Extending the life of existing infrastructure: structural rehabilitation conference review

Author: Matthew Los, WSP

Date published

11 January 2023

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Extending the life of existing infrastructure: structural rehabilitation conference review

Date published

Matthew Los, WSP

Date published

11 January 2023


Matthew Los, WSP

The Structural rehabilitation conference 2022 discussed challenges and opportunities presented in the asset management and infrastructure of bridges.

‘How do we make the most of our carbon investments?’. Lila Tachtsi, Asset Management Director at National Highways, launched the 2022 'Structural rehabilitation conference' with an insightful keynote speech on the challenges and opportunities faced by private and public asset owners, along with the strategic direction that National Highways are taking toward enhancing, maintaining, and operating the road network in England.

There has been a clear shift in the role of structural rehabilitation in the management of ageing infrastructure, along with its contribution toward achieving organisational, national, and global carbon reductions. As Lila discussed, the onus is on asset owners to ‘renew more and build less’, whilst maximising the value derived from existing assets.

On 8 December 2022, 60 participants gathered at the IStructE Headquarters in London, with a further 40 participants from all over the world joining remotely, to attend the daylong event chaired by WSP’s head of profession, Mungo Stacy.

The conference explored current challenges and opportunities in the asset management sector through three sessions, which covered inspection, testing, and monitoring; assessment and diagnostics; and strengthening. Attendees were also involved in a panel discussion on the future of rehabilitation.


Session 1: Inspection, testing and monitoring

In the first session, attendees gained insight into how bogie-mounted high-resolution photography and laser scanners have been implemented in condition surveys of London Underground tunnels. This was followed by an overview of the various strategies available for the testing and monitoring of different types of bridges.
Leveraging such technologies to extract the most value from inspections provides a more detailed understanding and consideration of the value of the information we capture during an inspection adds to investigations.

Julia Bush, Senior Research Scientist at Mind Foundry, presented her work on using digital technology and machine learning to extract more value from bridge inspections.

It is apparent that although some inspection activities are being digitalised in the industry, many of the limitations from conventional ‘pen on paper’ data capture have been inherited, such as inefficiencies in locating, recording, and overlaying defect information. The possible benefits future technologies could bring to inspection were discussed, including the potential to reduce subjectivity and conservatism in manual condition scoring, given the trend for human inspectors to overcompensate for uncertainty.

Julia reiterated the need for a more agile data structure going forward and expanded on the role that artificial intelligence and reinforcement learning could play in unlocking efficiencies in the capture and processing of inspection data. For example, providing automated suggestions of similar defects on comparable structures in an asset network. This was followed by a discussion on how technology could support improvements in structural health monitoring, defect tracking and assessing change in condition.

Session 2: Assessment and diagnostics

The second session explored the role that sophisticated assessment techniques, including advanced finite element analysis and detailed risk-based assessments, have in justifying the continued use, or change of use, of existing infrastructure.

The presentations ranged from how advanced assessment techniques were used in the assessment of existing railway gantries on the Elizabeth line; applied in the investigation into the load-carrying capacity of a fire-damaged post-tensioned bridge; and demonstrated positive assessment outcomes for various types and scale of steel bridges.

The need for a deeper understanding of structural behaviour to gain greater insight into the capability of existing infrastructure was clear. This was followed with the recognition that ‘all models are wrong… (but can be useful)’ in assisting these investigations and enabling a more detailed understanding of how assets behave and may be predicted to behave, which would increase the opportunity for asset owners to prolong the lifespan of their assets. The positive assessment outcomes presented illustrated the paradox that sometimes the best outcome when working with existing infrastructure is the do-nothing option!

The session demonstrated some of the outstanding ingenuity which exists in the sector and some clear examples of knowledgeable assessment engineers going beyond the codes and reverting to first principles to extract better results for structural assets.


Session 3: Strengthening

The third session explored strengthening, as even when a robust source of inspection data is available and sophisticated techniques have been utilised to assess the current load-carrying capacity of a structure, intervention may still be required. Strengthening or refurbishment can be the most appropriate option for asset owners to arrest further deterioration of an asset, bring it up to capacity and prolong its lifespan.

Attendees found out how alternative strengthening solutions were used in the management of existing cast iron assets in the London Underground; the rehabilitation of three post-tensioned concrete box girder bridges dating from the 1970s; as well as the ongoing Hammersmith Bridge stabilisation works. All the presentations exhibited ingenuity in the development of permanent strengthening solutions, as well as in the temporary works to implement these solutions.

The need for collaboration across the supply chain to enable the delivery of optimal strengthening works was identified and some of the procurement challenges were discussed, including the point that clients are often provided with what is specified, and not what is needed to extract the most value from an asset. This highlighted the challenge put on assessment engineers to demonstrate the added value of alternative solutions over a lower capital cost option and to work closely with clients to identify the costs and benefits in the earlier stages of rehabilitation schemes.

Session 4: Panel discussion

The conference concluded with an interactive discussion between the attendees and a board of distinguished panellists. It was clear that much of the complexity around the challenges faced in asset management are derived from the need to keep up with the pace of change, be this the rate of deterioration of our infrastructure, pressures to deliver more robust solutions within tighter budget constraints or even changes in the climate and traffic.

This highlighted the need to transition away from the traditional ‘reactive’ decision-making model to a more proactive, performance-based approach to asset management, aligned with principles of strategic planning, asset stewardship, stakeholder collaboration and value engineering.

The need to improve knowledge share across the sector was reinforced, along with the need to promote successful rehabilitation schemes to help address the apparent disconnect in the industry between the perceived attractiveness of working in the design of new structures rather than working in the field of existing assets.

A clear takeaway from the event was the intellectual and practical challenges that come from working with existing structures and the need for attracting and developing skilled assessment engineers to design and deliver rehabilitation schemes going forward, with the push for more sustainable asset management, and to meet the net-zero commitments across the industry. With the drive to digitalise our methods of inspection, and the implementation of technologies to meet industry needs, the event demonstrated that it is indeed an exciting time to be in the field of asset management!