Due to the government restrictions in the Covid-19 pandemic, all construction work was suspended on site until the beginning of June.
During June, the piling subcontractor recommenced the main civil piling works completing this by September and the final structural integrity tests finished during October. This operation took one month less than anticipated.
Equipment deliveries started to arrive during September and are being stored locally to the site until the civil works are advanced sufficiently to start installation of the equipment.
ACCIONA´s main civil structures subcontractor mobilised on site during September and started to prepare for the construction of the concrete floor slabs which are required to install the boiler and other equipment. The slabs are constructed on top of the piles and together will be strong enough to support the weight of the mechanical equipment. The construction of the boiler slab started during October and is expected to be complete by the end of November.
At the same time, works have commenced on the installation of the waste bunker building walls which are constructed entirely from reinforced concrete.
The process used for constructing the waste bunker is called ´slipform´. This operation involves the placing of concrete into a slim mould called a shutter that is continually being raised by hydraulic jacks, leaving the formed concrete wall below it. At the end of the operation, the shutter will be 27m in the air on top of the concrete wall which it has been used to create. Speed is the main advantage of this system, reducing the time taken to construct the walls from several months using traditional shuttering methods to just a couple of weeks. The whole operation will involve more than 100 people working two shifts over a period of 12 days to complete the waste bunker structure. An example of the slipform process can be viewed below;