Project summary

Service provided:  Risk management and monitoring services during bridge replacement
Location:  Tacoma, Washington - USA
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Client:  WSDOT (Washington State Department of Transportation)
Period of the service:  February 2015-August 2018
Sixense solutions used: 

Images of the project



WSDOT (Washington State Department of Transportation) proposed to create two new HOV lanes, one in each direction of travel, along a 3.14-mile section of I-5 between Port of Tacoma Road and M Street. The Northbound Portland Avenue to Port of Tacoma Road HOV (NB) was the largest of 3 packages that completed the entire project. The project also constructed a new crossing over the Puyallup River with a change in alignment and removed the existing Puyallup River I-5 bridges.


Sixense’s Monitoring Network

Sixense Northern America was contracted by Hamilton Construction Company to address the monitoring scope in one of the main bridge replacement programs in the state of Washington. They were hired to monitor the project’s critical construction work, including ground improvements, embankment construction, pile driving, and jet grouting.

The monitoring network included:


Project Challenges

The complex nature of this project meant real-time monitoring solutions were imperative to ensure a smooth construction progress.

  1. Three railroad properties required monitoring including two Class 1 (BNSF, UP) and a short line (Tacoma Rail).
  2. Project stretched on both banks of the Puyallup, making navigating the site a challenge.
  3. Instruments had to be protected from third parties by setting up poles and brackets and keeping associated parts out of reach as frequently as possible.
  4. High number of prisms were scattered over a large area.
  5. Many different types of structures were monitored: railroads, bridges, utilities, embankments, and retaining walls.
  6. Harsh weather in the fall and winter months created additional stress on the monitoring systems. This was resolved by enhanced weatherproofing using helmets, waterproof boxes, and conduits.
  7. No permanent power available led to a fully solar-powered solution for all the instrumentation.



I-5 NB HOV: Final Takeaway

Along the way, Sixense overcame complex challenges and provided a successful risk management solution during the I-5 Northbound bridge replacement. The company’s services minimized potential risks and ensured the project was completed safely.

Once the work was finished, the I-5 NB HOV project provided operational improvements and reduced traffic congestion, enhancing the quality of life for those commuting and residing in Tacoma, Washington.


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Project Key figures

9 AMTS (Cyclops)
250 Targets
17 Settlement Plates
6 Piezometers
5 Vibration Monitors