Diving in Driebergen
Two weeks ago, we told you that you could see a construction pit filled with water in the Driebergen-Zeist station area. This water is needed in order to have enough water pressure to keep the sheet piling up straight and to prevent it from collapsing. The construction pit will be the southern square of the new station area.
A team of professional divers is currently preparing this enormous bathtub for the pouring of underwater concrete. This is not something one encounters everyday on a construction site, but for the divers it is business as usual. Wim Janssen, the head of the diving team explained: ‘We do this every day. We are also working on the new sea lock in IJmuiden. And we did all the diving operations when the Costa Concordia was salvaged in Italy.’
Chiselling and welding
‘The Driebergen job is a fairly small, but long-term job. We'll be working here for a couple of months,’ said Wim. ‘We're removing the grout, a cement mixture, from the sheet piling. It's sometimes stuck on so hard that we need to chisel it off. The sheet piling should be very clean so as to enable the right adhesion for the underwater concrete. Later on, we'll also be welding under water to apply concrete anchors so as to make the concrete wall even more robust. And when the concrete is hard enough, we can pump the construction pit dry.'