Estimating Fatigue Life of Patroon Island Bridge Using Strain Measurements;Special rept

摘要

The design fatigue life of a bridge component is based on the stress spectrum the component experiences and the fatigue durability. Changes in traffic patterns, volume, and any degradation of structural components can influence the fatigue life of the bridge. A fatigue life evaluation, reflecting the actual conditions, has value to bridge owners. This report presents a study where the remaining fatigue life of the Patroon Island Bridge, which carries Interstate 90 over the Hudson River, was estimated as part of a structural integrity evaluation and a larger evaluation of the entire interchange. The Patroon Island Bridge consists of ten spans. Seven spans are considered the main spans and consist of steel trusses and concrete decks. The other three spans are considered approach spans and consist of plate girders. The overall bridge length is 1,795 feet. Procedures outlined in the AASHTO Guide Specifications for Fatigue Evaluation of Existing Steel Bridges and strain data from critical structural members were used to estimate the remaining fatigue life of selected bridge components. The results indicate that most of the identified critical details have an infinite remaining safe fatigue life and others have a substantial fatigue life, however the remaining fatigue life has not been determined for damaged and cracked members.