Preface

The oldest of all of the engineering disciplines, Civil Engineering, enjoys a proud history of providing society with infrastructure systems to ensure economic prosperity and a high quality of life. In recent years, a number of grand challenges have emerged that fundamentally jeopardize the profession’s ability to continue designing and maintaining infrastructure with the high level of performance as experienced in the past. For example, structures in urban environments are seeing unprecedented levels of demand from growing populations leading to higher levels of deterioration occurring at faster rates. This is an especially demanding issue for civil engineers in developed nations who are now dealing with a growing number of infrastructure components exceeding their intended design lives (typically half a century). It is costlier to maintain the safe operating condition of aging infrastructure. Another challenge for civil engineers is the need to continue to improve the design of their infrastructure to withstand extreme loadings associated with natural hazard events including earthquakes and tropical storms. An especially pressing challenge is the frequent occurrence of failures at points of interconnection between two or more interdependent infrastructure systems. Unfortunately, functional interdependencies create the potential for cascading failures that can result in systemic disasters. A case in point was the progression of infrastructure system failures that occurred during both Hurricane Katrina (2005, New Orleans) and the Tohoku Earthquake (2011, Japan). The breaching of the levees in New Orleans led to cascading failures that ultimately crippled an entire city; to this day, New Orleans has not fully recuperated from this natural disaster. The Tohoku Earthquake offered another case of cascading failures with the failure of a protective sea wall setting off a chain reaction of failures leading to the meltdown of the Fukushima nuclear reactors; Fukushima remains an ongoing disaster with major public health implications for the coming century.

The civil engineering community is facing yet another grand challenge in how to innovatively design and construct more durable and safer infrastructure systems while being responsible stewards of the natural environment. The field is now exploring new ways of designing resilient infrastructure with lower levels of embodied energy, while emitting lower levels of green-house gasses during construction.

The magnitude and scale of these challenges are necessitating new approaches to learning how infrastructure systems behave under both normal and extreme load conditions. Sensors are a key technology that allows civil engineers unprecedented levels of observation of operational infrastructure systems. Surveillance and observation are the main elements that aid professions to appropriately model their systems, improve system designs, and optimize future operations and maintenance processes. Concurrent to the growing demand for sensing, there has been a proliferation of new enabling technologies to improve capabilities of sensing systems while lowering their costs and simplifying their deployments. The creation of new, micro-scale sensors through the adoption of micro-electro-mechanical systems (MEMS) has led to a new generation of sensors with compact forms and low costs. In addition, the adoption of low power microprocessors that benefit from Moore’s Law has helped create a class of ‘intelligent and smart’ sensors with computing autonomy. Similar to Moore’s Law, Eldholm’s Law is projecting continued improvement in wireless communications. The result has been scalable, high rate wireless communication standards that have been optimized for wireless communications within sensor networks. Undoubtedly, these trends have improved the sensing arsenal available to civil engineers to observe their systems while lowering traditional barriers to adoption including cost and ease of use.

At the outset, the editors felt there was a pressing need to create an authoritative reference of established and emerging sensing technologies impacting the field’s ability to monitor its infrastructure systems. With that goal in mind, the editors invited the leaders of the field to provide detailed overviews of sensing hardware in Volume 1 of the two volume set. Specifically, Volume 1 concentrates on describing explicit sensor types and data acquisition methods relevant to the civil infrastructure domain. Sensors have the potential to generate unprecedented amounts of data; this can create a bottleneck in the decision-making process of engineers. In order to aid decision makers responsible for the operation and upkeep of infrastructure, data analysis systems are direly needed to process growing amounts of sensor data. The experts in the domain of data interrogation and decision support systems were invited to author chapters in Volume 2 of the book. Furthermore, Volume 2 showcases how sensors and sensing systems are already being used to observe specific infrastructure system types. The editors home these case studies provided the basis for others to implement impactful sensing systems of their own.

At the beginning of this book project, the editors felt there was an equally pressing need for a comprehensive reference that could be used to educate students. Specifically, graduate programs in civil engineering have begun to add new disciplinary concentrations that are intended to train students to be the thought leaders that will usher in the solutions required to solve some of the aforementioned grand challenge problems. For example, many universities across the globe are now offering a specialization in ‘infrastructure systems’ with the goal of training students to approach infrastructure system problems with a ‘systems’ perspective. Sensors are a key enabling technology required to observe operational infrastructure systems. For this reason, these new graduate programs now offer courses in sensors, sensing systems, and data processing using sensor data. This book has been designed to offer educators a reference book that offers students a complete review of the fundamental operational principles of current and future sensor technologies (Volume 1) and showcasing the use of these sensing technologies to observe real-world systems (Volume 2). The book is written assuming students are upper-level undergraduates or at the post-graduate level.

When undertaking a project of this scale, it should be acknowledged that the project was only possible due to the support and encouragement of the editors’ peers in the international research community. The pace of technological development that has occurred over the past quarter century has been fueled by the intellectual vitality and camaraderie of the research community engaged in sensing technologies for infrastructure monitoring. The editors are grateful that this community was willing and eager to contribute to this book. The result is a reference that accurately represents the state-of-the-art of the field and the impact sensing technologies has in solving emerging problems in the field of civil infrastructure systems. Enjoy reading!