Improving the evaluation of fracture critical bridges using measured rainflow response

A strain data acquisition system known as MicroSAFE was used in the field to evaluate two fracture critical bridges for the Texas Department of Transportation. This system was tested for its applicability for future use by TxDOT. The first bridge is located in downtown Austin, TX and is an exit ramp for Interstate-35. The MicroSAFE units were used to record rainflow strain data and that information was used to determine a fatigue life for the bridge. A second bridge south of San Antonio, TX was also evaluated and the rainflow data was corroborated with a weigh-in-motion sensor located near the bridge. The MicroSAFE units were found to be a viable option for TxDOT, with the data suggesting that the determination of a fatigue life should affect the inspection schedule for a bridge