The Terraced Tower

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17-06-2020

The Terraced Tower

The Terraced Tower gives Rotterdam skyline a new look

Following on from the towers Montevideo (158 m), New Orleans (152 m) and the Maastoren (165 m) at the Kop van Zuid, BESIX Nederland continues to build on the Rotterdam skyline. In the autumn of 2017, the multidisciplinary construction firm started work on a 100-meter high residential tower on the northern side of the Maas, commissioned by developer Provast. The Terraced Tower will contain a variety of modern city apartments, of which 258 for rent and 86 for sale. The tower takes its name from the terraces stretching along the entire width of all residences, providing spectacular views over the city and the Maas.

Publication by Lieke van Zuilekom, 29 April 2020. Image | Buro JP. Source: Stedenbouw

“The Terraced Tower was tendered as an Engineer & Build commission based on a Definitive Design”, explains Michel Mulder, Operations Manager at BESIX Nederland. “Using Royal HaskoningDHV’s structural design as the basis, our own engineering office designed the rest of the construction of the residential tower. Furthermore, we also took care of the architectural and aesthetic optimisation of the building in close collaboration with OZ Architects. In the autumn of 2017, we started demolishing the old office building on the site, including the existing foundations at level -1.” He explains that The Terraced Tower is being realised in the primary flood defence area at the Boompjes, which holds back the high water of the River Maas. “The Hertekade is also adjacent to the north side of the plot, with the Scheepmakershaven behind it. This means that we have water to deal with on both sides, which presents specific challenges for the foundations.”

Complex play of forces

“We have excavated the soil to a level of almost 3 storeys”, explains Mulder. “Then we added a new, thick foundation floor. For the construction, the choice was made for concrete poured on site and in-situ walls. The facade will be built from timber frame construction elements combined with aluminium frames. The building becomes narrower towards the top, with some floors projecting outwards. In order to deal with this interplay of forces, with pressure from the dike body of the Boompjes and the water on both sides, we have used a construction pit with a stamp frame and anchors on multiple layers.” As there is a line of cables and pipes running straight through the project site that cannot be disturbed, BESIX Nederland first poured a concrete slab. “We excavated the basement underneath this. We also used the concrete slab to provide good support for the stamp frame.”

“We have to deal with water on both sides, which puts special demands on the foundations.”

Logistic challenges

Alongside the construction itself, the urban location is also challenging, emphasises Mulder. Especially in terms of logistics. “We actually do not have a construction site. Furthermore, the Boompjes is an important transit route to and from the city. In order to avoid disrupting the traffic flow, we have placed our tower cranes on two portals. Lorries carrying construction supplies can drive underneath them.” All deliveries are just-in-time, he explains. “There is also close consultation when it comes to using the tower cranes. And this is no easy task, with three construction flows and over 120 people on site today. We also have to deal with all kinds of issues concerning the coronavirus. Luckily, our construction partners are very flexible and willing to help, so that construction can continue as normal as possible. They really deserve a great compliment for this.”

Customisation

Structural work has now progressed up to the 11th floor. The facades are being installed three storeys below this, explains Mulder. “The finishing work is now also underway.” The rental apartments are being finished in line with the Programme of Requirements of the owner, CBRE Global Investors. “For the owner-occupier apartments, it is possible for the residents to choose their own kitchen, bathroom, internal doors, tiles and wall and floor finishings. This makes each and every owner-occupier apartment bespoke. In order to help the residents make these choices, we have not only set up special showrooms, but also appointed a dedicated advisor.”

‘The building becomes narrower towards the top, with some floors projecting outwards.’
The facade is built from timber frame construction elements in combination with aluminum frames (by Byldis).

The facade is built from timber frame construction elements in combination with aluminum frames (by Byldis).