At our Blackfriars Bridge Foreshore site, we are working in a cofferdam, a dry working area built into the river, which we have split into two sections.
In the eastern section of our cofferdam, we constructed a 3,700 tonne concrete culvert, which will intercept sewage and redirect it towards the new super sewer. Once the culvert was in full shape, we carefully flooded this section of the cofferdam and floated it 100m-along the river into its final position below Blackfriars Bridge. Following the successful float-out of the culvert, we re-sealed the cofferdam and carefully drained the cofferdam to form a dry working area. We have now commenced the concrete works to build the new Combined Sewer Outfall (CSO) concrete structures.
In addition to the works being undertaken within the site, there is a team that are undertaking works within the existing Low Level 1 sewer; the team are preparing the sewer by removing the silt that has accumulated within it through the years. The clean-out of the silt will enable the installation of a liner within the sewer in preparation for the future diversion of the sewer into the Tideway CSO structures.
We are currently excavating our 53m-deep shaft within the western section of our cofferdam, a dry working area built into the river. We had previously excavated our shaft to 25m deep before pausing excavation as our tunnel boring machine, Ursula, passed directly below.
To complete this work, we will be using the spray concrete lining method. As each section of the shaft is excavated, we will spray concrete onto exposed ground to build the walls of the shaft. All materials excavated from the shaft will be removed from site by barge.
If you have any questions about this or our site at Blackfriars Bridge Foreshore please get in touch with our helpdesk on 08000 30 80 80 or [email protected]