I-Corps - Seismic Fragility Monitoring and Estimation System

Oklahoma State University, Stillwater OK

Investigators

Abstract

The broader impact/commercial potential of this I-Corps project is the development of a tool for checking the health of a structure, such as a high-rise condominium, by continually monitoring its resonance. The rate of degradation, or “fatigue,” is a critical parameter required for risk assessment but is difficult to determine as the key damage indicators such as cracks, warps, and shear generally appear in inaccessible locations, e.g., behind wall coverings, in ceilings, and under foundations. Assessing fatigue without relying on conscious identification of such indicators remains a gap in the current knowledge. The proposed technology is based on the fundamental understanding that as structures degrade with time and exposure to the elements, their resonance changes. Currently, there is a strong demand for technology to assist with predictive structural maintenance in areas such as single and multistory buildings, windmills, oil platforms, dams, and bridges. The proposed technology is designed to alert the owners and operators to any significant changes in their assets, which will allow them to schedule more detailed inspections in time to identify the exact nature of the ongoing failure and have it repaired before it turns into more significant problem and expense. This I-Corps project is based on the development of a technology to estimate the fragility of a structure by monitoring its resonance. The proposed technology uses both hardware and software development. The proposed hardware comprises a multi-sensor unit with telemetry capabilities to capture the full scope of motion and relay the information in near real time. The multi-sensor unit comprises elements of an accelerometer, gyroscope, and GPS, which respectively allow the recording of linear and torsional motions and displacements. The software uses windowing and stacking methods that minimize noise and enhance the characteristic modes of a structure. The hardware may be installed in stationery as well as mobile structures irrespective of their shape complexity and constituent material. The recorded data are transmitted to a “base” high-performing computing infrastructure. At the base station, the data are cataloged, archived, and analyzed for changes in the resonance pattern using advanced processing algorithms. In general, a greater change in resonance has been associated with higher fragility. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.