Problem issued: With approximately two million highway and railway bridges, of which almost 10% are characterised as structurally deficient and 14% as functionally obsolete, there is a huge challenge for assessing, repairing and strengthening bridges in Europe and worldwide. Indicatively, the average bridge is 43 years old and almost half a trillion trips are taken on a daily basis across structurally deficient bridges, on which world economies and travellers safety heavily rely upon Thus, ageing bridges require urgently strengthening and efficient monitoring, to avoid incidents like the very recent failure of the bridge in Italy. Notably, deck deficiencies are not necessarily the result of deterioration and strength degradation, e.g. corrosion and/or cumulative fatigue effects, but might be related to increases in traffic volumes and loads, e.g. permissible axle weights, or increases in code requirements. Hence the widening and strengthening of bridges are among the most pressing needs for enhancing mobility in EU networks, and this is the main motivation of this Fellowship for pursuing an integrated framework for the efficient and sufficient strengthening of bridges and their monitoring on the basis of long-distant inspection using guided waves (GW), examining and improving the interface response to achieve full embedment.
Importance to society: It is accepted that bridgeworks within Europe have a total value of around €50bn and a moderate 2% increase in their load capacity or life would result in savings of the order of €1bn. Notwithstanding the number of EU bridges that need retrofitting, there is a lack of integrated legislation frameworks and code provisions within the EU and worldwide, whilst the new Eurocode 8-3 is expected to cover only the seismic retrofit of bridges, yet is it not expected to provide guidance on the urgent need for the enhancement of the capacity of existing bridge decks against increased traffic loads. Also, in engineering and monetary terms, there is an urgent need for efficient asset management and plan a strategy based on performance, monitoring and resilient data.
Objectives
Obj. 1 To define the Interface Efficiency Indices (InterFeis). The indices will be correlated to the stiffness of the
strengthened structural element and the properties of the interface using spectral elements. These InterFeis will be defined for the most critical bridge decks with deficiencies, for a reasonable number of representative types of decks (e.g. voided slab decks, precast beams, box girder).
Obj. 2 To utilize an expedient, long-distant inspection method of GW for the first time in bridge inspection in order to
detect, map and characterize the potential discontinuities within the interfaces. To achieve this, the spectral approach will assist in examining different zones and damages within the bridge deck, defining the range of values of InterFeis taking into consideration the bridge performance and exposure conditions.
Obj. 3 To increase the interface efficiency using novel adhesive bond layers containing nanoparticles towards the
development of advanced strengthening systems for bridges. The improved efficiency will be measured with InterFeiS, both numerically and experimentally.
Obj. 4 To use IntereFeiS as a reliable tool towards the quantification of the redundancy of the retrofitted bridge. The
crucial loss of stiffness/capacity of existing bridge decks locally in critical cross sections will be matched with IntereFeis which will be ready to use for rapid decisions of further time-efficient intervention on the bridge
