Seismic Rocking Isolation of an Asymmetric Frame on Spread Footings
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 140, Issue 1
Abstract
Rocking isolation is a relatively new design paradigm advocating the intense rocking response of the superstructure as a whole, instead of flexural column deformation. This is accomplished through intentionally underdesigning the foundation to guide plastic hinging below the ground surface rather than in the columns. A 2-story, 2-bay asymmetric frame is used to explore the effectiveness of this novel design approach. Finite-element dynamic analyses are performed using as seismic excitation idealized pulses and 20 real accelerograms, taking into account material (soil and superstructure) and geometric (uplifting and effects) nonlinearities. A conventionally, Eurocode-designed frame and its foundation are compared to a design featuring the same frame but with substantially underdesigned (unconventional) footings. It is found that the performance of the unconventional system is advantageous, as not only does it escape collapse but it also suffers reparable damage. Despite their reduced width, the residual settlements of the underdesigned footings are comparable to those of the conventional ones. However, the analyses also reveal that residual rotation and differential settlement of the underdesigned footings may be unavoidable and must be critically evaluated—a need exaggerated by the asymmetry of the examined frame. Three possible ways of improvement at the foundation level are studied: (1) a single conventional tie beam, monolithically connected to the footings; (2) two separate tie beams hinged at each footing (allowing rotation, but resisting axial deformation); and (3) a hybrid system, comprising a single continuous tie beam connecting the three footings but externally hinged to each of them. The first solution hardly offers improvement, as it hinders rocking, and the second fails to reduce differential settlements. The hybrid solution provides encouraging results in terms of residual rotation and differential settlement, while it does not hinder the development of beneficial rocking isolation mechanisms and fully restrains horizontal differential movements.
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Acknowledgments
The authors are thankful for the financial support provided through the research project DARE, by the European Research Council’s (ERC’s) IDEAS Programme, in Support of Frontier Research. Contract No. ERC-2-9-AdG228254-DARE. The authors also acknowledge the anonymous reviewers for their very thoughtful comments and suggestions.
References
ABAQUS 6.9 [Computer software]. Providence, RI, ABAQUS.
Anastasopoulos, I., Gazetas, G., Loli, M., Apostolou, M., and Gerolymos, N. (2010). “Soil failure can be used for seismic protection of structures.” Bull. Earthquake Eng., 8(2), 309–326.
Anastasopoulos, I., Gelagoti, F., Kourkoulis, R., and Gazetas, G. (2011). “Simplified constitutive model for simulation of cyclic response of shallow foundations: Validation against laboratory tests.” J. Geotech. Geoenviron. Eng., 137(12), 1154–1168.
Anastasopoulos, I., Loli, M., Gelagoti, F., Kourkoulis, R., and Gazetas, G. (2012). “Nonlinear soil–foundation interaction: Numerical analysis.” 2nd Int. Conf. on Performance-Based Design in Earthquake Geotechnical Engineering, Patron Editore, Bologna, Italy, Paper No. 10.03.
Anastasopoulos, I., Loli, M., Georgarakos, T., and Drosos, V. (2013). “Shaking table testing of rocking−isolated bridge pier.” J. Earthquake Eng., 17(1), 1–32.
Apostolou, M., Gazetas, G., and Garini, E. (2007). “Seismic response of slender rigid structures with foundation uplifting.” Soil Dyn. Earthquake Eng., 27(7), 642–654.
ASCE. (2000). “Prestandard and commentary for the seismic rehabilitation of buildings.” FEMA 356 Prepared for FEMA, Reston, VA.
Beck, J., and Skinner, R. I. (1974). “The seismic response of a reinforced concrete bridge pier designed to step.” Earthquake Eng. Struct. Dynam., 2(4), 637–655.
Bertero, V. V. (1976). “Establishment of design earthquakes: Evaluation of present methods.” Int. Symposium on Earthquake Structural Engineering, St. Louis, 551–580.
Chatzigogos, C. T., Pecker, A., and Salencon, J. (2009). “Macroelement modeling of shallow foundations.” Soil Dyn. Earthquake Eng., 29(5), 765–781.
Chopra, A., and Yim, S. (1985). “Simplified earthquake analysis of structures with foundation uplift.” J. Struct. Eng., 111(4), 906–930.
Deng, L., and Kutter, B. L. (2012). “Characterization of rocking shallow foundations using centrifuge model tests.” Earthquake Eng. Struct. Dynam., 41(5), 1043–1060.
