Abstract
Piled raft foundations, wherein a small number of connected piles are utilized as settlement reducers, have been widely used for high-rise buildings. Recently, a new technique has been introduced by disconnecting the piles from the raft and inserting a cushion layer between them. In such cases, the piles are considered as soil reinforcement components rather than structural members. To explore the feasibility of utilizing the disconnected piled raft foundation, a series of experimental model tests were conducted to examine the load–settlement behavior and pile load sharing ratio of the connected piled raft (CPR) and disconnected piled raft (DCPR) foundation systems using cushions of different thicknesses and stiffnesses. In addition, ABAQUS 3D finite element analyses were performed to analyze the axial stress along the piles and the bending moments along the raft. The results indicated that the total settlement of the system was minimized significantly when disconnected piles were used. In addition, the disconnected technique provided a significant reduction in the axial stress along the piles and the bending moment along the raft compared with that of the CPR. These findings may be accompanied by economic and environmental benefits.
Similar content being viewed by others
References
Alhassani AMJ, Aljorany AN (2020) Parametric study on unconnected piled raft foundation using numerical modelling. Journal of Engineering 26(5):156–171, DOI: https://doi.org/10.31026/j.eng.2020.05.11
Azizkandi AS, Baziar MH, Yeznabad AF (2018) 3D dynamic finite element analyses and 1 g shaking table tests on seismic performance of connected and nonconnected piled raft foundations. KSCE Journal of Civil Engineering 22(5):1750–1762, DOI: https://doi.org/10.1007/s12205-017-0379-2
Azizkandi AS, Rasouli H, Baziar MH (2019) Load sharing and carrying mechanism of piles in non-connected pile rafts using a numerical approach. International Journal of Civil Engineering 17(6):793–808, DOI: https://doi.org/10.1007/s40999-018-0356-2
Baziar MH, Ghorbani A, Katzenbach R (2009) Small-scale model test and three-dimensional analysis of pile-raft foundation on medium-dense sand. International Journal of Civil Engineering
Bolton MD, Gui MW, Garnier J, Corte JF, Bagge G, Laue J, Renzi R (1999) Centrifuge cone penetration tests in sand. Géotechnique 49(4):543–552, DOI: https://doi.org/10.1680/geot.1999.49.4.543
Burghignoli A, Jamiolkowski M, Viggiani C (2007) Geotechnics for the preservation of historic cities and monuments: Components of a multidisciplinary approach. Proceedings of the 14th European Conference on Soil Mechanics and Geotechnical Engineering, Madrid, Spain 24–27
Burland JB, Broms BB, De Mello V (1978) Behaviour of foundations and structures. Building Research Establishment Garston
Cao XD, Wong IH, Chang MF (2004) Behavior of model rafts resting on pile-reinforced sand. Journal of Geotechnical and Geoenvironmental Engineering 130(2):129–138, DOI: https://doi.org/10.1061/(asce)1090-0241(2004)130:2(129)
Chow YK (1987) Iterative analysis of pile–soil–pile interaction. Geotechnique 37(3):321–333, DOI: https://doi.org/10.1680/geot.1987.37.3.321
Das BM, Ramana GV (2011) Principles of soil dynamics. Cengage Learning. Stanford, USA
Davis E H, Poulos HG (1972) The analysis of piled raft systems. Aust. Geomechs. Journal G2:21–27
El-Garhy B, Abdel Galil A, Youssef A, Abo Raia M (2013) Behavior of raft on settlement reducing piles: Experimental model study. Journal of Rock Mechanics and Geotechnical Engineering 5(5):389–399, DOI: https://doi.org/10.1016/j.jrmge.2013.07.005
