Speaking

Recognizing the potential deficiencies of older post-tensioned (PT) conditions, the Cincinnati Department of Transportation and Engineering (CDOTE) retained Burgess & Niple (B&N) to inspect, perform non-destructive testing (NDT), develop rehabilitation plans and provide CEI services during the construction phase of Bridge 690, a significant PT concrete structure. 

The project's first phase consisted of in-depth inspection, extensive documentation research, and review of past contract documents. Next, a post-tensioned inspection plan was created and served as the scope for the project’s second phase.

The project’s third phase involved developing repair plans for the structure based on the findings from the first two phases. The final phase included providing CEI services for the preservation of the structure as part of the CDOTE construction inspection team for the PT repairs. The remedial grouting of the tendon duct voids was difficult due to the significant amount of loose grout in the voids. Of the 170 borescope test locations, 100 revealed major voids, with water present at several locations.

The rehabilitation construction began in April 2024 and was completed in July 2024 with the submittal of all construction documentation to CDOTE. The repairs consisted of:

• Measurement of the full length of each void, if possible
• Borescope inspection of each void interior after cleaning
• Calculation of each void’s potential volume
• Actual grout volume pumped into each void

The final documentation submittal to CDOTE consisted of approximately 1,100 pages.