Mall roof for the Mediacite retail centre in Liege, BelgiumEdit profile
The roof to the Mediacite retail centre in Liege, Belgium, was in fact an afterthought by the client. With the design and construction work for the main buildings well under way, Ron Arad Architects and Buro Happold joined the project late to design the centre piece of the new development. It was a brave move by the client, Wilhelm and Co, with their brief to lift the overall appearance and the quality of the mall spaces and make the space an attraction for Liege. The scheme was taken from initial sketches to a buildable scheme in a very short period of time, with the Buro Happold team working very closely with Ron Arad and his team to develop the conceptual idea of intersecting ribs that follow and define the more than 350m long and just up to 30m wide mall space into a structure, rather than just a decorative elements. This involved an initial period of optimisation of the number of ribs, their depth, their makeup and their arrangement, as well as an investigation of the geometrical characteristics of the roof shape, making maximum use of shell action and allowing the ribs to flow as freely as possible. The structure, which is triangulated only in areas of movement joints and fire curtains, pushes the steel ribs to a maximum, relying on their axial strength as well as their bending resistance. The structure is a hybrid that takes advantage of shell action where possible but also resolves the often inconsistent boundary conditions presented by the concrete structure underneath. All details, as well as the end points and transitions of the different parts of the mall roof were designed following a clearly aligned structural and architectural logic, which is visible and can be experienced throughout. With a tight timeframe the Buro Happold team drove the procurement of this unique piece of structure. A two-stage tender, based on a highly selective tender list, ensured that risks could be minimised and the fabricator be brought into the process as early as possible, so that the ambitious canopy could be constructed within the budget constraints given. As a result of this, Iemants, a Belgian steelwork contractor, joined the team six months into the design and proved an invaluable partner in the process of developing and value engineering the scheme. The design process focussed on a close collaboration between the partners and the team used a parametric design approach from the very start of the project, moving from the sketch models that developed the sculptural qualities of the roof to a fully scripted data transfer process between architect, engineer and fabricator, including all steps of the analysis and the production of fabrication information. During the process drawings became illustrations but the information exchange was fully digital. Construction of the roof started on site in less than ten months from from inception. Whilst the interfaces with the existing concrete structure beneath created some challenges, the insertion of the sculptural piece of roof structure into the concrete base structure progressed surprisingly smoothly considering its late introduction. And the client’s gamble has paid off. Despite the downturn in global retail sector, Mediacite was virtually fully let when it was opened to the public in late 2009. The roof has transformed Mediacite from a standard shopping centre into a fantastic architectural experience that attracts visitors from far outside Liege. As one guest said to me at the opening party: “The space puts a smile on my face`. A great reward for our work.