Special Sessions - EUROSTRUCT

Abstract
In order to achieve better performance in the travelling time, the railway infrastructure has grown significantly in the last decades, especially with the construction of new bridges and viaducts. In terms of high speed railways, for example, the necessity to ensure smoother tracks with larger curve radius resulted in new railway lines with a high percentage of bridges. Therefore, to face these challenges, the research related to railway bridges is becoming increasingly important among the railway engineering community.
Within the framework outlined above, this special session aims to bring together the latest achievements, research and studies regarding the design, construction, monitoring, maintenance and management of railway bridges. Theoretical, experimental and computational investigations, or a combination of them, are welcome in this session. The scope of the present session encompasses, but is not restricted to, the following topics: railway bridge design, train bridge interaction, track bridge interaction, soil structure interaction, train-induced ground vibrations, transition zones, reliability and runnability of railway bridges in strong winds and/or earthquake-prone areas, traffic safety on railway bridges, train riding comfort, structural damage identification, Bridge Information Modeling (BrIM) and life cycle assessment.

Abstract
Over the past few years, significant effort has been devoted to modeling and predicting structural deterioration. The recent developments have been crucial for planning optimal maintenance strategies and minimizing disruptions due to the occurrence of shock events. Several models and prediction tools are informed by the collection of data with inspections, Non-Destructive Testing (NDT), and Structural Health Monitoring (SHM). Also, multiple formulations to quantify the Value of Information (VoI) provided by such procedures have been put forward. A proper quantification of the VoI can further enhance the benefit of information adapted deterioration models for decision support. The scope of this Special Session is to bring together expert researchers and academics interested in the various aspects of deterioration modeling and quantification of the VoI. The latest developments in theoretical and computational approaches will be analyzed and discussed. Contributions addressing practical applications are also encouraged.

Abstract
Many bridges and viaduct dating back to ’50 and ’60 of the last century are approaching the end of their design lifetime. In most European countries costs related to maintenance of infrastructures reach a quite high percentage of the construction budget and additional costs in terms of traffic delay are due to downtime related to the inspection and maintenance interventions. In the last 30 years, the rate of deterioration of these infrastructures has increased due to increased traffic loads, climate change related events and man-made hazards. The events related to recent bridge failures, including the collapse of the Morandi bridge in Italy, tragically highlighted the need to improve maintenance policies in order to increase the safety for people and goods and to reduce losses of infrastructure functionality and related consequences. In this focus, Structural Health Monitoring (SHM) is one of the key strategies with a great potential to support the informed management of transport infrastructures.
In 2018 Regione Lombardia and Politecnico di Milano launched a project for the definition of criteria and guidelines for maintenance and management of roadway infrastructures. The project is aimed at developing a risk-based bridge maintenance prioritization methodology at regional scale and providing recommendations for design and implementation of bridge SHM systems. As a support to validation and practical application of the proposed approach, SHM systems were designed and implemented on nine exemplary bridges in Lombardy and are currently collecting data that will provide information about the bridges’ health. This Special session will provide the venue to present and discuss the preliminary outcomes of the SHM research and applications developed within this project and foster discussions and further collaborations.

Abstract
BRIDGE|50 is a research project established jointly by Politecnico di Milano and Politecnico di Torino with public authorities and private companies for a wide experimental campaign on a prestressed concrete viaduct dismantled after a 50-year lifetime in the context of the Torino-Ceres construction works (http://www.bridge50.org). A group of 29 deck beams, including 25 I-beams and 4 box beams, and 2 pier caps have been moved and stored in a testing site. The on-site experimental activities include non-destructive diagnostic tests, full-scale load tests up to collapse, and samples collected for laboratory tests. The objective is gathering new data concerning the life cycle safety and reliability of aging bridges exposed to deterioration processes. This framework of data will provide knowledge advances for public authorities managing infrastructure networks and represent key information to improve existing methods for lifetime assessment of reinforced and prestressed concrete structures. The results of the research project are expected to contribute a modern approach to life-cycle design of bridges and to improve safety, maintenance, and management of existing infrastructure systems. This Special Session is aimed at presenting advances of the ongoing activities, including the preliminary experimental results of the full scale load tests, and fostering future research activities and implementation in practice of life-cycle design, assessment, maintenance, and management of bridges and critical infrastructure networks.

