ClientING Real Estate
ArchitectOntwerpgroep Trude Hooykaas
Project size12.000 m2 GFA
Start of project2002
Consulting servicesStructural design, detailed design drawings and calculations
An out of use crane track was located on the IJ river’s north banks. In the past, the track was used to fuse two halves of new ships. Originally, the crane track was intended to be demolished alongside the shipyard. The cranes had already been blown off the track with explosives. However, architect Trude Hooykaas recognized the structure’s and location’s potential. Initially attempting to develop an office building on her own, she later interested ING Real Estate in the project. Aronsohn was then involved to answer the project’s many structural challenges. The most important challenge was the starting point that at least 12.000m2 of office environment would have to be realised in order to make the project feasible. To Aronsohn, it was clear that the crane track structure’s limits would have to be sought in order to achieve this goal.
Aronsohn has investigated information about the crane track structure on three locations: the original architect’s (Postma) archive, the municipal archive and the archive of general contractor De Hollandsche Beton Mij. Combined, the contractor’s shape and reinforcement drawings and the data from the municipal archive created a clear image of the structure. Additionally, information concerning a load capacity test of the pile foundation was found and proved valuable. Consequently, Aronsohn has calculated the entire concrete structure according to the laws and regulations in 2002. This revealed the structure’s capacity. Specifically, it became clear that the structure’s water side had a greater load capacity than the structure’s land side. This draws back on the crane track’s original purpose, which had cranes exerting the greatest load on the water side. The load capacity test results and additional cone penetration tests provided an excellent basis for determining the exact limits of the pile foundation’s load capacity in cooperation with the Delft Laboratory for Soil Mechanics. It became apparent that the piles had a greater capacity than the pile caps. In order to make the column’s capacity in accordance with the piles’ carrying capacity, extra tie-beams were installed to the pile caps. This was done in a semi-dry construction pit. A complicating factor was the damage discovered on the structure’s upper side as a result of ASR (alkali-silica reaction). Additionally, the under-surface had been damaged. The damages have been analysed and restored in cooperation with Intron. The under-surface’s restoration was done by means of sprayed concrete and additional reinforcement as an extension of the structure’s main reinforcements.
It was important to realise an office building of at least 12.000m2 in order to recover the initial investments. The horizontal capacity of the existing structure limited the building to a maximum of four storeys. It was decided to keep the bottom floor detached from the concrete structure, leaving the possibility for three more storeys. The floors’ width followed from their length. They have been placed eccentrically, with a greater projection on the water side because of the extra carrying capacity on that side. To stay within the bounds of the structure’s capacity, extremely light construction was required. As a result, Infra+ floors with integrated installations have been applied and concrete core activation is installed in the flooring. All in all a significant innovation. The integration of installations ensured limited height and thus reduced wind loads.
The new structure’s main carrying structure has a fire resistant coating and meets 90 minute fire grading regulations. Although the Infra+ floor has undergone fire tests, additional measures have been taken to account for the risks that come with the wooden floor screed. LBP Sight has proved with Fire Safety Model ‘OZone’ that the average temperature during a fire will not exceed 450 degrees Celsius. During a fire, the façade glass will give in after several minutes, greatly reducing the temperature increase as would be expected based on a common fire temperature curve. This increases the wooden floor’s burn-through time significantly, preventing the steel profiles from getting hotter than the room’s temperature. Based on Aronsohn calculations, it was shown that the floor plates’ steel joists themselves did not require fire resistant coating. Only the Top Hat Q beams on which the plate girders rest required coating.
Awards: Green buildings & Special Jury Award, Mipim 2008, Cannes (Fr), 13-3-2008, (Dutch) National Steel prize 2008.