Structural Health Monitoring
Learn how our working health monitoring is responding to America's infrastructure crisis.

Project Showcase

Chicago Full-Scale Monitoring Program (CFSMP)

This NSF-funded, full-scale monitoring program for signature buildings around the globe, including the world’s tallest building, Burj Khalifa, has allowed systematic validation of the design process for tall buildings and assumptions governing their dynamic properties and impacts on habitability performance.
CFSMP was established as a collaborative effort between the University of Notre Dame, the structural design firm Skidmore, Owings, and Merrill, LLP (SOM) in Chicago, and the Boundary Layer Wind Tunnel Laboratory (BLWTL) at the University of Western Ontario (UWO). By 2002, the program was monitoring three tall buildings in Chicago and has since expanded to include two tall buildings overseas in alliance with the Samsung Corporation. Measured responses of the buildings to various wind events are compared to the predictions of wind tunnel tests and FE models in order to assess the current
design practice. DYNAMO@ND has augmented this with additional databases of full-scale acceleration responses for the Boston Hancock and over 60 additional buildings in South Korea.

Project Website: www.nd.edu/~windycty/

Recommended Reading

Kijewski-Correa, T., A. Kareem, Y.L., Guo, Y.L., Bashor, R., and Weigand, T. (2013), “Performance of Tall Buildings in Urban Zones: Lessons Learned from a Decade of Full-Scale Monitoring,” International Journal of High Rise Buildings, 2(3): 179-192.

Kijewski-Correa, T., Kilpatrick, J., Kareem, A., Kwon, D.K., Bashor, R., Kochly, M., Young, B.S., Abdelrazaq, A., Galsworthy, J., Isyumov, N., Morrish, D., Sinn, R.C. and Baker, W.F. (2006), “Validating the Wind-Induced Response of Tall Buildings: A Synopsis of the Chicago Full-Scale Monitoring Program,” Journal of Structural Engineering, ASCE, 132(10): 1509-1523.

Bashor, B., Bobby, S., Kijewski-Correa, T. and Kareem, A. (2012) “Full-Scale performance evaluation of tall buildings under wind,” 13th ICWE Special Issue, Invited Paper, Journal of Wind Engineering & Industrial Aerodynamics, 104-106: 88-97.

Kijewski-Correa, T. and Pirnia, J.D. (2007), “Dynamic Behavior of Tall Buildings Under Wind: Insights from Full-Scale Monitoring,” The Structural Design of Tall and Special Buildings, 16, 471-486.


SmartSync Technologies

Vertically distributed monitoring of tall buildings can be particularly challenging given the height of these structures. To overcome limitations of both wired and wireless system, the SmartSync system was created to use the building’s existing Internet backbone as a system of virtual instrumentation cables. Within this framework, data streams from distributed sensors are pushed through network interfaces in real time and seamlessly synchronized and aggregated by a centralized server, which performs basic data acquisition, event triggering, and databasing while also providing a powerful interface for data visualization. This enables a completely modular and scalable approach to structural health monitoring and can readily interface a wide variety of sensors, data formats (digital and analog), and even variable sampling rates and can be used concurrently for wind or seismic monitoring, with dual triggering mechanisms (top down versus bottom up) designed to activate the sensor arrays in case of either hazard. This system has successfully monitored Burj Khalifa (formerly Burj Dubai) since 2008.

Recommended Reading:

Kijewski-Correa, T., Kwon, D., Kareem, A., Bentz, A., Guo, Y., Bobby, S., and Abdelrazaq, A. (2013). “SmartSync: An Integrated Real-Time Structural Health Monitoring and Structural Identification System for Tall Buildings.” Journal of Structural Engineering, Special Issue: Real-World Applications for Structural Identification and Health Monitoring Methodologies, 139(10): 1675–1687.

Cycon, J. (2008) Design and Validation of a Real-Time Structural Health Monitoring System Interfacing Through a Local Area Network, MSCE Thesis, University of Notre Dame, Notre Dame, IN.


Decentralized Damage Detection in Civil Infrastructure using Multi-Scale Wireless Sensor Networks

The interest in the ability to monitor a structure and detect, at the earliest possible stage, any damage to it has been pervasive through the Civil Engineering community, even before the catastrophic collapse of the I-35W Bridge over the Mississippi in the summer of 2007. This was driven largely by the fact that the current manual inspection and maintenance philosophy charged with preventing such failures cannot detect damage in its early stages, and the labor burdens associated with it are extremely heavy. In response, this project proposed a two stage wireless SHM process. To enhance performance, we offer a network architecture that is organized into a multi-scale format, with data fusion of decentralized real-time damage decisions based on spatially distributed heterogeneous sensors, operating under a restricted activation scheme and within the computational constraints of the wireless platform with the objective of minimizing intrusion, enhancing the reliability of automated detection, maximizing network lifetime and eliminating the need for strict synchronization and transmission of large amounts of data. This resulted in the development of a Bivariate Regressive Adaptive INdex (BRAIN) for damage detection that proves to be more robust and accurate than previous formats, (2) a Restricted Input Network Activation Scheme (RINAS) with a new image-based vehicle classification algorithm that not only reduces the size of reference databases and enhances detection reliability, but also relieves computational burdens and extends network lifetime and (3) an offline damage localization technique employing Dempster-Shafer Evidence Theory that is capable of effectively isolating damage positions even for minor loss levels.

