Oxford heritage science facilities to support research into historic cast-iron bridge

Specialist heritage science facilities at the University of Oxford will be used to investigate a historic cast-iron bridge as part of a project supported by the first RICHeS Access Fund.

The project, Informing the Conservation of a Heritage Bridge through Multi-Scale Characterisation of Historic Cast Iron, is co-led by Dr Kasun Kariyawasam and Dr John Bennets of WSP Ltd and Professor Sinan Acikgoz. It is one of 43 projects supported through the first Research Infrastructure for Conservation and Heritage Science (RICHeS) Access Fund, which is providing more than £500,000 to enable organisations across the UK to access specialist heritage science facilities and expertise. The work will also receive match funding from the asset owner.

The project will use the Oxford Collaboration in Heritage Science Research and Engagement (OCHRE), one of the heritage science investments established through the wider RICHeS programme. The University of Oxford is the project's service provider.

The research focuses on the Grade 1 listed Old Wye Bridge in Chepstow, recognised as the world's largest pre-1830 cast-iron road bridge. Spanning the border between England and Wales, the 200-year-old structure features a rare arch lattice design. The research will use advanced scientific analysis to characterise historic cast iron from the bridge. Understanding the material's properties and condition will provide evidence to inform decisions about its conservation and future management.

The work builds on Oxford's expertise in characterising to historic construction materials. The behaviour of these materials significantly differs from modern materials and characterising them requires developing customised testing techniques due to limited availability of samples and their distinct mechanical behaviour. OCHRE offers the specialist facilities required to do this.

Professor Sinan Acikgoz is a Co-Investigator on the OCHRE project and will lead the characterisation work that will be carried out as a part of this project. Researchers will perform a comprehensive investigation on small samples retrieved from the bridge. First, using optical and electron microscopy alongside X-ray diffraction analysis, they will examine the metal's microscopic makeup, chemical composition, and rust or corrosion products to determine how it was originally made and how it has aged. Next, they will conduct 3D X-ray scanning (micro-CT)—similar to medical CT scans—to look deep inside the metal, mapping out hidden internal defects, voids, and crack distributions. Finally, the team will perform strength and fatigue tests, stretching and compressing the samples— in some cases while conducting CT scans —to observe how internal flaws cause the iron to deform and fail under load.

The equipment that will be used for this project is spread across various departments of the university. The loading tests will be conducted at the Department of Engineering Science (including the fatigue rig run by Prof Barbara Rossi), while the microscopy work will also use the facilities at the Departments of Materials and Geography. The project will also involve a collaboration with the I12 beamline of the Diamond Light Source, led by Dr Genoveva Burca. The new project demonstrates how the heritage science infrastructure developed through OCHRE can be made available beyond the University, enabling external researchers and heritage organisations to access specialist engineering capabilities to address practical conservation challenges.

Prof Sinan said: “I am really grateful for the funding opportunity provided by the Riches Access fund to characterise this extremely rare material. It provides an opportunity for us to demonstrate how our research facilities and expertise can help to extend the life of ageing heritage bridges. The importance of these structures for their local communities go beyond their role as transport links”.

Dr John Bennets, Head of Structures Asset Management at WSP in the UK said "Assessing the structural capacity of heritage cast iron is incredibly challenging due to its hidden defects and variable microstructures. Our partnership perfectly demonstrates how industry and academia can collaborate to solve real-world engineering problems. The data Oxford provides will be fundamental to the ongoing management of the structure, giving us the robust assessment criteria needed to work towards securing the future of this vital crossing and heritage asset for the local community".

Dr Kasun Kariyawasam, Principal Engineer at WSP in the UK said “We are looking forward to collaborating with Professor Acikgoz, whose team is at the forefront of heritage materials testing. By leveraging cutting-edge capabilities both at Oxford and Diamond Light Source, we will move beyond the standard material testing typically used in civil engineering to observe damage and crack propagation in this historic cast iron at a fundamental level.”

The Pricipal Investigator of OCHRE, Prof. Heather Viles said: “As leader of the OCHRE project I am delighted to see our facilities being used for this exciting and impactful research”.

The first RICHeS Access Fund is supporting projects spanning historic bridges, archaeological sites, museum collections, archival records and maritime heritage. A second Access Fund call has been issued for autumn 2026. Read more: RICHeS Access Fund announcement