Monitoring bridges: how to manage infrastructure assets with IoT

The most innovative monitoring systems for bridges and infrastructures with the help of BIM and IoT sensors

Bridge monitoring is an essential preventive action for the security of infrastructure and its users.

There are currently new technologies that facilitate and improve infrastructures’ monitoring such as sensors, digital tools, artificial intelligence and IoT systems. In this article, we will explore the role of bridge management software in infrastructure heritage management focusing on the technologies used and bridge monitoring.

monitoring with an IoT BIM platform

What is Bridge Monitoring?

Bridge monitoring is a process that involves the observation and collection of data regarding the structural and functional conditions of a bridge. Through adequate monitoring systems, it is possible to identify any anomalies or materials’ degradation, ensuring works’ safety, efficiency and durability over time.

How to assess existing bridges’ safety

The safety assessment of existing bridges is based on several parameters, including:

• Age;
• material;
• type of structure;
• load;
• atmospheric agents exposure.

Evaluation methodologies include:

• visual analysis;
• drone inspection;
• use of sensors and monitoring systems;
• calculation of load-bearing capacity through mathematical models and specialized software.

Inspection and monitoring

Bridge monitoring and inspection surveys are two complementary approaches to assessing bridge safety. Monitoring consists of detecting data in real time through sensors and monitoring systems allowing a continuous evaluation of structural conditions. Inspection investigations, on the other hand, involve a visual analysis or the use of specific technologies at predetermined times.
Visual inspections and the compilation of bridge defect sheets are fundamental processes to ensure the safety and proper infrastructure’s maintenance. During these inspections, technicians and engineers examine decks condition to identify any structural problems or damage, documenting results to plan any repairs or maintenance. Below are some of the main steps for visual inspection and compilation of bridge defect sheets.

1. planning and preparation: before proceeding with the inspection it is important to plan and properly prepare the activity. This includes reviewing historical information about the bridge, identifying examining critical areas, gathering the necessary tools and equipment;
2. preliminary inspection: the inspection begins with a general visual analysis of the bridge, to detect any obviously damage or degraded signs. This may include cracks, corrosion, erosion, distortions or other structural anomalies;
3. detailed inspection: The inspectors proceed with a more thorough examination once the areas of interest are identified. This may include the use of specific diagnostic tools such as test hammers, endoscopes or ultrasonic thickness gauges, to more accurately assess severity and extent of defect detected;
4. documentation: inspectors fill out defect sheets during inspection, recording all relevant details, including defects location their severity and extent, as well as any recommendation for repair or maintenance. These tabs can be used later to determine priorities for interventions and monitor progress over time;
5. data analysis and final report: once the inspections and defect sheets compilation have been completed, engineers analyse the collected data and draw up a final report that summarises the results. This report may be used to inform maintenance decisions, repair or improvement of infrastructure;
6. monitoring and maintenance: finally, it is important to continue monitoring and maintaining bridges over time, carrying out periodic inspections, implementing recommendations deriving from inspection reports. This will help ensure the long-term safety and infrastructure’s durability.

The advantages of bridge monitoring includes the ability to detect anomalies or degradation early, reducing risks and maintenance costs. However, the installation and management of monitoring systems require specific resources and expertise. Inspection surveys, on the other hand, may be cheaper and less complex, but they offer a less detailed and continuous view of bridge conditions.

The integration of both methods allows to obtain a complete and accurate view of bridge conditions and to plan more effective maintenance interventions.

Example of bridge monitoring: IOT and BIM

An example of a bridge’s IOT and BIM technologies based monitoring system, involves the use of sensors connected to a communication network to detect data on structural conditions, such as deformations, vibrations, temperature and corrosion. Then, the bridge’s BIM (Building Information Modeling) model integrates the data from sensors. This allows you to view and analyze information in real time. Hence supporting infrastructure management and maintenance.

The case of the “Canalone” viaduct

The proposed case study relates to the monitoring with innovative systems of the Canalone viaduct, located along the Naples-Salerno motorway. The research project is the result of the collaboration of six Italian universities, including the Department of Structures for Engineering and Architecture of the Federico II University of Naples.

monitoring | The case study of the Canalone viaduct

It is a viaduct with a structural type of upper archway, in reinforced concrete, with a span of 120 m and 11 bays.

First, we require an infrastructure’s 3D BIM model to manage the data from innovative sensors installed on the viaduct itself.

The sensors installed are:

• 48 pressure sensors (the first group installed in pairs on the bridge pillars, 75 cm from the deck beam’s intrados to analyze the rolling load, the second  group installed on the deck arch with the aim of verifying the tension state and the overall discharge of the deck subject to traffic load);
• 6 triaxial accelerometers installed on the two on-board beams to analyze the dynamic properties of the structure monitoring their evolution over time;
• 3 thermocouples.

The system is completed with:

• 8 nodes for the management of pressure sensor data;
• 2 knots for accelerometers;
• 1 4G router and fiber connection system.

For data processing it was necessary to refer to a domain of standard values, useful to define whether the movements are due to random factors or deriving from problems due to heavy vehicles passing. After recounting, analysing and processing data, they must be visualise with the help of interoperability platforms. An interoperability platform must provide access, traceability, allow the storage of data related to the work, allow real-time monitoring and provide alerts and reports.

With usBIM.IoT it is possible to integrate BIM models and IoT systems. It is possible to load the 3D BIM model inside the platform, complete with sensors applied to the real infrastructure. The sensors are associated with a colour and a range of reference values. When the data collected by the sensors arrives, the 3D model is updated in real time. Therefore reporting the results detected by the sensors on site. The verification is also carried out visually with the help of the colors associated with the different types of sensors.

