuminated tower, glass facade and illuminated sign

The structural system of the tower relies on its central reinforced concrete core and a group of eight circular columns around it supporting the square concrete slab with cantilevered corners. This regular arrangement provides a robust structural skeleton that takes on the exponential rotation experienced by the floors at each level.

This distinctive 48-metre-high office tower carefully balances cost-effectiveness and flexibility, is designed to naturally reduce energy consumption, and yet is responsive to the hot desert climate.

AQSO arquitectos office. Image of the top floor of the tower, where you can see the illuminated sign with the Zain brand.