Mechanical Identification and Model Validation for Shear-Type Frames

In the field of civil structural engineering great effort is being devoted to develop robust identification procedures for characterisation of dynamical behaviour, that concern characterisation of both modal and structural parameters. In this work, a procedure for identification of "shear- type" multi-storey frames in free vibrations is tested. "shear-type" models are very often used in civil engineering and are characterised to have just a few significant degrees of freedom (dofs, i.e. floor displacements). The procedure is composed by two consecutive steps: (1) identification of the experimental modal model from data acquisition in time domain; (2) updating of an a priori finite element model (FEM) of the structure by comparing identified modal quantities. A rational fractional polynomial technique is used to obtain the experimental modal behaviour of the structure and an eigensensitivity model updating technique to modify the structural parameters of an FEM. The whole procedure is applied to a laboratory three floor "shear-type" framed structure to provide an updated FEM. An experimental validation is performed using the updated model to predict the effect of structural modifications upon the modal behaviour variation both in the laboratory frame and in the FEM.