Earthquakes and Structures

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Seismic retrofitting by base-isolation of r.c. framed buildings exposed to different fire scenarios

  • Mazza, Fabio (Dipartimento di Ingegneria Civile, Universita della Calabria) ;
  • Mazza, Mirko (Dipartimento di Ingegneria Civile, Universita della Calabria)
  • Received : 2017.08.12
  • Accepted : 2017.10.03
  • Published : 2017.09.25
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Abstract

Base-isolation is now being adopted as a retrofitting strategy to improve seismic behaviour of reinforced concrete (r.c.) framed structures subjected to far-fault earthquakes. However, the increase in deformability of a base-isolated framed building may lead to amplification in the structural response under the long-duration horizontal pulses of high-magnitude near-fault earthquakes, which can become critical once the strength level of a fire-weakened r.c. superstructure is reduced. The aim of the present work is to investigate the nonlinear seismic response of fire-damaged r.c. framed structures retrofitted by base-isolation. For this purpose, a five-storey r.c. framed building primarily designed (as fixed-base) in compliance with a former Italian seismic code for a medium-risk zone, is to be retrofitted by the insertion of elastomeric bearings to meet the requirements of the current Italian code in a high-risk seismic zone. The nonlinear seismic response of the original (fixed-base) and retrofitted (base-isolated) test structures in a no fire situation are compared with those in the event of fire in the superstructure, where parametric temperature-time curves are defined at the first level, the first two and the upper levels. A lumped plasticity model describes the inelastic behaviour of the fire-damaged r.c. frame members, while a nonlinear force-displacement law is adopted for the elastomeric bearings. The average root-mean-square deviation of the observed spectrum from the target design spectrum together with a suitable intensity measure are chosen to select and scale near- and far-fault earthquakes on the basis of the design hypotheses adopted.

