The need for innovative structural design in response to architectural innovation is demonstrated by the Markthal in Rotterdam. An awe-inspiring architectural and engineering masterpiece, the building consists of a huge arch containing more than 200 apartments, restaurants and shops, overlooking a 100-stall public market. It is not just the design of the building that pushes the boundaries of what is possible but also its location on waterlogged ground near the docks.
The challenges were addressed by experts at our Advanced Technology Research Centre who developed and verified innovative technical solutions. The extreme water pressure and scale of the footprint have resulted in some of the most complex foundations ever built in the Netherlands.
Re-thinking the role of foundations to counter the force of water
Rotterdam is criss-crossed with canals, rivers and docks so the plan to build a new structure near the Maas river, with foundations the size of two football pitches and four storeys deep was a considerable challenge. To counter the upwards force of the water, engineers had to re-think the role of the foundations.
The solution involved drilling 2,500 foundation piles 30m into the ground to prevent the structure from rising. Interlocking steel panels were used to make a huge waterproof wall, held in place with a massive concrete grid. Digging then continued for a further 11m, into which groundwater flooded, providing a counterpressure to hold the walls in place below the grid. Finally, highly-skilled construction workers in diving equipment installed reinforcement steel at the bottom of the lake to knit together the piles and concrete, creating a rigid box. Concrete was poured in, the site drained of 40 million litres of water and the 3D waterproof foundations were complete.
Apartments cast in concrete and stacked like huge bricks
Arches use their own weight and gravity as a source of strength, making a very efficient structure. In this case, it meant the apartments had to fit into the arch itself. This was done by casting the walls and floors of the apartments in concrete on site using tunnel form construction methods. Each apartment was placed into position like a brick, creating the curve of the arch. The method had additional benefits in that it is efficient in terms of time and money.
The top of the curve created a further challenge. In building upwards, each apartment was supported by the one below. However, this was not possible for the top. To solve the problem, a reinforced tower set on tracks provided temporary support as floors were craned into position.
Massive glass façade requires strength and flexibility
The ends of the arch are physically closed to provide protection from the weather but have been kept as transparent as possible to attract visitors into the lively and colourful interior. This is achieved with a glazed façade consisting of steel cables which create a suspended net onto which glass panels are hung. The cable net façade is the largest of its kind in Europe and requires the flexibility to withstand heavy storms during which movement of the panels can extend more than a half a metre.
The result is a dramatic hybrid city-centre building which brings together a traditional marketplace with space for people to live, eat, shop and park. It now attracts more people every day than the Eiffel Tower in Paris.