Recommended Reading:

Kijewski-Correa, T. and Su, S. (2009) “BRAIN: A Bivariate Data-Driven Approach to Damage Detection in Multi-Scale Wireless Sensor Networks,” Smart Structures and Systems, 5(4): 415-426.

Kijewski-Correa, T., Haenggi, M. and Antsaklis, P. (2006) “Wireless Sensor Networks for Structural Health Monitoring: A Multi-Scale Approach,” Proc. Structures Congress, 17th Analysis and Computation Specialty Conference, May 18-21, St. Louis.

Su, S. (2012) Decentralized Damage Detection in Civil Infrastructure Using Multi-Scale Wireless Sensor Networks, PhD Dissertation, University of Notre Dame, Notre Dame, IN.


CITI-SENSE

Given the expense associated with most SHM systems and need for expert involvement, the vast majority of bridges have not been able to benefit from these technologies. By recognizing that the target end users have limited budgets and large inventories of bridges, it is unreasonable to expect that even a low cost sensor network could or should be permanently installed on every bridge. It is similarly ridiculous to expect transportation officials to become advocates for such technologies when they have been effectively isolated from these technologies themselves. Thus CITI-SENSE: A Citizen-Centric Health Monitoring Paradigm for Civil Infrastructure operates within this reality to deliver to these end users a rapidly re-deployable, self-organizing wireless sensor network with decision support tools that autonomously estimate damage and guide maintenance decisions without disrupting normal operations. Through these advances, this project seeks to empower stakeholders to more pro actively maintain their bridge inventories and even for its users to self-report payloads to enhance safety, while minimizing repair costs and commuter disruption.

Recommended Reading:

Kijewski-Correa, T., Su, S. and Montestruque, L. (2012) “A Citizen-Centric Health Monitoring Paradigm Using Embedded Self-Locating Wireless Sensor Networks,” Proceedings of Structures Congress 2012, 20th Analysis and Computation Specialty Track, March 29-31, Chicago.

Kijewski-Correa, T., Montestruque, L., Su, S., and Savona, G. (2010) “A Rapidly Re-Deployable Wireless Sensor Network for Structural Assessment by Non-Expert End Users: The CITI-SENSE Concept,” Proceedings of 5th World Conference on Structural Control and Monitoring, July 12-14, Tokyo, Japan.


Networked Sensing in Built and Natural Environments

Many important applications in wireless sensor networks can be interpreted as anomaly or threat detection tasks. Whether it be in the release of a chemical/ biological /radiological (CBR) agent in a city, by air, surface or water, the penetration of a perimeter boundary or secure zone by an intruder or the appearance of defects in components and systems, the tasks required remain the same: (1) collect data from distributed sensors, (2) process and transmit that data wirelessly, (3) execute an assessment of the threat or anomaly. These three tasks require considerable hardware, middleware and software development, particularly if real-time detection and interfacing to end users (emergency responders, managers, division leaders) is required. This project developed various hardware, middleware and software and then demonstrated the capabilities using a variety of applications and an interdisciplinary team of civil, environmental and electrical engineers. The primary deliverable of DYNAMO@ND in this project was development of an embedded environmental sensor network using commercial off the shelf (COTS) embedded sensor network technologies to collect distributed meteorological and chemical concentration data and perform real time hybrid plume detection by integrating sensor data with computational models (e.g., CT-Analyst).

Project Website: www.nd.edu/~crane/

Recommended Reading:

Kijewski-Correa, T., Henderson, A., Montestruque, L. and Rager, J. (2009), “Real-Time Sensor Fusion to Enhance Plume Detection in Urban Zones,” Proceedings of 11th Americas Conference On Wind Engineering, June 22-26, San Juan, Puerto Rico.

Rager, J. (2009) Real-Time Detection of Plume Boundaries in a Chemical, Biological, or Radiological Event, MSCE Thesis, University of Notre Dame, Notre Dame, IN.


Performance of Global Positioning Systems for Monitoring in Urban Habitats

SHM traditionally employs accelerometers or LVDTs/strain gages, which are unable to resolve the global displacements of the structure, including static, quasi-static and dynamic components. Given the need to observe these various response components, global positioning systems (GPS) have become a viable alternative for SHM. While GPS has been successfully applied in full-scale deployments, issues such as movement of the reference site, potential accuracy fluctuations due to satellite losses and multipath effects remain concerns. In particular, the latter two considerations pose significant issues when monitoring in urban habitats. Thus extensive validation studies and techniques to remove multipath signatures have been developed in this project to understand better the limitations of this technology and strategies to improve performance.