Keywords

References

  1. Baltzopoulos, G., Vamvatsikos, D. and Iervolino, I. (2016), "Analytical modelling of near-source pulse-like seismic demand for multi-linear backbone oscillators", Earthq. Eng. Struct. Dyn., 45(11), 1797-1815. https://doi.org/10.1002/eqe.2729
  2. Bommer J.J. and Acevedo, A.B. (2004), "The use of real earthquake accelerograms as input to dynamic analysis", J. Earthq. Eng., 8(1), 43-91.
  3. Bray, J.D., Rodriguez-Marek, A. and Gillie, J.L. (2009), "Design ground motions near active faults", Bull. NZ Soc. Earthq. Eng., 42(1), 1-8.
  4. Dwaikat, M.B. and Kodur, V.K.R., (2009), "Hydrothermal model for predicting fire-induced spalling in concrete structural systems", Fire Saf. J., 44, 425-434. https://doi.org/10.1016/j.firesaf.2008.09.001
  5. ESD. European Strong Motion database. http://esm.mi.ingv.it/.
  6. Eurocode 1 (2004), Actions on structures - Part 1-2: General actions, actions on structures exposed to fire. C.E.N., European Committee for Standardization.
  7. Eurocode 2 (2004), Design of concrete structures - Part 1-2: General rules, structural fire design. C.E.N., European Committee for Standardization.
  8. Felicetti, R., Gambarova, P.G. and Meda A. (2009), "Residual behavior of steel rebars and R/C sections after a fire", Constr. Build. Mater., 23(12), 3546-3555. https://doi.org/10.1016/j.conbuildmat.2009.06.050
  9. Foti, D. (2015), "Local ground effects in near-field and far-field areas on seismically protected buildings", Soil Dyn. Earthq. Eng., 74, 14-24. https://doi.org/10.1016/j.soildyn.2015.03.005
  10. Ghobarah, A. (2004), "On drift limits associated with different damage levels", Proceedings of the International Workshop on the Performance-Based Seismic Design: Concepts and Implementation, Bled, Slovenia.
  11. Gilmore, A.T. (2012), "Options for sustainable earthquake-resistant design of concrete and steel buildings", Earthq. Struct., 3(6), 783-804. https://doi.org/10.12989/eas.2012.3.6.783
  12. Italian Ministry of Public Works (1996), "Norme tecniche per le costruzioni in zone sismiche e relative istruzioni", D.M. 16-01-1996 and C.M. 10-04-1997, n. 65/AA.GG..
  13. Iwan, W.D. (1997), "Drift spectrum: measure of demand for earthquake ground motions", J. Struct. Eng., 123(4), 397-404. https://doi.org/10.1061/(ASCE)0733-9445(1997)123:4(397)
  14. Lee, J., Xi, Y. and William, K. (2008), "Properties of concrete after high-temperature heating and cooling", ACI Mater. J., 105, 334-341.
  15. Mazza, F. (2015a), "Seismic vulnerability and retrofitting by damped braces of fire-damaged r.c. framed buildings", Eng. Struct., 101(15), 179-192. https://doi.org/10.1016/j.engstruct.2015.07.027
  16. Mazza, F. (2015b), "Comparative study of the seismic response of RC framed buildings retrofitted using modern techniques", Eng. Struct., 9(1), 29-48.
  17. Mazza, F. (2017), "Behaviour during seismic aftershocks of r.c. base-isolated framed structure with fire-induced damage", Eng. Struct., 140(1), 458-472. https://doi.org/10.1016/j.engstruct.2017.03.008
  18. Mazza, F. and Labernarda, R. (2017), "Structural and nonstructural intensity measures for the assessment of base-isolated structures subjected to pulse-like near-fault earthquakes", Soil Dyn. Earthq. Eng., 96, 115-127. https://doi.org/10.1016/j.soildyn.2017.02.013
  19. Mazza, F. and Vulcano, A. (2010), "Nonlinear dynamic response of r.c. framed structures subjected to near-fault ground motions", Bull. Earthq. Eng., 8(6), 1331-1350. https://doi.org/10.1007/s10518-010-9180-z
  20. Mazza, F. and Vulcano, A. (2012), "Effects of near-fault ground motions on the nonlinear dynamic response of base-isolated r.c. framed buildings", Earthq. Eng. Struct. Dyn., 41(2), 211-232. https://doi.org/10.1002/eqe.1126
  21. Mollaioli, F., Lucchini, A., Cheng, Y., and Monti G. (2013), "Intensity measures for the seismic response prediction of base-isolated buildings", Bull. Earthq. Eng., 11(5), 1841-1866. https://doi.org/10.1007/s10518-013-9431-x
  22. Mostafaei, H. (2013a), "Hybrid fire testing for assessing performance of structures in fire - Methodology", Fire Saf. J., 58, 170-179. https://doi.org/10.1016/j.firesaf.2013.02.005
  23. Mostafaei, H., (2013b), "Hybrid fire testing for assessing performance of structures in fire - Application", Fire Saf. J., 56, 30-38. https://doi.org/10.1016/j.firesaf.2012.12.003
  24. NTC08 (2008). Technical Regulations for the Constructions. Italian Ministry of the Infrastructures, D.M. 14-01-2008 and C.M. 2-2-2009.
  25. PEER. Pacific Earthquake Engineering Research Center database. http://peer.berkeley.edu/smcat/search.html.
  26. PROSAP. PROfessional Structural Analysis Program. Thermal analysis. Ferrara (Italy). http://www.2si.it.
  27. Somerville, P.G., Smith, N.F., Graves, R.W. and Abrahamson, N.A. (1997), "Modification of empirical strong motion attenuation relations to include the amplitude and duration effect of rupture directivity", Seismol. Res. Lett., 68(1), 199-222. https://doi.org/10.1785/gssrl.68.1.199
  28. Sorace, S. and Terenzi G. (2014), "A viable base isolation strategy for the advanced seismic retrofit of an R/C building", Contemp. Eng. Sci., 7(17-20), 817-834. https://doi.org/10.12988/ces.2014.4549
  29. Sorace, S. and Terenzi, G. (2015), "Seismic performance assessment and base-isolated floor protection of statues exhibited in museum halls", Bull. Earthq. Eng., 13(6), 1873-1892. https://doi.org/10.1007/s10518-014-9680-3
  30. Tavakoli, H.R., Naghavi, F., Goltabar, A.R. (2015), "Effect of base isolation systems on increasing the resistance of structures subjected to progressive collapse", Earthq. Struct., 9(3), 639-656. https://doi.org/10.12989/eas.2015.9.3.639
  31. Youssef, M.A. and Moftah, M. (2007), "General stress-strain relationship for concrete at elevated temperatures", Eng. Struct., 29(10), 418-430. https://doi.org/10.1016/j.engstruct.2006.05.008
  32. Zerbin, M. and Aprile, A. (2015), "Sustainable retrofit design of RC frames evaluated for different seismic demand", Eng. Struct., 9(6), 1337-1353.