Innovation in the detection of structural problems of bridges

Acoustic monitoring of bridges

Artificial intelligence, technology and the ability to remotely monitor structures are some of the most modern and useful innovations to enter the construction industry in recent times. This is particularly true in the field of structural and geotechnical monitoring. To check and maintain the long-term structural health and safety of assets, this field implements several highly effective methods with broad applicability, immediate operability and reliable efficiency.  

Acoustic monitoring of bridges is one of these innovations, aimed at accurately detecting any problems with structural cables in a non-invasive and efficient way. 

 Our internationally experienced expert, Nicolas Cortes, explains how this technology can be used to maintain the structural safety of bridge projects; what the benefits are and how it works. 


Nicolas Cortes, SHM Expert

Could you please describe the technology behind the acoustic structural monitoring of cable structures? How does it work specifically? 

The technology uses piezoelectric sensors designed to detect the noise (vibration in material) generated by the failure of a structural cable wire as it releases the energy stored during its tensionning.

Sound travels witin the infrastructure (similar in frequency range, but very different from a microphone that is used to record  sounds travelling in air).

Our system is designed to record  every sound produced within the structure. These recordings are made by each individual sensor with an highly accurate synchornisation (µs). An advanced triggering condition strategy ensures that only the  sounds of interest are recorded. These short-time recordings are called „events”.

Drawing on over 20 years of experience, we have developed an Artificial Intelligence (AI)-based filtering algorithm that pre-processes the events and retains only those that match the acoustic signatures of a wire break. In a final step, an expert analyst confirms whether the event is an actual wire break. We use proprietary software with a localisation tool to analyse the events and identify where the event occurred. The technology applies to the monitoring of all types of structural cables used in civil engineering (stay cables, post-tensioning cables, pre-tensioning cables, suspension cables, anchor cables, etc.).   


EverSense Acoustic

Why is acoustic structural monitoring important / mandatory for bridges? 

Acoustic monitoring is not mandatory. It is usually used in cases where corrosion or fatigue is suspected (or found during inspections) and the structural cables (e.g. stay cables or post-tensioning cables used to increase the load-bearing capacity of a bridge) are at risk.

What are the risks to be  considered by public authorities/beneficiaries of these structures – if they do not implement acoustic structural monitoring on bridges? 

Partial / total structural  failure of the bridge is the main risk. Cables are designed to increase the load-bearing capacity of bridges, so failure of one or more cables can put the structure at risk. As a result, traffic restrictions or repair work may be decided upon.   

What are the main benefits of implementing acoustic structural monitoring on bridges? Please comment on the expected outcomes and results.  

Acoustic monitoring makes it possible to follow the progressive degradation of structural cables, to prioritize maintenance on specific parts of the bridge, and in some cases decide wether the bridge is still safe for operations (or within certain traffic load restrictions). It is a very valuable source of information for engineering departements to take into account.

Acoustic monitoring is usually  complementary to other NTD solutions to provide a complete picture of some keystructural elements. It is the only technology available that has the sensitivity to detect and continuously monitor the event of a single wire break and to identify the structural element involved. No other technique can currently provide this level of sensitivity to damage, on a continuous monitoring basis.

What is the main way of working with this type of structural monitoring? How can it be used/adapated locally, in bridge projects? 

Ageing cabled-bridges with a serious suspicion of corrosion or fatigue should be targeted. It may be possible to instrument only specific cables or a local section where specific ageing has been observed.This partial approach can optimise the cost of a system that could be expensive and not necessarily usefull if applied without prior consideration.

This monitoring can provide confidence in the rate of ageing (if few events are observed) or allow time to organise cable replacement (if significant damage is observed).


Maintenance strategies: enhancing asset performance

Maintenance strategies: enhancing asset performance

Maintenance strategies are critical to ensuring the longevity and safety of infrastructure assets across all industries. Ranging from corrective to proactive, they play a critical role in extending asset lifespan, optimizing performance, and mitigating the risk of downtime and failure.

Recent incidents, such as bridge collapses, underscore the urgency of robust maintenance practices to protect critical structures. As infrastructure management paradigms evolve, it is critical to select appropriate maintenance approaches that consider asset criticality, operational needs, and technology integration.maintenance strategies

The integration of technologies such as sensors and data analytics has revolutionized maintenance practices, enabling real-time monitoring and predictive insights. By understanding the importance of maintenance and leveraging technological advances, organizations can effectively manage infrastructure assets to ensure operational efficiency, regulatory compliance, and stakeholder confidence.

