A Two-Stage System Identification of Truss Bridge from Limited Measured Static Responses

System identification of Structures has become significantly important, particularly in the context of safety, timely intervention for maintenance and to exploit better usefulness in future. Truss bridges are suitable for moderate spans and were extensively used in railways. However, the condition of these age-old bridges became essentially important to assess for safety and reliability. A lot of research activities mostly adopting inverse dynamic approaches have been attempted to identify the structural system. The requirement of incorporating sophisticated instrumentations and efficient numerical techniques of the mathematical problems is complex and may not be feasible due to some practical constraints in many situations. System identification of structures based on limited static responses is simple and seems to be an attractive proposition. But, the accuracy of the predicted structural properties depends on the location of measurement degrees of freedom (MDOF) & amount of data used. A system identification technique with limited static responses at selected MDOF based on sensitivity analysis is studied in this proposed paper. The two-stage analysis processes include selection of measured degrees of freedom (MDOF) from sensitivity analysis and subsequent identification of structural parameter of truss is developed and studied. The structural property is identified at the element level using applied forces and corresponding measured displacement at those sensitive MDOF as selected. The proposed method seems to be efficient and suitable for practical problems of truss bridges, as it is able to identify the structural damage from limited measured data.