CONDITION MONITORING OF PRESTRESSED CONCRETE BRIDGES

The paper describes a recent condition monitoring project for the Grangetown, Cogan and Taff viaducts near Cardiff, South Wales. The project aimed to make the best use of past, present and future instrumentation-based condition monitoring data, to plan future maintenance and refine future design. All three viaducts were built by the balanced cantilever post-tensioned precast concrete segmental method with epoxy adhesive joints, known as the 'glued segmental method'. The project was carried out from 1987 to 1995, and had the following phases: (1) collating the viaducts' performance data into a concise and useful form; (2) a diagnostic analysis of the historic data to study trends; and (3) devising a strategy for continuing data acquisition, processing, and diagnosis. After the project's completion, ongoing condition monitoring began in 1996. Two of the viaducts were instrumented in 1987, and the third in 1994-95. The paper reviews the project's records, draws attention to the significant data collected on the three viaducts, and briefly discusses those data. The principal costs in the ongoing condition monitoring are identified, and some recommendations are made about how to continue it. Several conclusions are presented about experience with the embedded strain gauges and other sensors used.