Parallel sessions

Seven countries hosted a parallel programme consisting of four sessions with 15 minutes presentation and 5 minutes discussion, and an overall wrap-up with all speakers.

National themes and hosts

Digitalisation New refurbishment techniques Tunnel safety and security Inspection, investigation and monitoring during service life Sustainability Challenges for infrastructure asset management Toolbox for the tunnel owner
Helen Roth and Karine Næss Frafjord Roland Leucker and Götz Vollmann Max Wietek Andrea Pigorini Eric Premat Elvira Haezendonck and Bart de Pauw Sallo van der Woude

Sessions per round

15.00h • Round 1 (including overall introduction)

ICT-based tunnel safety: a case for procedural and parametric 3D modelling of Norwegian road tunnels
Naeem Khademi (University of Stavanger)

Safety of road tunnels has traditionally been a domain explored primarily in depth by risk and safety management experts. As a multidisciplinary field of research and innovation, this has also included the application of many other fields — from fire safety and emergency response to medical science, human psychology, transportation and structural engineering. However, new opportunities arise from the rapid emergence of novel information and communication technologies (ICT) in recent years. Access to aggregate sensory data (i.e. big data), more efficient and faster communication technologies (e.g. IoT, vehicular networks and 5G) and more advanced computational techniques (e.g. machine learning) are major enablers of a more sophisticated and data-driven ICT-based tunnel safety approach.

In this presentation, we will look at one particular use-case, where using publicly available road data and with a data-driven approach, we have been able to procedurally and parametrically produce medium-fidelity 3D model of any given road tunnel in Norway, something that is substantially useful for a plethora of tunnel safety use-cases ranging from emergency response and road user training using virtual reality to simulation of new technologies in tunnels and ultimately the development of digital twins.
Renovation tunnels Schiphol - practical lessons of a renovation project
Herman Kraaij (Vialis) and Jeffrey Rundberg (Schiphol NV)

The Buitenvelderttunnel consists of four tubes for traffic, public transport and bicycle traffic. One of the tubes is a combined tube for traffic and public transport and the direction of travel can be adjusted in the C-tube. During the renovation, there were always at least 2 tunnel tubes open to allow traffic. The availability of the connection is essential for the airport and had priority over the realization during the renovation.
New operational road tunnel safety issues
Max Wietek (ILF Consulting Engineers) and Ingo Kaundinya (BAST)

In the last one and a half years, ITA COSUF, the ITA Committee on Operational Safety of Underground Facilities, has developed a vision based on discussions, both in public and internal workshops, in order to carefully consider the latest and future developments of modern means of transportation from the underground infrastructure perspective. The vision development was backed up with a cooperation between ITA COSUF and PIARC, formally governed by a Memorandum of Understanding between the two organisations that was signed in 2005.

Solutions for societal challenges due to our efforts towards low carbon energy and a smart mobility environment have a significant impact on underground transportation facilities and their operational safety. ITA COSUF identified in a very early stage already this trend – resulting in the first Workshop on New Energy Carriers in Tunnels and Underground Installations, organized by L-surF and endorsed by ITA COSUF on 20 November 2008 in Frankfurt (Germany) with representatives from the tunnel safety community, blue light services, and first responders. As currently the most pressing developments are finding entrance in automotive technologies, ITA COSUF decided to dedicate the Vision Paper to road tunnels and consequently also take care of the fact that the changing energy carrier composition in urban environments has a major impact on operational safety and following urban population. Main objective of the Vision Paper is to highlight the need for Horizon Europe (2021 and further) to support future research activities to answer how changing demands from society should be managed by stakeholders of underground transportation infrastructure.
Tunnelling 4.0: New technologies and future perspectives for maintenance, refurbishment interventions and upgrading
Andrea Pigorini (Italian Tunnelling Association) and Marco Ranieri (PricewaterhouseCooper)

To debate and share knowledge and best practices about new technologies and future perspectives for maintenance, upgrading and refurbishment of tunnels is really important because as for European countries we have often to manage and operate tunnels that have been built since 19th century, probably using wood for prelining and masonry and bricks for final lining and the need to industrialize the maintenance process and eventually the rehabilitation works is an issue.

