Review of Infrastructure Health in Civil Engineering by Mohammed M. Ettouney and Sreenivas Alampalli

The rapidly increasing costs of building new infrastructure, or maintaining existing ones, are well documented by both engineers and nonengineers alike. Unfortunately, the subject matter has been addressed in a confusing manner. The authors of this two-volume book set aim to integrate all components of the field in an objective manner suited for technical considerations by civil engineers and infrastructure decision makers. The authors used infrastructure health as a metaphor for their integration approach. By doing so, they produced an infrastructure health in civil engineering (IHCE) treatise that is original in its approach. The authors argued that infrastructure health is analogous to human health in that infrastructures are born, live, and then die. The aim of civil infrastructure engineers and decision makers is to ensure that infrastructures attain a healthy life during all phases of their existence. The authors were careful to note that the currently popular concepts of structural health monitoring (SHM) are only small components within the more general concept of infrastructure health. Engineers need to monitor structural health, but there is more to structural health than just monitoring. There is the all-important decision-making (DM) process that should presage structural health monitoring and continue during the execution of the SHM process and after the SHM has ended.

To set up the scene, the authors devoted a good part of the treatise to introducing several important theories of infrastructure health. These include the theory of multihazards, the theory of inspection, and the theory of instrumentation. They also introduced several principles, such as the serendipity principle and triangulation principles in IHCE. Those theories and principles can be of benefit to researchers and practitioners alike in understanding how to deal with complex issues of infrastructure health. A detailed study of how some of these rules apply to infrastructure health during different phases of the life of infrastructures was presented by the authors.

The authors subdivided the stages of IHCE into four components: measurements, structural identification (STRID), damage identification (DMID), and decision making. The authors offered a detailed study of measurements and sensing as applied to civil infrastructures. This included mechanics of sensing and how they produce their results. In addition, optimal sensor numbers and locations are presented by the authors. The authors addressed the structural identification issue as an added time dimension to the single dimension of conventional structural analysis. This addition is not in the Newtonian sense (in which it is accommodated by inertia), but in the sense of real time. As time passes, the properties of the infrastructure change (mostly degrade); the structural identification process is the process of analyzing the structure in a manner that recognizes such time degradations. The authors studied several STRID concepts, such as modal identification, parameter identification, statistical energy analysis (SEA), and scale independent methods (SIM). The damage identification process combines the results of sensing and STRID into recognizing the type of damage that might inflict the structure. The authors provided several important damage identification methods such as acoustic emission, infrared, and ultrasonic. The theory, practice, and case studies were provided to help readers understand the use of these techniques. As a part of DMID, the authors described methods of signal processing and neural networks and their use in the DMID field. Finally, the authors complemented their argument that the decision-making process is perhaps the prime component in the IHCE by providing detailed theoretical and practical sections about DM process. This included reliability, risk, stochastic process, and economics and life cycle analysis. In all of those sections, the costs and benefits of any/all decisions and methods were analyzed in an objective manner by the authors.

In part II of the treatise, the authors provided seven applications chapters to their IHCE approach. These applications included bridge scour, earthquakes, corrosion of ordinary and prestressed reinforced concrete, and fatigue. The use of advanced materials in infrastructures was also presented by the authors in two distinct chapters: FRP utilization in bridge decks and in wrapping applications. In all of these applications, the physical problems were described first. The authors then proceeded to describe how the infrastructure’s health is affected in each of these situations. The different sensing, STRID, DMID, and finally DM processes that can be applied in each of these applications were presented at length. Whenever pertinent, discussions of life-cycle analysis, cost-benefit analysis, and practical case studies were provided by the authors. These seven applications chapters provide an integrated in-depth analysis and guide on how infrastructure health should be addressed from either a hazards (scour, earthquakes, corrosion, or fatigue) viewpoint, or a utilization of new materials (fiber-reinforced polymers) viewpoint. This includes optimized cost-saving methods that will help professional engineers and other infrastructure stakeholders meet the challenges of new and aging infrastructures. Missing from this part of the treatise is other hazards, such as wind, fire, and aspects of flooding, such as storm surge.

Recognizing that appropriate modern management methods are needed to ensure high performance IHCE, the authors devoted the last four chapters to infrastructure management. Actual field testing issues were presented first, using bridge testing as a case in point. The authors then talked about bridge management issues. These included inspection, maintenance, rehabilitation, deterioration, and life-cycle issues. A whole chapter was then devoted to different theories and objective analysis of life-cycle analysis. The authors argued that in life-cycle analysis of civil infrastructures, there need to be three issues that should be addressed equally: costs, benefits, and life spans. Finally, the authors ended their IHCE treatise by discussing some important aspects of infrastructure security. They showed that to ensure secure infrastructures at reasonable costs, the decision makers need to address the issue of security by using risk-based methods.

In all, the authors acknowledged that the continually increasing demands on infrastructure mean that maintenance and renewal require timely, appropriate action that maximizes benefits while minimizing cost. To be as well informed as possible, decision makers must have an optimal understanding of an infrastructure’s condition—what it is now, and what it is expected to be in the future. Written by two respected engineers, Infrastructure Health in Civil Engineering is presented in two corresponding volumes that integrate the decision-making concept into theoretical and practical issues. Infrastructure Health in Civil Engineering sets up the path, details, and needs for a new field in civil engineering: infrastructure health.