Climate change is an important global challenge to be addressed in the coming years. Climate change can be considered as a long-term risk issue brought about by changes in the long-term average climate but also in the short-term extreme events. Transport infrastructure systems, which are designed to be operational over a long time period, are increasingly likely to experience the impact of climate change over their lifetime. Knowledge of future climatic conditions is essential in order to aid infrastructure owners manage the impact of climate change on both existing and planned infrastructure. There is a clear need to minimise the negative impacts arising from the changing climate and adapt to the changes expected in the future by introducing them into current design and assessment practice. In the long term, future load increases are likely to become significant as well. An improved and more reliable definition and estimation of the risk and costs of climate and increasing loading demand impacts on infrastructure should underpin this effort.The proposed project is an initiative to evaluate the potential significance of the anticipated changes to climate, weather as well as increasing load demand on bridges and to quantify the risks posed to the existing infrastructure in terms of bridge safety, expected failure costs and additional maintenance and adaptation expenses. The project will focus on failure modes associated with bridge scour, material deterioration, temperature stress cycling and movement and bearing deterioration. A novel methodology for estimating the risk of collapse of bridges under the effect of changing climate and increasing loading demands will be developed. The time evolution of risk will be captured through quantifying the probability of failure of the bridge over time for each of the above mentioned modes as well as quantification of the consequences of failure. A probabilistic framework, which is able to capture uncertainties, is essential towards quantifying the effects of climate change on the bridge infrastructure in terms of the increase in risk, i.e. reduction in safety, as well in terms of expected additional future costs arising from maintenance, replacements and adaptation plans. Case studies will at first focus on metallic bridges, though the framework could be adapted and applied to other bridge types such as concrete and masonry. The proposed methodology will have the potential to incorporate input in the form of local future climate change predictions and will offer the opportunity to establish a bridge risk ranking map for any given bridge population characterising the vulnerability of a bridge structure, depending on its location, to climate change and changing live load effects.The individual objectives of the proposed work are identified as follows:I. Development of a novel probabilistic methodology for the estimation of risk of collapse of bridges under changing environmental and load demand conditions.II. Evaluation of the effect of increased river flooding, arising from climate change, on the scour risk ranking and reliability of bridges.III. Evaluation of the effects of climate change and increasing live loading on material deterioration and bridge reliability.IV. Evaluation of the effects of temperature changes due to climate change on bridge thermal movements, stress cycling and bearing performance. V. Application of the developed methodology, in the form of case studies, for the estimation of the reliability and risk of collapse of a number of typical bridge types.The proposed work will benefit from collaboration with a mix of organisations i.e. Network Rail, TGP, HR Wallingford and TRL and will allow them to meet the future challenges associated with the long-term management of bridge infrastructure. This will allow diverse needs and opinions to be captured, and provides a powerful repository of knowledge/expertise that will be exploited by the project team.

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

The lifetime extension of existing highway and building reinforced concrete infrastructure is a priority in terms of economic prosperity and a more sustainable future. The ability to reduce disruption, and amortise the embodied energy and the environmental impact of construction over an extended period will lead to direct, tangible and significant savings in energy and resource consumption. As construction typically accounts for up to 10% of the UK's GDP, and half of UK construction activity is associated with refurbishment and repair, it is clear that there is substantial scope to implement efficient technological innovations in the construction sector. In the UK, a major challenge is that, not only is the average age of our infrastructure increasing, but also the loading requirements are becoming more demanding. So the national pool of structures requiring intervention due to deterioration, changes of use, and/or a lack of strength is growing. For reinforced concrete (RC) structures, fibre-reinforced polymer (FRP) materials have been used as additional reinforcement to increase, or reinstate, strength capacity. These materials have a high strength-weight ratio, are durable and easy to install. To date, carbon FRP resin bonded strengthening systems have been the most common. The market share of FRP-strengthening applications has resulted in a proliferation of usage across the industry, and indeed continues to grow year on year. However, the development of our understanding has not kept pace with the growth in applications. There are significant gaps in our knowledge when typical large bridge or building structures and practical strengthening configurations are considered. The shear strengthening of RC structures is a particular challenge due to accessibility issues, the brittle nature of shear failures and the complex mechanics of the behaviour. Initial design guidance has played an important role in establishing the basis for the use of FRP systems but this guidance has necessarily drawn upon the results of specific studies which often only encompass a subset of possible parameters and interactions e.g. small-scale rectangular beams. However, there is an increasing body of evidence that suggests that a number of aspects of the fundamental shear behaviour are not captured in existing guidance. Recent studies have highlighted apparent contradictions between the predicted and observed behaviour of FRP strengthened large scale structures and structures with complex geometries. In particular, work at Cambridge University and Bath University have shown that in T-beams, which are considered representative of slab-on-beam structures, the current guidance can be unconservative yet for large scale rectangular beams, overly conservative. These contradictions pose difficulties since large-scale, slab-on-beam structures constitute a large proportion of the infrastructure that surrounds us and represents a target area for the use of FRP strengthening for lifetime extension. In the current project, a comprehensive experimental and analytical programme will be undertaken to understand the fundamental mechanics of beams strengthened in shear using bonded carbon FRP fabric systems. The effect of size will be investigated by considering strengthened T-beams with scales ranging from 'laboratory' scales to realistically sized structures found in practice. These targeted studies will lead to improved design approaches which reflect a comprehensive understanding of the failure mechanisms and the interactions that depend on the geometry and size of the structure. The deliverables will have a significant and timely impact through the provision of practical, safe and durable technological advances to enable the upgrading of existing RC structures to meet the demands of the 21st century.

This project addresses deficiencies in our fundamental understanding of how continuous reinforced concrete (RC) structures actually behave when they have been strengthened using fibre reinforced polymer (FRP) materials. Presently, we ignore any plasticity in such systems altogether, but this is potentially financially disastrous, overly conservative or, even worse, unsafe when considering how to best prolong the lifetime of existing RC structures. This proposal will deliver urgent structural-mechanics-based insight into how we might exploit redistribution of bending moments in FRP-strengthened continuous concrete structures such that our strengthening schemes are cost effective, safe and reliant on sound principles.