Monitoring the health of a system is very important, whether it be a human system or an engineering system. We monitor operations to ensure we are aware of the effect of time on the system and to be ready for any future changes.
The case of a structural system is no different. A structure’s monitoring is essential, as unlike a human system, a structure cannot adapt to changes on its own. For example, so many factors can cause a steel structure to lose its stiffness if we do not take necessary actions. So, someone must monitor a structure to keep track of changes in the structural properties of the structure.
Structural/Civil engineering structures are susceptible to external forces like wind load and seismic load. These loads can cause severe damage if the fundamental properties of a structure are allowed to deteriorate with time. Damage repair is costly. In this way, a structural health monitoring system can moderate high repair costs by monitoring and detecting changes in structural properties as they happen.
Structural health monitoring (SHM) is a process of assessing the health of a structure through a smart and automatic monitoring system. An ageing structure incurs more cost with time, and this has become an ongoing concern. Studies show that the United States utilizes way over $200 billion every year on plant equipment and structures maintenance. Structural health monitoring (SHM) intends to lighten these worries by supplanting schedule-based maintenance with as-required maintenance. Hence, saving the cost of unneeded maintenance on the one hand and minimizing impromptu maintenance, on the other hand. For a structural health monitoring system to be compelling, it must be cost-effective and guarantee safety.
SHM finds application in many engineering industries, such as aerospace and structural engineering. However, the application of SHM technology in structural engineering is still growing. The SHM process involves the assessment and observation of a structure over time using occasionally sampled measurements from a sensing system. SHM provides a powerful tool for damage assessment and performance evaluation of engineering structures.
Structural health monitoring has multiple applications. However, its application in the structural engineering industry is still in its infancy. Most engineering structures are beyond their design life. However, SHM will help the structural engineering firm, responsible for maintaining those engineering structures, to know the design life of the structure and correct deformities or deteriorations in the structure. It tends to the issue of maintenance of ageing structures, which is a noteworthy worry of the structural engineering industry.
The application of SHM in new structures can result in reduced design costs.
A structural engineer, when designing a structure, ensures the structures must be able to withstand all possible loads. Even after construction, structures face external loads, and with time the structure’s ability to withstand these loads deteriorate and may result in structural damage. Therefore, it is vital to monitor the health of the structure.
Currently, the monitoring of existing structures involves scheduled-maintenance and visual inspection. However, studies show that it is difficult to analyze the structural condition of a structure by only visual inspection. Structural health monitoring alleviates this concern. SHM uses advanced sensors and real-time assessments to monitor the structure’s health.
Additionally, SHM assesses the performance of engineering structures in a proactive manner using data interpretation algorithms to evaluate the current condition correctly and to predict the remaining service life.
A structural health monitoring system for engineering structures often includes observation by sensing systems and the evaluation by data interpretation algorithms. In general, both global and local health monitoring strategies are important for sufficient damage identification and safety assessment of large engineering structures.
The development of successful SHM methods generally depends on two key factors; sensing technology and the associated signal analysis and interpretation algorithms. An SHM system typically consists of many vital components, including sensors, data acquisition, data transmission, data processing, data management, health evaluation, and decision making. Each of these components is equally important in assessing the health state of a civil structure.
The sensing component of the SHM system includes the selection of sensor types, their number, and location. The data acquisition component involves selecting the excitation methods, signal conditioning, and data acquisition hardware. The measured data needs to be transmitted by wired or wireless transmission networks.
The two categories of SHM strategies are global and local. In general, both global and local monitoring strategies provide different types of information and support different types of analysis.
However, selecting an appropriate monitoring strategy largely depends on the structure concerned, the type of analysis, or both. For example, a global monitoring approach has to be chosen when accessibility to specific parts of the structure is impossible. Whereas, in the cases like analyzing a specific structural failure mechanism at local areas such as crack or fatigue, information on the local material and geometrical properties, as well as stress state, may be needed to assess the structural condition at the local level.
Structural health monitoring technology can improve the design and management of engineering structures in many ways, a few of which are;
Admittedly, Structural health monitoring ensures that a structure’s health is properly monitored. Resulting in reduce design costs and replacing scheduled maintenance with aa-required maintenance.
However, its benefits show that it is viable and should be fully implemented in the structural engineering industry.