Timmerhuis Building: ArcelorMittal structural steels contribute to BREEAM Excellent rating

Detailed information

Past meets present

In the early 1950s, Rotterdam began a programme to reconstruct the city centre, much of which had been destroyed during World War II. One of the first buildings to be completed was the Timmerhuis on a site near the town hall. The Timmerhuis included offices and shops and quickly became an icon of Rotterdam’s centre.

After more than 50 years of use, the Timmerhuis fell into disrepair. Rotterdam City Council decided to demolish the existing structure and build a new Timmerhuis that was in keeping with the city’s philosophy of creating a sustainable ‘living city’.

Architectural design by OMA

To realise this 'living city' philosophy, the architectural office OMA (Office for Metropolitan Architecture) was selected.

This new building for the city hall needed to accommodate municipal services, offices, and residential units, so OMA conceived a modular building with repeated units gradually set back from the street as they rise into two irregular peaks. The building's composition of smaller cells creates an impressive, complex form when viewed from Coolsingel, one of Rotterdam's main arteries, and allows for subtlety and adaptability as the new building meets the Stadstimmerhuis (a municipal building from 1953), which surrounds it on two sides.

The Timmerhuis's innovative structural system generates maximum efficiency and versatility both in construction and in program: units can adapt to either office space or residential parameters as desired. Green terraces on higher levels provide the possibility of an apartment with a garden in the heart of urban Rotterdam. On the street level, the structure allows for generous open space, with modules overhanging rather than encroaching into an interstitial area, encouraging an active and open engagement between the Timmerhuis and the city.

Steel by ArcelorMittal

The new Timmerhuis earned the nickname ‘The Cloud’ thanks to its unique steel skeleton, which allowed the architects to design a building that appears to be floating above the open space at ground floor level.

Construction was carried out by CSM Steel Structures – a renowned builder of high-quality steel buildings. ArcelorMittal was the sole supplier of the steel quarto plates and profiles which formed the structure of the building and allowed for quick completion.

Work on the building’s steel skeleton began at the end of November 2013 and met the goal of delivering the completed Timmerhuis in 2015.

Koen Winters, manager of CSM’s purchasing department, explained the advantages of using ArcelorMittal steel in the new Timmerhuis: “The plates from ArcelorMittal have low equivalent carbon content (CEV). This increases our efficiency as we need less heating in the shop. We can also order what we need directly from the factory, so we have the exact sizes and number of profiles or plates that we need for the project. That results in less waste and reduces the number of penetration welds required.”

BREEAM Excellent rating and a sustainable design

The design brief called for the Timmerhuis to be “the most sustainable building in the Netherlands.” As such, the atriums of the building function like lungs holding warmth in the summer months and cold in the winter months and then releasing this energy as required. In addition, a triple glazed curtain wall facade with high-tech insulation ensures exceptional energy efficiency.

The sustainable design led to the building receiving an ‘Excellent’ rating under the internationally recognised BREEAM methodology (Building Research Establishment Environmental Assessment Method). BREEAM is one of the most important and widely used systems to measure the sustainability characteristics of modern buildings.

Factors influencing the ‘Excellent’ score include the use of steel (which can be completely recycled at the end of the building’s life) and the fact that the steel travelled by sea from our mill in Gijón, Spain to Vlissingen in the Netherlands. “ArcelorMittal is also ISO 14001 certified,” explains Winters. “This was an added advantage in the allocation of this order.”

A high level of logistical service

“ArcelorMittal [was] able to provide the customer with a high level of logistical service,” noted Nicolas Dujardin, Account Manager for ArcelorMittal Europe - Flat Products. “This was very challenging due to the distance between the mill and the customer. The success of the project has only been possible thanks to the open communication between the customer, our local agency, and the customer service team at the mill.”

Unique plates require unique service

Three main structural steel grades were used in the plates for the Timmerhuis: S355J0+N, S355J2+N, and S355K2+N. These steels have a guaranteed minimum yield and tensile strength. They are suitable for most construction applications.

Many of the plates were ordered with specific Z-tests (Z15, Z25, Z35) and a US-test (S1E1) to establish the through thickness ductility of the steel. This was necessary because the main structure consists of ‘Vierendeel’ beams with full penetration welds between columns and beams.

Almost every plate in the new Timmerhuis was tailor made to specific dimensions. This enabled the client to minimise waste as each plate had its own unique place in the construction.

“All of the plates for the Timmerhuis [were] delivered to the customer and they are very satisfied with our service,” noted Dujardin. “I would like to thank everybody who has made this project a success. ArcelorMittal was able to provide outstanding service, comparable with that of a local mill, but from a distance. Because ArcelorMittal is able to offer this level of service, we will continue to capture interesting steel construction projects in Western Europe.”

Timmerhuis in numbers

The budget for the new Timmerhuis was approximately €100 million. ArcelorMittal supplied heavy plates and 2000 tonnes of sections to the project.

Building height: 60 m; 14 storeys in the north tower and 11 storeys in the south tower

The completed 0.5-hectare Timmerhuis site (including the old Stadstimmerhuis) provides:
•    84 apartments covering 12 000 m² with a mix of large and small living spaces
•    office space of 25 400 m² in the existing and new part of the building including facilities for the Rotterdam City Administration
•    120 underground parking places covering 3900 m²
•    exhibition space covering 1630 m²
•    retail space covering 2070 m²