A9 BaHo: Bauer installs 12,000 anchor piles up to 45 meters deep

The originally German firm BAUER from Mijdrecht is helping to widen and deepen the A9 near Amstelveen. Together with De Vries Titan, it is forming a foundation combination. Their task? Installing no fewer than 12,000 anchor piles for the deepened freeway at the level of
of Amstelveen. This is the largest anchor pile work for a Dutch infrastructure project.

Commissioned by Rijkswaterstaat, VeenIX is widening and deepening the A9 between Badhoevedorp and Holendrecht. Near Amstelveen, 1.6 kilometers of the highway will be sunken with three covers: at the Oude Dorp, the Stadshart and at the level of the Bovenlandpad. Here, the A9 will soon be almost 11 meters below sea level. "Without load-bearing anchor piles, the sunken basin in which the road will be located would float," explains Eelco van der Velde, director BAUER Funderingstechniek. BAUER Funderingstechniek B.V., with offices in Mijdrecht, is the Dutch branch of the world-renowned German BAUER Group. It is an expert in specialized foundation technology, such as grout anchors, anchor piles and soilmix techniques. "We install long anchor piles that we drill into the ground up to about 50 meters below NAP. This totals 12,000 piles. We do this, among other things, with the first KLEMM brand electric anchor drilling machine. The anchor piles are piles formed in the ground. First, we drill a hole up to 50 meters deep with a diameter of 250 mm. Then we place a threaded steel rod of the brand SAS and fill the hole with grout. In the Netherlands, we are the only contractor who obtain SAS material directly from the factory. The advantage of this is that we are flexible and can deliver quickly. After curing, these piles can handle heavy forces and keep the sunken highway firmly in place." Installation of the 12,000 anchor piles will be done in two phases. The first phase, the north side of the sunken box will be completed by BAUER this spring. Next year, construction of the south side is expected to begin.

Pole Optimization

VeenIX was able to carry out pile optimization based on the test piles from BAUER and DVT, one of BAUER's strengths. "Through pile trials and testing, we optimized the diameter and size of the piles. In this case, VeenIX was able to shorten the piles because they had more shaft friction. This is beneficial for the price, but also for the environment and lead time."

German discipline and Dutch flexibility
The installation of the 12,000 anchor piles near Amstelveen is the largest drilled anchor pile work in the Netherlands to date. That makes the project extra special for Van der Velde. "We haven't had this going on before. A lot of highly motivated, mostly German, colleagues and machines are working on it. It also requires good coordination with all subcontractors. The planning is as we call it, penciled in. It requires flexibility and creativity to respond quickly to the situation, always with a high safety awareness. But that suits us well. This is where our German discipline, quality and labor morale, together with Dutch flexibility, come into their own."