AN EXPERIMENTAL STUDY ON LOADING CONDITION OF PILED RAFT FOUNDATION
Foundation of many structure like transmission, radio and television towers are subjected to inclined compressive and uplift loads. Additionally, foundation of tall buildings and bridges are also subjected to high lateral loads along with other verticals loads coming for the superstructure. In such cases, to increase the load bearing capacity of such foundation system and to decrease the corresponding vertical and lateral deflection piles may be employed along with raft footing. This paper presents an experimental study of the effectiveness of using short piles either rigidly connected or hinged to the raft (instead of long piles) on the behavior of a loaded raft. The load configuration was designed to simulate rafts under inclined loads. Several arrangements of piles with different lengths and numbers along with the effect of the relative density of the soil and the load inclination with vertical were studied. Test results indicate that the inclusion of short piles adjacent to the raft edges not only significantly improves the raft bearing pressures but also leads to a reduction in raft settlements and tilts leading to an economical design of the raft. However, the efficiency of the short piles-raft system is dependent on the load inclination ratio and pile arrangement. Also, connecting short piles rigidly to the raft gives greater improvement in the raft behavior than hinged piles for case of obliquely loaded pile raft system.
Burland, J. B., Broms, B. B., and De Mello, V. F. (1977) “Behavior of foundations and structures.” Proc., 9th Int. Conf. on Soil Mechanics and Foundation Engineering, Vol. II, 495–546.
Poulos, H. G., and Davis, E. H. (1980). Pile foundation analysis and design, Wiley, New York.
Clancy, P., and Randolph, M. F. (1993). “An approximate analysis procedure for piled raft foundations.” Int. J. Numer. Analyt. Meth. Geomech., 17(12), 849–869.
Randolph, M. F. (1994). “Design methods for pile groups and piled rafts.” Proc., 13th Int. Conf. on Soil Mechanics and Foundation Engineering, Vol. 5, 61–82.
Horikoshi, K., and Randolph, M. F. (1996). “Centrifuge modeling of piled raft foundation on clay.” Geotechnique, 46(4), 741–752.
Kim, K. N., Lee, S. H., Kim, K. S., Chung, C. K., Kim, M. M., and Lee, H. S.(2001). “Optimal pile arrangement for minimizing differential settlements in piled raft foundations.” Comput. Geotech., 28(4), 235– 253.
Prakoso, W. A., and Kulhawy, F. H. (2001). “Contribution to piled raft foundation design.” J. Geotech. Geoenviron. Eng., 127(1), 17–24.
Poulos, H. G. (2001). “Piled raft foundations: Design and applications.” Geotechnique, 51(2), 95–113.
Cunha, R. P., Poulos, H. G., and Small, J. C. (2001). “Investigation of design alternatives for a piled raft case history.” J. Geotech. Geoenviron. Eng., 127(8), 635–641.
Small, J. C., and Zhang, H. H. (2002) “Behavior of piled raft foundations under lateral and vertical loading.” Int. J. Geomech., 2(1), 29–45.
Reul, O., and Randolph, M. F. (2004). “Design strategies for piled rafts subjected to non uniform vertical loading.” J. Geotech. Geoenviron. Eng., 130(1), 1–13.
Wong, I. H., Chang, M. F., and Cao, X. D. (2000). “Raft foundations with disconnected settlement reducing piles.” Design application of raft foundations and ground slabs, Chap. 17, Thomas Telford, London, 469–486.
Cao, X. D., Wong, I. H., and Chang, M. F. (2004). “Behavior of model rafts resting on pile-reinforced sand.” J. Geotech. Geoenviron. Eng., 130(2), 129– 138.
Meyerhof, G. G. and Ranjan, G. (1972) “The Bearing Capacity of Rigid Piles under Inclined Loads in Sand: Vertical Piles”, Canadian Geotechnical Journal, Vol. 9, 430-446.
Roy, S., Chattopadhyay, B.C., Sahu, R.B. (2012). “Load Deformation Characteristics of Circular Raft-Pile Combination Subjected to Oblique Loadings” Indian Geotechnical Conference, Delhi, 2012.
Roy, S., Chattopadhyay, B.C., Sahu, R.B. (2013). “Pile Behavior under Inclined Compressive Loads- A Model Study” Electronic Journal Geotechnical Engineering, Vol. 18, 2181-2205.
- There are currently no refbacks.