Huge milestone for Thames Tideway project

8 April 2024

London’s new Supersewer is making fantastic progress, with all underground work now completed 9 years after the first ground was broken.  Hewson was contracted to redesign the upper portion of the Carnwath Road shaft.  25m in diameter and 42m deep, the shaft was the launching site for TBM Rachel, and her seven kilometre journey from Fulham to Acton.  

The shaft also forms the junction between three tunnels and features a mezzanine plant room floor below the roof slab.  Our value engineering exercise enabled the required elements to be constructed ‘top down’ – eliminating the need for 20,000m³ of falsework volume and allowing work at the top and bottom of the shaft to take place simultaneously.