The economic prosperity of our nation depends upon massive networks of infrastructure systems including transportation networks, waterway networks, pipelines, and electrical grids, just to name a few. Furthermore, urban environments can be viewed as a “system of systems” with complex interactions and interdependencies existing between individual systems.
Historically, the civil engineering profession has emphasized the resilient design of the individual infrastructure components that make up these systems. Comparatively less attention has been paid to how infrastructure components interrelate and interact to make up a dynamic system. As a result, recent natural catastrophes such as Hurricane Katrina (2005) and the Northridge Earthquake (1994) have revealed that society is vulnerable to catastrophic cascading failures that occur due to a lack of resiliency in the points of interconnection between individual infrastructure systems.
Today, infrastructure systems are growing even more interdependent through information and sensing technologies being introduced for the monitoring and control of infrastructure systems. As urban environments grow to keep pace with trends in population densification, a balance must be struck between community resiliency and sustainable use of natural resources. This is fundamentally a systems problem defined by the flow of the natural resources that go into the construction and operation of infrastructure system and the negative consequences (e.g., greenhouse gases) that result over the full life-cycle of infrastructure systems.
This program area emphasizes the analysis, design, and optimization of civil infrastructures, using the concepts from systems theory, information theory, decision theory, and sustainable design. The program also focuses on the enhancement of resiliency and sustainability of infrastructure systems via integration of nontraditional technologies, such as embedded sensing, intelligent control, and advanced materials technologies.
Civil infrastructure systems are highly dynamic, with behaviors that vary on wide temporal and spatial scales. These dynamic systems can be highly complex, entailing both deterministic and stochastic properties. To model complex infrastructures systems with time-varying behaviors, system theory is a powerful tool that allows analytical and computational methods to fully describe the complex dynamics of independent and interdependent infrastructure systems.
Cyber-physical systems are a new class of sensor-rich engineered systems that entail not only sensors but computing and actuation, cohesively integrated for monitoring and control applications. The Infrastructure Systems group is advancing cyber-physical system science with the aim of embedding sensing, computing and actuation technologies in the civil infrastructure domain including in instrumented infrastructure, intelligent vehicle systems, monitoring and control of regional power and water distribution systems, among many more.
Large civil structures, such as high-rise buildings and long-span bridges, must be designed under enormous uncertainty, regarding the extreme loads (such as earthquakes, extreme winds, storm surge, blast loads, etc) they may be required to sustain in the course of their service life. One of the major challenges facing the Civil Engineering community today entails the search for creative ways to reduce the risk of catastrophic damage due to these extreme loads, and to enhance the resiliency of urban infrastructure. One means of enhancing resiliency is by designing infrastructure to be intelligently adaptive. Examples include the use of control systems to adapt the dynamic behavior and structures to suppress extreme deformations and stresses, as well as structures that intelligently adapt their shape and stiffness when damaged.
Feedback control of large-scale intelligent infrastructure demands a persistent sensing backbone to inform real-time decision making. Research is being conducted to develop ultra-low power sensing technologies to facilitate long deployment lifetimes, while reducing the cost and size of sensing devices. The data sets associated with this infrastructure will become vast, and must be addressed via a combination of Civil and Environmental Engineering domain knowledge, as well as Systems theory, Computer Science, and Electrical Engineering.
To support the development of next generation civil infrastructure systems that are intelligent, construction materials must possess functionalities responsive to the surrounding environment without human intervention. Current research focuses on the interdisciplinary bio-inspired design of cement based composites that are self-sensing, self-healing, self-thermal regulating, and self-cleaning for transportation, water, and building systems.
To achieve unprecedented resiliency of the built environment in harmony with the natural environment, infrastructure systems must be designed with scale linking down to the micro and nano-scale of material structure. Research is ongoing in the development of advanced composites that protect civil infrastructure against multi-hazards such as earthquakes, hurricanes, fire and projectile forces. These materials are designed for greenness in production, durable in use and the resulting infrastructure system reconfigurable at end of life, thus achieving extreme reduction in life cycle carbon and energy footprints.
Traditional water systems were built to serve the “analog economy,” where various ownership and management boundaries are loosely interconnected to meet the needs of an oftentimes under-informed water consuming public. Intelligent water grids have the potential to revolutionize the interaction between hydrologic systems, and man-made infrastructure. Through advances in sensing, computation and control it is possible to couple the flow of water, with the flow of information, permitting modern water infrastructure to make automated decisions based on an intimate knowledge of its overall state.
Researchers in the Infrastructure Systems group are studying nontraditional techniques for generating energy to power civil systems. Presently, the focus is on scavenging energy from vibratory phenomena, a concept with many applications. One of these pertains to low-power sensing for infrastructure monitoring. Many times, these sensors are embedded in a civil system in a manner that makes them physically inaccessible for their entire service life. In such cases, ambient vibration energy may be one of the only potential sources of power in proximity to the sensor. Another example pertains to ocean wave energy conversion, in which floating structures are interfaced with power conversion systems to generate utility-scale renewable energy for coastal communities. In both these examples, scavenging vibratory energy is challenging, due to fundamental limitations of conversion technologies and the unpredictable nature of the resource.