Insite in Birmingham City: Structural engineering for LPS Tower Blocks

Birmingham City LPS Tower Blocks

At Curtins, our Insite approach has been developed to support building owners, landlords, and other Accountable Persons in meeting requirements for the Building Safety Act. Insite establishes an evidence-based understanding of a building's structural inherencies and identifies where further investigation may be required.

By following our structured assessment process, we help clients move from uncertainty to a clear, proportionate, and demonstrably managed safety strategy. This provides confidence that building safety risks have been properly considered and supports the continued safe occupation and future use of residential buildings. We have successfully applied this approach across a wide range of higher-risk residential buildings, advising landlords and other Accountable Persons on the structural risks associated with their property portfolios; supporting their compliance with the Building Safety Act.

Insite in action on Birmingham LPS Blocks

Curtins' Liverpool and Birmingham offices are working with Equans and Birmingham City Council to deliver structural engineering services for the refurbishment of Large Panel System (LPS) construction buildings, specifically constructed using the Bison Wall frame system. Built using post-war prefabrication techniques, LPS buildings are known to present inherent structural risks, particularly relating to disproportionate collapse. 

To address these challenges, Curtins applied our Insite approach. Acting as both a framework for Building Safety Case reporting and a guide through the evolving regulatory landscape, Insite establishes an evidence-based understanding of a building’s structural behaviour and identifies where further investigation is required.

Structural risk assessments using digital techniques

Curtins implemented a structured assessment process, beginning with a comprehensive desk-top review of available records and archive information, confirming the buildings’ LPS typology as Bison Wall frame construction.

This initial phase was enhanced through the use of digital survey techniques, including drone-based scanning and aerial data capture, to obtain accurate and up-to-date information on the external fabric and overall condition of the buildings. The survey outputs were integrated into digital models to support a preliminary structural risk assessment (pSRA), which was followed by a targeted intrusive investigation programme to determine the as-built structural details and current condition. The findings enabled completion of a detailed structural risk assessment (dSRA), providing a clear understanding of the buildings’ structural risks.

All survey, investigation, and design data was managed within a Common Data Environment (CDE) using Autodesk collaboration tools, including Autodesk Construction Cloud. This facilitated real-time coordination between design team members, improved version control, and ensured a consistent, transparent flow of information between stakeholders throughout the project lifecycle.

Mitigating risks of disproportional collapse

Based on this evidence-led approach, proposals were developed to enhance structural performance, including mitigating the risk of disproportionate collapse and delivering wider general improvements to the buildings.

A structural exoskeleton frame, approved by BRE, was installed to provide alternative load paths and strengthen connections between floors and walls. This was complemented by the introduction of internal tying, installation of panel restraint brackets, grouting to improve load transfer and connection integrity, and localised strengthening of floor panels to enhance overall robustness and structural continuity. These measures were integrated with the design of a new external insulating envelope.

Delivering a prioritised plan of actions

Our team delivered structural engineering services across RIBA Work Stages 1–7, supporting the development and delivery of a comprehensive refurbishment strategy. The outcome equipped the client with a prioritised plan of actions, supporting ongoing safety, asset management, and compliance with current building safety legislation.

Overall, Insite enabled a transition from uncertainty to a clearly defined, proportionate, and demonstrably managed safety strategy, providing confidence that structural risks have been appropriately identified and mitigated, and supporting the continued safe occupation and future use of the buildings.