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Non linear analysis of rc structures, performance based seismic design and displacement based design approaches

Keywords: nonlinear models, RC structures, nonlinear dynamic analysis, pushover analysis, Performance Based Seismic Design (PBSD), Displacement Based Design (DBD) and Assessment (DBA)
Fig. 1. Spread plasticity model with degradation (Landi).
Non linear analysis of rc structures, performance based seismic design and displacement based design approaches - Fig. 2
Fig. 2. Fibre model (Landi).
Non linear analysis of rc structures, performance based seismic design and displacement based design approaches - Fig. 3
Fig. 3. Adaptive pushover analysis (Landi).
Non linear analysis of rc structures, performance based seismic design and displacement based design approaches - Fig. 4
Fig. 4. Displacement spectrum (Landi).

The research group is involved in the development of new analytical models and in the implementation of original computer programs for the nonlinear static and dynamic analysis of reinforced concrete (RC) structures. The prediction and the control of the inelastic response represent, indeed, fundamental elements of the seismic design. The research started with the realization of a new global model based on the subdivision of the elements in segments. Subsequently it has been proposed a new fibre model based on the flexibility approach and the MCFT theory as constitutive relationship, able to account for the nonlinear flexural-shear interaction of RC members. The models have been then applied for studying various aspects of the nonlinear seismic response of RC structures. The pushover analysis, that is a non-linear static analysis performed by applying lateral forces gradually increasing up to collapse, may provide an alternative both to conventional linear methods and to more complex methods based on non-linear dynamic analyses.

In recent years innovative methodologies have been proposed for the seismic design of building structures, such as Performance Based Seismic Design (PBSD) and Displacement Based Seismic Design (DBD). The core idea of the PBSD (PEER, Vision 2000, California) resides in the capacity of defining and satisfying a number of given performance objectives (association of a structural performance level to an earthquake design level). The new concept introduced by the DBD (Priestley and Calvi) lies in the development of a design method based upon the displacements (instead upon the forces).

Some of the studies performed by the group have been aimed to the validation of the DBD methodology developed by Priestley and Calvi with reference to new and existing RC structures. Within the related research projects a collaboration is activated for the preparation of a model code and examples. Moreover extensions of the DBD procedure have been proposed for asymmetric structures and infilled RC frames.

Main publications

Landi, L., Tardini, A., Diotallevi, P.P. (2016). A Procedure for the Displacement-Based Seismic Assessment of Infilled RC Frames. Journal of Earthquake Engineering, in press, published online 18 February 2016, pp. 1-27.

Palermo, M., Trombetti, T. (2016). Experimentally- validated modelling of thin RC sandwich walls subjected to seismic loads, Engineering Structures, vol. 119, pp. 95-109.

Landi, L., Pollio, B., Diotallevi, P.P. (2014). Effectiveness of different standard and advanced pushover procedures for regular and irregular RC frames. Structural Engineering and Mechanics, vol. 51, 3, pp. 433-446.

Benedetti, A., Landi, L., Merenda, D.G. (2014). Displacement-Based Design of an Energy Dissipating System for Seismic Upgrading of Existing Masonry Structures. Journal of Earthquake Engineering, vol. 18, pp. 477-501.

Palermo, M., Ricci, I., Gagliardi, S., Silvestri, S., Trombetti, T., Gasparini, G. (2014). Multiperformance seismic design through an enhanced first-storey isolation system, Engineering Structures, vol. 59, pp. 495-506.

Palermo, M., Hernandez, R.R., Mazzoni, S., Trombetti, T. (2014) On the seismic behavior of a reinforced concrete building with masonry infills collapsed during the 2009 L'aquila earthquake, Earthquake and Structures, vol. 6, 1, pp. 45-69.

Palermo, M., Gil-Martín, L.M., Trombetti, T., Hernández-Montes, E. (2013) In-plane shear behaviour of thin low reinforced concrete panels for earthquake re-construction. Materials and Structures, vol. 46, 5, pp. 841-856.

Paparo, A., Landi, L., Diotallevi, P.P. (2012). Extension of Direct Displacement-Based Design to Plan-Asymmetric RC Frame Buildings. Journal of Civil Engineering and Architecture, vol. 6, 10, pp. 1280–1291.

Ceccoli C., Trombetti T., Biondi. D. (2011). Structural evaluation of the Palazzo della Civilta` Italiana in Rome. Structure and Infrastructure Engineering. vol. 7, pp. 147- 162.

P.P. Diotallevi, L. Landi, C. Gianni. (2010). “Effectiveness of 3D multi-modal pushover for planasymmetric RC frames”. Proceedings of the 14th European Conference on Earthquake Engineering, Ohrid, Republic of Macedonia, August 30- September 03, 2010.

B. Ferracuti, R. Pinho, M. Savoia, R. Francia (2009). Verification of Displacement-based Adaptive Pushover through multi-ground motion incremental dynamic analyses. Engineering Structures, Vol. 31, 8, pp. 1789-1799.

B. Ferracuti, M. Savoia, R. Pinho (2008). Force/Torque Pushover Method For Plan Irregular Structures. Nonlinear Static Methods for Design/ Assessment of 3D Structures. R. Bento & R. Pinho (Eds.) 5-6 May 2008 Lisbon, Portugal.

P.P. Diotallevi, L. Landi, F. Cardinetti. (2008). A fibre beam-column element for modelling the flexure-shear interaction in the non-linear analysis of RC structures. Proceedings of the 14th World Conference on Earthquake Engineering, Beijing, China.

P.P. Diotallevi, L. Landi. (2006). “Response of RC structures subjected to horizontal and vertical ground motions”, Proceedings of the 100th Anniversary Earthquake Conference Commemorating the 1906 San Francisco Earthquake, San Francisco, California.

Research projects

Research project RELUIS3, Line 7 (2014-2016): “Development of displacement based approaches for the seismic loss assessment in the pre and post-retrofit condition”, task of Bologna: “Post- 1970 RC buildings”. Research project RELUIS2, Line 2 (2010-2013): “Development of displacement based approaches for the vulnerability evaluation”, task of Bologna: “Reinforced concrete structures with and without masonry infills” National Coordinators: Prof. G. M. Calvi and Prof. T. J. Sullivan; Resp. of the Bologna Unit: Prof. A. Benedetti.

National Research Project PRIN (1999-2001): “The safety of reinforced concrete structures under seismic actions with reference to design criteria of resistance to collapse and damage limitation of Eurocode 8” Local Resp.: Prof. P.P. Diotallevi; National Coordinator: Prof. A. Castellani.