Speaking

The Kentucky Transportation Cabinet (KYTC) commissioned a two-phase investigation of the W. H. Natcher (constructed in 2002) and W. H. Harsha (constructed in 2001) cable-stayed bridges to diagnose deterioration in the stay cable systems (SCS) and develop rehabilitation plans to extend service life. The multidisciplinary team performed visual inspections, borescope assessments, ultrasonic testing (UT) at upper and lower anchorages and vibration testing to estimate cable forces, supplemented by laboratory analyses of grease and water samples. Widespread cracking was documented at upper and lower connection sleeves—concentrated at fusion couplers—with grout voids confirmed at all borescoped locations on both bridges' lower sleeves, facilitating water ingress and threatening long-term durability. Lower anchorage caps on both bridges exhibited water mixing with grease, elevated grease water content (5–12%) and reduced viscosity, although UT detected no wire section loss within 10 feet of anchorages.

On Harsha, additional free-length stay pipe cracking was observed, likely influenced by construction or environmental factors, and wind-tie components showed poor condition and probable over-tensioning. Vibration testing revealed individual cable force deviations of -26% to +23% (Natcher) and -19% to +41% (Harsha) relative to analytical references, yet maximum measured demand remained at 42% of GUTS, below the 80% design threshold.

Proposed repairs include replacement of fusion couplers with welded HDPE half-shells, pressure grouting of voided sleeves, renewal of anchorage cap gaskets and grease, PE plastic welding of pipe defects, replacement of neoprene boots, application of protective tape and installation of friction-based wind damping systems. Plans and specifications were completed for both structures, and repairs for both structures are currently in progress. This session will provide a practical framework for diagnosing SCS water ingress, grout voiding and sleeve fatigue, as well as implementing comprehensive preservation strategies for aging cable-stayed bridges.