Methodology for the Quantitative Evaluation of the Remaining Fatigue Life of Fracture Critical Bridges

Two fracture critical bridges were instrumented using miniature, battery-powered data acquisition systems as part of this investigation. The measured rainflow response was then used to estimate the remaining fatigue life of each bridge. The primary advantages of the monitoring system are that the units were designed to be installed easily in the field and interpretation of the rainflow data is straightforward. However, to utilize the full potential of the monitoring system, analytical models of each bridge must be developed prior to instrumentation and careful evaluation of the rainflow data is required.

Incorporating the data acquisition units into regular inspections of fracture critical bridges will represent a significant change in TxDOT procedures. However, the rainflow data provide a quantitative metric for identifying the bridges that are most vulnerable to fatigue damage and will assist TxDOT in setting priorities for inspection and replacement of these bridges as they approach the end of their service life.