Every year more than 2.000km of tunnels in Italy and more than 10.000km worldwide, belonging to the widespread existing network of infrastructure, undergo daily maintenance, and some of them undergo significant renewal or enlargement works. With regard to Italian rail and road infrastructures, age and complexity of many of the main structures like tunnels (over 50 years old on average) are currently showing a need to act and react with an important and widespread monitoring plan and predictive maintenance approach.

Maintenance activities are going to be improved and accelerated from the introduction of innovative of technologies, such as the adoption of BIM and digital twin tools, artificial intelligence and new materials and construction techniques. Unlocking the potential of such new technologies is the enabling factor to improve productivity and meet the safety, resilience, quality and efficiency requirements. Moreover, the engineering and construction industry could drive the economic recovery caused by the Covid-19 pandemic, thanks to large infrastructure investments program that will have access and hopefully will exploit the resources provided from the Recovery Fund (750 bln).
The COB sustainability programme
Onno Sminia (COB/Croonwolter&dros)

During 2020, the COB has launched five projects to explore the role of sustainability in tunnels and to develop tools for increasing this sustainability. In this session these tools will be presented.

Firstly, a checklist was created to identify points for improving sustainability in tunnels. During 2020 this checklist was incorporated in the broader COB health checkup for tunnels, the structural health analysis (SHA). In this process a second 'tool' also is used, the Thinktank. This group of experts is gathered to assist projects with specific questions about sustainability. The Thinktank is therefore responsible for assessing sustainability when an SHA is performed on an existing tunnel. The third project was aimed at updating the catalogue for energy reduction in tunnels. This catalogue was first created in 2019 and has been updated with the latest insights and technological developments to provide handholds to parties willing to improve the usage of energy in tunnels. Another multiyear project is to decrease energy usage of tunnel lighting. During 2020 a programme has been designed that links insights and new technologies to pilot projects in 2020 and 2021.

For decreasing the amount of materials that is used in tunnels a survey was held to assess the willingness of the sector to set-up an e-waste circularity hub (project 5). Due to an overwhelming positive reponse, this project will run into 2021 with the exploration what kind of e-waste we are actually facing in the coming years and which options we have to reuse the installations in the most circular way possible.
A strategic asset management framework for improving transport infrastructure
Laura Molinari and Elvira Haezendonck (University Brussels)

Today, a sound and appropriate infrastructure asset management to guarantee high-quality transport infrastructure is a priority for multiple policymakers. While the competitive quality of transport infrastructure in a number of Western European countries is deteriorating, the volumes of freight and passengers, as well as the expected service levels of all modes of transport for citizens and businesses, are increasing sharply. In response, infrastructure asset managers have developed and integrated technical and operational system innovations. What is direly missing, however, is a long-term asset vision (for example: which modal shift do we aim within which time span?), and the knowledge and implementation of strategic principles behind a strong transport infrastructure network (for example: who decides or should optimally decide on the life-cycle and upgrade of assets?).

This study attempts to fill this gap by singling out the key challenges in view of a more strategic approach of asset management of mainland infrastructure, focusing on transport by road, rail and barge. Our literature study identifies best practices, barriers and potential solutions for improving asset management of three different transport modes. In addition, we develop a framework to foster better asset management practices by civil servants and policymakers in different regional and policy contexts. Through in-depth interviews with Belgian chief administrators, the strategic principles and identified framework are tested over all different types of mainland infrastructure and particular recommendations are given. We propose that ‘one model does not fit all’, neither in theory, nor in practice, and that a variety of models could better suit the goals of different policies and is salient to adapt to the regional context as well as the particular transport mode.
Case: SHA of the Limfjordtunnel
Niels Højgaard Pedersen (Vejdirektoratet)

