Blackfriars bridge temporary cofferdam analysis

THE BRIEF

Robert West was appointed to provide the detail design of a temporary cofferdam at Blackfriars to enable dewatering of a section of the foreshore for construction of a shaft to the new Thames Tideway tunnel.

VALUE-ADDED SOLUTION

A challenging aspect of the design was to model and understand the deflections and stresses in the structure due to the varying stiffness of a combi wall section, the twin wall cofferdam and the existing river wall.

The analysis was undertaken using an FEM analysis; horizontal membrane forces and bending moments were also modelled.  In addition, we investigated the possibility of global or local buckling through a eigenvalue stability analysis.

FINAL OUTCOMES

The analysis allowed us to optimise the design solution and improve buildability.