Piling equipment and methods 137vertical is 1 in 75. Maximum deviation of finished pile from the specified rake is 1 in 25 for
piles raking up to 1:6 and 1 in 15 for piles raking more than 1:6. Relaxation permitted in
exceptional circumstances subject to implications of this action. Other more stringent toler-
ances are specified for diaphragm walls and secant and contiguous piles.
American Concrete Institute Recommendations: The position of the pile head is to be
within 75 to 150 mm for the normal usage of piles beneath a structural slab. The axis may
deviate by up to 10% of the pile length for completely embedded vertical piles or for all
raking piles, provided the pile axis is driven straight. For vertical piles extending above the
ground surface the maximum deviation is 2% of the pile length, except that 4% can be
permitted if the resulting horizontal load can be taken by the pile-cap structure. For bent
piles the allowable deviation is 2% to 4% of the pile length depending on the soil conditions
and the type of bend (e.g. sharp or gentle). Severely bent piles must be evaluated by soil
mechanics’calculations or checked by loading tests.
The significance of positional tolerance to piling beneath deep basements is noted in
Section 5.9.
3.5 Constructing piles in groups
So far only the installation of single piles has been discussed. The construction of groups of
piles can have cumulative effects on the ground within and surrounding the pile group.
These effects are occasionally beneficial but more frequently have deleterious effects on the
load/settlement characteristics of the piles and can damage surrounding property.
Precautions can be taken against these effects by the installation methods and sequence of
construction adopted. Because the problems are more directly concerned with the bearing
capacity and settlement of the group as a whole, rather than with the installation of the piles,
they are discussed in Sections 5.7 to 5.9.
3.6 References
3.1GEDDES, W. G. N., STURROCK, K. R., and KINDER, G. New shipbuilding dock at Belfast for Harland and
Wolff Ltd, Proceedings of the Institution of Civil Engineers, Vol. 51, January 1972, pp. 17–47.
3.2FAWCETT, A. The performance of the resonant pile driver, Proceedings of the 8th International
Conference, ISSMFE, Moscow, Vol. 2.1, 1973, pp. 89–96.
3.3RODGER, A. A. and LITTLEJOHN, G. A. Study of vibratory driving in granular soils, Geotechnique,
Vol. 30, No. 3, 1980, pp. 269–93.
3.4VIKING, K. The vibratory pile installation technique, Pile Driver, Pile Driving Contractors
Association, USA, Spring 2005, pp. 27–35.
3.5 American Petroleum Institute, Recommended Practice for Planning, Designing and
Constructing Fixed Offshore Platforms, API RP2A, 2000 edn.
3.6WILLIS, A. J. and CHURCHER, D. W. How much noise do you make? A guide to assessing and man-
aging noise on construction sites, Construction Industry Research and Information Association
(CIRIA), London, Report PR 70, 1999.
3.7WELTMAN, A. J. (ed.), Noise and vibration from piling operations, Construction Industry Research
and Information Association (CIRIA), London, Report PSA/CIRIA PG7, 1980.
3.8SHELBOURNE, H. Decibel rating-the important factor, Construction News, Piling and foundations
supplement, 13 December 1973, p. 47.
3.9 Building Research Establishment. Damage to Structures from Ground-borne Vibration, BRE
Digest 403, Watford, 1995.