The Limfjord tunnel in the northern part of Denmark was constructed in 1965-1969. It is an immersed tunnel, 582 metres long and consists of two tubes, each with three lanes. Since its construction fifty years ago, the traffic has increased steadily from 29000 vehicles per day to close to 100000 today. The tunnel is part of the Trans European Road Network. Since the commissioning of the tunnel in 1969, settlements were measured and recorded on a regular basis. It soon became evident that the settlements were considerably greater than foreseen in the original design. Furthermore, leakages and cracks were observed through the early stages. Settlements, leakages and cracks have been the main reasons for repairs the tunnel has been undergoing since its opening and have often challenged traffic flow. In 2016-17 the settlements had reached a level which in 2018 led to the Danish Road Directorate's appointment of an expert group, with the aim of assessing the tunnel's current condition and expected remaining lifetime. In addition, the expert group was asked to give recommendations for the future maintenance, repair and possible retrofitting strategies.

The presentation will explain how asset management of tunnels is organized and carried out in the Danish Road Directorate, and which drivers and decision processes have led to the establishment of the expert group, how the situation was handled in relation to the asset owner (the Minister for Transport) and other stakeholders. The presentation will in brief present the conclusions and recommendations of the expert group enabling the Danish Road Directorate to keep the tunnel operative in the future.


15.25h • Round 2

Tunnel Digitalization Center – Digital services for tunnel maintenance
Veronika Petschen (Amberg Engineering) and Klaus Wachter (Scaut association)

This presentation will introduce the SCAUT project Tunnel Digitalization Center (TDC). Together with industry partners, SCAUT has developed and commissioned a demo center of a digital tunnel build in a real tunnel environment. It offers the unique opportunity to experience the interaction and transformation from real to digital directly in the tunnel. New technologies and innovative concepts can be prototyped and demonstrated on a scale of 1:1, leading to a better understanding of complex operations and processes as well as a high level of cost-efficiency.

The focus of the project is on cross-phase and cross-divisional system solutions that span the entire value chain and life cycle of tunnel systems – starting from the design with BIM resp. modelling the existing structures, the subsequent structural work and electromechanical equipment to the operating phase and digital maintenance services using a digital twin. In particular, the interaction between different partners is demonstrated using common use cases and building a partner ecosystem.

In the presentation, special attention will be given to digital tools and services for optimising the maintenance processes. A software solution will be presented using artificial intelligence to automate the identification of disorders in order to optimise predictive maintenance. The software can be connected to a digital twin containing all the information about the structure. Point clouds as well as information from various sensors can be integrated into this BIM model with the help of a GIS. In addition, several models can be interconnected. With these technologies, it is possible to start changing the periodically inspections to permanent digital observation of the structures on the infrastructure network in order to enable event driven interventions and optimize predictive maintenance.
Sprayable geopolymer concrete for improvement of fire resistance and upgrading of underground railway structures
Götz Vollmann (Ruhr University Bochum, Institute for Tunnelling and Construction Management)

The existing tunnel structures in Germany are characterised by progressive ageing. In addition, the authorities have reviewed and updated some of the guidelines over several years. If deterioration now requires repairs, these new requirements must be taken into account. This can sometimes lead to a considerable increase in the requirements for durability, resistance or structural fire protection. In the German research project KOINOR, a sprayable geopolymer is being developed, which should fulfill the requirements for a tunnel lining regarding the new guidelines. It focuses on high fire resistance as well as high resistance to other concrete-aggressive substances such as chlorides or sulphates.