Deng, L., Kutter, B. L., and Kunnath, S. K. (2012a). “Centrifuge modeling of bridge systems designed for rocking foundations.” J. Geotech. Geoenviron. Eng., 138(3), 335–344.
Deng, L., Kutter, B. L., and Kunnath, S. K. (2012b). “Probabilistic seismic performance of rocking-foundation and hinging-column bridges.” Earthquake Spectra, 28(4), 1423–1446.
European Committee for Standardization (CEN). (2009). “Design provisions for earthquake resistance of structures. Part 5: Foundations, retaining structures and geotechnical aspects.” Eurocode 8, Brussels, Belgium.
Faccioli, E., Paolucci, R., and Vivero, G. (2001), “Investigation of seismic soil–footing interaction by large scale cyclic tests and analytical models.” Proc., 4th Int. Conf. on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics, San Diego, Paper No. SPL-5.
Fukui, J., Shirato, M., Yoshinori, N., and Ryuichi, A. (2005). “Experimental study on the residual displacement of shallow foundations subjected to cyclic loads.” Technical Memorandum of PWRI, 4027, Public Works Research Institute, Tsukuba, Japan.
Fukushima, Y., Irikura, K., Uetake, T., and Matsumoto, H. (2000). “Characteristics of observed peak amplitude for strong ground motion from the 1995 Hyogoken Nanbu (Kobe) earthquake.” Bull. Seismol. Soc. Am., 90(3), 545–565.
Gajan, S., and Kutter, B. L. (2008). “Capacity, settlement, and energy dissipation of shallow footings subjected to rocking.” J. Geotech. Geoenviron. Eng., 134(8), 1129–1141.
Gajan, S., and Kutter, B. L. (2009a). “Contact interface model for shallow foundations subjected to combined cyclic loading.” J. Geotech. Geoenviron. Eng., 135(3), 407–439.
Gajan, S., and Kutter, B. L. (2009b). “Effects of moment-to-shear ratio on combined cyclic load-displacement behavior of shallow foundations from centrifuge experiments.” J. Geotech. Geoenviron. Eng., 135(8), 1044–1055.
Gajan, S., Kutter, B. L., Phalen, J. D., Hutchinson, T. C., and Martin, G. R. (2005). “Centrifuge modeling of load-deformation behavior of rocking shallow foundations.” Soil Dyn. Earthquake Eng., 25(7–10), 773–783.
Garini, E., and Gazetas, G. (2013). “Damage potential of near-fault records: Sliding displacement against conventional ‘intensity measures’.” Bull. Earthquake Eng., 11(2), 455–480.
Gazetas, G., Anastasopoulos, I., Adamidis, O., and Kontoroupi, T. (2013). “Nonlinear rocking stiffness of foundations.” Soil Dyn. Earthquake Eng., 47(April 2013), 83–91.
Gazetas, G., Apostolou, M., and Anastasopoulos, I. (2003). “Seismic uplifting of foundations on soft soil, with examples from Adapazari (Izmit 1999, earthquake).” BGA Int. Conf. on Foundation Innovations, Observations, Design & Practice, British Geotechnical Association, London, 37–50.
Gelagoti, F. (2010). “Metaplastic response and collapse of frame-foundation systems and the concept of rocking isolation.” Ph.D. thesis, National Technical Univ., Athens, Greece.
Gelagoti, F., Kourkoulis, R., Anastasopoulos, I., and Gazetas, G. (2012a). “Rocking-isolated frame structures: Margins of safety against toppling collapse and simplified design approach.” Soil. Dyn. Earthquake Eng., 32(1), 87–102.
Gelagoti, F., Kourkoulis, R., Anastasopoulos, I., and Gazetas, G. (2012b). “Rocking isolation of frame structures founded on separate footings.” Earthquake Eng. Struct. Dynam., 41(7), 1177–1197.
Gerolymos, N., Gazetas, G., and Tazoh, T. (2005). “Seismic response of yielding pile in non-linear soil.” Proc. 1st Greece–Japan Workshop on Seismic Design, Observation, and Retrofit of Foundations, G. Gazetas, Y. Goto, and T. Tazoh, eds., National Technical Univ. of Athens, Athens, Greece, 25–36.
Gourvenec, S. (2007). “Shape effects on the capacity of rectangular footings under general loading.” Géotechnique, 57(8), 637–646.
