Evaluation and Repair of Wrought Iron and - Purdue e-Pubs ...

1155. REPAIR AND REHABILITATION RECOMMENDATIONSWhen investigating the condition and capacity of a historic iron truss bridge, it isoften beneficial to study the behavior of the truss members in reference to each other.Unexpected movement, shaking, and deflections could reflect underlying structuralproblems within the truss bridge. For historic truss bridges, common problems usuallyconsist of un-symmetric connections, severely strained and damaged pins, eyebarcracking and failure, elongated and slack members, traffic damaged and bent members,and various stages of corrosion resulting in loss of cross-section. Once trouble areas arefound in the bridge, the material properties of the structural members should bedetermined and the damage repaired accordingly.5.1 Determination of Material Properties of Bridge MembersBefore any repairs can be completed on an iron truss bridge it is first essential todetermine the materials that are present in the bridge. Many engineers initially may havetrouble in determining the existing materials from visual inspection alone. Bridges thatwere constructed during the late nineteenth century could consist of a variety of materialscommonly used at that time, such as cast iron, timber, steel or wrought iron. It isextremely important to accurately determine the materials used in these historic bridgesto properly evaluate their condition.To determine what materials were utilized in any existing historic bridge, it isuseful to locate the history and manufacturer of the bridge. Often agencies that maintainthe bridge will have documentation of the bridge’s history and construction documents.If these are unavailable, however, it might be beneficial to search for any ornamental