McGhee Tyson Airport Knoxville, TN

Metal bracket installation for providing extra support to the precast double T joist. GPR was used to locate reinforcement layout to avoid drilling or damaging the steel reinforcement system of the structure.

The Challenge

Company was contracted to perform a structure scanning service in real time to locate any unseen reinforcement inside the concrete structures. The project was located on the second floor of the main parking garage at the airport in Knoxville Tennessee. The objective was to locate steel or possible post tension cables in the concrete joists and marking them aaon the surface with permanent markers to supply information for future metal plate installation. The bolt locations on the metal plate were used to find a clear spot for drilling. The purpose of the scanning was to utilize a non-invasive scanning method to determine the layout of steel reinforcement in order to avoid drilling into them and compromising the integrity of the structure. 

The Method

We utilized a high frequency, 2.6GHz GPR unit with which to conduct real time scanning. Due to the lack of space on the side of the beam the palm antenna provided us a suitable solution. The dielectric value was determined in a direct mode by taking a physical measurement of the thickness of the concrete joist then adjust the dielectric value in accordance with the thickness measurements. The scanning was performed from an elevated platform by using a Baker Scaffold in order to conduct the work safely. 

Scanning was carried out in real-time mode and the reinforcement layout was determined successfully. At the end, the metal brackets were installed safely, which provided more structural support to the joists.