Published Wed 15th Mar 2023
Bridges play a critical role as the backbone of any country. Rail bridges and highway bridges allow for the safe and easy transport of goods and for people. However, due to the constant exposure to various environmental and external factors, such as weather and heavy traffic loads, they are subject to wear and tear, making them vulnerable to structural damage. To prevent closures and collapses of bridges, it is essential to monitor their structural health regularly. Though biennial inspections play a crucial role in this monitoring, wireless sensors can augment inspections and reduce risks on our most vulnerable and critical structures.
In the not-too-distant past, wireless monitoring systems were dismissed out of hand due to battery life issues, connectivity issues, and some over promising and underdelivering by manufacturers.
Today’s wireless technology is proven, precise and capable – even though it might not be the right choice for every bridge monitoring application. It is used alongside complementary technologies such as LVDT displacement sensors, vibration and environmental monitoring instruments and AMTS automated motorized total stations by bridge engineers around the world to get information quickly and easily for critical and remote applications. The use of wireless solutions allows for more flexibility in managing a construction project and more information for engineers to utilize while planning and executing rehab or keeping an eye on a “problem structure”.
Wireless sensor nodes are compact and easy to install devices that are capable of detecting and monitoring a variety of physical parameters. They can be used to monitor structural health by detecting movement of the substructure and ground movement of the surrounding area, particularly near flood zones and during high velocity water events. These sensors can be installed on the virtually any part of the bridge structure and connected wirelessly to a solar powered communications gateway that sends data updates and alerts to remote users via a cloud-based portal.
One of the key advantages of wireless condition monitoring systems is that they can be quickly installed without the need for extensive wiring. This means that they can be used in areas that are difficult to access or where wiring would be cumbersome, such as in the middle of a longer span bridge, in remote locations where power supply? is difficult, or areas over water where differential rotation, tilt or deflection might need to be measured. They are also highly portable, which means that they can be easily moved from one location to another as required. Additionally, some nodes, equipped with optical displacement sensors, integrated with tilt sensors, can easily measure differential displacement of bridge members during critical rehab activities such as deck replacement. These nodes are not limited by line of sight or weather conditions, as some more traditional methods may be.
Another important advantage of wireless sensor nodes is their long battery life. This is crucial for structural health monitoring (SHM) systems, as it allows the sensors to operate continuously without the need for frequent maintenance or battery replacements. Most Senceive sensors can operate for more than 10 years based on 30-minute sampling.
With so many bridges in an owner’s inventory, one of the most significant benefits of the Senceive wireless sensor nodes is their ability to alert bridge owners and operators in real-time when structural damage or potential problems are detected. The sensors can send alerts to mobile devices, enabling bridge owners and operators to take immediate action to address any issues. This can help to prevent serious damage or collapse of the bridge and ensure the safety of the public. Senceive’s InfraGuard system can be incorporated to provide photos of the structure as part of the alerts received by the owners.
Plainly speaking, wireless sensor nodes have come a long way and now are an essential tool for monitoring the structural health of bridges during regular operation for vulnerable or high-profile bridges, during rehab or other construction work, or during extreme weather events to monitor performance during the events and recovery thereafter. They are quick to install, have a long battery life, can alert bridge owners and operators in real-time, and are not limited by line-of-sight requirements or weather conditions.