Asset lifecycle management

Understanding the asset lifecycle is crucial for developing effective maintenance strategies. It includes stages like installation, operation, degradation, intervention, repair, and eventual decommissioning. Metrics like Time to Maintenance (TTM), Time to Failure (TTF), and Time to Repair (TTR) indicate asset performance and maintenance efficacy.

Different maintenance strategies

Maintenance isn’t just a response to failures but a proactive endeavor. Strategies include:

  • Corrective maintenance: Addresses issues as they occur, suitable for unexpected failures with limited resources.
  • Preventive maintenance: Involves scheduled inspections and maintenance tasks to forestall potential failures, ideal for assets with predictable degradation patterns.
  • Condition-based maintenance: Relies on real-time data and condition monitoring technologies to trigger maintenance, appropriate for assets with variable usage patterns.
  • Predictive maintenance: Forecasts failures using advanced analytics and historical data, suitable for assets with well-understood failure modes.

Cost Analysis

Evaluation of maintenance strategies includes consideration of failure costs (repair and consequential costs), maintenance costs (intervention, equipment, storage, training, and administrative costs), and monitoring costs (hardware, software, data management, labor, calibration, and maintenance costs).

If you would like to read our full news, please visit our website dedicated to Beyond Asset, our digital asset management solution, by clicking here.

Webinar – Sissterra

Sixense and the Association of Geotechical & Geoenvironmental Speclialists – AGS-HK are pleased to invite you to our technical webinar held by Maria Saadé and Clément Mogenier, Sixense geophysics experts.

Sissterra is a turnkey solution for 3D underground imaging in restricted environments. It is a unique passive seismic solution using ambient noise generated by human activity to image the subsoil and monitor dynamic changes beneath the surface.

Join our webinar to find out more about our solution :

📅 Date: 13 January 2023

Time: 18:30 – 19:30 (Hong Kong Time)

💻 The webinar will be conducted through Zoom. Successful applicants will be informed by emails with a Zoom’s link to the webinar.

💲 The webinar is free of charge

Registration: AGS (HK) Technical Seminar 13 January 2023 (

Please register not later than 9 January 2023. Successful applicants will receive webinar details on 10 January 2023.


Sissterra® is a 3D passive tomography solution for imaging the subsoil at high resolution. The measurements require the deployment of a network of autonomous, non-intrusive and easy to deploy, seismic nodes on the surface of the study area. The network does not have to be regular and can be adapted to the area of study. Its design can be defined relatively to the depth of investigation (depends on the dimensions of the network) and the lateral resolution needed (equal to the spacing between nodes) and can allow to investigate deep and shallow depths without requiring any active source such as explosives or truck-mounted vibrators.

The Rayleigh waves hidden in the noise signal are extracted by the computation of a cross-correlation between each pair of receivers. This procedure multiplies the number of measurements since we consider pairs of receivers and not individual ones. Dispersion curves obtained from the cross-correlations are inverted into shear velocity variations with depths. The resulting 3D Vs model can allow the highlight of the main geological features in the area, the different seismic horizons, and contrasts that can be interpreted as heterogeneities, weathered soil, cavities, etc.

About the speakers:

Dr. Maria Saadé is currently Expert in Seismic method and mainly the SISSTERRA solution for Sixense Group in Nanterre, France.
She did her PhD in Seismology, specialized in passive monitoring at Institut de Physique du Globe de Paris in 2016. She held then 2 postdocs at the university, the 1st one in the seismology team working on passive imaging and monitoring for earthquakes in Japan and the 2nd one in the planetology team working with the scientific team of the NASA InSight mission.
At Sixense, she worked on several projects including: extensions to Paris metro lines, construction sites, dams and seismic risk analysis with different entities such as the CEA (French Alternative and Atomic Energies Agency) and EDF (Electricity of France), tunneling projects in France and Luxembourg, deep underground storage facilities in Morocco, the NEOM project in Saudi Arabia.

Mr. Clement Mogenier is currently Senior Project Manager for Sixense Group in Lyon, France.

He received his MSc in Applied Geosciences in 2006 from Université Savoie Mont Blanc, France. He spent his whole career as an Engineering Geophysicist for Sixense Group in Europe and in Hong Kong SAR.

He has been involved in large scale geophysical surveys for several major construction projects in France: the Eastern High Speed railway, extensions to Paris and Lyon metro networks, Lyon-Turin Base Tunnel (TELT)… and also overseas in Africa, Western Europe, Asia, Middle East, Oceania for large infrastructures projects like the West Island and South Island Lines, the Shatin to Central Link in Hong Kong, the Nam Theun 2 dam in Lao, the Metro Tunnel Project in Melbourne, or more recently the NEOM project in Saudi Arabia.

