20 years of monitoring a geogrid reinforced soil wall supporting a bridge abutment

A major bridge structure was constructed in 1993 on the Pacific Highway over the Tweed River at Barney’s Point, NSW as part of an upgrade project. Both bridge abutments are supported by geogrid reinforced soil walls with a multi-tiered segmental block facing system. This was the first large scale use of such a system by the Roads and Maritime Services in NSW. In order to manage the technical risk associated with this new abutment type, they were monitored with a comprehensive instrumentation program. Monitoring commenced during construction and data has been routinely processed and reviewed in order to assess the wall movements and forces in the reinforcement and to predict future movement. This paper presents the long-term monitoring data collected and results from a back-analysis are discussed.