Predictive maintenance and SHM (Structural Health Monitoring):
Transforming your infrastructure management

Predictive Maintenance (PdM) combined with Structural Health Monitoring (SHM) is revolutionizing the management of critical infrastructure such as bridges, dams, and pipelines, to face challenges like ensuring longevity and safety while adapting to climate change. These advanced technologies predict maintenance needs, reducing costly unscheduled downtime and enhancing the durability of vital structures. This article explores the application of PdM and SHM in infrastructure, detailing their operational mechanisms, benefits, and strategies for successful deployment.

The basics of predictive maintenance and structural health monitoring

Understanding predictive maintenance

Predictive Maintenance (PdM) is a proactive maintenance strategy that uses data analysis to predict when an equipment failure might occur, so that maintenance can be planned based on the actual condition of the equipment. This approach helps to prevent unexpected equipment failures and reduce unnecessary preventive maintenance activities.

PdM involves the use of various types of sensors to collect data on equipment condition. This data can include vibration, temperature, pressure, and other types of information that can indicate potential problems. Advanced analytics and algorithms are then used to identify patterns in the data that may signify a future failure.

The evolution of predictive maintenance (PdM)

Early stages: Predictive maintenance has been around since the early 1990s. Initially, its application was limited due to the lack of sophisticated sensors and computing power. Traditional predictive maintenance was industry-specific, focusing on machines with complex, custom-built models.

Advent of IoT and cloud computing: The advent of the Internet of Things (IoT), cloud computing, data analytics, and machine learning has significantly expanded the practicality and applicability of PdM. The IoT has enabled the collection of vast amounts of data from various sensors installed on infrastructure. Cloud computing has provided the infrastructure to store and process this data.

Role of data analytics and machine learning: Data analytics and machine learning have revolutionized predictive maintenance, transitioning it from reactive to proactive approaches. By analysing vast data sets and patterns, these technologies enable early detection of equipment issues, optimise maintenance, enhance reliability, and extend asset lifespan. Machine learning algorithms, after undergoing rigorous training on historical data encompassing sensor readings, maintenance actions, and past failures, evolve into virtual experts capable of recognizing precursors to faults.

The role of structural health monitoring

Structural Health Monitoring (SHM) is a process used to identify damage in a structure. SHM systems can provide real-time information about the structural integrity of bridges, buildings, and other structures. This information can be used to make informed decisions about necessary repairs and maintenance, improving safety and operational efficiency.

SHM involves the use of sensors to monitor a structure over time. The data collected from these sensors is then analysed to identify any changes that may indicate damage or structural degradation. This can include changes in the material properties, geometry, and boundary conditions of the structure.

How predictive maintenance and SHM work together?

Predictive Maintenance (PdM) and Structural Health Monitoring (SHM) are like the doctors of our infrastructure. They keep a close eye on the health of our buildings, bridges, and more, much like a doctor would monitor a patient’s vital signs.

Here’s how they work together:

  • Sensors: Just like a doctor uses a stethoscope or thermometer, PdM and SHM use sensors attached to the structure. These sensors can measure things like how much a building is shaking (vibration), how much stress is on a bridge (strain), how hot a machine is getting (temperature), or how much pressure is in a pipe (pressure).
  • Data Collection: These sensors are constantly collecting data, like a doctor taking regular check-ups to understand a patient’s health.
  • Data Analysis: This data is then analysed, much like a doctor would look at test results. The goal is to find any signs that something might be wrong – like wear and tear on a machine, or a potential failure in a bridge.
  • Taking Action: If the data analysis shows that there might be a problem, the maintenance teams can then take action. This is like a doctor prescribing medicine or recommending surgery to fix a health issue. The teams can fix the problem before it gets worse, which helps to keep our infrastructure safe and last longer.

Practical applications of predictive maintenance and SHM in infrastructure

Here are a few examples of how Predictive Maintenance and Structural Health Monitoring can be implemented in various types of infrastructure.

1.    Bridges

Bridges are vital components of transportation networks, and their failure can have severe consequences. PdM and SHM can significantly enhance the maintenance of bridges. Sensors such as accelerometers and strain gauges can monitor vibrations and stress levels, providing real-time data on the bridge’s health. For example, accelerometers can detect unusual vibrations indicating structural weaknesses, while strain gauges measure the stress on bridge components, allowing for timely repairs.

Example: The Golden Gate Bridge in San Francisco uses a comprehensive Structural Health Monitoring (SHM) system with over 300 sensors to monitor wind speed, temperature, and stress on the bridge’s components. This system helps engineers detect potential issues early and plan maintenance activities effectively.

2.    Dams

Dams are crucial for water supply, flood control, and hydroelectric power. PdM and SHM can help ensure their structural integrity. Sensors can monitor water pressure, seepage, and structural deformations. For instance, piezometers measure water pressure within the dam, and crack meters track the growth of fissures. By analysing this data, potential issues like leaks or structural weaknesses can be detected early, preventing catastrophic failures.

Example: The Hoover Dam employs an extensive network of over 500 sensors to monitor structural integrity, measuring factors such as water pressure, seepage, and concrete temperature. This data is critical for analysing and predicting potential problems, ensuring the dam’s safety and functionality.

3.    Pipelines

Pipelines transport essential resources like water, oil, and gas. PdM and SHM can prevent failures that lead to environmental disasters and significant economic losses. Sensors can monitor pressure, flow rate, and temperature. Advanced techniques such as acoustic emission monitoring can detect leaks by identifying sound waves generated by escaping fluids. This allows for precise and timely interventions, ensuring the pipeline’s integrity.

Example: The Trans-Alaska Pipeline utilizes Predictive Maintenance (PdM) to monitor the flow and pressure of oil transported through the pipeline. Acoustic sensors detect leaks by identifying sound waves generated by escaping oil, helping to prevent environmental disasters and maintain the pipeline’s efficiency.

