Case Study: Locating Voids in Grouted Tendon Ducts of a Post-Tensioned Highway Bridge, Northeastern USA

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Problem: Identify areas where there are full or partial voids in the tendon ducts in post-tensioned bridge girders.

Results: In a preliminary test, Impact-Echo identified areas of full or partial voids in three of fourteen girders tested.

Verification: Tendon ducts were opened and inspected. Photo (above right) shows duct identified by impact-echo as ungrouted.

Outcome: Impact-Echo used to locate voids in grouted tendon ducts throughout the bridge. Empty and partial grouted ducts re-grouted.