This presentation shows the first results on the applicability of a sprayable geopolymer concrete. For this purpose, investigations of the geopolymer application process and its fire loading material properties are discussed. First fire tests also indicate a substantial fire resistance and no spalling issues with this new material, which could help with many current problems of underground structures in general and railway tunnels in special.
Cyber security
Jasper Kimstra (Kimpro) and Johannes Braams (TEC Tunnel Engineering Consultants)

This presentation will start by explaining the reason the working group was put together and the way in which it has been operating since its inception. We’ll discuss the intended audience for the 'living document' and the way we expect it to be useful during the lifecycle of a tunnel. Secondly, we’ll shed some light on the content of the living document: what is it that we are sharing with the tunnel community? Also, we’ll discuss what makes up the basis of this living document. Furthermore, as this is a living document, we’ll shortly describe the plans we have for subjects to be included in future releases of the living document. Afterwards, we can answer all sorts of questions, for instance about what is so special about this production and how the conditions were created to make its inception possible.
Damages on lining induced by the construction of a new tunnel and the design of refurbishment: a case history
Salvatore Miliziano (University of Rome)

This presentation deals with the behaviour of the lining of an old tunnel during the construction of a new tunnel located very close to the existing one. The case history concerns the modernization works of the E78 Siena-Grosseto road in the central of Italy. During the excavation of the new tunnel, the plane concrete lining of the existing one was seriously damaged. Concrete detachments and, in a specific stretch, uplifts and deformations of the road platform were observed. As a consequence, the road was closed and the construction of the new tunnel suspended. With the aim of re-opening the road as soon as possible, and minimizing the inconveniences to the users, a provisional intervention (cheap and rapidly put in place) was designed and realized.

The first part of the presentation - after the description of the events, surveys and measures carried out - describes the geotechnical model and the criteria followed for the calibration of the numerical model employed to support the design choices (in the design). The design is also described.

After the completion of the rehabilitation works, the road was re-opened and the works for the new tunnel construction re-started. The deformations of the old structure were taken under control through a monitoring system based on many optical benchmarks (micro-prisms) installed on the lining of the old tunnel, arranged in twenty different sections. The spatial position of the micro-prisms were monitored by a high precision automated total station and real time elaboration and transmission to the control/surveillance structure. The agreement between the values of displacements measured and the predicted ones was very good. Thus, the availability of a good geotechnical model and a numerical model calibrated on the measures of the stress of the existing lining, are crucial in order to obtain accurate predictions.
Alternative modes of transport also take precedence in tunnels
Guillaume Planchenault and Antonin Gosset (Arcadis)

This presentation will focus on the development of reflections identifying the tunnel as an opportunity for transit and no longer as a strictly regulatory or technical constraint. Historically, urban tunnels, whether they are built for a metro, a train or for road transit, have the direct or indirect objective of relieving congestion on winding and narrow roads on the surface. Road tunnels are all dedicated solely to the transit of private vehicles, heavy goods vehicles and marginally to public transport by bus, which are melted into the traffic mass. The current environmental context favours the development of public transport (metro, bus, BHNS, tramway) and alternative modes of transport such as cycles, EDPM (motorised personal transport vehicles) or pedestrian transport. In this context, the tunnel must also be transformed and integrate these new modes where, some time ago, it was unimaginable to do so. There are many new practices under study or already in progress, which show a radical change in the management of urban transit.
Asset management of tunnels from the BIM perspective
Natasha Blommaert (Agentschap Wegen en Verkeer)

The Agency for Roads and Traffic (AWV) wants to achieve safe, smooth and sustainable mobility for all road users in Flanders. As an asset manager, we are responsible for managing, maintaining and optimizing 7000 km of freeways, 7700 km of bicycle paths and numerous other assets, including several tunnels. That is why AWV is happy to explain its vision and approach to asset management. We aim to maintain infrastructure networks in a reliable and future-oriented manner. To manage the transport network of the future, driven by innovation and digitalization, we focus, among other things, on building information management (BIM). In this way, we map out our tunnels in detail and seize the benefits of BIM to make our asset information management transparent for life cycle asset management purposes. After all, no smooth mobility without reliable and future-proof infrastructure networks as a foundation!
Structural health analysis: getting a grip on the actual residual lifespan of civil structure of tunnels
Brenda Berkhout (TEC Tunnel Engineering Consultants)

