Load Testing & Monitoring
Displacement data was collected from 5 locations on the bridge, providing real-time data
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The Challenge
- Observed cracking in the masonry arch bridge
- Rapid response needed to avoid key rail corridor closure
The century-old granite, stone arch, Ballardvale Bridge, crosses the Shawsheen River near Andover, Massachusetts, and serves the Massachusetts Bay Transportation Authority’s (MBTA) Boston – Haverhill Line and also carries Amtrak’s Northeast Corridor trains and freight rail.
In mid-October 2008, the Massachusetts Bay Commuter Railroad Company, the regional rail arm of the MBTA, placed an emergency request to Geocomp concerning an observed crack in the masonry arch bridge. The challenge was to respond rapidly to avoid bridge closure of a key rail corridor through instrumentation of an aging bridge.
The Solution
The emergency request to Geocomp concerning an observed crack in the masonry arch bridge required rapid response to avoid bridge closure of a key rail corridor through instrumentation of an aging bridge. Geocomp responded within just one day and began conducting in-service load testing and monitoring using its iSiteCentral® system. Displacement data was automatically collected from five locations on the bridge to show the influence of trains traveling over the bridge after it developed a large crack in one pier.
Geocomp’s monitoring provided real-time accurate data enabling decision makers to overturn an initial decision to restrict train speeds on the bridge. The increased speeds subsequently reduced delays and improved the MBTA’s on-time performance.