Eslami A, Malekshah SS (2011) Analysis of non-connected piled raft foundations (NCPRF) with cushion by finite element method. Computational Methods in Civil Engineering 2(2) Fioravante V, Giretti D (2010) Contact versus noncontact piled raft foundations. Canadian Geotechnical Journal 47(11):1271–1287, DOI: https://doi.org/10.1139/t10-021
Hor B, Song MJ, Jung MH, Song YH, Park YH (2016) A 3D FEM analysis on the performance of disconnected piled raft foundation. Japanese Geotechnical Society Special Publication 2(34):1238–1243, DOI: https://doi.org/10.3208/jgssp.kor-21
Horikoshi K, Randolph MF (1996) Centrifuge modelling of piled raft foundations on clay. Geotechnique 46(4):741–752, DOI: https://doi.org/10.1680/geot.1997.47.2.389
Horikoshi K, Randolph MF (1997) On the definition of raft — soil stiffness ratio for rectangular rafts. Géotechnique 47(5):1055–1061
Jamiolkowski M, Ricceri G, Simonini P (2009) Safeguarding Venice from high tides: Site characterization and geotechnical problems. Proc. 17th Int. Conf. on Soil Mechanics and Geotechnical Engineering, Alexandria 3209–3227
Katzenbach R, Arslan U, Moormann C (2000) Piled raft foundation projects in Germany, Design applications of raft foundations, Hemsley JA Editor. Thomas Telford, DOI: https://doi.org/10.1680/daorf.27657.0013
Kim KN, Lee SH, Kim KS, Chung CK, Kim MM, Lee HS (2001) Optimal pile arrangement for minimizing differential settlements in piled raft foundations. Computers and Geotechnics 28(4):235–253, DOI: https://doi.org/10.1016/s0266-352x(01)00002-7
Liang FY, Chen LZ, Shi XG (2003) Numerical analysis of composite piled raft with cushion subjected to vertical load. Computers and Geotechnics 30(6):443–453, DOI: https://doi.org/10.1016/s0266-352x(03)00057-0
Park HJ, Ko KW, Song YH, Song MJ, Jin S, Ha JG, Kim DS (2020) Centrifuge modeling of disconnected piled raft using vertical pushover tests. Acta Geotechnica 15(9), DOI: https://doi.org/10.1007/s11440-020-00928-6
Pecker A (2004) Design and construction of the Rion Antirion Bridge. Geotechnical Engineering for Transportation Projects 216–240, DOI: https://doi.org/10.1061/40744(154)7
Poulos HG (2001) Piled raft foundations: Design and applications. Geotechnique 51(2):95–113
Randolph MF (1994) Design methods for pile groups and piled rafts. International Conference on Soil Mechanics and Foundation Engineering 61–82
Reul O, Randolph MF (2003) Piled rafts in overconsolidated clay: Comparison of in situ measurements and numerical analyses. Geotechnique 53(3):301–315, DOI: https://doi.org/10.1680/geot.2003.53.3.301
Saadatinezhad M, Lakirouhani A, Jabini Asli S (2021) Seismic response of non-connected piled raft foundations. International Journal of Geotechnical Engineering 15(1):66–80, DOI: https://doi.org/10.1080/19386362.2019.1565392
Ta LD, Small JC (1996) Analysis of piled raft systems in layered soil. International Journal for Numerical and Analytical Methods in Geomechanics 20(1):57–72, DOI: https://doi.org/10.1002/(sici)1096-9853(199601)20:1<57::aid-nag807>3.0.co;2-0
Tradigo F, Pisanò F, Di Prisco C, Mussi A (2015) Non-linear soil–structure interaction in disconnected piled raft foundations. Computers and Geotechnics 63:121–134, DOI: https://doi.org/10.1016/j.compgeo.2014.08.014
Cooke RW (1986) Piled raft foundations on stiff clays — a contribution to design philosophy. Geotechnique 36(2):169–203, DOI: https://doi.org/10.1680/GEOT.1986.36.2.169
Wong IH, Chang MF, Cao XD (2000) Settlement-reducing piles. Design Applications of Raft Foundations 469
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Alhassani, A.M.J., Aljorany, A.N. Experimental and Numerical Modeling of Connected and Disconnected Piled Raft. KSCE J Civ Eng 27, 2442–2454 (2023). https://doi.org/10.1007/s12205-023-0437-x
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12205-023-0437-x