Published Wed 3rd May 2023
Bridges are critical infrastructure, serving as key transport links for both people and goods. They must be designed, built, and maintained to the highest standards to ensure safety and usability. With over 100,000 U.S. bridges being used beyond their design life the need for rehabilitation work is widespread. An example of work required for structures spanning water is the replacement of fenders that are relied on to protect a structure from impact with vessels and other objects such as flood debris and ice. The replacement of new fenders involves demolition of existing piles and installation of new ones which can potentially cause damage to the existing bridge structure, particularly to the foundations, piers and abutments. Monitoring the bridge's tilt and pier convergence during construction is vital, especially with rail bridges. Recent industry publication coverage in ENR magazine, has highlighted the importance of monitoring a bridge during fender replacement using remote and wireless condition monitoring systems, and the benefits it brings to the bridge owner and construction team.
Monitoring during fender replacement is crucial to understand impact to the bridge's structural integrity. In the case of rail bridges, maintaining track geometry during construction is essential to ensure safe and efficient rail operations. Even minor track geometry variations such as changes in cross-level and twist can increase the risk of dangerous and disruptive derailment. When rail derailment does happen the consequences can be extreme and even tragic. Continuous monitoring using remote and wireless condition monitoring systems can help detect potential misalignment issues and allow for prompt corrective measures to be taken. Rail bridge monitoring projects can benefit from the use of wireless track monitoring sensors.
It is particularly important to monitor rail bridges during construction works to ensure track alignment is maintained.
One of the most important parameters to monitor during fender replacement is the bridge's tilt. Tilt can be caused by a number of factors including: rotational movement resulting from construction actions associated with the weight of the new fenders, the removal of old fenders, and the excavation of soil around the piers. If the bridge tilts excessively, it could become unstable or even collapse.
Another key parameter to monitor during fender replacement is pier convergence. Pier convergence is the inward movement of the piers due to the weight of the new fenders. Excessive convergence could lead to the piers cracking or breaking, which could lead to bridge failure.
Wireless remote condition monitoring systems provide an effective way to monitor a bridge's condition during and after the fender replacement. Traditional manual monitoring methods may not be as effective as they rely on access for visual inspections that can be prone to human error and may miss crucial signs of structural damage or instability, while use of automated total stations can be limited by factors including access, line of sight issues, and weather conditions. By contrast, Senceive’s wireless monitoring systems offer continuous, accurate, and reliable monitoring data that can be viewed on a web-based portal or bespoke visualization software. Automated alerts of potential problems can be sent to bridge engineers and owners.
Wireless remote condition monitoring systems offer the advantage of near real-time monitoring, allowing the bridge owner and construction team to take immediate action if any issues arise. Equipped with this continuous flow of data from multiple sensors across a structure, the construction team can often recover the cost of the monitoring program by accelerating the work and minimizing track access for inspection and maintenance. Early detection and quick response can minimize the impact of any problems and prevent costly repairs or even bridge closures. Keeping the instrumentation in place after the construction phase can provide a structural health monitoring solution to inform future maintenance and repair plans, ensuring the bridge remains safe and operational for years to come. This can all be done with minimal maintenance to the monitoring system.
Senceive’s wireless tilt nodes and integrated tilt and optical displacement sensor nodes are used on infrastructure worldwide for this application and are proven to save time and money, enhance efficiency and improve safety.
Optical Displacement Sensors can measure relative movement of two separate objects, such as bridge piers or beams.
In conclusion, monitoring for excessive movement and other indications of distress during fender replacement using wireless remote condition monitoring systems can contribute to a significant reduction in both the cost and risk of the work, particularly for rail bridges. Early detection of potential problems can prevent catastrophic failures and minimize the impact of any issues that arise. Insight from continuous data can often help a construction team accelerate their work because they have a virtually real-time picture of the impact their activity is having on the structure. Remote and wireless condition monitoring systems provide an accurate, reliable, and cost-effective way to monitor the bridge's condition during and after the fender replacement, allowing the bridge owner and construction team to take prompt corrective measures to ensure the bridge remains safe and operational.