Challenge

Traditional data collection methods were unable to determine the depth of the drilled shaft foundations.  Since we had a drill rig on site to collect a rock core for determining the soil/rock strength parameters we could use the same machine to core through the concrete foundation to determine its depth.  The tower was on a mountain peak and the foundation 2-3’ above grade so we had to build a ‘bridge’ to get the rig high enough to core the foundation.

Result

After every 5’ core run was completed, the crew checked the core sample to determine if it was concrete or not.  After coring 12’ of concrete, the core samples consisted of sandstone meaning we were past the bottom of the foundation.  Based on this information, we could determine the entire length of concrete as well as the embedment depth of the foundations.  After that information was determined, the crew pulled the drill rig forward and took rock core samples to the bottom of foundation depth so we would have the rock properties needed to analyze the existing foundations.