Seismic Retrofit of Existing Buildings Led By Non-Linear Dynamic Analyses

Seismic Retrofit of Existing Buildings Led By Non-Linear Dynamic Analyses

Maria Cristina Porcu Juan Carlos Vielma Francesco Panu Claudia Aguilar Giuseppe Curreli

University of Cagliari, Cagliari, Italy.

Pontificia Universidad Catolica de Valparaiso, Valparaiso, Chile.

MSc Civil Engineer - independent researcher, Italy.

Page: 
201-212
|
DOI: 
https://doi.org/10.2495/SAFE-V9-N3-201-212
Received: 
N/A
|
Accepted: 
N/A
|
Published: 
9 September 2019
| Citation

OPEN ACCESS

Abstract: 

Although still little used in practice, the non-linear time-history (NlTH) analysis is the most powerful method to design new earthquake-resistant buildings. This kind of analysis may even help the designer to assess the seismic performance of existing buildings and suitably plan their retrofit. With refer- ence to a pre-seismic-code r/c building and to a suite of Italian spectrum-consistent earthquakes, the paper highlights the advantages of adopting NlTH analyses to evidence critical features in the seismic response of existing buildings and to assess in advance the effectiveness of their retrofit strategy. To this purpose, the behaviour of the retrofitted building should be suitably modelled. This paper shows how this can be done when carbon fibre reinforced polymer is used to strengthen the critical sections. Two advanced finite element programmes are adopted in parallel to carry out the numerical analyses: SAP2000 and SeismoStruct. The differences involved in the numerical model are discussed and the main advantages of a three-step procedure based on the NlTH approach are evidenced.

Keywords: 

FRP reinforcement, non-linear dynamic analysis, seismic retrofit of r/c buildings, ductility.

  References

[1] Porcu, M.C., Bosu, C. & Gavrić, I., Non-linear dynamic analysis to assess the seismic performance of cross-laminated timber structures. Journal of Building Engineering, 19, pp. 480–493, 2018. https://doi.org/10.1016/j.jobe.2018.06.008

[2] Carvalho, G., Bento, R. & Bhatt, C., Nonlinear static and dynamic analyses of reinforced concrete buildings-comparison of different modelling approaches. Earthquake and Structures, 4(5), pp. 451–470, 2013. https://doi.org/10.12989/eas.2013.4.5.451

[3] Porcu, M.C., Code inadequacies discouraging the earthquake-based seismic analysis of buildings. International Journal of Safety and Security Engineering, 7(4), pp. 545–556, 2017. https://doi.org/10.2495/safe-v7-n4-545-556

[4] Mazza, F., Mazza, M. & Vulcano, A., Base-isolation systems for the seismic retrofitting of rc framed buildings with soft-storey subjected to near-fault earthquakes. Soil Dynamics and Earthquake Engineering, 109, pp. 209–221, 2018. https://doi.org/10.1016/j.soildyn. 2018.02.025

[5] Porcu, M.C., Partial floor mass isolation to control the seismic stress in framed buildings. International Journal of Safety and Security Engineering, 9(2), pp. 157–165, 2019. doi: 10.2495/SAFE-V9-N2-157-165

[6] Porcu, M.C., Numerical assessment of a stress control method based on rigid-plastic inertia-limiters. Proceedings of the Fourteenth International Conference on Civil, Structural and Environmental Engineering Computing. eds. B.H.V. Topping & P. Iványi, Civil-Comp Press, 2013. https://doi.org/10.4203/ccp.102.42

[7] Ghiani, C., Linul, E., Porcu, M.C., Marsavina, L., Movahedi, N. & Aymerich, F., Metal foam-filled tubes as plastic dissipaters in earthquake-resistant steel buildings. In IOP Conference Series: Materials Science and Engineering, 416(1), 2018. https://doi. org/10.1088/1757-899x/416/1/012051

[8] Symans, M.D., Charney, F.A., Whittaker, A.S., Constantinou, M.C., Kircher, C.A., Johnson, M.W. & McNamara, R.J., Energy dissipation systems for seismic applications: current practice and recent developments. Journal of Structural Engineering, 134(1), pp. 3–21, 2008. https://doi.org/10.1061/(asce)0733-9445(2008)134:1(3)

[9] Porcu, M.C., Ductile behavior of timber structures under strong dynamic loads. In Wood in Civil Engineering. InTech, 2017. https://doi.org/10.5772/65894

[10] CEN. Eurocode 8: Design of Structures for Earthquake Resistance - Part 1: General Rules, Seismic Actions and Rules for Buildings. European Comitee for Standardization, Brussels, p. 232, 2004.

[11] Iacobucci, R.D., Sheikh, S.A. & Bayrak, O., Retrofit of square concrete columns with carbon fiber-reinforced polymer for seismic resistance. Structural Journal, 100(6), pp. 785–794, 2003. https://doi.org/10.14359/12845

[12] CSI, SAP2000 v.20. Integrated Finite Element Analysis and Design of Structures Basic Analysis Reference Manual, Computers and Structures, Inc., Berkeley, Cal., USA, 2016.

[13] SeismoSoft., SeismoStruct 2016—A computer program for static and dynamic nonlinear analysis of framed structures, available from http://www.seismosoft.com

[14] Vielma, J.C., Barbat A. & Oller, S., Seismic response of the RC framed buildings designed according to Eurocodes. Chapter in Computational Methods in Earthquake Engineering. Springer. Heildelberg. Germany. ISBN: 978-94-007-0052-9, 2010.

[15] Vielma, J.C. & Mulder, M., Assessment of the response reduction factors of plan-irregular RC buildings. WIT Transactions on the Built Environment, 172, pp. 47–57, 2017. https://doi.org/10.2495/eres170051

[16] Vielma, J.C., Barbat, A.H. & Oller, S., Seismic safety of low ductility structures used in Spain. Bulletin of Earthquake Engineering, 8(1), pp. 135–155, 2010. https://doi.org/10.1007/s10518-009-9127-4

[17] Vielma, J.C., Barbat A.H. & Oller, S., Seismic performance of buildings with waffledslab floors. Proceedings of the Institution of Civil Engineers - Structures and Buildings, 162(3), pp. 169–182, 2009. https://doi.org/10.1680/stbu.2009.162.3.169

[18] D.M. 16 Giugno 1976, Norme tecniche per l’esecuzione delle opera in cemento armato normale e precompresso e per le strutture metalliche. In Italian.

[19] FEMA-356, Prestandard Commentary for the Seismic Rehabilitation of Buildings. Federal Emergency Management Agency, Washington, DC, 2000.

[20] Iervolino, I., Galasso, C. & Cosenza, E., REXEL: computer aided record selection for code-based seismic structural analysis. Bulletin of Earthquake Engineering, 8(2), pp. 339–362, 2010. https://doi.org/10.1007/s10518-009-9146-1

[21] Ambraseys, N., Smit, P., Douglas, J., Margaris, B., Sigbjörnsson, R., Olafsson, S. & Costa, G., Internet site for European strong-motion data. Bollettino di Geofisica Teorica ed Applicata, 45(3), pp. 113–129, 2004.

[22] BIAXIAL bending v2.4, 2006. http://www.reluis.it