A cyber-physical systems (CPS) approach to temporary structures monitoring

The construction industry has had a high record of structural failures and safety problems for decades. Some of these problems, such as occupational injuries, quality of structure, and speed of construction project are affected by temporary structures (i. e. scaffolding, temporary support system, and formwork system). In many cases, these temporary structures are regarded as static structures without appropriate monitoring of temporal changes in their stability. To be specific, it is estimated that three quarters of the construction workers in the United States work on or near temporary structures. The improper management of temporary structures results in 100 deaths, 4500 injuries, and costs $90 million every year. While significant deployments are being made in the structural health monitoring of constructed facilities, such as bridges, dams and other civil infrastructure, inadequate attention has been paid to temporary structures. Developments in information and communications technologies, notably the advent of Cyber-Physical Systems (CPS), are changing the way in which structures are monitored. With the bidirectional coordination possible between physical artefacts and their virtual representations, CPS offers an approach that can facilitate the monitoring and active control of temporary structures in such a way as to prevent structural failures and safety hazards on the job site. This research focused on the development and validation of a Cyber-Physical Systems approach to safety monitoring of the temporary structures widely used on the construction job site. The objectives of the research include investigating CPS implementation in construction industry, assessing CPS applicability to temporary structures, reviewing safety regulations of temporary structures, developing a CPS-based prototype system for temporary structures monitoring, and evaluating the performance of the prototype CPS system. In order to conduct the research, several research methods were utilized, including literature reviews, rapid prototyping, laboratory experiments, and an evaluation workshop. In particular, research problems were clarified through literature review. In reviewing the key features of CPS, enabling technologies and current applications in various industries were summarized to identify the opportunities for CPS use in tackling important problems in the construction industry. To establish the applicability of CPS in temporary structures, the safety issues of temporary structures were investigated to identify the failure patterns of some commonly used temporary structures. The potential benefits and barriers of CPS application to temporary structures were also explored. Based on the CPS applicability analysis, a CPS prototype system for temporary structures monitoring was designed and developed by linking the virtual model (based on the Navisworks Management platform) and the physical structures. This prototype system was tested through laboratory experiments under 5 failure scenarios and evaluated for performance by industry experts. The evaluation of the developed CPS prototype system involved key industry experts and confirmed that CPS offers an effective approach to advanced monitoring of temporary structures; the developed CPS prototype system works effectively in the monitoring of temporary structures; and there are a number of benefits and barriers associated with CPS application to temporary structures. In addition to the safety monitoring of scaffolding systems, which was demonstrated as an example of temporary structures, various potential application areas have been identified for CPS application to temporary structures monitoring. While the proposed TSM method has provided an example of how to closely integrate the virtual model and the physical components of temporary structures for structural monitoring, more applications and extensible benefits can be realized based on it. In general, this research explored and validated CPS application for the monitoring of temporary structures. It identified CPS enefits and applicability to the area of temporary structures monitoring, developed a CPS prototype for the monitoring of temporary structures, conducted experimental tests to check and refine the prototype system, and conducted workshop evaluation of the prototype system for performance analysis. By taking advantage of CPS, this research provides a new approach to assisting safety superintendents in the monitoring of temporary structures through bi-directional communication between physical structures and their virtual models. This research has contributed to a deeper understanding of the potential of Cyber-Physical Systems (CPS) to address critical problems in the construction industry, using temporary structures monitoring as an effective example application.