Many tunnels are approaching the end of their design lifespan, which increases the chance of hindrance and malfunctions. At the moment it is still very difficult to reliably determine the actual (structural) scope of a tunnel renovation reliably. More insight is needed into the condition of the tunnel. For this, the COB network developed and carries out a structural health analysis (SHA). A structural health analysis is a process with knowledge workshops and (field) studies. The process starts with an inventory of available knowledge and information about the tunnel structure. All data is structured and ordered by using COB products. The information is analysed by the COB expert groups, identifying important potential risks and drawing up advice for additional research. The tunnel manager then analyses both the current and future structural status of the tunnel. Based on the results, a condition assessment is carried out and the scope for a (possible) renovation is determined. After the renovation has been carried out, the tunnel is 'healthy' and a health declaration can be drawn up for the tunnel.  


15.45h • Round 3

Digital transformation of tunnel renovations. Case: renovation Koningstunnel The Hague
Jeroen Groenewegen (Infranea) and Stijn Seuren (Siemens Mobility)

Infranea and Siemens Mobility Netherlands (in collaboration with Heijmans) have meticulously prepared the Koningstunnel project to manage potential risks during implementation to the maximum. The Koningstunnel is a geometrically complex work next to the central station in The Hague, with entry and exit lanes and differences in the number of lanes per traffic tube and tunnel section. Opened in 2000, this tunnel also contains more than forty technical installations, such as lighting, ventilation, traffic detection, camera surveillance, emergency telephones and water pumps. In 2019, all obsolete installations were replaced and new ones added to meet new tunnel safety requirements. The service building was also modernized and expanded to accommodate more installations and operate them. To shorten the turnaround time for the renovation and to guarantee safety, the Municipality of The Hague had decided to completely close the tunnel. All parties involved had experience with comparable renovations and the use of BIM, system engineering (SE) and virtual reality (VR). A digital tunnel twin has been created by Siemens, the source files of which always provide an unambiguous truth to everyone. Infranea supplied all the necessary data from the BIM process for the construction of these digital tunnel twin. In that process we used new technologies and methods such as parametric design and best practices in the field of reverse engineering, systems engineering and scrum. Siemens has also applied the digital twin to make the project transparent to all stakeholders, including during implementation, and to test and validate all systems virtually and dynamically. During the implementation, the digital twin was further deployed for the training of administrators and emergency services. With this approach, we have contributed to the digital transformation of this inner city tunnel renovation project.
Temporary ventilation and measures to assure air-quality during rail tunnel refurbishment works
Peter Reinke (HBI Haerter AG)

During refurbishment of rail tunnels, the tunnel environment needs to comply with the occupational health requirements, must assure the functionality of the machinery and allow the intended refurbishment works with as little hindrance as possible. Additionally, the availability of the tunnel for regular train operation of the tunnel has to be maintained, either full-time or during selected time slots of the refurbishment works in many cases. Health and safety has become more and more important on work sites within the last decades. A particular challenge is the control of the concentration of dust in the tunnel air. More recently, authorities have stopped construction works if health requirements were found to be violated or the required ventilation was missing. Thus, for the benefit of workers health, the uninterrupted progress of the construction works and then safety of all tunnel occupants, the proper planning of temporary ventilation and any potential additional measures is required.

This presentation shall address the required design methodology including latest digital tools for the design and control of temporary ventilation and other ventilation measures. The key intention is to highlight the various boundary conditions affecting a ventilation and air-quality concept and the principal layout of the system. The presentation will address as well the risks of inadequate air quality and work site conditions. Various examples of stationary and mobile temporary ventilations and dust control measures in rail tunnels and monitoring and control concepts shall be presented. In addition, a digital tool shall be presented showing state-of-the-art simulation of temporary ventilation systems.
From innovation to regulation
Kees Both (Etex Group)

