Excavation pits & pile foundations

FRANKI places diaphragm walls next to Chinese border

The high fences, which feature cameras in each corner, make it impossible to see inside. And, in the future, it will no longer be possible to park within thirty metres of the location. Welcome to the Eurojust construction site in The Hague, where Franki Grundbau is literally establishing the foundations for crime prevention in Europe.

It is quiet on the stately Johan de Wittlaan. The embassies of Sweden, South Korea and China all look as they have been abandoned. These three buildings are adjacent to a huge construction pit, where 50,000 m3 of sand has been excavated. This is where Heijmans is constructing the foundations of a new complex for Eurojust, the judicial organisation where 28 countries unite in their fight against serious cross-border crime. The new-build complex in The Hague must be handed over at the end of 2016. And the bad news for European crime syndicates: the building will have no fewer than thirteen high-rise storeys, five low-rise storeys and have a total surface area of 18,500 m2. A three-storey underground car park will also be located next to the complex.

FRANKI places diaphragm walls next to Chinese border

Tjeerd van der Spaa, manager Heijmans Infra, has been involved in the project for several months. He works in one of the adjacent buildings, where the Patents Office was once housed. It is a challenging project for a variety of reasons, he says. “There are strict confidentiality protocols. And, if you do not sign the VOG (certificate of good conduct), which gives you the ‘green light‘ to work in the field of justice, there is no way you can work here. That‘s understandable, because not everyone is pleased with the work carried out by Eurojust.”

The location is another complicating factor. The construction pit is located in an inner city area featuring embassies, consulates and the Yugoslavia tribunal. The client, the Central Government Real Estate Agency, wants Heijmans to keep construction-related nuisance to a minimum. “Noise levels at the site cannot exceed 65 dB. And this had an impact on which foundation techniques could be implemented. Therefore, we decided to contact Hamburg-based Franki Grundbau during the tender phase. The company is a subsidiary of Heijmans and has a solid reputation when it comes to heavy-duty foundation structures. They can deal with jobs for which Heijmans does not possess the required equipment.”

In the end, 28-metre diaphragm walls came out as the best and least problematic geo-technical solution. The German team from Franki started its activities in The Hague in November 2014. Within the space of four months, they had poured 49 concrete wall panels measuring between 5.3 and 9 metres in width. Once finished, the edges of the waterproof construction foundation measured
a whopping 400 metres.

The expertise and know-how offered by VIT, which is part of Franki, was essential. The company, which specialises in anchoring and injection techniques, supplied 159 grout anchors measuring between 20 and 25 metres in length. These anchors add extra stability to diaphragm walls and are generally placed at an angle of 25 to 45 degrees. “However, in this project, VIT placed the anchors at an angle of 60 degrees. It was the only way to avoid touching the Chinese territory of the adjacent embassy.”

Tjeerd thoroughly enjoyed working with the German team. “They work independently and know what they are doing. In addition, they are very gründlich (thorough).” He also praises the friendliness of his German colleagues.

Familiar territory
The Netherlands is becoming familiar territory to Franki, which has been operating under Heijmans since 2002. That's the opinion of project leader Jens Loeffler, who works at the Franki division in Düsseldorf. “In the past two years, we have completed four large projects in collaboration with Heijmans: the ‘VleuGel’ multi-layer rail junction near Utrecht; six kilometres submerged motorway (A4) at Delft-Schiedam; the underground St.-Jan car park in Den Bosch and now the Eurojust in The Hague.”

There are short lines of communication with management in the Netherlands, he confirms. Franki is informed about large infrastructure projects very early in the tender process. “I think Heijmans Netherlands has great trust in our capabilities. Even though we are a small company (300 employees), we have a lot of expertise and know-how.”

During the Eurojust project, Jens initially had to stay two or three days a week in the Netherlands. But the Franki team was quickly able to operate autonomously. “It is a very efficient team, which found its rhythm without much supervision. In terms of soil, the Netherlands has a relatively simple geological structure, which features sand, clay and mud. In Germany, you tend to encounter rock, granite clay stone and gravel in many locations.”

“Verbesserung” is one of the principles championed by management at Franki. Technical innovations have allowed us to be even more effective in finding solutions for the most complicated issues. However, we also focus on safety and costs of failure. Jens believes collaboration with Heijmans is likely to increase in the coming years. “This is only the beginning.” Language barriers? They're rarely encountered, despite all the grammatical rules. Aus, bei mit, nach, seit, von zu? For get them all. The only thing that counts in specialised civil engineering is: Zusammenarbeit mit Franki.

More information
Jens Loeffler
Projectmanager Franki Grundbau

Jens Löffler Projektmanager FRANKI Grundbau

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