Analysis of Structure Monitoring Data for the Commodore Barry Bridge
A two-week structure health monitoring was conducted by another firm in the thru-truss spans of the Commodore Barry Bridge circa 2017. A total of 36 strain gages were installed in the truss top chord and diagonal members near the PA tower. The original data analysis included temperature-induced stresses, which exhibited significant amplitudes as they moved in sync with daily temperature cycles, and are not suitable for the fatigue and fracture evaluation of these truss members. To accurately capture fatigue stress ranges, it is necessary to separate the live load-induced stress from the total measurements. CHI conducted further analysis of the collected monitoring data, using the spectral transformation method and the rain-flow algorithm. As a result, the fatigue stress ranges for all strain gages were substantially reduced, more than 45%, and they are all below the Constant Amplitude Fatigue Thresholds (CAFT) for infinite life design.
Delaware River Port Authority (DRPA)