Hardin, B. (1978). “The nature of stress-strain behavior for soils.” Earthquake Engineering and Soil Dynamics, ASCE Specialty Conf., Vol. 1, ASCE, Reston, VA, 3–-90.
Kawashima, K., Nagai, T., and Sakellaraki, D. (2007). “Rocking seismic isolation of bridges supported by spread foundations.” Proc., 2nd Japan–Greece Workshop on Seismic Design, Observation, and Retrofit of Foundations, Japan Society of Civil Engineers, Tokyo, 254–265.
Kourkoulis, R., Anastasopoulos, I., Gelagoti, F., and Kokkali, P. (2012a). “Dimensional analysis of SDOF systems rocking on inelastic soil.” J. Earthquake Eng., 16(7), 995–1022.
Kourkoulis, R., Gelagoti, F., and Anastasopoulos, I. (2012b). “Rocking isolation of frames on isolated footings: design insights and limitations.” J. Earthquake Eng., 16(3), 374–400.
Kutter, B. L., Martin, G., Hutchinson, T. C., Harden, C., Gajan, S., and Phalen, J. D. (2003). “Status report on study of modeling of nonlinear cyclic load–deformation behavior of shallow foundations.” PEER Workshop, Univ. of California, Davis, CA.
Martin, G. R., and Lam, I. P. (2000). “Earthquake resistant design of foundations: Retrofit of existing foundations.” Proc. GeoEng 2000 Conf., Melbourne, Australia.
Mergos, P. E., and Kawashima, K. (2005). “Rocking isolation of a typical bridge pier on spread foundation.” J. Earthquake Eng., 9(2), 395–414.
Negro, P., Paolucci, R., Pedretti, S., and Faccioli, E. (2000). “Large-scale soil–structure interaction experiments on sand under cyclic loading.” Proc. 12th World Conf. on Earthquake Engineering, Auckland, New Zealand, Paper No. 1191.
Panagiotidou, A. I., Gazetas, G., and Gerolymos, N. (2012). “Pushover and seismic response of foundations on stiff clay: Analysis with P-delta effects.” Earthquake Spectra, 28(4), 1589–1618.
Paolucci, R., and Pecker, A. (1997). “Seismic bearing capacity of shallow strip foundation on dry soils.” Soils Found., 37(3), 95–105.
Paolucci, R., Shirato, M., and Yilmaz, M. T. (2008). “Seismic behaviour of shallow foundations: Shaking table experiments vs numerical modeling.” Earthquake Eng. Struct. Dynam., 37(4), 577–595.
Park, R., and Paulay, T. (1975). Reinforced concrete structures, Wiley, New York.
Pecker, A. (1998). “Capacity design principles for shallow foundations in seismic areas.” Proc., 11th European Conf. on Earthquake Engineering, Vol. 3, Balkema, Rotterdam, Netherlands.
Pecker, A. (2003). “Aseismic foundation design process, lessons learned from two major projects: The Vasco de Gama and the Rion Antirion bridges.” ACI Int. Conf. on Seismic Bridge Design and Retrofit, Univ. of California, San Diego.
Pecker, A., and Pender, M. J. (2000). “Earthquake resistant design of foundations: New construction.” Proc., GeoEng 2000 Conf., Vol. 1, Melbourne, Australia, 313–332.
Priestley, M. J. N., Calvi, G. M., and Kowalsky, M. J. (2007). Displacement-based seismic design of structures, IUSS Press, Pavia, Italy.
Priestley, M. J. N., Seible, F., and Calvi, G. M. (1996). Seismic design and retrofit of bridges, Wiley, New York.
Robertson, P. K., and Campanella, R. G. (1983). “Interpretation of cone penetration tests. Part II: Clay.” Can. Geotech. J., 20(4), 734–745.
Vintzileou, E., Tassios, T. P., and Chronopoulos, M. (2007). “Experimental validation of seismic code provisions for RC columns.” Eng. Struct., 29(6), 1153–1164.
Vucetic, M., and Dobry, R. (1991). “Effect of soil plasticity on cyclic response.” J. Geotech. Engrg., 117(1), 89–107.
XTRACT 3.0.3 [Computer software]. Rancho Cordova, CA, Imbsen.
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Journal of Geotechnical and Geoenvironmental Engineering
Volume 140 • Issue 1 • January 2014
Pages: 133 - 151
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© 2014 American Society of Civil Engineers.
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Received: Sep 6, 2012
Accepted: Jul 24, 2013
Published online: Jul 27, 2013
Published in print: Jan 1, 2014
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