CASE STUDY 

Safeguarding Structures During Nearby Construction

Originally constructed in 1868, the Burlington Bridge is the first iron bridge across the Mississippi. While the original engineering proved solid as BNSF used it as Chicago to Denver mainline, it’s met challenges in the modern era prompting the U.S. Coast Guard to declare it a navigational hazard.

The Challenge

More than 300 trains crossed the Burlington Bridge every month and tons of travel on barges below. It was therefore decided that shutting down rail or river traffic during the construction of a new bridge would only be allowed during a single 30-hour period. With such heavy usage demands, constant river level changes and the inherent complications of working with a 115 year old bridge, monitoring was key to this project. Knowing how and when the bridge moves, vibrates, tilts and bends proved critical for establishing a safe working environment as well as maintaining the bridge’s operational status.

The Solution

BNSF installed SENSRnet to reliably monitor the existing Burlington Bridge while crews constructed its replacement mere meters away. SENSRnet is a network of versatile sensors mounted in strategic locations throughout a structure to monitor more than 16 factors that can affect safety and stability. Installed in just a few hours at one-fifth the cost of competing systems, SENSRnet provided the safe and efficient monitoring solution BNSF needed. Thanks to the online monitoring portal, engineers had access to data in real time, enabling them to make informed decisions wherever they were located.

The Result

BNSF utilized the data generated by SENSRnet to understand what was happening to the pier on a daily basis. By comparing preconstruction baseline readings with the new responses, the design team was able to analyze new inputs and responses against known safe responses. Thanks to SENSRnet, BNSF engineers were able to detect significant movement of a pier, as well as monitor the effects of a flood and an earthquake.

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