A model updating method with strain measurement from impact test for the safety of steel frame structures

Conventional model updating methods for structures mainly use modal parameters, which are global structural responses such as natural frequency, mode shape, and modal damping obtained through vibration measurements. A model updated using those modal parameters can accurately estimate global structural responses and is used to evaluate the state of a structure. However, when using modal parameters only in model updating, a difficulty arises regarding safety assessment and response prediction of local structural members. To ensure safety of structural members, this study proposes a model updating method using the strains measured from the impact tests in structural members of steel frame in addition to modal parameters. In the model updating technique proposed in this study, error functions are set as the differences between measured and model's modal parameters and the maximum strain subject to impact force, and the functions are minimized using a multi-objective optimization algorithm. The strain responses predicted in the updated model are used in the safety assessment of structural members in steel frames. The proposed method was experimentally verified through impact hammer loading tests on a planar steel moment frame. Furthermore, the stresses obtained from the model updated with modal parameters only and the model updated by the proposed method were compared.