PSI - Issue 44

Mariano Di Domenico et al. / Procedia Structural Integrity 44 (2023) 480–487 Di Domenico, Ricci, Verderame / Structural Integrity Procedia 00 (2022) 000–000

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Fig. 3. “Best” predictions of the proposed model: (a) specimen No.2 by Soesianawati et al. (1986); (b) specimen 214-08 by Zhou et al. (1987); (c) specimen B2 by Sakai et al. (1990). 7. Conclusions In this paper, the results of the cyclic experimental tests performed on ductile rectangular reinforced concrete columns with deformed bars have been processed to define characteristic points of the lateral base moment – chord rotation response envelope. Four characteristic points have been determined: yielding, maximum, conventional ultimate at 20% strength degradation, and collapse, at zero lateral load capacity. The value of base moment corresponding to these points can be determined based on mechanical principles or is intrinsic to the definition itself of the characteristic points of the response. On the other hand, based on the processed experimental data, empirical equations are derived for calculating chord rotation values corresponding to the four characteristic points. The proposed cyclic response envelope can be implemented in OpenSees by adopting Pinching4 Material model, which also allows modeling the cyclic degradation of unloading stiffness, reloading stiffness, and the pinching effect. Based on the processed experimental data, average values of the hysteretic parameters that should be adopted to model these phenomena are calibrated. Unfortunately, no clear trend was found allowing the calculation of the hysteretic parameters as a function of geometric or mechanical features of a column, or of the axial load ratio. Further studies are needed to cover this issue. The proposed model can be adopted for nonlinear static and dynamic analyses for the seismic assessment of new and existing buildings. Acknowledgements This work was developed under the financial support of ReLUIS research project – WP11, funded by the Italian Department of Civil Protection. References Berry, M., Parrish, M., Eberhard, M., 2004. PEER Structural Performance Database: User's Manual, Version 1.0. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, USA. Di Domenico, M., Ricci, P., Verderame, G.M., 2021. Empirical calibration of hysteretic parameters for modeling the seismic response of reinforced concrete columns with plain bars. Engineering Structures, 237. Haselton, C.B., Liel, A.B., Taylor-Lange, S., Deierlein, G.G., 2008. Beam-column element model calibrated for predicting flexural response leading to global collapse of RC frame buildings. PEER Report No. 2007/03. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, USA. McKenna, F., Fenves, G.L., Scott, M.H., 2004. OpenSees: Open System for Earthquake Engineering Simulation. Pacific Earthquake Engineering Research Center. University of California, Berkeley, CA, USA. Sakai, Y., Hibi, J., Otani, S., Hiroyuki, A., 1990. Experimental Study on Flexural Behavior of Reinforced Concrete Columns Using High-Strength Concrete. Transactions of the Japan Concrete Institute, 12, 323-330. Sivaramakrishnan, B., 2010. Non-linear modeling parameters for reinforced concrete columns subjected to seismic loads. The University of Texas at Austin. PhD Dissertation.