• Shannon & Wilson

    Automated Monitoring System along U.S. Highway 36

    Colorado, United States

Project Summary

Historic Flooding Causes Erosion, Rockslides

In early September 2013, historic rainfall and flooding caused USD 2 billion in property loss and extensive damage to Colorado infrastructure, including many roads and bridges. One of those affected was U.S. Highway 36, a key artery for tourists, trucks, and local traffic. The damage closed US 36 for two months, resulting in very long detours for motorists.  While the road was subsequently repaired and re-opened, the rainfall and flooding had deeply destabilized surface material on the road cuts along its corridor. Portions of US 36 navigate steep, hard rock slopes that presented a risk of rockfall hazards to the traveling public even before the flood. Following the weather event, the soil beneath many large and medium-sized boulders above the road washed away due to surface erosion, increasing the likelihood of serious rockfalls that put people, vehicles, and road infrastructure at risk.

Establishing Continual Monitoring in Remote Areas

To ensure the safety of passengers and the operational state of the highway, the Colorado Department of Transportation retained Seattle-based full-service engineering firm Shannon & Wilson to implement an automated monitoring system that would provide remote and real-time access to the rock slope’s conditions and alert road maintenance crews of any slope movement. While evaluating the area, the design team realized the project brought unique challenges. Much of US 36 travels along a rugged landscape with limited access. Given the difficulty of installing new sensors in the area, Shannon & Wilson wanted to incorporate them in their new system rather than replace them. Additionally, the remote site does not have access to grid-based power, and the cell reception at the remote location is intermittent to poor. As a result, Shannon & Wilson needed a solution that could operate without being connected to the electrical grid or local cellular service. 

Automating Alerts to Worsening Slopes

To address the challenges of the site, Shannon & Wilson selected Bentley Systems’ sensemetrics Infrastructure Internet of Things cloud platform to collect and manage the suite of geotechnical and environmental sensors. Shannon & Wilson utilized the platform’s plug-and-play connectivity to support solar panels and integrated rechargeable lithium ion batteries, providing self-sustained power to all sensors. They also used sensemetrics’ intelligent communication system, consisting of embedded LPWAN radios and cell modems, to easily deploy a dynamic and resilient automation system for the project. All IoT devices and sensors along the project area are now managed using cloud-orchestrated tools. With the system in place, CDOT can receive alerts to worsening slopes, respond to developing issues, make informed decisions, and take the necessary measures to respond.

Providing Cost-effective Monitoring

The continual data provided by the sensor system has improved safety and enhanced asset management along stretches of US 36 where known rockfall hazards could complicate or even endanger vehicular travel. In addition to real-time readings that issue alerts, CDOT receives data that provides a longer-term picture to understand ground and rock movements as well, tracking seasonal and annual trends, along with daily performance and alert exceedance data. The system empowers CDOT to make informed decisions in rockfall hazard areas that are critical to protecting DOT infrastructure and, most importantly, the safety of the traveling public. Bentley’s cloud-connected technology was applied to CDOT’s legacy sensors for less than USD 450 per unit, providing cost-effective sensor data that would otherwise have to be manually collected, an expensive and less effective option.

Project Playbook: sensemetrics

Outcome/Facts
  • To address rockfall from erosion along U.S. Highway 36, Shannon & Wilson needed to improve ground monitoring in a remote area with poor cellular reception while using legacy sensors.
  • The continual data provided by sensemetrics has improved safety and enhanced asset management along US 36.
  • Data from the sensors provide a longer-term picture to understand ground and rock movements, helping prevent damage and ensure safety.
  • The monitoring system was applied to CDOT’s legacy sensors for less than USD 450 per unit.