Bridge monitoring system

A bridge monitoring system is a set of tools and technologies used to assess and maintain the structural conditions of bridges over time. It allows to detect any problems or structural damage, providing bridges’ useful maintenance and management information. A complete and professional bridge monitoring system consists of the following main components:

1. sensors – sensors are devices that detect and measure various structural and environmental parameters of a bridge. We will be discussing more extensively in the following paragraphs dedicated to IOT;
2. Data Acquisition System (DAS) – The DAS is the component that collects and stores data from sensors. It consists of data acquisition units, which perform the conversion of the analogue signal to digital and store the data for subsequent processing;
3. communication system – this system allows the transmission of data between the sensors, the DAS and the control center. It can use different technologies, such as cables, wireless networks or fiber optics, depending on the specific needs of the project;
4. center control and monitoring – this is the station where operators and engineers analyze monitoring system’s collected data. The control center is equipped with software and hardware dedicated to data processing and visualization, allowing easy interpretation of the information collected;
5. analysis and diagnostics software – these programs are used to process and analyze collected data, in order to identify any anomalies or trends that may indicate structural problems. The software may include machine learning algorithms, numerical models and statistical analysis techniques to improve the reliability and accuracy of diagnoses;
6. alarm and notification system – in case of detection of critical or potentially dangerous conditions, the monitoring system can automatically generate alarms and notifications to alert the operators and engineers responsible. This allows for timely intervention to prevent further damage or dangerous situations.

In summary, a professional and detailed bridge monitoring system is composed of a series of sensors, a data acquisition system, a communication system, a control and monitoring center, analysis and diagnostic software and an alarm and notification system.

Types of bridges, most frequent pathologies and corresponding types of monitoring

The main types of bridges include arch, girder, shelf, cable and suspension bridges. Each type of bridge can present specific pathologies, such as corrosion, cracks, sags or deformations. Appropriate monitoring varies according to the type and pathologies present. In addition to include methods such as monitoring deformations, vibrations, temperature or corrosion.

Types of Bridge Monitoring

The types of bridge monitoring are:

• static;
• dynamic;
• environmental.

Static monitoring deals with deformations detection of permanent loads. While dynamic monitoring deals with vibrations and stresses induced by traffic and wind. Environmental monitoring, on the other hand, focuses on parameters such as temperature, humidity and corrosion. Which can affect the life and safety of the bridge.

Dynamic bridge monitoring

Dynamic bridge monitoring focuses on detecting vibrations and stresses induced by traffic, wind and seismic events. Through the analysis of the collected data, it is possible to identify any structural anomalies, evaluating the bridge stresses and predicting its duration over time.

Design and installation of a monitoring system

The design and installation of a bridge monitoring system requires a accurate analysis of infrastructure specific needs, the choice of devices and monitoring methods as well as the definition of a data transmission communication’s network. In addition, it is important to provide for device maintenance and calibration procedures as well as the system management training of personnel

What is IoT and how can it be used for bridge monitoring

The Internet of Thing (IoT) is a set of interconnected devices that communicate with each other through the internet. These devices may include sensors, actuators and data processing systems. IoT can be used to monitor different bridge parameters such as vibration, deformation, temperature and traffic. Therefore enabling real-time monitoring and more efficient maintenance.

Currently you can also use BIM and IoT integration to manage IoT devices directly from the BIM model. In practice, the data collected by the sensors is sent to a gathering data application, making it visible in real time on an IFC format 3D BIM model.

The BIM model’s enrichment with IoT ecosystems information facilitates its management.

IoT technologies for bridge monitoring

Vibration and deformation sensors

Vibration and deformation sensors are IoT devices that detect structural variations of bridges, providing valuable information about their integrity. These sensors can detect anomalies and report any problems before they become serious thus allowing for timely intervention.

Temperature and humidity sensors

Variations in temperature and humidity can affect the durability of materials used in bridges. IoT sensors that monitor these parameters allow you to identify problems such as corrosion and wear of materials, facilitating its preventive maintenance planning.

Traffic monitoring sensors

IoT traffic sensors can detect vehicles weight and flow providing useful data to manage and to assess the impact of traffic on infrastructure. Later, this data can help implementing measures aimed at reducing the load on bridges and improving their durability.

Analysis and alarm systems for data management

There are many ways to extract useful information. Managing and analyzing data collected by IoT sensors is one. Additionally alarm systems can process data in real time, generating notifications in case of anomalies or potentially dangerous situations thereby allowing rapid and targeted intervention.

Benefits of Bridge Monitoring with IoT

The use of IoT in bridge monitoring allows greater risk prevention and better emergency management. Thanks to the data collected in real time it is possible to identify and solve problems before they become critical. Therefore ensuring a higher level of security.

Maintenance efficiency

Real-time monitoring of bridges via IoT makes it possible to optimize maintenance processes intervening only when and where necessary. This reduces intervention times and reduces inconvenience to traffic.

Cost reduction

Thanks to the possibility of identifying and solving problems in a timely manner. Specifically, implementing IoT in bridge monitoring can lead to a reduction in maintenance costs. Avoiding more expensive interventions at a later time.

The Challenges in Implementing IoT

Despite the many benefits, the adoption of IoT in bridge monitoring also brings challenges, such as cybersecurity, data privacy, as well as the need for upfront investment for device installation and integration. However, considering the long-term benefits in terms of safety, efficiency and cost reduction, experts believe that implementing IoT in infrastructure is a valid and sustainable investment.

The Future of Infrastructure Monitoring with IoT

The future of infrastructure monitoring with IoT is promising with new technologies and solutions constantly evolving. Artificial intelligence and ​​machine learning​​ could integrate into monitoring systems. This would further improve data analysis and problem prediction. In addition, the advent of 5G technology could improve connectivity and data transmission speed. Thereby making monitoring even more effective and timely.