Use ground-penetrating radar (GPR) to locate embedded rebar and post-tensioned tendons before core drilling or destructive testing in a parking structure

Steps

1. Scan the planned core-drilling or sampling location with GPR before any destructive work to map the depth and layout of conventional reinforcing steel and, critically, post-tensioned tendon profiles.
2. Cross-reference GPR results against original structural drawings where available, since PT tendon drape profiles change depth across a span and a location safe for coring at one point may not be safe a few feet away.
3. Mark cleared drilling locations directly on the deck surface based on the GPR scan, keeping an adequate clearance margin from any detected tendon or rebar to avoid severing a post-tensioning strand.
4. Have the scan performed or directly supervised by a technician/engineer experienced specifically with parking structure PT layouts, since misreading a GPR signature in a congested reinforcement zone is a common cause of tendon strikes.
5. Document each cleared and completed core location on the condition assessment report's plan drawings so future assessments and repair contractors know where prior destructive testing occurred.