InSAR and Earth Observation Techniques for Infrastructure (C805)

The development of Earth Observation techniques

Earth Observation covers a wide range of technologies that have come of age throughout the past two decades and are expanding into a new era of cloud processing, very high-resolution and near real-time service delivery with the use of spaceborne data within infrastructure asset management.

The launch of the new CIRIA guidance report

We are delighted to announce that the new CIRIA (Construction Industry Research and Information Association) guidelines on Earth Observation and InSAR technology in civil infrastructure is now available.

Produced by a consortium led by Sixense and Imperial College London, the guidance report improves accessibility to Earth Observation technology by understanding techniques and products applied to infrastructure management.

What you will learn about ?

The report draws on the extensive experience of the consortium members and detail current practices, illustrated with case study examples, and outline respective advantages and limitations of the various techniques to assist all users and in particular those involved in asset management and construction. It forms an important step towards establishing the use of Earth Observation techniques as a matter of ongoing best practice for asset management in civil infrastructure projects.

Follow the link below to order your copy:

For more information, please contact

How we can build more resilient infrastructure projects?

A sustainable infrastructure also means a more resilient one. For that matter, we asked Bunafsha Mislimshoeva, Head of International Projects Development at Resallience (our design office specialised in climate resilience), to explain more about this concept and how we can build more resilient transport infrastructure projects, in the context of an everchanging climate environment.

Let’s see what our expert Bunafsha has to say about this. ?

? Could you please explain to us the importance of building a more resilient infrastructure? Please provide us with a bit of context: where does this urgency come from and why now?

The urgency of building climate resilient infrastructure has been there at least for the last two and half decades. Already during the early Conferences of the parties (COPs) of the United Nations Framework Convention on Climate Change (UNFCCC) climate change impacts on infrastructure have been raised. This urgency became more evident after the Paris Agreement which was negotiated and agreed upon by 196 countries in 2015. This conference and the follow up COPs indicate a clear consensus about the impacts of climate change on infrastructure among all other sectors. The report of the Intergovernmental Panel on Climate Change (IPCC), which was released in the beginning of this year, indicated an urgent need for climate change adaptation and mitigation across countries and sectors. The IPCC, for example, also mentions that by 2050 urban areas will be home third of the world’s population. This means that our infrastructure will have to accommodate more people, but at the same time should become more resilient. Any impact on infrastructure will increase the exposure of big share of the population of cities and create a cascading effect across critical infrastructures. Therefore, building resilient infrastructure is crucial as never before. Bunafsha Mislimshoeva, Head of International Projects Development at Resallience

? What does building climate resilience actually mean?  

It basically means to plan, design, build and operate infrastructure that anticipates impacts of climate change, preparing for these impacts and adapt to them. As a result, the impacts of climate change may not be fully eliminated but they can be reduced to the extent possible. In more concrete terms it means that new infrastructure considers climate change impacts that may occur over the lifetime of that infrastructure. As for the existing infrastructure it is about managing them differently, for example during the maintenance, renovation to reduce the impacts of climate change. So it is about acting and not re-acting to the impacts of disasters. The link between infrastructure and climate change is rather complex and two-sided because infrastructure can both - contribute to climate change but also be affected by climate change. For example, the built environment generates nearly 50% of annual global CO2 emissions and at the same time continuously impacted by extreme events. As the frequency and intensity of climate and weather extremes increases, our infrastructure will need to adapt to better absorb these shocks. Therefore, the upcoming few years play decisive role for the development of our infrastructure. Metaphorically speaking, we need to design and construct our infrastructure in a way that it can be bend but not break. Bunafsha Mislimshoeva, Head of International Projects Development at Resallience

? How do you see the degree of preparation of other countries regarding the subject of climate resilience? Is Europe ready to act or has it already started planning?

