Engineering Commons^™

Nondestructive Evaluation Of Structural Defects In Concrete Slabs, Ehsanul Kabir

Electronic Theses and Dissertations

Nondestructive testing (NDT) is a reliable method for determining the structural integrity of new and old construction and understanding the condition of structural defects. It is widely acknowledged that the interpretation of nondestructive evaluation (NDE) has a significant impact on the reliability and consistency of this technology. However, NDT data acquisition remains subjective and heavily dependent on the operator’s knowledge and expertise. As a result, there are still issues to be resolved regarding the imaging and diagnostic procedures for NDT-based concrete inspection. NDT methods such as ground penetrating radar (GPR), and impact-echo (IE), have been extensively used to inspect concrete …

Continuous Long-Term Health Monitoring Using Ultrasonic Wave Propagation, Ece Erdogmus

Nebraska Department of Transportation: Research Reports

No abstract provided.

Long-Term Evaluation Of The Acoustic Emission Weld Monitor, Theodore Hopwood Ii

Kentucky Transportation Center Research Report

The Kentucky Transportation Research Program conducted an extended 10- month evaluation of the Acoustic Emission Weld Monitor (AEWM) in a bridge fabrication shop. That device was used to detect welding flaws during typical production of butt-welds on flanges and webs used in steel bridges. A total of 153 welds were monitored.

AEWM test results were compared with visual inspection and double- blind results of conventional nondestructive testing routinely conducted on the welds. The AEWM did not miss any flaws detected visually or by nondestructive testing. Three AEWM flaw indications were confirmed by conventional nondestructive testing (radiography).

A large number of …

Reliability Assessment Of High-Risk Steel Bridges By Nondestructive Test Methods, Theodore Hopwood Ii, Vishwas G. Oka, Robert C. Deen

Kentucky Transportation Center Research Report

Fatigue-crack related failures of high-risk (fracture-critical) steel bridges may be prevented through application of nondestructive tests (NDT). Economical reliability assessment of those structures requires 1) application of a suitable NDT method, 2) testing of fatigue-susceptible members, and 3 ) periodic retests of those members to preclude problems with growing or previously undetected flaws.

Six conventional NDT techniques were tested in the laboratory using buttweld configured specimens having intentionally embedded cracks. Those NDT methods were 1) visual inspection, 2) magnetic-particle testing, 3) dyepenetrant testing, 4) florescent-enhanced surface testing, 5 ) eddy-current testing, and 6) ultrasonic testing. The other NDT methods provided …

Acoustic Emission Monitoring Of In-Service Bridges, Theodore Hopwood Ii, David W. Prine

Kentucky Transportation Center Research Report

An experimental acoustic emission (AE) device, the GARD Acoustic Emission Weld Monitor (AEWM), has been field tested on six bridges during this study. In addition, the device was used to test three other bridges under separate contracts from state highway agencies. The device was evaluated to determine if it could detect fatigue-crack growth on in-service steel bridges.

The AEWM employs a proprietary three-step model (filter) to reject noise-related AE activity and detect and locate defects subject to varying stress conditions. The unit uses built-in microprocessors to compare incoming data to the model. If defect-related AE activity is detected, the AEWM …

Demonstration And Preliminary Evaluation Of The Acoustic Emission Weld Monitor, Theodore Hopwood Ii, Robert C. Deen

Kentucky Transportation Center Research Report

This report describes the demonstration and preliminary evaluation of the microprocessor-based acoustic emission weld monitor (AEWM) developed for the Federal Highway Administration by GARD Inc. of Niles, IL. The equipment was tested successfully on butt welds in several fabrication shops by the Kentucky Transportation Research Program (KTRP). Some problems were encountered in monitoring fillet welds.

The AEWM was demonstrated to personnel from 20 state agencies representing FHWA Regions 1, 3, 4, and 5. The demonstrations were performed at three different fabrication shops in Pennsylvania, Georgia, and Wisconsin.

A preliminary evaluation of the AEWM is included. Also, the summary of a …