2nd Edition

Single Piles and Pile Groups Under Lateral Loading

By Lymon C. Reese, William F. Van Impe Copyright 2011

    The complexities of designing piles for lateral loads are manifold as there are many forces that are critical to the design of big structures such as bridges, offshore and waterfront structures and retaining walls. The loads on structures should be supported either horizontally or laterally or in both directions and most structures have in common that they are founded on piles. To create solid foundations, the pile designer is driven towards finding the critical load on a certain structure, either by causing overload or by causing too much lateral deflection.

    This second edition of Reese and Van Impe’s course book explores and explains lateral load design and procedures for designing piles and pile groups, accounting for the soil resistance, as related to the lateral deflection of the pile. It addresses the analysis of piles of varying stiffness installed into soils with a variety of characteristics, accounting for the axial load at the top of the pile and for the rotational restraint of the pile head. The presented method using load-transfer functions is currently applied in practice by thousands of engineering offices in the world. Moreover, various experimental case design examples, including the design of an offshore platform pile foundation are given to complement theory. The rich list of relevant publications will serve the user into further reading.

    Designed as a textbook for senior undergraduate/graduate student courses in pile engineering, foundation engineering and related subjects, this set of book and CD-ROM will also benefit professionals in civil and mining engineering and in the applied earth sciences.

    Techniques for design
    Introduction
    Occurrence of laterally loaded piles
    Nature of the soil response
    Response of a pile to kinds of loading
    Models for use in analyses of a single pile
    Models for groups of piles under lateral loading
    Status of current state-of-the-art

    Derivation of equations and methods of solution
    Introduction
    Derivation of the differential equation
    Solution for Epy =kpyx
    Validity of the mechanics

    Models for response of soil and weak rock
    Introduction
    Mechanics concerning response of soil to lateral loading
    Influence of diameter on p-y curves
    Influence of cyclic loading
    Experimental methods of obtaining p-y curves
    Early recommendations for computing p-y curves
    p-y curves for clays
    p-y curves for sands above and below the water table
    p-y curves for layered soils
    p-y curves for soil with both cohesion and a friction angle
    Other recommendations for computing p-y curves
    Modifications to p-y curves for sloping ground
    Effect of batter
    Shearing force at bottom of pile
    p-y curves for weak rock
    Selection of p-y curves

    Structural characteristics of piles
    Introduction
    Computation of an equivalent diameter of a pile with a noncircular cross section
    Mechanics for computation of Mult and EpIp as a function of bending moment and axial load
    Stress-strain curves for normal-weight concrete and structural steel
    Implementation of the method for a steel h-section
    Implementation of the method for a steel pipe
    Implementation of the method for a reinforced-concrete section
    Approximation of moment of inertia for a reinforced-concrete section


    Analysis of groups of piles subjected to inclined and eccentric loading
    Introduction
    Approach to analysis of groups of piles
    Review of theories for the response of groups of piles to inclined and eccentric loads
    Rational equations for the response of a group of piles under generalized loading
    Laterally loaded piles
    Axially loaded piles
    Closely-spaced piles under lateral loading
    Proposals for solving for influence coefficients for closely-spaced piles under axial loading
    Analysis of an experiment with batter piles

    Analysis of single piles and groups of piles subjected to active and passive loading
    Nature of lateral loading
    Active loading
    Single piles or groups of piles subjected to active loading
    Passive loading
    Single piles or groups of piles subjected to passive loading

    Case studies
    Introduction
    Piles installed into cohesive soils with no free water
    Piles installed into cohesive soils with free water above ground surface
    Piles installed in cohesionless soils
    Piles installed into layered soils
    Piles installed in c-φ soil
    Piles installed in weak rock
    Analysis of results of case studies
    Comments on case studies

    Testing of full-sized piles
    Introduction
    Designing the test program
    Subsurface investigation
    Installation of test pile
    Testing techniques
    Loading arrangements and instrumentation at the pile head
    Testing for design of production piles
    Example of testing a research pile for p-y curves
    Summary

    Implementation of factors of safety
    Introduction
    Limit states
    Consequences of a failure
    Philosophy concerning safety coefficient
    Influence of nature of structure
    Special problems in characterizing soil
    Level of quality control
    Two general approaches to selection of factor of safety
    Global approach to selection of a factor of safety
    Method of partial factors (psf)
    Method of load and resistance factors (LRFD)
    Concluding comment

    Suggestions for design
    Introduction
    Range of factors to be considered in design
    Validation of results from computations for single pile
    Validation of results from computations for pile group
    Additional steps in design

    APPENDICES
    Broms method for analysis of single piles under lateral loading
    Nondimensional coefficients for piles with finite length, no axial load, constant Ep/Ip, and constant Epy
    Difference equations for step-tapered beams on foundations having variable stiffness
    Computer Program COM622
    Non-dimensional curves for piles under lateral loading for case where Epy =kpyx
    Tables of values of efficiency measured in tests of groups of piles under lateral loading
    Horizontal stresses in soil near shaft during installation of a pile
    Use of data from testing uninstrumented piles under lateral loading to obtain soil response
    Eurocode principles related to geotechnical design
    Discussion of factor of safety related to piles under axial load

    Biography

    Professor Van Impe received his MSc and PhD degree in civil engineering at the Ghent University in Belgium where he has been professor of Geotechnics since 1982 and full professor since 1991. Prof. Van Impe has been an emeritus professor since March 2011 but remains active as a consultant and as manager of AGE bvba. He has been also a full professor at the Catholic University of Louvain in Belgium. He has a 35+ years long career in geotechnics.
    He is a member of the Belgian Royal Academy of Overseas Sciences. He was elected Vice-President for Europe of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE) in 1994, World President of ISSMGE in 2001 and the President of the umbrella society of the 3 geo-engineering sister societies FedIGS (Federation of the International Geo-Engineering Societies) in 2008. His main field of experience is deep foundations, ground improvement and soil parameter analysis, currently dealing mostly with crushable soils.