Situation
Due to the size of the tower, multiple hoists had to be installed in order to move people and material efficiently. In order to achieve this, the hoist masts had be anchored to a suspended concrete slab approximately every 3 floors. The slab throughout the tower contained a very tight grid of in-slab heating lines approximately four inches apart, along with two rebar layers, electrical conduits and Post-Tension cables.
A regular GPR scanning company had been brought in prior to drilling the anchors. Although they had successfully marked out the rebar pattern and some heating lines, they had missed some heating lines that were hiding directly below rebar and consequently two heating lines were hit whilst drilling.
In addition to the immediate repair costs, project delays were incurred and with the presence of post-tensioned cables in the slab, further errors could not be risked.
Solution
Our Xradar technician used the Enhanced Concrete Imaging system of Xradar to successfully identify all embedded objects within the suspended concrete slab. Over the course of two years as the building rose, Our technicians successfully scanned every single hoist tie back area for the entire building, for three hoists. During this time all other slab penetrations, cores and anchors in the project have been successfully scanned using Xradar.
