9319878 Aktan This is a proposal for research focused on deterioration mechanics of aged steel truss bridges, to develop a rational approach for quantitative assessment of the condition of these bridges. The scope includes the following phases. (1) An in-depth study of the properties of chemically and mechanically aged and deteriorated materials. This phase will include a study of how the fundamental characteristics of materials (including the fatigue properties) change with age and are affected by deterioration. (2) Laboratory studies of six full-length built-up members salvaged from the two destroyed highway bridges. (3) Development of a practical procedure for estimating the actual type and extent of deterioration. This procedure will enable predicting critical responses of bridge members and of complete bridges; (5) Calibration of the proposed analytical procedure by simulating the experimental responses of the two highway bridges tested to failure. This calibration will be done through nonlinear system- identification studies.