Michele Morici
University of Camerino
Italy
michele.morici@unicam.it

Abstract
The maintenance in service with an appropriate structural safety level of historic Masonry Arch Bridges (MAB) is a current need that has given rise to a discussion in the scientific community, aimed at developing optimal strategies of diagnostic, monitoring, assessment and strengthening of these structures. This special session promotes a discussion on new methods for the diagnosis, SHM and condition evaluation of roadway and railway masonry bridges. Moreover, contributions focused on simplified and detailed numerical modelling of MAB are welcome. Finally, the session is open to receive any research activity, case study, experimental results and numerical analysis outcomes concerning the repair and the strengthening of MAB with traditional or innovative techniques.

• Structural assessment of Masonry Arch Bridges;
• Nonlinear behaviour of Masonry Arch Bridges;
• Case studies of Masonry Arch Bridges assessment and repair;
• Innovative techniques and advanced materials for the strengthening of Masonry Arch Bridges;
• SHM of Masonry Arch Bridges.

Abstract
The road network faces major challenges: aging buildings, increasing traffic loads, the effects of climate change, new quality requirements and a limited budget for road infrastructure. In order to maintain a reliable road network, new, innovative approaches must be pursued. This applies in particular to bridge structures. At present, their maintenance management is based on regular building inspections. Damage is only discovered when it is obvious. This procedure is damage-based and reactive. However, damages and problems of the structure are often already announced inside the building. The bridges of the future should be able to provide information about their condition and its development at an earlier stage and in addition to the building inspections.
The aim of this special session is to present in-depth numerical reliability-based assessment methods for bridge systems and to make them available to a larger number of engineering offices and infrastructure operators. The deepened numerical reliability oriented assessment methods serve for the provision of relevant information and for the holistic assessment of bridge systems and have a significant effect on the efficient and targeted use of the limited budget in bridge maintenance.
The core outputs of the project for the infrastructure managers (InfB.) and the engineering community (IngG.) should be (a) the creation of accessibility to the deepened numerical statistical building blocks and reliability oriented evaluation methods for the holistic evaluation of bridge systems, (b) the creation of a guideline for the risk reduced application of the deepened procedures, and (c) the development of a sustainable training programme. These three approaches have so far not been prepared for engineering communities. and infrastructure managers. in any of the European countries and worldwide and are therefore to be classified as highly innovative.

Abstract
Within the context of assessment of existing bridges and flyovers, the use of multi-disciplinary strategies, integrated monitoring systems (where data from heterogeneous sensor networks are simultaneously collected and processed) and the development of “digital twin” models is quickly increasing in diffusion and importance. The Mini-Symposium is intended to focus on recent developments regarding the experimental and/or numerical assessment, monitoring and control of the behavior of bridges under different types of loads (e.g. moving loads, vehicle-bridge interaction, seismic loads) with special attention given to innovative procedures in real applications, the integration of different experimental methods and the consideration of different phases of existing bridges life cycle. Suitable topics include, but are not limited to, the following: (a) Multi-disciplinary strategies of assessment and SHM; (b) Design, implementation and management of monitoring systems; (c) Vibration-based tuning of FE models (Digital Twinning); (d) Effects of environmental and operational variability on collected structural parameters.

Abstract
Structural Health Monitoring (SHM) has established in recent years a strong complement to traditional approaches of structural assessment, which largely rely on visual inspection strategies. Particularly for bridges, a large portion of which is currently approaching end of their nominal life, monitoring offers a viable means for preserving serviceability and safety and prompting for intervention, where necessary. This mini-symposium covers recent theoretical and applied developments in the domain of structural health monitoring with applications to bridges. Emphasis is placed on the robust interpretation of the SHM findings. Work pertaining to all four levels of condition assessment is welcomed including, detection, localization and characterization of damage severity, as well as prediction of remaining lifetime. We further encourage submissions that report on actual-scale field measurements or works exploiting Machine Learning for forming grey (hybrid) or black box data-driven diagnostic and prognostic models.

