1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

A new simplified structural model, which is termed as the improved fish-bone model (IFB), is presented in the paper's first part. The model is an extension of the conventional fish-bone model. It can be used for seismic analysis of older and contemporary predominantly plan-symmetric reinforced concrete frame buildings. The IFB model approximately accounts for the importance of structural elements and the potential redistribution of demands between frame buildings' elements. The latter is crucial for the seismic analysis of older frame buildings. Because of reduced degrees of freedom, it can be easily used to perform numerous numerical simulations based on non-linear response history analysis, demonstrated in the second part of the paper. The IFB model capability and accuracy is shown for the most important engineering demand parameters of selected pseudo-dynamically tested full-scale frame buildings. Further on, the IFB model's is used to estimate the fragility functions based on the response history analyses for a set of selected accelerograms. It is shown that the new IFB model is capable to accurately simulate the non-linear seismic response of a contemporary and older frame building compared to the simulated response of the conventional MDOF model. The main advantages of the IFB model are the computational robustness and computational efficiency, which becomes particularly pronounced for the buildings with many structural elements and seismic loss estimations of buildings and the response history analyses of building portfolios.