Maintenance of infrastructure, including bridges, is a pressing global challenge that drains trillions of investment worldwide. Integral abutment bridges (IABs) are jointless structures without bearings or expansion joints, which require minimum maintenance, hence offering significant cost savings to Highways and Railway Agencies.
The popularity of IABs is the result of their advantages over their counterparts, i.e. the jointed bridges. Superior durability, noise reduction, structural redundancy and elimination of the risk of unseating and aesthetic possibilities are some of the advantages of IABs. However, integral bridges are not currently covered by Eurocodes. Hence, amongst other mandates of the Eurocode Committees, IABs have gained significant attention in an effort to encourage practitioners to design IABs.
In the UK, where almost 70 % of the bridges are integral, new design guidelines are available, which however limit their length and the skewness. The main reason behind these limitations is the complicated soil-structure interaction (SSI) effects due to abutment movements. As a result of these SSI effects, excessive backfill settlements, abutment failures and variation of stresses within the prestressed deck have been recorded by numerous studies.
IAB designs become even more challenging when seismic actions and/or other hazards must be considered. Hence, knowledge gaps exist in the understanding and design of IABs, whilst no framework exists for the risk assessment of IABs subjected to earthquakes or multiple hazards.
This seminar will present published research to enable a better understanding of the response of integral abutment bridges under thermal loads, earthquake excitations and excessive floods that cause scouring of the foundations. Advanced numerical modelling will be presented on the basis of realistic models of the structure and the soil.
Current modelling techniques will be assessed on the basis of accuracy, including basic modelling assumptions for the foundations and the abutment and oversimplifications related to the stiffness and/or the damping of IABs. The seminar will continue with the presentation of smart designs for IABs with recycled materials as a means to minimise the soil-structure interaction effects for delivering longer IABs and/or having large skewness.
The presentation will conclude with recent findings on the multi-hazard risk assessment of IABs and in particular the sequential occurrence of flooding and seismic effects on the vulnerability analysis of representative highway and railway IABs. Future research and design opportunities will be discussed on the basis of the ongoing research.
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