PSI - Issue 44

Olivier LHERMINIER et al. / Procedia Structural Integrity 44 (2023) 528–535 LHERMINIER Olivier / Structural Integrity Procedia 00 (2022) 000–000

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3.3. Pushover vs. non-linear transient analysis

In order to validate the pushover analysis, transient nonlinear analyses have been performed with four x-y pairs of accelerograms at PGA = 0.15 g. The parameters used for the transient non-linear calculation are the same as for the pushover analyses. The evolution of F x − F y loads at the basis of the building is given in 7a, together with the polygons which rely the eight F x − F y pairs of the eight pushover analyses. The graphical comparison shows that the results from transient analyses are well enveloped by the polygons. Moreover, maximum and minimum torsion moments obtained from transient analysis are also well estimated by pushover (cases P9 and P10), see 7b. b.

4. Conclusions

The E-DVA method for performing pushover analysis with a multi-modal load pattern applied to buildings submit ted to multi-component earthquakes has been presented. Inspired by the Direct Vectorial Addition, the load pattern used for the calculation of the capacity curve is defined as a linear combination of the modal load patterns; a suit able definition for modal weighting factors ( α -factors) is given using the notion of elliptical response envelopes. The E-DVA pushover approach has been applied to the SPEAR building under an earthquake with two horizontal compo nents: ten di ff erent pushover load cases have been considered, including two load cases maximizing and minimizing the torsion moment at the building basis. A new definition of dominant modes is presented and applied to this case study. Pushover analysis results have been compared with transient non-linear analysis results, proving that E-DVA approach provides a good assessment of maximum forces and maximum torsion moment at the basis of the SPEAR building under a two-component seismic action at the PGA level used to perform experimental tests. This is obtained for forces having any horizontal direction, not necessarily parallel to the earthquake component directions x and y. ASCE-4-16, 2017. Seismic analysis of safety-related nuclear structure. ASCE Standard, Reston, Virginia, US. Der Kiureghian, A., 1979. On the response of structures to stationary excitation. EERC Report NO. UCB / EERC-79 / 32 . EDF, 1989–2022. Open source on www.code-aster.org. finite element Code Aster , analysis of structures and thermomechanics for studies and research. http://www.code-aster.org . Erlicher, S., Huguet, M., 2016. A new approach for multi-modal pushover analysis under a multi-component earthquake, in: Proceedings of Technological Innovations in Nuclear Civil Engineering (TINCE) conference, Paris, France. pp. 1–13. Erlicher, S., Lherminier, O., Huguet, M., 2020. The e-dva method: A new approach for multi-modal pushover analysis under multi-component earthquakes. Soil Dynamics and Earthquake Engineering 132, 106069. Erlicher, S., Nguyen, Q., Martin, F., 2014. Seismic design by the response spectrum method: a new interpretation of elliptical response envelopes and a novel equivalent static method based on probable linear combinations of modes. Nuclear Engineering and Design 276, 277–294. Huguet, M., Lherminier, O., Erlicher, S., 2018. The e-dva pushover method for multi-modal pushover analysis with multi-component earthquake: analysis of two irregular buildings, in: Proceedings of Technological Innovations in Nuclear Civil Engineering (TINCE) conference, Paris, France. pp. 1–12. Huguet, M., Lherminier, O., Erlicher, S., 2019. Approche e-dva: une nouvelle me´thode pour la de´finition des modes dominants du calcul modal spectral et pour l'analyse pushover multimodale et multi-direction, in: 10e`me Colloque AFPS (in French), Strasbourg, France. pp. 1–12. Lherminier, O., Erlicher, S., Huguet, M., 2018. Multi-modal pushover analysis for a multi-component earthquake: an operative method inspired by the direct vectorial approach, in: Proceedings of the 16th European Conference on Earthquake Engineering, Thessaloniki, Greece. pp. 1–12. Menun, C., Der Kiureghian, A., 2000. Envelopes for seismic response vectors. i: Theory. Journal of Structural Engineering 126, 467–473. Negro, P., Fardis, M. (Eds.), 2005. SPEAR : Seismic Performance Assessment and Rehabilitation of Existing Buildings, International Workshop, European Laboratory for Structural Assessment (ELSA). References