Structural health monitoring (SHM) and damage assessment of civil engineering infrastructure are complex tasks. Structural health and strength of structures are influenced by various factors, such as the material production stage, transportation, placement, workmanship, formwork removal, and concrete curing. Technological advancements and the widespread availability of Wi-Fi networks has resulted in SHM shifting from traditional wire-based methods to Internet of Things (IoT)-based real-time wireless sensors. Comprehensive structural health assessment can be performed through the efficient use of real-time test data on structures obtained from various types of IoT sensors, which monitor several health parameters of structures, available on cloud-based data storage systems. The sensor data may be subsequently used for various applications, such as forecasting masonry construction deterioration, predicting the early-stage compressive strength of concrete, forecasting the optimum time for the removal of formwork, vibration and curing quality control, crack detection in buildings, pothole detection on roads, determination of the construction quality, corrosion diagnosis, identification of various damage typologies and seismic vulnerability assessment. This review paper summarizes the applications of the wireless IoT technology in the monitoring of civil engineering infrastructure. In addition, several case studies on real structures and laboratory investigations for monitoring the structural health of civil engineering constructions are discussed. 

Structural health monitoring of civil engineering structures by using the internet of things: A review

Smart and precise sensing is very important for the protection of both environment and personal security in modern civilized society. There are numerous sensing devices for detecting physical and chemical changes such as temperature, humidity, pressure, and chemical species. In this regard, conducting polymers is at the core of attention for the fabrication of next-generation sensor applications. Polypyrrole (PPy), is one of the emerging intelligent materials with a wide range of applications in the field of optical, electronic, and electrochromic devices and sensors. The stability in a different environment, ease of deposition from aqueous and non-aqueous media, adherence to diverse substrates, and high electrical conductivity made PPy a unique choice for sensor development. In recent years, PPy has proven an excellent candidate for sensing volatile organic compounds (VOCs) due to its selectivity and sensitivity towards target gas molecules, and detection of inorganic gases and VOCs. Consequently, to develop outstanding sensing devices attempts have been dedicated to developing PPy-based sensors for excellent mechanical and electrochemical performance. This review aims to provide a recent overview of progress in PPy-based advanced sensing devices. This review aims to provide a recent overview of progress in PPy-based advanced sensing devices. We have systematically discussed the challenges and future development of various sensing devices. Furthermore, the current understanding and performance evaluation of gas sensing mechanisms in PPy-based sensors are discussed theoretically and experimentally. We have also identified gaps in the state-of-the-art and hope that this study would lead to further research works into using PPy to make gas sensors. Finally, the future directions of various sensors with advanced PPy-based sensing systems have been prospected. 

Polypyrrole-based sensors for volatile organic compounds (VOCs) sensing and capturing: A comprehensive review

Strain is one of the most frequently monitored parameters in civil structural health monitoring (SHM) applications, and strain-based approaches were among the first to be explored and applied in SHM. There are multiple reasons why strain plays such an important role in SHM: strain is directly related to stress and deflection, which reflect structural performance, safety, and serviceability. Strain field anomalies are frequently indicators of unusual structural behaviors (e.g., damage or deterioration). Hence, the earliest concepts of strain sensing were explored in the mid-XIX century, the first effective strain sensor appeared in 1919, and the first onsite applications followed in the 1920′s. Today, one hundred years after the first developments, two generations of strain sensors, based on electrical and fiber-optic principles, firmly reached market maturity and established themselves as reliable tools applied in strain-based SHM. Along with sensor developments, the application methods evolved: the first generation of discrete sensors featured a short gauge length and provided a basis for local material monitoring; the second generation greatly extended the applicability and effectiveness of strain-based SHM by providing long gauge and one-dimensional (1D) distributed sensing, thus enabling global structural and integrity monitoring. Current research focuses on a third generation of strain sensors for two-dimensional (2D) distributed and quasi-distributed sensing, based on new advanced technologies. On the occasion of strain sensing centenary, and as an homage to all researchers, practitioners, and educators who contributed to strain-based SHM, this paper presents an overview of the first one hundred years of strain sensing technological progress, with the objective to identify relevant transformative milestones and indicate possible future research directions.

https://www.mdpi.com/1424-8220/22/6/2397/pdf?version=1647784344

Bhagyesh Rane

Papers

Structural health monitoring using wireless smart sensor network – An overview