Exploiting the resilience of masonry arch bridge infrastructure: a 3D multi-level modelling framework

Masonry arch bridges still form the backbone of the UK's transport infrastructure; approaching 50% of bridge spans on the UK rail and regional highway networks are masonry. However, a number of prominent failures suggest we may be at a tipping point - brought about by a perfect storm of the increasing age of the structures, new traffic loading demands, climate change effects pushing structures to new limits and severely restricted maintenance budgets.

To respond to the challenging times ahead there is a need to develop a much greater understanding of how real bridges behave, moving beyond traditional 2D idealisations and identifying the extent to which bridges are capable of 'autogenously healing' under cycling loading. This is important as, currently, bridge engineers faced with a damaged bridge simply do not have the tools needed to make informed assessment decisions, and may needlessly strengthen or demolish a structure even if it could, in reality, be repaired at comparatively modest cost. The goal is to provide those responsible for the management of bridges with a powerful suite of analysis modelling tools and a robust overarching multi-level framework capable of being applied to the diverse population of masonry arch bridges in-service today (i.e. undamaged, damaged and repaired).

To achieve this a team of experienced researchers with complementary expertise has been assembled. Medium and large-scale experimental tests will be used to develop and validate analysis tools of different levels of sophistication, with high-level, high-fidelity models, capable of simulating the actual masonry bond and material response, used to calibrate novel intermediate-level and lower-level tools suitable for rapid practical assessment.

WHO WILL BENEFIT?
Key beneficiaries will be bridge owners and their nominated consultants, including UK consultants engaged in bridge assessment and upgrading work for clients overseas. The general public who ultimately pay for maintenance, refurbishment and renewal of the large numbers of masonry arch bridge spans in the UK through taxation and/or fares, and who use them on a daily basis, will also benefit. Additionally, since many of the research outputs will be widely applicable, a range of other parties should also benefit, for example those engaged in the preservation, conservation and rehabilitation of heritage masonry structures such as fortifications and religious buildings, and the associated tourism industry.

HOW WILL THEY BENEFIT?
The research will provide tools and clear guidance to help reduce the numbers of needless interventions to masonry arch bridges, and also to ensure that required interventions are more sympathetic and appropriate, saving both money and delays to users of transport infrastructure. The UK is a global leader in masonry arch bridge research. The planned programme will help maintain this position, both by providing usable research results and by providing suitably trained individuals (3 PDRAs and 3 PhD students). Clear benefits to industry can be expected to be realised within two years of completion of the research.

WHAT WILL BE DONE TO ENSURE THAT THEY HAVE THE OPPORTUNITY TO BENEFIT?
Representatives of key stakeholder organisations will participate on the project Steering Group and Advisory Board to ensure the impact of the work is maximised (see partner letters). We will also run a series of three workshops at locations across the UK to disseminate results to practising bridge engineers. These will be supported by the Council of the International Masonry Society (IMS), who have a growing membership of masonry specialists drawn from over 40 countries worldwide.

A key outcome will be an assessment guidance document for use by practitioners, to be published by the respected industry body CIRIA and developed in close collaboration with the industrial partners. A number of industrial partners will also utilise the advanced yet practical assessment tools developed in this project to assess bridges that have hitherto been challenging to assess reliably (e.g. bridges of skew construction and bridges subjected to commonly encountered 3D loading regimes). Advice and feedback obtained will be used to refine the tools and the associated guidance.