An adaptive version of the capacity spectrum method is proposed to estimate deformation demands of steel moment-resisting frames under seismic loads. Its computational attractiveness and capability of providing satisfactory predictions of seismic demands in comparison with those obtained by other advanced nonlinear static procedures in literature are examined. Both effectiveness and accuracy of these approximated methods based on pushover analysis are verified through an extensive comparative study involving both regular and irregular steel moment-resisting frames. The results obtained by nonlinear static procedures and nonlinear dynamic time-history analysis under spectrum-compatible accelerograms are eventually compared. The proposed procedure generally gives a more accurate solution than that obtained from the other nonlinear static procedures.
Adaptive Pushover
Seismic performance of a mixed rc-masonry building strengthened with fiber composites
In this paper the performance-based assessment of a masonry building strengthened with fibre re- inforced polymers to improve seismic resistance is carried out. At first, a specific procedure was used to calibrate the finite element model according to the experimental dynamic properties. Then, pushover analysis was carried out with an adaptive load pattern which allows for the redistribution of load as an effect of non-uniform yielding. A homogenous and isotropic smeared cracked model was used for non linear modelling of masonry. An incremental non-iterative procedure, that is an adaptive extension of the capacity spectrum and the inelastic demand response spectra method, was used for the displacement-based seismic assessment of the building. The proposed procedure was validated by comparison with the results from seismic response testing on a scale model. The final objective of the paper is the assessment of the effectiveness of retrofit as far as the safety not only at collapse but also at the other limit states.
For this paper is available an extended abstract after the text in Italian