Abstract
Europe has a large heritage of bridges, in masonry, r.c. or steel, over fifty years old, many of which were designed with technical standards very different from the current ones and, therefore, assuming moving loads different from those of the present codes. Safeguarding these infrastructures is of fundamental importance to ensure their efficiency, durability and reliability and can be pursued through an appropriate maintenance program that avoids the occurrence of serious irreversible damage.
These bridges were built in different eras, using different materials, whose mechanical characteristics are not known and difficult to model, and with different technologies, some of which are no longer used. Their geometry is often unknown and inspections are difficult due to the complexity of reaching all structural components, such as the foundations. Obviously, in order to define an improvement intervention or a maintenance program, detailed knowledge of the structure is essential.
The risk classification is part of a general multilevel approach that, on the basis of a simple census of the existing structure, leads to the determination of a “class of attention” and, when necessary, to a safety check. On the basis of the classification and check, the resilience analysis of the road networks can be done. Obviously, census of the structures, as well as initial and special inspections, are fundamental to point out any defect or damage and to make assessments with respect to the possible relevant structural (static and foundational), seismic and hydro-geological (hydraulic and landslide) risks.
The Italian Ministry of Infrastructure has recently issued the Guideline for managing the safety of existing bridges in order to prevent inadequate levels of damage by making the risk acceptable. It is composed of three parts, on the census and risk classification, safety verification and surveillance and monitoring of existing bridges and viaducts. The approach is developed on 6 different levels, with an increasing degree of depth and complexity, and five classes of attention are considered.
This Guideline is to be improved and updated in the future, with particular reference to the classification of bridges as part of the risk management. This Special Session will be the most appropriate venue to present and illustrate new ideas for the improvement of the guideline and eventual extension to other European countries.

Abstract
Recent events highlighted the catastrophic consequences of corrosion phenomena affecting reinforced concrete (RC) and pre-stressed bridges. If the effects of aggressive environmental conditions on traditional RC infrastructures – at material (concrete and reinforcing steel), section and element level – were widely investigated in the current and past scientific literature, the interest on the residual performance of pre-stressed bridges under corrosion attack is increasing because of the severity damages (even collapse, in the extreme condition) and of the relative consequences at urban and territorial scale. Corrosion affects materials, leading to a deterioration of the mechanical performance of both rebars, strands and concrete. The correlation between the corrosion entity – including different phenomena such as chlorides’ attack, H-embrittlement, carbonation, stress corrosion, corrosion fatigue – and its effects on the residual bearing capacity of bridges needs to be assessed by combining the results of experimental investigations with numerical simulations accounting for different corrosion damage scenarios and including corrosion effects. By this way, it will be possible to determine reliable methods to estimate the residual bearing capacity of bridges in presence of aggressive environmental conditions, providing the base for the application of prevention/protection measures increasing the infrastructure service life.

Abstract
Concrete structures are exposed to media that trigger a degradation process, which leads to damage and high maintenance costs. Especially the concrete infrastructure of the motorway networks is under high exposures of aggressive media, which are chlorides, as well as heavy and cyclic loads. But there are also others. Condition monitoring is an essential tool that supports the assessment of structures in terms of security, but also can be used to determine cost effective maintenance intervals.
The objective of this session is to bring together experts and discuss:

• Condition monitoring for durability and safety of concrete structures, including visualization, assessment and prognosis to improve predictability.
• Morphing of inspection results and measured data to condition indices (classes) to support the maintenance work and an overall condition index for structure assessment.

Abstract
Structures and infrastructures can be exposed during their service-life to extreme loads. These actions can be induced by natural events (e.g., wind, earthquakes, landslides, tsunamis etc.) or man-made causes (e.g., impacts, blasts, etc.). Secondary effects induced by extreme loads are relevant for a proper safety evaluation. For instance, the response of structures subjected to the combined action of earthquake and fire hazards has gained attention in recent years, motivated by post-earthquake fire events that were observed mainly in large metropolitan areas, in which significant losses occurred to both life and property.
For the abovementioned reasons, a realistic evaluation of the structural response due to extreme loads is a matter of growing importance in many civil engineering situations, no longer reserved to the field of military defense technologies. This session encourages the submissions of contributions addressing one or more of these topics. The topic to be covered are but not limited to:

• robustness of structures and infrastructures to exceptional loads;
• progressive collapse analyses;
• simulation of impacts and blasts events on structural systems;
• modeling and assessment of structures under fire, earthquakes, and tsunami loads;
• effects of extreme wind loads on structural integrity of built environment.