Recommended Reading:

Kijewski-Correa, T. and Kochly, M. (2007), “Monitoring the Wind-Induced Response of Tall Buildings: GPS Performance and the Issue of Multipath Effects,” Journal of Wind Engineering and Industrial Aerodynamics, 95(9-11): 1176-1198.

Kijewski-Correa, T., Kareem, A. and Kochly, M. (2006) “Experimental Verification and Full-Scale Deployment of Global Positioning Systems to Monitor the Dynamic Response of Tall Buildings,” Journal of Structural Engineering, ASCE, 132(8): 1242-1253.

Kijewski-Correa, T. (2005), “GPS: A New Tool for Structural Displacement Measurement,” APT Bulletin, 36(1): 13-18.

Kijewski-Correa, T. and Kareem, A. (2003), “The Height of Precision,” GPS World, 14(9): 20-34.

Kochly, M. (2006) Validation of Global Positioning Systems for Monitoring Civil Infrastructure Systems: Performance Assessment and Removal of Multipath Effects, MSCE Thesis, University of Notre Dame, Notre Dame, IN.  


Citizen-Sensing for Assessment of Civil Infrastructure: Proof-of-Concept for Tall Buildings

COMING SOON


Data Mining Strategies to Support Long-Term Monitoring of Critical Infrastructure: A Tall Buildings Case Study

COMING SOON

 

 

Making the Case for Structural Health Monitoring

The world’s great buildings, bridges, and various other structures have survived mainly because of
their engineers’ heuristics, experience, and creative geniuses. In this era, the necessity to deliver infrastructure in a timely and efficient manner drove extremely simplistic and idealistic models of
constructed systems to permit analysis and design with limited resources and capabilities. Eventually, these practices driven by necessity formed the basis of many of our prescriptive codes. Although more sophisticated modeling approaches are available today, the same pressures to deliver infrastructure in a timely and efficient manner with limited resources often drives modern engineers to continue to opt for simplicity. One can argue that these approaches, when coupled with modern codes and standards and sound heuristic principles, have enabled experienced engineers to efficiently develop safe designs. However, the primary shortcoming of these approaches is their inability to accurately simulate the actual performance of constructed systems, which in turn necessitates considerable conservatism in the design process. More importantly, trends within the profession are testing the limits of this historical approach. Powerful modeling, analysis, and visualization tools have permitted free-form architecture of increasing complexity. Even for more traditional structural forms, the movement toward performance-based engineering and the need for highly optimized and efficient designs to maintain competitiveness in the global marketplace again challenges the overly simplified approaches of old. Moreover, interest in sustainability and the a priori consideration of life cycle costs implies the need to more seriously consider sophisticated modeling not only in the design of new systems but also in the retrofit, restoration, and preservation of aging urban infrastructure. Unfortunately, although such refined models have the ability to simulate behavior with more resolution, they require far more information to mitigate the influences of bias and yield reliable results. This understanding has resulted in a growing recognition for the need to correlate these models with experimental data, particularly in situ data from constructed systems.

Civil infrastructure is second only to health care in annual expenditures in the United States, and although the health care industry benefits from substantial corporate-sponsored research and development, much directed to the advancement of state-of-the-art diagnostics, the same sadly cannot be said for civil infrastructure, despite the fact that strong parallels can be drawn between human health monitoring and structural health monitoring, as the above image demonstrates. However, this trend is not resigned solely to the medical profession. The use of advanced diagnostic tools, embedded sensors, and condition assessment is commonplace in many other engineering applications, e.g., automobiles and aircraft. In these applications, structural identification (St-Id) serves an important role to bridge the gap between models used in design and the manufactured system by correlating these models with experimental observations/data and reliably assess performance.

This is but one of the benefits of long-term monitoring of both private and public civil infrastructure. These benefits include:

1. Enhancing our understanding of in-situ behavior, especially for complex systems or those manifesting suspect performance

2. Validating our design practices, including as-built dynamic properties and the accuracy of our methodologies to predict responses at various limit states of design

3. Facilitating rapid condition assessment, which are critical for early damage detection to facilitate pro-active repairs or rapid reoccupation after damaging events.

4. Informing intelligent operations and management, including prioritizing rehabilitation efforts on portfolios of bridges, as well as guiding operations and shut down procedures in the extreme events.

DYNAMO@ND has contributed to these areas for over a decade through assorted projects, most notably focused on tall buildings in urban habitats.


Recommended Reading

Catbas, F.N., Kijewski-Correa, T., Aktan, A.E., Eds. (2012) Structural Identification of Constructed Facilities: Approaches, Methods, and Technologies for Effective Practice of St-Id, Amer Society of Civil Engineers, ISBN-10: 0784411972, ISBN-13: 978-0784411971.

Catbas, F.N. and Kijewski-Correa, T., (2013) “Structural Identification of Constructed Systems: A Collective Effort Toward an Integrated Approach that Reduces Barriers to Adoption,” Journal of Structural Engineering, Special Issue: Real-World Applications for Structural Identification and Health Monitoring Methodologies, ASCE, 139(10): 1648-1652.