Rocky Mountain Pass

Having passed a four-year assessment of its in-service performance on an interstate highway through Colorado’s Rocky Mountains, mageba’s TENSA®POLYFLEX®Advanced flexible plug expansion joint has now been installed on several other nearby bridges.

The town of West Vail in Colorado, approximately 160 km west of Denver, is nestled in the Rocky Mountains at a height of about 2500 m above sea level. At this high altitude, the town’s average low temperature falls below freezing point eight months a year, and snowfall is approximately 5 m per year. With such demanding weather conditions, it is little wonder that the Colorado Department of Transportation takes great care in selecting the expansion joints that will facilitate the movements of the bridges on the I-70 interstate highway that passes through the town. In any environmental conditions, a bridge’s expansion joints are susceptible to damage and deterioration from the constant opening and closing movements to which they are subjected and from the loading and abrasion from millions of vehicle wheels. But the demands are typically much greater on an interstate highway in a snowy mountain location, due to low temperatures, the use of salt and grit to improve driving conditions, potential damage from snow-clearing vehicles, and perhaps the use of snow chains or spiked tires by drivers.

The I-70 interstate is an important transcontinental highway that stretches roughly 3500 km from Utah in the western United States to Baltimore, Maryland on the east coast. Taking its responsibility to the highway’s users seriously, the Colorado Department of Transport has taken time to evaluate the suitability of the expansion joints used in the bridges on the highway where it passes through the Rockies. In 2017, the state authority launched a pilot program to assess the durability and performance of the TENSA®POLYFLEX®Advanced flexible plug expansion joint for use on its own highways, with their specific demands and environmental conditions. Four years after a first expansion joint of this type was installed on a bridge on the I-70 where it passes through the mountains, enough evidence had been gained of the joint’s suitability for use, and it was decided to specify its use in two other similar structures. mageba was awarded to supply four expansion joints that were installed in September and October 2021.

For bridge owners that are not able to spend several years evaluating the in-service performance of this expansion joint type before using it more widely, a great deal of confidence can be gained from the experience of its use on bridges all around the world – including as reported on in our previous newsletter articles from applications in Sweden, Canada and Australia. Confidence can also be gained from the extensive laboratory testing to which it has been subjected. For example, the certification testing carried out in connection with the awarding of a European Technical Approval, with validity across the European Union, included

  • Testing of the material’s bond strength

  • Assessment of the material’s ageing and temperature characteristics

  • Mechanical resistance testing

  • Fatigue resistance testing

  • Movement capacity testing

  • Assessment of surface flatness before and after fatigue and movement testing

  • Watertightness testing

  • Skid resistance testing

  • Testing of resistance to chemicals such as oil, fuel and de-icing agents

  • Testing of aging due to temperature, ozone, UV-radiation and weathering

  • Testing of freeze-thaw performance

With so much evidence available from strenuous laboratory testing, combined with the in-service testing of its use on structures all around the world, every bridge owner can have confidence that the TENSA®POLYFLEX®ADVANCED flexible plug expansion joint will provide excellent service for many years – no matter how demanding the environment.

Bridge designer: Colorado Department of Transportation
Contractor: ABCO Contracting, Inc.
Owner: Colorado Department of Transportation

The TENSA®POLYFLEX®ADVANCED flexible plug expansion joint offers all the benefits of a traditional asphaltic plug expansion joint, but offers vastly superior strength, performance, durability, and flexibility with respect to installation

Having already proven its durability and performance on a pilot project on the I-70 interstate highway in the Colorado Rocky Mountains, the TENSA®POLYFLEX®ADVANCED flexible plug expansion joint has now been approved for use on further structures

In September and October 2021, four expansion joints with movement capacities of up to 75 mm were installed to replace existing small-movement joints on short-span bridges in similar high-altitude locations on the same stretch of highway

In this mountain location, bridge expansion joints are subjected to sub-freezing temperatures (average daily lows) eight months a year, and experience snowfall of approximately 5 m per year

The demanding environment of such high-altitude locations makes it necessary, when selecting an expansion joint solution for use, to consider such issues as low-temperature performance, the use of salt, grit and snow-clearing equipment, and perhaps the use of snow chains or spiked tires by drivers