In May and June, OpenIJ will be very busy with the sinking operation of the inner head (number 1 in the picture). Furthermore, work will also be carried out on the local control buildings (numbers 2 in the picture), on the connection between the lock gate chamber and the lock sill of the outer head (number 3 in the picture); also, construction activities will be carried out near the Middensluiseiland (numbers 4 in the picture).
Sinking operation of the lock gate chamber for the inner head
Two lock gates are to be installed into the inner lock head chamber (number 1 in the picture), namely the gate on the canal side (the inner gate) and the spare lock gate. The sinking operation of the lock gate chamber for the inner head will be done in the same way as last year's sinking operation of the lock gate chamber for the outer head, except that the inner lock head chamber is much larger, namely 80 meters long, 55 meters wide and 25 meters high. In the coming months, the lock gate chamber will be sunk into the ground centimetre by centimetre. This will be done by dredging away the sand underneath the structure, using remote-controlled robot arms. Dredging is fully automatically and monitored 24 hours a day and 7 days a week, using CCTV cameras, sensors and measuring instruments installed under the floor of the lock gate chamber.
Local control buildings
Concrete pouring operations for the basement floors and basement walls of the local control buildings East and West have been completed recently and OpenIJ is now starting with the construction of the ground floors and walls of these buildings (numbers 2 in the picture). Each lock gate has its own local control building from which the respective gate can be operated. Local control, if necessary, can be achieved independently of the Lock Operation Centre (SOC).
Between the lock gate chamber and the lock sill of the outer head a relatively narrow cofferdam has been constructed, the so-called 'letterbox cofferdam' (number 3 in the picture). The letterbox cofferdam connects the enormous lock gate chamber to the lock sill of the outer head and owes its name to its relatively narrow size, namely 4 metres wide, 27 metres long and as much as 25 metres deep. Excavating this cofferdam is no easy task and that is why OpenIJ deploys a special hydraulic excavator. This type of excavator has a telescopic arm that makes it possible to excavate sand from great depths and bring it to the surface at lightning speed.
Dividing wall and guard wall
The dividing wall is situated on the Middensluiseiland next to the future approach channel to the new sea lock. During the next few months, reinforcement steel will be installed and concrete will be poured for the construction of the dividing wall and the guard wall (numbers 4 in the picture). Anchors will be installed to various parts of the construction that have already been finished. These anchors are necessary to ensure the structural strength of the dividing wall and the guard wall.