Effect of in-situ variability of soil on seismic design of piled raft supported structure incorporating dynamic soil-structure-interaction

Abstract Inherent variability of soil considerably affects the seismic design of piled raft supported structures. Conventional design of such structure adopts fixity at base level of superstructure and pile head. However, soil–pile–superstructure interaction largely affects the fundamental frequency and design forces in columns and piles. In contrast, fixed base assumption cannot capture soil structure interaction (SSI) effect. In addition, uncertainty in soil may further leads to a change in the dynamic behavior of the system. This study examines the effect of inherent variability of undrained shear strength of soil in seismic design of structures supported by piled raft foundation embedded in soft clay. Superstructure is modeled as lumped mass stick model and piled raft slab is modeled as rigid plate. Pile is modeled as Euler–Bernoulli beam element and soil resistance is modeled using linear Winkler springs attached to the pile. Dynamic analysis is carried out in time domain to estimate the responses. Monte Carlo simulation technique is used for probabilistic assessment of the fundamental frequency and forces at column and pile attributing a wide range of parametric variation of a representative soil–piled raft–superstructure system. The study shows that the fundamental frequency and forces in column and pile changes significantly due to soil variability.

[1]  William T. Holmes,et al.  The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures , 2000 .

[2]  S. J. Boone,et al.  Comparative evaluation of building responses to an adjacent braced excavation , 1999 .

[3]  Sekhar Chandra Dutta,et al.  Seismic response of soil-pile raft-structure system , 2015 .

[4]  Amir M. Kaynia,et al.  Forces in pile foundations under seismic loading , 1996 .

[5]  Bruce R. Ellingwood,et al.  A new look at the response surface approach for reliability analysis , 1993 .

[6]  Sekhar Chandra Dutta,et al.  Effect of Flexibility of Foundations on its Seismic Stress Distribution , 2008 .

[7]  George Gazetas,et al.  Lateral Dynamic Response of Constrained‐Head Piles , 1983 .

[8]  Kohji Tokimatsu,et al.  Effects of inertial and kinematic interaction on seismic behavior of pile with embedded foundation , 2005 .

[9]  Denys Breysse,et al.  Reliability analysis of a piled raft accounting for soil horizontal variability , 2007 .

[10]  Bak Kong Low,et al.  Probabilistic analysis of laterally loaded piles using response surface and neural network approaches , 2012 .

[11]  Daniel W. Wilson,et al.  Seismic Soil-Pile-Structure Interaction Experiments and Analyses , 1999 .

[12]  Stefano Pampanin,et al.  Probabilistic evaluation of soil–foundation–structure interaction effects on seismic structural response , 2011 .

[13]  Joseph E. Bowles,et al.  Foundation analysis and design , 1968 .

[14]  Han Yingcai,et al.  Seismic response of tall building considering soil-pile-structure interaction , 2002 .

[15]  Emmanouil Rovithis,et al.  Seismic analysis of coupled soil-pile-structure systems leading to the definition of a pseudo-natural SSI frequency , 2009 .

[16]  Mark Yashinsky.  Chapter B. The Loma Prieta, California, Earthquake of October 17, 1989 - Highway Systems , 1998 .

[17]  G. L. Sivakumar Babu,et al.  Effect of soil spatial variability on the response of laterally loaded pile in undrained clay , 2008 .

[18]  G. Gazetas.  FORMULAS AND CHARTS FOR IMPEDANCES OF SURFACE AND EMBEDDED FOUNDATIONS , 1991 .

[19]  S. Haldar,et al.  Response of Euler–Bernoulli beam on spatially random elastic soil , 2013 .

[20]  G. Baecher.  Reliability and Statistics in Geotechnical Engineering , 2003 .

[21]  George Gazetas,et al.  Seismic response of end-bearing single piles , 1984 .

[22]  W. Puła,et al.  Reliability of rigid piles subjected to lateral loads. a revised approach , 2012 .

[23]  Sashi K. Kunnath,et al.  Influence of soil–foundation–structure interaction on seismic response of the I-880 viaduct , 2004 .

[24]  Nicos Makris,et al.  Dynamic pile‐soil‐pile interaction. Part II: Lateral and seismic response , 1992 .

[25]  K. Phoon,et al.  Characterization of Geotechnical Variability , 1999 .

[27]  Yukio Tamura,et al.  Damping Evaluation Using Full-Scale Data of Buildings in Japan , 2003 .

[28]  G. Mylonakis,et al.  Seismic Soil-Structure Interaction: New Evidence and Emerging Issues , 1998 .

[29]  Cee Ing Teh,et al.  Reliability analysis of laterally loaded piles using response surface methods , 2000 .

[30]  Sekhar Chandra Dutta,et al.  Inelastic seismic demand of low-rise buildings with soil-flexibility , 2010 .

[31]  J. Guin,et al.  COUPLED SOIL-PILE-STRUCTURE INTERACTION ANALYSIS UNDER SEISMIC EXCITATION , 1998 .

[32]  Luis Esteva,et al.  Influence of dynamic soil–structure interaction on the nonlinear response and seismic reliability of multistorey systems , 2007 .

[33]  Peter Lumb,et al.  The Variability of Natural Soils , 1966 .

[34]  Ross W. Boulanger,et al.  Dynamic Experiments and Analyses of a Pile-Group-Supported Structure , 2001 .

[35]  George Gazetas,et al.  Dynamic response of pile groups with different configurations , 1993 .