Projects

Dynamic Evaluation of Stay-Cables – East Huntington Bridge

Description

The East Huntington Bridge is a cable-stayed bridge that carries WV 106 over the Ohio River between Huntington, West Virginia and Proctorville, Ohio. Two planes of stay-cables, each composed of 31 cables arranged in a fan formation, span from a single tower to the east and west edges of the main and side spans of the bridge. Shortly after construction of the bridge, the stay-cables were discovered to be susceptible to large amplitude vibration in certain wind-rain conditions. To mitigate the issue, the stay-cables were retrofitted with viscous dampers that were installed near the cable anchorage points in the tower.

Since 2011, CTLGroup has served as the specialty engineering consultant for the dynamic evaluation of the East Huntington Bridge stay-cables. Our work has been part of the West Virginia Department of Transportation’s multi-year inspection program of the Ohio River crossing. CTLGroup has taken part in inspections thus far in 2011, 2016, and 2018.

CTLGroup’s dynamic evaluation has involved instrumenting the stay-cables with accelerometers and exciting the stay-cables to measure their damped, free-vibration response. The vibration records were then post-processed and analyzed by CTLGroup engineers to estimate the stay-cable damping coefficients in order to evaluate the effectiveness and remaining life of the externally attached dampers.

As part of the recurring study, CTLGroup has also performed calculations to estimate tensile forces in the stay-cables using natural frequency data determined from our field vibration measurements. Our cable force calculations follow taut string theory, with modifications to account for boundary conditions, bending stiffness, sag, and other characteristics of the stay-cables.