Unfortunately, there are no available rankings or indexes or so to show the preparedness of all countries with focus on resilience only. However different rankings are available which use diverse methodologies to rank the performance of countries on climate change. The results are however similar, or at least show similar trends. The results show that Denmark, Sweden, Norway, UK, Morocco, Finland, and Malta at forefront of tackling climate change. Many other EU countries also received high rankings and are within the top 10 countries, which is a good indication of Europe taking active actions. There is a lot happening following the European Green Deal and the implementation of related policies as well as regulations. Europe aims to be the first climate-neutral continent by 2050 which requires ambitious changes across sectors including infrastructure. The role of businesses, cities initiatives, investors and generally making funds available for implementation is very critical now. It all boils down to actions and consequent changes on the ground which require substantial funding and financing. So, yes, Europe is ready to act and slowly but surely, we are witnessing the impacts of these acts on the ground in our daily life. There is a strong political shift and even if we are far away from the goals, we should not lose hope and optimism and each of us should play its part. Bunafsha Mislimshoeva, Head of International Projects Development at Resallience

Digitisation in the construction sector: a story to be written

In terms of digitisation, the construction industry is slowly starting its transformation. However, solutions already exist which will soon allow the two worlds of construction and operations, for building and infrastructure, to communicate with one another, while very little interaction was possible up until now. Pascal Berger, CEO of Sixense Group, explains.



The digitisation process in the construction industry is going at a slower pace than in other sectors. How far have we come in this respect?

We are still at the beginning of the journey, even if digitisation is already in place in numerous areas, such as quality control or supply chain, which follow established standardized processes. However, as far as the core business is concerned, construction on one hand and infrastructure operations on the other, digital tools are still not visible at a large scale. There are many stakeholders collaborating and interacting in these activities. One of the challenges that digitisation addresses is the orchestration of these actors, who need to have access to a common source of information continuously and updated in real time. In this context, the key principles to be implemented are the digitisation of the operational tasks and the capture of real time information to provide updated status on the work or the asset.


What is the main purpose?

The ultimate objective is to monitor the full life cycle of the infrastructure in order to help make decisions during construction, operations and maintenance. Today, the two worlds of construction and operations continue to exist separately. Both are being digitised, but independently. Therefore, there is still a gap between these two worlds, which do not yet communicate efficiently. A seamless process between them needs to be built; the goal being to manage and control the data throughout the full life cycle.


Are there already solutions to achieve this?

We do have a solution under development. It is a data integration platform called Beyond. This platform can be activated during the construction phase, just as it can be used during the operations and maintenance phase. Digitisation will then expend through the multiplication of use cases generating value. Over time, the multiplication of such use cases will create a seamless connection between construction and operations, through the emergence of common standards relevant for both domains.


Environmental responsibility is one of the new challenges facing construction companies. Will digitisation enable the industry to meet its commitments on this topic?

Environment is a major stake for these new technologies, in which I also include artificial intelligence, and how they can contribute to this challenge. These technologies offer new ways of ensuring infrastructure and building sustainability, which essentially means expending their lifespan. Thanks to real-time monitoring, it will become possible to get a better understanding of how these infrastructures age and evolve. Civil Engineers will be able to optimise their maintenance so that buildings and infrastructures can last longer, while anticipating and managing risks, whether these risks are linked to ground events (landslides, subsidence, etc.) or to the structure of the edifice itself.



An article from #JMLECO BFM Business by Scribeo (France)

Sixense coauthors the new ASCE publication

The American Society of Civil Engineers represents more than 150,000 members of the civil engineering profession in 177 countries. Founded in 1852, ASCE is the nation’s oldest engineering society. ASCE stands at the forefront of a profession that plans, designs, constructs, and operates society’s economic and social engine – the built environment – while protecting and restoring the natural environment.


ASCE’s newest publication

ASCE recently released its newest book, “Remote Sensing for Monitoring Embankments, Dams and Slopes, GSP 322”. It provides information on selecting and deploying a monitoring network to assess the behaviour, geometry, total and differential for embankments, dams, and slopes (EDS) movement, and potential risks of the EDS movement on people and infrastructure. It includes information on a broad range of technologies for deploying remote sensing:

  • Radio Detection and Ranging (radar),
  • Synthetic Aperture Radar (SAR),
  • Interferometric Synthetic Aperture Radar (InSAR),
  • Light Detection And Ranging (LiDAR),
  • Digital photogrammetry and image processing,
  • Microelectromechanical Systems (MEMS),
  • Automatic Motorised Total Stations (AMTS), and
  • Unmanned Aircraft Systems (UAS).


Sixense’s contributions to the book

This book, sponsored by the Geo-Institute Embankments, Dams and Slopes Technical Committee is the product of many practitioners’ and academicians’ contributions over a period of more than 24 months. Employees from Sixense USA and Iberia contributed to this collective work through book planning and co-authoring the InSAR, AMTS, Satellite Internet, and Case Histories chapters. Practitioners and researchers will find this publication useful in understanding and utilising currently available remote sensing technology and to advance and refine the monitoring of embankments, dams and slopes.


Both the print and e-book are available for purchase on ASCE Bookstore.
More detailed information about individual book chapters can be found on ASCE library.