Remodelling of 20 Finsbury Circus presented a unique challenge due to the anticipated significant load redistribution to its foundations, potentially causing ground movement. While such scenarios are typically manageable, the complexity heightened as the site was situated adjacent to a delicate 1874 cut-and-cover tunnel, a vital component of the world’s oldest underground railway. Given the historical significance of the tunnel and its crucial role in transportation, an in-depth study was imperative to ensure the preservation of this heritage structure and the uninterrupted operation of the essential transport link.

In response to this challenge, a meticulous and detailed 3D Finite Element Analysis (FEA) model was devised, encompassing the building sub-structure and the surrounding ground. This advanced modelling approach facilitated a comprehensive prediction of the potential effects of the 1874 cut-and-cover tunnel due to the building remodelling. The analysis revealed that the proposed changes would not result in any adverse impacts on the historic structure and approval for the redevelopment was granted.

Highlights

• Study of site investigation and records for the cut and cover tunnel asset.

• 3D FEA model of building sub-structure and surrounding ground.

• Simulation of existing building load and the load redistribution associated with the remodelling.

• Prediction of strains on old railway tunnel within acceptable limits.

• Planning approval granted.