Design Considerations for Rocking Foundations on Unattached Piles
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 140, Issue 10
Abstract
By appropriately reducing the size of the footing, rocking behavior caused by seismic loading can occur about the footing base. Recent research has shown how rocking shallow foundations can result in improved seismic performance of bridges. One concern of rocking systems is the potential for significant settlement accumulation in poor soil conditions. This research explores the effectiveness and practicality of using unattached piles to mitigate settlement while still allowing rocking. Two series of centrifuge tests investigated the performance of individual footing-column-mass structural models in these soil conditions on unattached piles. The lateral load connection between the rocking foundation and piles is an important consideration; a variety of possible shear key configurations capable of transferring lateral and dead loads to the piles while allowing separation associated with rocking are discussed. Unique design issues associated with rocking on unattached piles and methods to address these issues are described. Concepts are presented to support the evaluation of the effect of excess pore pressure on the pile capacity. Methods of evaluating effects of pile capacity, number of piles, and arrangement of piles on the residual settlement and base shear coefficient to initiate rocking on piles are also described.
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Acknowledgments
This work was supported primarily by the Pacific Earthquake Engineering Research Center under the project “Last Hurdles for the Implementation of Rocking Foundations for Bridges.” The authors acknowledge the suggestions, concept discussions, and assistance of Professor Steve Mahin, Professor Sashi Kunnath, Professor Shideh Dashti, Lijun Deng, Manny Hakhamaneshi, Dan Wilson, Chad Justice, Ray Gerhard, Peter Rojas, Lars Pedersen, and Anatoily Ganchenko.
References
Algie, T. B., Pender, M. J., Orense, R. P., and Wotherspoon, L. M. (2010). “Dynamic field testing of shallow foundations subject to rocking.” Proc., New Zealand Society for Earthquake Engineering Conf., 1–8.
Allmond, J., and Kutter, B. L. (2012). “Centrifuge testing of rocking foundations on saturated and submerged sand: Centrifuge Data Report for JDA01.” UCD/CGMDR-12/01, Univ. of California at Davis, Davis, CA.
Allmond, J., and Kutter, B. L. (2013). “Centrifuge testing of rocking foundations on saturated and submerged sand: Centrifuge Data Report for JDA02.” UCD/CGMDR-13/01, Univ. of California at Davis, Davis, CA.
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., Kourkoulis, R., Gelagoti, F., and Papadopoulos, E. (2012). “Rocking response of SDOF systems on shallow improved sand: An experimental study.” Soil Dyn. Earthquake Eng., 40, 15–33.
ASCE. (2007). Seismic rehabilitation of existing buildings (41-06), Reston, VA.
Dashti, S. (2009). “Toward developing an engineering procedure for evaluating building performance on softened ground.” Ph.D. dissertation, Univ. of California at Berkeley, Berkeley, CA.
Deng, L. (2012). “Centrifuge modeling, numerical analysis, and displacement-based design of rocking foundations.” Ph.D. dissertation, Univ. of California at Davis, Davis, CA.
Deng, L., and Kutter, B. L. (2012). “Characterization of rocking shallow foundations using centrifuge model tests.” Earthquake Eng. Struct. Dyn., 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., 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.
Deng, L., Kutter, B. L, and Kunnath, S. K. (2014). “Seismic design of rocking shallow foundations: Displacement-based methodology.” J. Bridge Eng., 04014043.
Espinoza, A., and Mahin, S. A. (2006). “Rocking of bridge piers subjected to multi-directional earthquake excitation.” Proc., 8th National Conf. on Earthquake Engineering, Earthquake Engineering Research Institute (EERI), El Cerrito, CA.
Fleming, K., Weltman, A., Randolph, M., and Elson, K. (2009). Piling engineering, 3rd Ed., Taylor & Francis, New York.
Gajan, S., and Kutter, B. L. (2008). “Capacity, settlement, and energy dissipation of shallow footings subjected to rocking.” J. Geotech. Geoenviron. Eng., 1129–1141.
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.
Gajan, S., Raychowdhury, P., Hutchinson, T., Kutter, B. L., and Stewart, J. P. (2010). “Application and validation of practical tools for nonlinear soil-foundation interaction analysis.” Earthquake Spectra, 26(1), 111–129.
Housner, G. W. (1963). “The behavior of inverted pendulum structures during earthquakes.” Bull. Seismol. Soc. Am., 53(2), 403–417.
Kramer, S. L., and Mitchell, R. A. (2006). “Ground motion intensity measures for liquefaction hazard evaluation.” Earthquake Spectra, 22(2), 413–438.
LPILE Plus 4.0 [Computer software]. Austin, TX, Ensoft.
Madabhushi, G., Knappett, J., and Haigh, S. (2010). Design of pile foundations in liquefiable soils, Imperial College Press, Hackensack, NJ.
Mayne, P. W. (2007). “Cone penetration testing state-of-practice.” NCHRP Project 20-05, Topic 37-14, National Cooperative Highway Research Program, Washington, DC.
Meyerhof, G. G. (1963). “Some recent research on the bearing capacity of foundations.” Can. Geotech. J., 1(1), 16–31.
Pecker, A., and Chatzigogos, C. T. (2010). “Non linear soil structure interaction: Impact on the seismic response of structures.” Earthquake engineering in Europe, geotechnical, geological, and earthquake engineering, 17th Ed., M. Garevski and A. Ansal, eds., Springer, New York, 79–103.
Priestley, M. J. N., Calvi, G. M., and Kowalsky, M. J. (2007). Displacement-based seismic design of structures, IUSS Press, Pavia, Italy.
Information & Authors
Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 140 • Issue 10 • October 2014
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Jun 22, 2013
Accepted: Jun 19, 2014
Published online: Jul 15, 2014
Published in print: Oct 1, 2014
Discussion open until: Dec 15, 2014
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