In-situ field measurements and numerical model identification of a multi-span steel railway bridge

In this paper, in situ field measurements and analytical model verification studies of a railway bridge that spans Karakaya Dam Lake between the cities of Malatya and Elazig in Turkey are presented. The bridge consists of 29 simply-supported steel trusses, each having a 64m span length, giving a total bridge length of 2029.60 m. To understand the actual behaviour of the bridge, static and dynamic tests on the bridge spans were performed. The bridge was instrumented with strain-gauges mounted on the surface of the bridge members, accelerometers placed on the piers, abutments, and truss members and an optical laser based displacement sensor located at mid-span. Then, a three-dimensional finite element model of the bridge was generated using commercially available finite element analysis software using frame elements, a thick shell, and spring and rigid bar elements. The initial numerical model was calibrated using an optimization procedure based on automatically adjusting the spring constants and rigid bar rigidities with the help of MATLAB. Finally, the validity of the calibrated FE model was examined by the vertical displacement measurements.