Innovation and research are key elements with a view to ensure availability in an effective and (cost)efficient way. The actual added value that may be brought to the society through innovation and research depends heavily, if not entirely, on if and how it is being adopted in regulations and standards. Over the last decades, worldwide activities have been undertaken on tunnel fire safety related regulations, and rather recently also actions in ISO and CEN, which will be discussed in this presentation. Such an overview may facilitate a coherent approach towards regulations and standards. Asset owners are among the key stakeholders profiting from up-to-date standards and regulations, allowing to benefit from innovations and research properly embedded in those standards and regulations. An overview of current activities in standards and regulations provides the asset owners with a glimpse into the future, as to what is in the pipeline of regulations development. This in turn facilitates timely anticipation and preparedness.
Inspection and monitoring for tunnels maintenance: analysis of experimental data
Gianpiero Russo (University of Naples)

Tunnels in Italy have a tradition which dates back to Romans. Tunnels excavated by roman architects inside the volcanic tuff formation about 2000 years ago are still open to the people and deserve our appreciation. However, a large tunnel production has taken place in the last 200 years and in the same area, which is the Napoli area, we have examples of such tunnels perfectly standing without significant maintenance. This is not always the case. Many tunnels require inspections and monitoring and many tools and methods are now available for carrying out both inspections and monitoring. Laser scanner, Lidar, digital image correlations, active and passive thermography, georadar and ultrasonic are only some of the techniques currently available to support the role of the investigator which is the professional involved in the inspection work.

Monitoring the behavior of the tunnels and their linings is another important task. This can be done both in short term or in the long term perspective giving the opportunity to evaluate the strain state and/or the stress state in the lining. Some examples partially from our files and partially by the literature will be briefly presented and discussed with the aim to learn from past experience to contribute to a vision and a strategy on the tunnel maintenance in the future and certainly beyond the present time.
A green tunnel in the city of light
Camille Jamet (Lombardi) and Mathieu Hermen (Metropole de Lyon)

The Croix-Rousse tunnel was opened in 1952. It is located in a dense urban environment and plays a major role in connecting the two banks of the Saône and Rhône rivers. Reflection on its major refurbishment began in 2000. The Greater Lyon Council chose to include this renovation project in a global approach to respond to urban, social, economic and above all environmental challenges. From a transport point of view, the objective was to avoid increasing road traffic in the tunnel and to encourage alternative traffic (cycles, pedestrians). The construction of an escape gallery made it possible to offer the level of safety required by regulations and to propose alternatives to motorised travel.
Cost-benefit analysis for fire, life safety and business continuity
Melchior Schepers (Fire Engineered Solutions) and Ruben Van Coile (Ghent University)

The FIERCE (Fire Integrated Environment for Risk Comprehension and Evaluation) framework is a holistic framework that provides stakeholders (authorities, tunnel safety officials, contractors, designers, …) with a tool to evaluate the safety level of a tunnel taking into account life safety, firefighter safety and expected downtime after a fire. To take into account the different scenarios including new energy carriers, the probabilistic approach allows for a strong focus on the trade-off to be made between costs and benefits of the fire safety installations. With the increase in DBFM projects and a shift in responsibility towards the contractor and/or tunnel safety officials it is clear that not only the initial investment cost is a determining factor but that also the potential costs associated with a loss of business continuity due to a tunnel closure (macro-economic impact) play a vital role in the selection of the adequate fire safety equipment. The FIERCE framework, being holistic in nature aims to take these considerations into account from the very start and offers all stakeholders an objective tool to decide on the most appropriate measures when it comes to tunnel fire safety based on financial and economic considerations.

The FIERCE framework consists of three interacting layers. The first layer includes the smoke spread and occupant evacuation as well as the probabilistic treatment of boundary conditions (e.g. wind or acceptable risk). Layer two addresses firefighter intervention, fire safety measures (ventilation, suppression, …), traffic influences and fire development. The third and final layer adds a financial analysis layer to the two underlying layers. The results of the underlying layers allow an assessment of the expected level of damage (LOD) and estimate the impact of the fire on business continuity. The results of such an analysis offer a tool to decision makers to accept an optimized solution for the entire lifecycle of the tunnel.
Instrumentation for the SHA
Willy Peelen (TNO)

The structural health analyzes (SHA, see session in round 2) performed by the COB network also include a set of instruments. These are being developed by TNO and Deltares, and will be presented in this session.

