Restoring Road Safety After a Thousand-Year Flood In early September 2013, historic rainfall and flooding caused wide- spread damage in parts of Colorado. This 1,000-year weather event caused USD $2 billion in property loss and extensive damage to local and state infrastructure, including many roads and bridges. One of those affected was US Highway 36, a key artery for tourists, trucks, and locals. One of the state’s busiest highways, it runs from Estes Park, Colorado, near the entrance to Rocky Mountain National Park, to the city of Boulder and east toward the Kansas border. 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. Difficulties with Site Access and Communications To ensure the safety of the traveling public and the operational state of the highway, the Colorado Department of Transportation (CDOT) decided they needed to upgrade the existing monitoring system to provide remote and real-time access to the rock slope’s performance at key locations identified through risk analysis. They retained en- gineering consulting firm Shannon & Wilson to design and install a state-of-the-art monitoring system to alert CDOT’s team to slope movement. Headquartered in Seattle, Washington, Shannon & Wilson provides integrated geotechnical engineering, engineering geology, environmental, and natural resource services worldwide and is a leader in providing consulting services to DOTs around the nation. 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. Many of the new monitoring devices could only be Shannon & Wilson Designs State of the Art Monitoring System to Prevent Severe Flooding on US 36 in Colorado Bentley’s IoT Cloud Solution Enables Project Team to Reliably Share Data and Cost Effectively Enhance Asset Management By Todd Roberts, P.G.
installed with the help of professional ropes crews. In May 2018, more than 30 previously installed crack meters were automated at two sites approximately 3,000 linear feet apart along the US 36 corridor, near Lyons, Colorado. Given the difficulty of the initial crack meter instal- lation, Shannon & Wilson decided to incorporate the existing sensors in their new system. Additionally, the remote site does not have access to a grid-based power, and the cell reception at the remote location is intermittent to poor. Shannon & Wilson needed a solution that could operate without connections to the electrical grid or a local wired in- ternet service. State-of-the-Art, Real-Time Condition Monitoring To address the challenges of the site, Shannon & Wilson selected sensemetrics, Bentley Systems’ Infrastructure Internet of Things (IoT) cloud platform, to collect and manage the data from the suite of geotechnical and environmental sensors. They used sensemetrics’ intelligent communication IoT devices, supporting both LPWAN and cellular communication, to easily deploy a dynamic and resilient auto- mation system for the project. The sensemetrics connectivity devices Project Summary Organization Shannon & Wilson Solution Roads and Highways Location Colorado, United States Project Objectives • To continually monitor a remote area of highway subject to rockfall. • To establish a cost-effective system that can provide alerts based on real-time sensor data. Products Used: sensemetrics Fast Facts • In 2013, historic rainfall and flooding caused USD 2 billion in property loss and extensive damage to Colorado infrastructure, including roads. • Damage caused to US Highway 36, a key artery for tourists, trucks, and local traffic, was repaired but remained subject to rockfall caused by erosion. • Shannon & Wilson needed to improve ground monitoring in a remote area with poor cellular reception while using legacy sensors. ROI • 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, saving a significant amount of time and money.
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September 2022
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