Galen E. McGill

Advanced fiber grating strain sensor systems for bridges, structures, and highways

Fiber Bragg grating sensor systems have wide application in the area of civil structures. The advantages of fiber grating strain sensors over electrical strain gauges such as greatly reduced size, EMI resistance, and higher temperature capability make them ideal choices for smart structure applications. Some of these fiber grating sensor systems can measure or detect multiaxis strain, transverse strain, temperature, bridge scouring, ice, and traffic flow.

Single- and multiaxis fiber-grating-based strain sensors for civil structure applications

There are approximately 576,000 major bridges, 3.2 billion square feet of bridge deck, and 162,000 miles of highways making up a part of the civil infrastructure system in the United States. Fiber grating strain sensors have the ability to play an important role in the health monitoring of these structures. The advantages of fiber optic sensors including EMI resistance, unobtrusive size, multiplexing/distributed capabilities, and environmental ruggedness, make them a logical choice for structural monitoring.

Traffic monitoring/control and road condition monitoring using fiber optic-based systems

There are several applications in the area of traffic monitoring and control as well as road condition monitoring where fiber optic based sensor systems are advantageous. This study focuses on the use of fiber optic sensors to monitor the strain state in structures. This monitoring accomplishes two main tasks: it assesses the health of the structure and provides useful data for traffic monitoring/control applications.

Fiber optic smart bearing load structure

As proliferation of structures incorporating composite materials occurs, the benefits of in-situ monitoring of the building materials in order to increase reliability and improve maintainability of the overall structure are being recognized. For example, measurement of shear-strain and load within bridge bearings can be directly related to the health and longevity of the structure. In this paper, the embedding of single and multi-axis optical fiber strain sensors within liquid molded load cells for structures such as bridges is reported. Fabrication and testing processes are presented, as well as test results.

Validating Dynamic Message Sign Freeway Travel Time Messages with Ground Truth Geospatial Data

U.S. transportation agencies have invested more than

Bond Strength of Electrochemically Aged Arc-Sprayed Zinc Coatings on Concrete

300 million in dynamic message sign (DMS) systems for communicating important messages to travelers, including weather conditions, incidents, construction, and homeland security and AMBER alerts. Recent FHWA policy encourages states to use their DMS infrastructure more effectively by displaying reliable travel-time information along freeway corridors. The Oregon Department of Transportation (ODOT), which maintains a freeway surveillance system in the Portland metropolitan area, calculates and reports travel-time estimates derived from inductive loop detector data. These estimates can be reported via 18 DMS and other traveler information systems but are displayed on a limited basis at key junction points during peak periods. Results are presented of an evaluation of ODOTs travel-time reporting capabilities by comparing the ODOT travel-time estimates with probe vehicle (ground truth) travel times. The freeway network was divided into 17 key corridors, a...

Rehabilitation and Preservation of Oregon's Historic Concrete Coastal Bridges

Abstract Research was conducted to determine the effect of electrochemical aging on large-area arc-sprayed Zn anodes for cathodic protection (CP) of bridges and other reinforced concrete structures. The study focused on the influences of total charge passed and concrete surface preparation on bonding of Zn to the concrete. Half the samples were preheated prior to being arc-sprayed with Zn. The preheated samples had initial bond strengths 80% higher than the unheated samples. This difference became insignificant after ≈ 200 kcoul/m2 (5.2 A-h/ft2). Bond strengths for all samples started to decrease after ≈ 600 kcoul/m2 (15.5 A-h/ft2). Changes in bond strength were correlated with observed changes in permeability of the Zn coating to water, electrical behavior of the Zn-concrete interface, charge-transfer resistance, and chemical composition at the Zn- concrete interface.

Thermal spray anodes for impressed current cathodic protection of reinforced concrete structures

Oregon’s Coastal Bridge Program was designed to preserve the economic and cultural resources invested in Oregon’s coastal bridges. The Oregon Coast Highway contains a significant concentration of bridges listed on or eligible for the National Historic Register. Many of these reinforced concrete structures are suffering extensive corrosion damage resulting from years of exposure to the marine environment. Oregon has developed this program to evaluate, prioritize, and preserve these magnificent bridges. Preservation of these bridges has relied on the innovative application of cathodic protection technology. This new technology has been applied successfully through a project design and construction process that includes ongoing interaction among design engineers, researchers, construction project management personnel, and contractors.