How AIM’s SAVI structures planning model enables smarter investment for bridges, gantries and retaining walls
Client:
UK Local Authorities (multiple)
Location:
United Kingdom
Consulting Partner:
Probit (direct configuration and support)
Asset Types:
Bridges, culverts, gantries, retaining walls
AIM Version Used:
AIM 4.0 with SAVI module
Key Outcome:
Whole-life modelling and investment planning for structures, replacing spreadsheets with a transparent, scalable platform
Across the UK, local authorities and highway operators are responsible for managing thousands of structural assets, including bridges, retaining walls, culverts, gantries and other above-ground infrastructure.
These assets are vital to public safety, economic resilience and long-term mobility. However, many authorities face challenges in understanding structural condition, prioritising investment, and justifying spend in line with national guidance such as the CIPFA (Chartered Institute of Public Finance and Accountancy) Code and HAMFIG (Highways Asset Management Financial Information Group) frameworks.
The Structures Asset Valuation and Investment (SAVI) model, delivered through AIM, gives them the capability to do just that, within a transparent, auditable and whole-life value approach.
The challenge
Traditional approaches to structures investment have often relied on fragmented spreadsheets, legacy scoring systems or time-consuming engineering reviews.
Authorities needed a better way to make consistent, risk-based decisions across large portfolios of bridges and retaining structures, many of which are ageing, load-sensitive, or critical to service continuity.
The challenge was not just to track condition, but to forecast deterioration, evaluate options, and demonstrate whole-life value in line with UK guidance.
Without the right tools, authorities risked either over-investing in non-critical assets, or failing to act in time to avoid costly failures.
Who worked on this project?
Probit developed the SAVI model in collaboration with a consortium of local authorities and asset management experts.
The methodology was designed to provide a UK-specific, spreadsheet-free model for planning structures investment, aligned with the HMEP/UKRLG guidance. SAVI was then implemented directly into the AIM platform, allowing for seamless integration with other asset classes and full scenario planning capability.
Probit provides configuration, support and training directly to local authorities adopting SAVI, including clients such as Hertfordshire County Council, who now use AIM and SAVI as their primary structures planning tool.
How was AIM used?
SAVI was fully embedded into AIM’s Risk Map module, enabling structures owners to plan investment over long-term horizons. Key features included:
- Asset-level condition scoring, using consistent inputs for elements like deck, bearings, and abutments
- Deterioration modelling, projecting condition over 120 years based on asset type and materials
- Performance assessment, using traffic impact, strategic value and safety weightings
- Optimisation engine, testing maintenance and renewal strategies under cost, risk and performance constraints
- Valuation reporting, producing figures aligned with CIPFA/HAMFIG requirements
- Scenario testing, exploring effects of budget cuts, deferred works, or risk-based prioritisation
All modelling is fully transparent and editable by the client, with no coding required.
The results
SAVI has helped local authorities achieve better strategic control over their structures programmes:
- Faster scenario modelling, replacing complex spreadsheets with rapid, repeatable analysis
- Improved investment targeting, focusing on structures with greatest performance impact or risk
- Stronger valuation confidence, with outputs aligned to national frameworks and audit expectations
- Greater internal adoption, with web-based tools that non-specialists can understand and use
- Integration with highways planning, using the same platform to model both roads and structures
Authorities can now plan investment over 5, 15 or even 120 years with greater clarity and defensibility
Dr Phil Jonkergouw
Managing Director, Probit
Technical insight
The SAVI model, as implemented in AIM, combines long-horizon deterioration modelling with performance-weighted valuation.
Each structure is modelled as a series of components (e.g. deck, support, parapet), each with its own condition profile and deterioration curve. These feed into a strategic risk profile that can be visualised, optimised and stress-tested across multiple scenarios.
The platform supports maintenance interventions, reactive repairs, and full renewal, with outputs covering condition scores, asset value, and performance impact.
By integrating SAVI with other AIM modules, authorities can plan and compare investments across the full asset base.
What comes next for AIM in the structures field?
Local authorities are continuing to roll out SAVI through AIM, both as a standalone planning tool and as part of wider multi-asset modelling.
Future developments may include climate resilience scoring, sustainability metrics, and automated survey data ingestion.
As digital maturity grows across the sector, SAVI is expected to play a central role in long-term investment strategy, business case development, and reporting to national government bodies.
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