The Challenge

The redevelopment required the removal of major sections of the existing structure, including the west stair core and central lightwell, while preserving critical elements of the existing building and maintaining overall structural stability throughout construction.

Key challenges included:

• Retention of the existing façade and supporting structure.
• Extensive demolition within a live urban environment.
• Complex party wall interfaces with multiple neighbouring properties.
• Installation of new structural steelwork within existing masonry walls.
• Maintaining diaphragm action and lateral stability during phased demolition.
• Delivering craneage and logistics solutions on a highly constrained central London site.
• Creating large new atrium and lift shaft openings through the existing structure.

Our Solution

CBE developed a comprehensive construction engineering strategy that enabled the works to be undertaken safely and efficiently while minimising disruption to the surrounding structures.

A detailed phased construction sequence was established, allowing demolition and new steelwork installation to progress while maintaining structural stability at every stage.

Our engineering solutions included:

• Temporary works strategies for phased demolition of the west core and central atrium.
• Stability assessments of retained masonry façades and party walls.
• Temporary support and installation methodologies for new frames within existing masonry walls.
• Construction sequencing to maintain load paths and lateral stability.
• Temporary support systems for floor cut-backs and new lift shaft construction.
• Detailed logistics and crane installation engineering.

Innovative Crane Engineering

One of the most significant engineering challenges involved the installation of a tower crane within the existing structure.

Due to programme constraints, the permanent columns beneath the crane location could not be strengthened before crane erection. CBE developed an alternative temporary support arrangement using spreader beams and twin Megashor towers at each crane support location, allowing the crane to be installed while permanent strengthening works proceeded below.

The solution enabled:

• Early crane installation.
• Continued access for column strengthening works.
• Efficient transfer of loads from the temporary system into the completed permanent structure.
• Reduced programme risk on a constrained city-centre site.

Managing Stability Through Construction

The project relied heavily on understanding the relationship between the existing and proposed stability systems.

CBE reviewed the existing masonry walls, retained façades and proposed structural interventions to develop a sequence that preserved structural integrity throughout demolition and reconstruction. Particular attention was given to maintaining diaphragm action during floor removals and ensuring adequate restraint to retained walls and columns during temporary conditions.

The resulting strategy allowed major structural alterations to be carried out while avoiding extensive façade retention measures and minimising temporary works requirements wherever possible.