Condition Assessments with Impact Echo – Concrete Beam

Dec 8

In a recent structural assessment project in Houston, Texas, OmniVueNDT employed advanced non-destructive testing (NDT) methodologies to evaluate the integrity of a concrete grade beam within a building. The primary objective was to identify and assess potential flaws or voids that might compromise the structural support of the beam. Unseen defects and flaws in concrete structures always mean bad news, even in the first phase of construction, and often result in significant structural concerns.

Upon the removal of formwork after a concrete pour, an observable and significant damage on the top left corner of the grade beam prompted the need for a thorough assessment. The chosen NDT technique for this project was the Impact Echo (IE) method, utilizing the PROCEQ Pundit PI8000 instrument (refer to Image #2). This method is particularly effective for detecting internal flaws, voids, and delaminations by analyzing stress wave reflections within the concrete structure.

To enhance the accuracy of the assessment, a high-frequency Ground Penetrating Radar (GPR) scanner, specifically the STRUCTURESCAN Mini from GSSI, was employed before the IE test. This step aimed to create a detailed layout of the rebar reinforcement within the concrete beam. The rebar layout information was then used to establish the grid for the subsequent Impact Echo testing, ensuring that the data collection process was precise and well-coordinated.

The Impact Echo tests were conducted on the concrete surface, following the predetermined rebar layout. The gathered data was processed using advanced computational techniques to generate a 2.5D numeric interpretation (refer to Image #3). Post-processing of the data resulted in an actual contour map, represented as a heat map (refer to Image #4). This contour map was seamlessly integrated with a LiDAR imaging 3D model to enhance the accuracy and visualization of the structural condition.

By utilizing a combination of Impact Echo, high-frequency GPR, and LiDAR imaging, OmniVueNDT provided a comprehensive understanding of the structural integrity of the grade beam. This multi-method approach enabled civil and structural engineers to make informed decisions regarding potential repairs or reinforcements, ensuring the long-term stability and safety of the building structure.

Non-destructive testing techniques such as these play a crucial role in modern structural assessments, offering detailed insights while eliminating the need for invasive procedures. This project demonstrates the effectiveness of advanced NDT methods in detecting hidden structural deficiencies before they become critical issues.