Near the small town of Saco, Montana, three bridges were constructed less than one mile apart along the same highway corridor, Montana State Route 243. Because of their proximity to each other, each bridge experiences essentially identical demands from weather, traffic, and winter maintenance. To assess bridge deck performance, each of the bridges was instrumented then each bridge was fitted with a different type of reinforced concrete deck.

The instrumentation is primarily concentrated in a single driving lane of one 15 m span on each of the three bridges. Strain gauges were placed in each bridge deck prior to casting the concrete. Three different strain gauge technologies were used in each bridge: 35 Vishay foil strain gauges bonded to reinforcing steel, 7 Vishay embedment-type strain gauges suspended in concrete, and 16 Geokon vibrating-wire strain gauges suspended in concrete.

Case Study Summary


Long-term bridge deck performance and live load testing of experimental bridge deck sites


Saco, Montana, USA

Products Used

CR5000  AM16/32B  CR10X  NL100  AM16/32A 


Western Transportation Institute: Peter Smolenski, Jeff Johnson, Eli Cuelho, Jerry Stephens

Participating Organizations

Montana Department of Transportation (MDT), Western Transportation Institute

Measured Parameters

CR5000 Deck Performance: strain (bonded foil, vibrating wire) temperature (thermistors) CR10X weather: air temperature, wind speed, wind direction, barometric pressure, relative humidity)

Related Website

Western Transportation Institute

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