With its six storeys above ground and three basement levels, Blox forms a bridge over and a tunnel beneath the busy H. C. Anderson Boulevard, which still separates the city centre from the long-deindustrialized urban harbour. To come to terms with the irregular geometry of the building and the large spans involved, Arup developed a complex load-bearing structure, consisting of simple steel columns and beams, four central concrete cores and 18 one- to two-storey-high steel trussed girders that span 30 m on average without intermediate support. Where such large spans were not necessary, the columns and beams were laid out in a tight grid with axial dimensions of between 5.3 m and nearly 9 m. Spanning between the steel beams are precast-concrete floor slabs that, in the office spaces, have no additional concrete topping. The structural thickness of the floors is generally 40 cm.
Over large areas, the steel skeleton frame extends down into the basement. Sheet-steel piling and intersecting bored-pile walls seal the underground spaces against groundwater. The floors here consist of the same hybrid steel-and-concrete construction as that used on the upper levels. Only the slab beneath the roadway was executed with prefabricated, prestressed concrete bridge girders with a depth of 57.5 cm and an additional concrete topping layer. Flexible bearings beneath the beams minimize sound transmission into the basement.
In the Blox development, as so often in OMA designs, the access principle runs counter to convention. Public entry to the DAC is via a kind of pedestrian underpass beneath the road. The architects have linked the ongoing route through the building with the type of spatial design for which they became famous in the 1990s and the early 21st century. Visitors make their way up to the exhibition storeys and finally to the cafe and roof terrace via Piranesian gorge-like spaces, staircases, ramps and seating steps. Cross-views to the offices and the fitness centre may possess a potential for irritation. In the main, the different user groups are separated only by panes of glass. Visible steel columns and beams convey some idea of the complex skeleton-frame construction. Exhibition activities are centred on a tall glass-roofed hall, which is surrounded, like an arena, by office areas. The facades bring out the concept of a composition consisting of containers stacked crosswise, without slavishly reproducing the mix of uses on the outside. Consisting largely of storey-height elements, the facades are a mixture of greenish low-E glass and double glazing with a translucent white screen-printed pattern or expanded metal in different colours.
