Simplified method for the seismic qualification using measured modal data

The seismic response estimation by the response spectrum method using only the experimental modal data are presented here. The modal participation factors (MPFs) used for the response estimation are calculated using the experimental mode shapes only. This response is compared with the response estimated using the conventional MPFs but the experimentally extracted mode shapes are used along with the mass matrix estimated corresponding to the measured degree of freedoms (dofs) using physical dimensions of the structure. The presented study eliminates the uncertainty associated with analytical modelling for evaluating mass matrix.