Case Study 4: Locating Voids in Grouted Tendon Ducts of a Post-Tensioned Highway Bridge, Northeastern USA.
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.