This paper presents numerical analysis of soil-structure-interaction (SSI) of tall reinforced concrete chimneys with piled raft foundation subjected to El Centro ground motion (1940) using finite element method. Seismic analysis in time domain was performed on the basis of direct method of SSI on the three-dimensional SSI system. The chimney, foundation, and soil were assumed to be linearly elastic in the analysis. The stress resultants and settlement of raft of piled raft foundation were evaluated under different soil properties and different geometrical features of raft and chimney. Soil properties were selected based on the shear wave velocity corresponding to sand in the loose to dense range. Chimneys with different elevations of 100？m, 200？m, and 400？m were taken with a ratio of height to base diameter of chimney of 17. Raft of different thickness was considered to evaluate the effect of stiffness of foundation. Results were analysed to assess the significance of characteristic of the ground motion. It is found that the response in the raft depends on the different parameters of chimney, foundation, and soil. It is also found that the higher modes of SSI system are significant in determining the response in the raft. 1. Introduction Most of the analysis of piled raft foundation neglects the effect of geometrical and material features of the superstructure. Generally the loads and moments from the superstructure to foundation are only considered for the analysis of foundation. The shape and size of the superstructure such as chimney have their own significance to determine the responses in foundation. Chimneys are tall and slender structures with tapering geometry. Analysis of such kind of chimney-foundation system that rests on soil which is of unfavorable geotechnical conditions will be too complex especially when it is subjected to earthquake ground motions. The present study deals with the seismic analysis of chimney with piled raft foundation considering the flexibility of soil in time domain. 2. Background of the Problem Very few studies have been carried out in the area of dynamic analysis of soil-piled raft-structure interaction compared to that of soil-pile-structure interaction [1–3]. Field measurements were taken by Yamashita et al. [4] to understand the static and seismic behavior of a piled raft foundation which is supporting a 12-story base-isolated building in Tokyo from the beginning of the construction to 43 months after the end of the construction. During the monitoring period of the building, Tohoku Earthquake (2011) struck the
References
[1]
I. Caliò, A. Greco, and A. Santini, “Simplified dynamic analysis of pile-soil-structure interaction,” in Proceedings of the 18th GIMC Conference Siracusa, September 2010.
[2]
B. K. Maheshwari, K. Z. Truman, M. H. El Naggar, and P. L. Gould, “Three-dimensional nonlinear analysis for seismic soil-pile-structure interaction,” Soil Dynamics and Earthquake Engineering, vol. 24, no. 4, pp. 343–356, 2004.
[3]
H. Tahghighi and K. Konagai, “Numerical analysis of nonlinear soil-pile group interaction under lateral loads,” Soil Dynamics and Earthquake Engineering, vol. 27, no. 5, pp. 463–474, 2007.
[4]
K. Yamashita, J. Hamada, and S. Onimaru, “Masahiko Higashino Seismic behavior of piled raft with ground improvement supporting a base-isolated building on soft ground in Tokyo,” Soils and Foundations, vol. 52, no. 5, pp. 1000–1015, 2012.
[5]
H. G. Poulos and E. H. Davis, Elastic Solutions for Soil and Rock Mechanics, John Wiley & Sons, New York, NY, USA, 1974.
[6]
W. G. K. Fleming, A. J. Weltman, M. F. Randolph, and W. K. Elson, Piling Engineering, Surrey University Press, London, UK, 2nd edition, 1992.
[7]
M. F. Randolph, “Design methods for pile groups and piled rafts,” in Proceedings of the 13th International Conference on Soil Mechanics and Foundation Engineering, vol. 5, pp. 61–82, New Delhi, India, 1994.
[8]
L. D. Ta and J. C. Small, “An approximation for analysis of raft and piled raft foundations,” Computers and Geotechnics, vol. 20, no. 2, pp. 105–123, 1997.
[9]
D. G. Lin and Z. Y. Feng, “A numerical study of piled raft foundations,” Journal of the Chinese Institute of Engineers, vol. 29, no. 6, pp. 1091–1097, 2006.
[10]
Z. Y. Ai and Y. C. Cheng, “Analysis of vertically loaded piles in multilayered transversely isotropic soils by BEM,” Engineering Analysis with Boundary Elements, vol. 37, no. 2, pp. 327–335, 2013.
[11]
D. D. C. Nguyen, S. B. Jo, and D. S. Kim, “Design method of piled-raft foundations under vertical load considering interaction effects,” Computers and Geotechnics, vol. 47, pp. 16–27, 2013.
[12]
E. Bourgeois, P. Buhan, and G. Hassen, “Settlement analysis of piled-raft foundations by means of a multiphase model accounting for soil-pile interactions,” Computers and Geotechnics, vol. 46, pp. 26–38, 2012.
[13]
M. Huang, F. Liang, and J. Jiang, “A simplified nonlinear analysis method for piled raft foundation in layered soils under vertical loading,” Computers and Geotechnics, vol. 38, no. 7, pp. 875–882, 2011.
