GNGTS 2019 - Atti del 38° Convegno Nazionale

332 GNGTS 2019 S essione 2.2 consisted on the dynamic modelling of a simplified ¼ scaled electrical auxiliary building of a nuclear power plant was tested, Fig. 2. Analytical fragility curves are constructed starting from the statistical elaboration of damage distributions that are simulated from analyses of structural models under increasing earthquake intensity. The analysis of the results thus obtained allowed to evaluate the seismic response of the structures and to correlate the damage, assessed by response parameter (like maximum interstorey drift, eigen frequency drop off of the damaged model) to a seismic motion parameter. More specifically, fragility curves have been defined using 50 synthetic input accelerograms for a total of 50 non linear runs and 50 linear runs. For each run some parameters were changed according to a Monte Carlo simulation in the hypothesis of log normal distribution of random variables (concrete tensile strength at each storey, additional structural damping, equivalent damping and stiffness of soil structure interaction). Analyses were run by applying acceleration at the foundation level. Fig. 2 - (a) Numerical model of the irregular wall building studied during the SMART 2013 Benchmark; (b) example of obtained fragility curve. Conclusions. Multi-layered shell modelling with PARC_CL 2.0 fixed crack model demonstrated to be a useful numerical tool for the prediction of the damaged response of structures subjected to strong input motions and to predict shear phenomena, rebars yielding and cracks opening in structures subjected to torsion and flexure-shear interaction. The presented modelling approach is also able to return good results in terms of global (displacements, floor spectra) and local (concrete and steel strains) EDPs assessment. The development of similar tools is useful for the evaluation of vulnerability of seismic resisting systems, like wall systems, which cannot be properly modelled using simplified framed elements, like beam elements. Therefore, further application of the presented multi-layered shell element modelling will be the study of fragility functions of existing RC tall buildings characterized by an internal core. References Abaqus 6.12. User’s and Theory Manuals 2012. <http://www.3ds.com> . Belletti B., Cerioni R., Iori I.; 2001: Physical approach for reinforced-concrete (PARC)membrane elements . ASCE J Struct Eng, 127 (12), 1412–26. Belletti B., Damoni C., Gasperi A.; 2013a: Modeling approaches suitable for pushover analyses of RC structural wall buildings . Eng Struct, 57 , 327–38. http://dx. doi.org/10.1016/j.engstruct.2013.09.023. Belletti B., Damoni C., den Uijl J.A., Hendriks M.A.N., Walraven J.C.; 2013b: Shear resistance evaluation of prestressed concrete bridge beams: fib Model Code 2010 guidelines for Level IV approximations . Structural concrete 2013b, 14(3) , 242-249.