Structural Health Indices for Steel Truss Bridges

Steel bridges represent a significant portion of the nation’s aging bridge inventory. The United States Army’s inventory has over two hundred steel bridges that are vital to the operation of nearly every Army Installation. The Army regularly inspects their bridges to ensure the continued functionality of the bridges. However, current inspection techniques and schedules may not be able to detect certain defects that could compromise bridge integrity. To supplement current inspection standards, the US Army Engineer Research and Development Center (ERDC), has contracted to install a structural health monitoring (SHM) system on the historic steel truss Government Bridge at the Rock Island Arsenal. ERDC envisions a system that measures strain, acceleration, tilt, and electrical resistance to determine the bridge’s structural health. Research into the usefulness of the Damage Locating Vector (DLV) method, and the damage indices that the method calculates, in detecting corrosion damage has been conducted. Numerical studies on a finite element model of the Government Bridge have indicated that the DLV method has potential as a damage detection algorithm on such a large structure. Laboratory experiments using corroded members in a model truss have additionally shown that the DLV can be used to monitor corrosion induced damage.