[14]
J. H. Lee, Y. Kim, and S. Jeong, “Three-dimensional analysis of bearing behavior of piled raft on soft clay,” Computers and Geotechnics, vol. 37, no. 1-2, pp. 103–114, 2010.
[15]
E. M. Comodromos, M. C. Papadopoulou, and I. K. Rentzeperis, “Pile foundation analysis and design using experimental data and 3-D numerical analysis,” Computers and Geotechnics, vol. 36, no. 5, pp. 819–836, 2009.
[16]
M. T. A. Chaudhary, “FEM modelling of a large piled raft for settlement control in weak rock,” Engineering Structures, vol. 29, no. 11, pp. 2901–2907, 2007.
[17]
J. P. Wolf, Dynamic Soil-Structure Interaction, Prentice Hall, New York, NY, USA, 1985.
[18]
A. Burman, P. Nayak, P. Agrawal, and D. Maity, “Coupled gravity dam-foundation analysis using a simplified direct method of soil-structure interaction,” Soil Dynamics and Earthquake Engineering, vol. 34, no. 1, pp. 62–68, 2012.
[19]
H. R. Tabatabaiefar and A. Massumi, “A simplified method to determine seismic responses of reinforced concrete moment resisting building frames under influence of soil-structure interaction,” Soil Dynamics and Earthquake Engineering, vol. 30, no. 11, pp. 1259–1267, 2010.
[20]
A. Gouasmia, K. Djeghaba, and M. Merzoud, “Direct approach to seismic soil-structure-interaction analysis: building group case,” International Review of Mechanical Engineering, vol. 3, no. 5, pp. 679–686, 2009.
[21]
K. Baba, K. Park, and N. Ogava, “Soil-Structure Interaction Systems on the base of the ground impedance functions formed in to a chain of impulses along the time axis,” in Proceedings of the 11th World Conference on Earthquake Engineering, Acapulco, Mexico, 1996.
[22]
J. P. Wolf and C. Song, “Some cornerstones of dynamic soil-structure interaction,” Engineering Structures, vol. 24, no. 1, pp. 13–28, 2002.
[23]
A. S. Arya and D. K. Paul, “Earthquake response of tall chimneys,” in Proceedings of the 6th World Conference, pp. 1247–1259, New Delhi, India, 1977.
[24]
N. S. Pour and I. Chowdhury, “Dynamic soil structure interaction analysis of tall multi-flue chimneys under aerodynamic and seismic force,” in Proceedings of the 12th International Conference of the International Association for Computer Methods and Advances in Geomechanics (IACMAG '08), pp. 2696–2703, Goa, India, 2008.
[25]
D. Mehta and N. J. Gandhi, “Time study response of tall chimneys, under the effect of soil structure interaction and long period earthquake impulse,” in Proceedings of the 14th World Conference on Earthquake Engineering, Beijing, China, 2008.
[26]
B. R. Jayalekshmi, D. Menon, and A. M. Prasad, “Effect of soil-structure interaction on along-wind response of tall chimneys,” in Proceedings of the 13th International Conference of the International Association for Computer Methods and Advances in Geomechanics (IACMAG '11), pp. 846–851, 2011.
[27]
H. van Koten, “Wind induced vibrations of chimneys: the rules of the CICIND code for steel chimneys,” Engineering Structures, vol. 6, no. 4, pp. 350–356, 1984.
[28]
IS:11089-1984, “Code of practice for design and construction of ring foundation,” Bureau of Indian Standards, New Delhi, India.
[29]
D. Menon and P. S. Rao, “Estimation of along-wind moments in RC chimneys,” Engineering Structures, vol. 19, no. 1, pp. 71–78, 1997.
[30]
J. E. Bowles, Foundation Analysis and Design, McGraw-Hill International Editions, Singapore, 1997.
[31]
NEHRP, “Recommended provisions for seismic regulations of new buildings,” Part 1, provisions, FEMA 222A, 1994.
[32]
H. Y. Fang, Foundation Engineering Handbook, Van Nostrand Reinhold, New York, NY, USA, 1991.
[33]
IS:4998 (Part 1)-1992 (Reaffirmed 2003), “Criteria for the design of reinforced concrete chimneys,” Bureau of Indian Standards, New Delhi, India.
[34]
T. Cakir, “Evaluation of the effect of earthquake frequency content on seismic behaviour of cantilever retaining wall including soil-structure interaction,” Soil Dynamics and Earthquake Engineering, vol. 45, pp. 96–111, 2013.
[35]
M. R. Kianoush and A. R. Ghaemmaghami, “The effect of earthquake frequency content on the seismic behavior of concrete rectangular liquid tanks using the finite element method incorporating soil-structure interaction,” Engineering Structures, vol. 33, no. 7, pp. 2186–2200, 2011.
