Some Inadequacies Of Common Design Procedures For Deep Foundations

This paper examines some aspects of common deep foundation design that the author considers may be inadequate. The following aspects are considered:

• Ignoring foundation interactions;
• Ignoring the beneficial effect of the raft;
• Assuming a rigid cap or raft;
• Over-simplification of the geotechnical profile;
• Ignoring the beneficial effects of basement walls;
• Ignoring the effects of ground movements;
• Ignoring kinematic effects in seismic design.

Each inadequate aspect will be considered in turn, with examples given of the possible consequences. Some aspects lead to conservative designs, while others tend to be unconservative. Suggestions will be offered for addressing the perceived inadequacies, some of which are likely to involve the application of innovative techniques.