#United States #Covington #Infrasense #GPR Survey #Bridge Inspection

Infrasense and Bridge Evaluations with Ground Penetrating Radar

Infrasense has made notable strides in the assessment of bridge structures using Ground Penetrating Radar (GPR). Recently, the company conducted an extensive survey of nine interstate bridge decks that each accommodate three to four lanes in both directions. The primary objectives of this initiative were to evaluate the rebar depth and the thickness of the asphalt concrete overlay present on the approach slabs of the bridges.

The GPR survey was executed using an advanced vehicle-based system equipped with a dual 1-GHz horn antenna. This system was complemented by an electronic distance-measuring instrument (DMI) affixed to the rear wheel, which supplied synchronized distance data in conjunction with the GPR measurements. Furthermore, a GPS unit was incorporated to gather high-resolution, differentially-corrected geo-spatial information, contributing to the precision of the data collected. An SIR-30 GPR system was employed, and its operation was initiated from within the survey vehicle, effectively controlling the entire data collection process. During the survey, data was gathered at a rate of two scans per foot as the vehicle navigated each surveyed lane.

The analysis of the GPR data concentrated on tracking the upper layer of rebar within the slabs while simultaneously reporting on the thickness of the concrete cover. It was observed that the majority of the eighteen slabs under review had asphalt overlays, the thickness of which was duly analyzed and documented. Due to irregularities often encountered laterally across a single slab, the thickness measurements of the asphalt overlay and the concrete cover were segregated into groups according to lateral offsets. An analyst played a pivotal role in selecting individual slab layers, and custom software was utilized to perform dielectric and thickness calculations based on this selected data.

The calculated layer thicknesses were reported at one-foot intervals along each of the approach and departure slabs surveyed. Alongside this, essential statistical values such as average, median, standard deviation, and the 25th and 75th percentiles were computed for both the concrete cover and the asphalt overlay across all eighteen slabs evaluated.

The analytical results for each surveyed bridge deck were compiled and presented in an organized tabular format, ensuring clarity in the reported data. This rigorous approach to analysis not only highlights Infrasense's comprehensive methodology but also signifies its commitment to facilitating the ongoing maintenance and safety of bridge infrastructures across the country.

Since its inception in 1987, Infrasense has been leveraging advanced technology to tackle challenging subsurface scanning needs. Their engineers have consistently demonstrated an ability to extract vital information nondestructively from a wide array of structures. In addition to their subsurface evaluation services, the firm has been involved in several research initiatives aimed at enhancing techniques in nondestructive evaluations.

To learn more about Infrasense and our extensive range of services, please visit Infrasense's website.