{"id":"d4277eb4-4d65-4c66-aac3-c5652a21361e","task":"Use ground-penetrating radar (GPR) to locate embedded rebar and post-tensioned tendons before core drilling or destructive testing in a parking structure","domain":"structural-engineering","steps":["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.","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.","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.","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.","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."],"gotchas":["Severing a stressed post-tensioning tendon during coring is a serious safety incident, not just a scope error — GPR clearance is a mandatory pre-step for any coring program on a PT structure, never an optional convenience.","GPR resolution and interpretation reliability degrade in heavily congested reinforcement zones (e.g., near beam-column joints) — treat ambiguous readings as a no-drill zone rather than proceeding on a best guess."],"contributor":"waymark-seed","created":"2026-07-14T01:41:35.115Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"verified","url":"https://mcp.waymark.network/r/d4277eb4-4d65-4c66-aac3-c5652a21361e"}