Developing a PdM and SHM solution

Data collection and integration

The foundation of an effective PdM and SHM solution is robust data collection. Sensors placed on infrastructure gather real-time data on various parameters. This data is combined with historical maintenance records and environmental information. Ensuring the accuracy and reliability of this data is crucial for developing predictive models.

Example: In a wind turbine, various sensors are installed to monitor its health. These include vibration sensors, temperature sensors, strain sensors or acoustic sensors. The data collected from these sensors is then integrated with other relevant information like historical maintenance (when and what maintenance was performed) records and environmental information (wind speed, humidity and temperature).

Creating predictive models

Data scientists use machine learning algorithms to analyse the collected data and develop predictive models. These models can identify patterns that indicate potential failures. For example, a model might predict the likelihood of a pipeline leak based on pressure fluctuations and temperature changes. By continuously refining these models with new data, their accuracy improves over time.

Example: Data scientists might use a machine learning algorithm, such as a Random Forest or a Neural Network, to analyse the collected data. These algorithms can identify complex patterns in the data that might be difficult for a human to spot.

For instance, the model might find that a specific pattern of vibration and temperature increase in a machine is often followed by a failure a few days later. This pattern would then be used to predict future failures.

Deployment and continuous improvement

Once developed, predictive models are deployed to monitor infrastructure in real-time. These models can be run on edge devices for immediate diagnostics or in the cloud for more comprehensive analysis. Continuous improvement is essential; as more data is collected, the models are refined to enhance their predictive capabilities.

The benefits and challenges of predictive maintenance and SHM

Benefits of PdM and SHM

The adoption of PdM and SHM in infrastructure offers numerous benefits, including:

  • Reduced downtime: By predicting potential failures before they occur, PdM and SHM can help reduce the downtime of infrastructure, leading to increased operational efficiency.
  • Cost savings: PdM and SHM can lead to significant cost savings. By performing maintenance only when it’s needed, organizations can avoid unnecessary maintenance costs. Also, by preventing major failures, they can avoid the high costs associated with such failures.
  • Increased safety: By detecting potential failures early, PdM and SHM can help prevent accidents and improve the safety of workers and the people.
  • Extended asset life: PdM and SHM can help extend the life of the infrastructure by ensuring that they are well-maintained, and any potential issues are addressed promptly.
  • Improved planning: With PdM and SHM, maintenance can be scheduled based on the actual condition of the infrastructure, rather than on a set schedule. This can lead to more efficient use of resources and better planning.

Overcoming challenges of predictive maintenance and SHM

Organizations may face different challenges when implementing PdM and SHM. These challenges include:

  • Data management: PdM and SHM systems generate large volumes of data, which can be challenging to manage. This includes ensuring the data is stored securely, organized effectively, and can be accessed quickly when needed.
  • Model accuracy: Ensuring the accuracy of predictive models is crucial. If a model is not accurate, it could lead to false positives (predicting a failure that doesn’t occur) or false negatives (failing to predict a failure that does occur). This requires rigorous testing and validation of models.
  • Costly resources: Implementing PdM and SHM systems can be resource-intensive, posing a challenge especially for smaller organizations. However, the long-term benefits, such as reduced maintenance costs and extended asset life, often justify the initial investment.
  • Technological limitations: There can be technological limitations, such as limited sensor capabilities, network connectivity issues, or computational constraints, that can pose challenges to the effective implementation of PdM and SHM.

Conclusion:

PdM and SHM are revolutionizing the way we manage and maintain our infrastructure. By harnessing the power of data and sophisticated analytics, these systems allow us to proactively care for vital structures like bridges, dams, and pipelines, enhancing their longevity and ensuring their safety. As we further tap into the capabilities of the Internet of Things (IoT), cloud computing, and machine learning, PdM and SHM are set to become essential tools in preserving the infrastructure that underpins our contemporary world.

Simultaneously, they are reshaping our approach to infrastructure maintenance. Through the collection and analysis of data, we’re able to anticipate and avert failures, guaranteeing the smooth and safe operation of crucial structures. As technological progress continues, the reach and impact of these systems will only grow, leading us towards a future of increasingly intelligent and efficient maintenance practices.

SHM’s Sixense solutions

Sixense, as part of its predictive maintenance and SHM offering, is involved in part of the cycle, implementing permanent sensors, spot checks, digital solutions and data analysis.

Sixense offers a complete range of services: SHM+, with the aim of maintaining and extending the lifespan of infrastructure and detecting and predicting their failures. Sixense monitors both the structure and its environment (use, weather, etc.) by integrating various measurements, often automatic, including by satellite. The SHM+ offer comprises several solutions, including EverScan, EverSense®, Beyond Monitoring and Beyond Asset. It is divided into three parts to ensure the safety and longevity of your structures:

Diagnosis and design: Define instrumentation objectives and design the monitoring system with:

  • Evaluation of the expected behaviour of the structure and identification of the phenomena to be monitored,
  • Definition of the general monitoring strategy and the scope of the instrumentation (global, local),
  • Identification of the parameters to be measured and the areas to be instrumented,
  • Selection of sensors and design of the system architecture.

Continuous monitoring: deploying a smart and robust monitoring system with:

  • Efficient and durable equipment to ensure continuity of service,
  • Skilled operators for installation, commissioning and maintenance,
  • Automatic alarms in case of significant events,
  • Data accessible at any time via a web application,
  • Periodic summary reports.

Decision support: interpret the data, assess the situation and support predictive maintenance with:

  • Adaptation and relevance of thresholds,
  • Interpretation of measurements and structural condition assessment,
  • Dynamic behaviour analysis,
  • Modelling and prediction of behaviour on digital twin.

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