Executive Summary

The goal of this project is to design and implement an innovative monitoring system for corrosion damage assessment of steel tendons in post-tensioned structures. The monitoring system is based on embedded arrays of piezo-composite transducers to generate and receive Guided Ultrasonic Waves (GUW) throughout the tendon. Advanced algorithms will be developed to enable the monitoring of the corrosion evolutionary path including: 1) initiation of corrosion damage (micro-scale), 2) loss of mass (macro-scale) of the steel strand, and 3) the failure of the strand. The proposed array will be able to operate in a dual monitoring mode: 1) Real-time continuous, and 2) Routine-based inspections.

Corrosion of the built environment has a very significant impact on society, affecting nearly every aspect of daily life in our nation. In monetary terms, corrosion degradation consumes at least 2-4 percent of the U.S. gross domestic product every year. The proposed research will have a positive impact on our society by enhancing public safety through early detection of corrosion damage and enabling planning and implementation of remedial measures to structures.

The research plan is divided into two phases. Phase I, Development of Statistical Algorithms for Corrosion Damage Assessment, in which algorithms capable of monitoring the evolutionary path of corrosion will be developed. Phase II, Implementation of the proposed system in accelerated corrosion laboratory tests, in which experimental simulations will be conducted to validate the effectiveness of the proposed system and to propose strategies for implementation in new and existing structures.

The work, exploiting low cost and robust piezo-composite transducers, will enable the development of a “smart strand” with sensing capabilities to inform decision makers on the need for repair to ensure safe and reliable structural performance. The uniqueness of this research resides in the development of embedded arrays of piezo-composite transducers with increased robustness, conformability to curved surfaces, and better performance in harsh environments than traditional monolithic piezoelectric transducers (PZT). The proposed activities will also fill gaps in the theoretical understanding of guided ultrasonic waves in a loaded 7-wires strand excited by embedded arrays of piezo-composite transducers. Accelerated corrosion testing will provide insights on the underlying corrosion mechanisms and the expected corrosive environment including temporal variations in the features of a GUW. The proposed work will significantly advance scientific and engineering knowledge in the area of corrosion prognosis and enhance our nation ability to detect early corrosion damage in infrastructure and to perform robust insitu condition assessments.

This project was cosponsored by the Research and Innovative Technology Administration of the U.S. Department of Transportation through the University Transportation Centers program.This project was cosponsored by the Research and Innovative Technology Administration of the U.S. Department of Transportation through the University Transportation Centers program.This project was cosponsored by the Research and Innovative Technology Administration of the U.S. Department of Transportation through the University Transportation Centers program.This project was cosponsored by the Research and Innovative Technology Administration of the U.S. Department of Transportation through the University Transportation Centers program.

This project was cosponsored by the Research and Innovative Technology Administration of the U.S. Department of Transportation through the University Transportation Centers program.