Instrumentation of the US Grant Bridge for monitoring of fabrication, erection, in-service behavior, and to support management, maintenance, and inspection

The replacement of the US Grant Bridge over the Ohio River in Portsmouth, OH, was initiated in 2001 when the original bridge was closed and demolished, and its substitute opened in 2006. The new design is a steel cable stay design with steel girders and floor-beams supporting a post-tensioned concrete deck system nearly 65' wide carrying one lane of traffic in each direction. The combination of epoxy-coating, grout filling, and outer tubing provides protection for the all-important structural cabling suspension system from both weather and corrosion. Ironically, however, these same features make it impossible to gain direct access to either the cables or the interior of the anchorages which, in turn, presents special challenges for inspection and rehabilitation of these critical bridge components on bridges of this type. It was envisioned that its long-term behavior and any associated changes in its structural condition could be best understood with the aid of a longitudinal study beginning during bridge construction, one that includes instrumented monitoring of both construction/erection and in-service phases of the life of this bridge. Such an approach, integrated with traditional bridge management techniques, would help lead to a safe and economical realization of the 100-year design life of this structure. A health monitoring system for the bridge would be designed, planned, and implemented, with data collection and archival throughout its construction and ultimately an automated, user-friendly interface on a dedicated website.