An important part of the set of instruments is a knowledge system that makes expert knowledge and information from all kinds of sources explicit, combines them and makes them easy to aquire. In addition, a monitoring intake template has been developed with which a monitoring plan can be drawn up in a systematic manner. To improve the monitoring itself, work is being done on data enhanced modeling: by including measurement data ​​in a model, the development of, for example, deformations can be predicted more accurately. The fourth part of the toolbox focuses on artificial intelligence (AI). There are various computer techniques that can already help detect leaks in tunnels, among other things. In addition, AI offers a good future perspective if more data becomes available from the SHA's.


16.05 • Round 4 (including overall wrap-up)

How to exploit rapid digital innovation in safety-critical application areas
Rune Winther (Multiconsult)

There is a considerable drive to exploit opportunities coming with new digital technologies, and it is easy to be carried away. Planning these new systems requires something different from the actors involved with risk management. Digital systems are different from analogue systems in terms of e.g. planning and how they act. If we fail to consider and acknowledge this, we may end up choosing solutions that are neither safe nor reliable. Professor Nancy Leveson puts it nicely in her article 'High pressure steam engines and computer software', and we will refer to her work in this session. We will discuss important principles for integrating safety and security in digital solutions, discuss safe and agile processes of developing digital systems and discuss advantages of using more dynamic safety documentation approaches, e.g. graphical safety cases.
Refurbishment with a water mist system for the Hugh L. Carey Tunnel in New York City
Tim Usner (FOGTEC)

The Hugh L. Carey Tunnel (formerly knows as Brooklyn-Battery Tunnel) is a underwater tunnel which connects Manhatten and Brooklyn. At the time of its opening, the tunnel was the longest underwater vehicular tunnel in the United States and the second-longest in the world, behind the Queensway Tunnel under the River Mersey in England. To raise its availability the Authority having Juristication (AHJ) decided to equip parts of the tunnel with a water mist system as a prototype with the option of protecting the whole tunnel afterwards. FOGTEC designed and provided this system as a sub-contractor for the general contractor Navillus. Full scale fire tests in order to proof the system performance where demanded by the AHJ. The tunnel is over 70 years old and therefore a challange for a refurbishment project. A lot of effort was put into a good design in order to satisfy the clients requirements.
Electric vehicle fires in underground infrastructures
Michael Kompatscher (Hagerbach AG)

Electric vehicle fires with lithium-ion batteries lead to new types of pollutant emissions. The presentation of the recent FEDRO (Federal Road Office) study shows that this changes the toxicological risks in underground traffic infrastructures because these pollutants do not occur in fires of conventional vehicles. These battery specific contaminations will not result in any lasting technical impairment of operations in underground car parks or road tunnels but they will make a careful handling of fire-fighting and cooling water essential.

An experiment was carried out in the underground facilities of Hagerbach Test Gallery Ltd, which provide a real environment for fire tests related to both underground car parks and road tunnels. The experiment focused on maximum damaging a lithium-ion battery (type NMC) used in a battery electric vehicle approved for traffic (status 2019). The analysis of fire residues and their impact on infrastructures was the main focus. Neither fire or crash tests were conducted with full electric vehicles nor were there any analyses on the probability of such damages.

The hypothesis that the emissions from electric vehicle fires in underground traffic infrastructures lead to lasting effects cannot be confirmed. The study concludes that a technical impairment of typical infrastructure components in underground car parks and road tunnels can be practically excluded. However, the battery specific emissions of an electric vehicle fire will lead to contamination which is of toxicological importance for decontamination and disposal work. Based on the findings, six risk-reducing measures can be derived, which are primarily of an organizational nature.
Structural and geotechnical monitoring for infrastructural asset management: new prospective
Paolo Mazzanti (NHAZCA)

An infrastructure consists of an integration of various engineering assets that play a key-role in the effectiveness of the whole system. Despite the important role of engineering and geotechnical assets on the efficiency of linear infrastructures (such as roads and highways, railways, pipelines, electric power lines, etc.) the role of the asset management has been often underrated and systematic management is still not applied and regulated by common practices. For example, even though transport authorities are pursuing several initiatives in the fields of natural hazards assessment and management and maintenance of transport corridors, they often deal with risk management in emergency conditions following extreme events (i.e. a landslide, a bridge collapse). In this context, structural and geotechnical monitoring activities can be very useful in supporting infrastructural asset management strategies.

