PSI - Issue 64

E. Michelini et al. / Procedia Structural Integrity 64 (2024) 1967–1974 1973 Elena Michelini, S ł awomir Dudziak, Simone Ravasini, Beatrice Belletti / Structural Integrity Procedia 00 (2019) 000–000 7

showing the deformed plots of the frame and the location of damage concentration, it can be seen that in this settlement scenario the structure’s failure is ruled only by steel failure in the plastic hinges formed in the accidental situation.

(a) (b) Fig. 7. Comparison among different models in the case of side column’s settlement (scenario No.2), in terms of: (a) sum of reactions vs. settlement curve, (b) diagram of normal forces for a settlement value u = 200 mm.

(a) (b) Fig. 8. Settlement of the side column: (a) Reactions or selected angles vs. settlement, (b) deformation (10x scaled) at the considered limit states with damage concentration indicated. Table 2. Total inclination and chord rotation values corresponding to the achievement of LS, for the two considered settlement scenarios. LS1 LS2 LS3 LS4 LS1 LS2 LS3 LS4 α (%) 0.003 0.325 0.651 1.195 0.190 0.378 0.486 0.586 5. Conclusions Based on the preliminary results presented in this work regarding the damage assessment of RC framed building subjected to large column settlements through NLFEA, the following conclusions can be drawn: • If properly validated, NLFE models using fiber frame elements can represent a useful tool to assess the response of buildings subjected to different scenarios. Numerical data can be useful for the derivation of fragility curves, relating the failure probability to specific variables depending on the accidental situation under consideration. • In the case of large column settlements, possible variables that can be considered for the derivation of fragility curves, and that can be easily measured on site through SHM systems for a near-real-time performance assessment, are: chord rotations of the beams next to the columns subjected to the strongest uneven settlement, inclination of the whole frame (which is more important for internal column settlement), deformations of all those structural parts subjected to tension in the accidental situation (e.g., crack widths in the vicinity of the columns subjected to settlement). Scenario No.1 Scenario No.2 θ 1 (%) θ 2 (%) 0.262 1.028 1.796 2.974 0.312 1.230 2.155 3.575 - - - - 0.529 1.784 3.130 5.285