Today, the monitoring activities, when performed, are mainly developed at local scale by using contact sensors. The last innovation in the monitoring field, in particular the opportunities coming from the Earth observation satellite sector, are still not fully exploited. In fact, in the last decades there has been a growing development of innovative techniques in the field of observational methods, for the characterization and monitoring of natural hazards and structures/infrastructures. The advantages offered by the most innovative monitoring technologies for asset management purposes will be presented and highlighted in some examples of recent applications.
Innovations in energy savings
Séverine Besson (CETU)

The construction, renovation and operation of road infrastructure, especially tunnels, generate environmental impacts. In a context where there is a need to reduce energy consumption and preserve the environment, it is essential to develop a policy to assess these impacts and identify ways of reducing them.

For underground structures, studies show that lighting is one of the main items of energy consumption during the operating phase. At the same time, recent technological developments, such as LEDs, now offer new prospects for significant reductions in energy consumption in road tunnels. Whether through fundamental research, applied research in laboratories, or experiments in the field during renovation operations, the CETU has undertaken considerable work to assess and measure these possible savings.

Does colour temperature have an influence on visibility? What are the limits of adapting lighting to luminance? What are the challenges of varying lighting to traffic speed? Are there alternatives to LED lighting? These are all issues that we would like to share with you in the search for lighting that guarantees safety for users whilst at the same time enabling savings. Reducing energy consumption is everyone's concern! The renovation of tunnels offers an opportunity to make headway in this direction by rethinking tunnel lighting and is a chance not to be missed!
Cross-asset, reliability-based life cycle management of tunnels
Urs Grunicke (UHG Consult) and Christoph Antony (ASFiNAG)

Tunnels on the primary road network are complex systems. The prerequisite of a good level of service is the seamless interaction of the various tunnel components (structural elements and technical equipment). Due to their heterogeneous nature, electrical and structural components are subject to divergent aging processes which require recurring maintenance procedures and rehabilitation measures. Considering the different specifications and requirements for electrical/mechanical and structural components, it is evident that there is a considerable mismatch of maintenance cycles between these groups. Hence, tunnel asset management faces the challenge to develop strategies to integrate both the necessary functional integrity of the individual components over their respective lifecycle and the requirement of an optimized management for the overall system. Yet, the synchronization of measures towards maximizing system availability must not contradict positive wear-and-tear contingencies of the various tunnel components.

We will present the results of the research programme OPtimAL, which aimed to solve this optimization task. A framework was developed and implemented into a prototype algorithm for Austria's ASFiNAG asset management systems. A major step in this work was the derivation of optimized lifecycles for structural and electrical/mechanical components of tunnels and their transfer to the overall asset portfolio of ASFiNAG.
Smart collaboration between tunnel owner and contractors: best of both worlds
Arnoud op den Kelder (Municipality of Amsterdam)

The Municipality of Amsterdam manages five road tunnels which are very important for good accessibility of the city. Some of these tunnels will have to be renovated in the coming years. This also applies to the traffic control center from which the tunnels are operated and monitored. In the Amsterdam Road Tunnels Approach programme, the municipality has laid down how the tunnels and the traffic center will be modernized in the period up to 2025.

For two tunnels, the Piet Hein tunnel and the Michiel de Ruijter tunnel, the work has already started. In both projects, the municipality works closely with market parties, but in different ways. The pros and cons of the various forms of cooperation are discussed in this session.