Pile Capacity and Driveability

This is the engineering core of the book. It starts with the basics: when a deep foundation is needed, what general considerations drive foundation selection, and how a pile carries load into the ground. Load transfer, overburden pressure, and the bearing capacity of piles on rock are explained in plain terms before any calculations begin.

Next comes the information you need before you can design anything. The chapter covers the phases of subsurface exploration, guidelines for minimum exploration programs, and the common tests used for pile foundations. It then compares allowable stress design with load and resistance factor design, and covers allowable pile stresses and handling stresses for concrete piles.

The static analysis section is the longest. It covers axial capacity in cohesionless and cohesive soils, pile group capacity and settlement, negative shaft friction, lateral squeeze of foundation soil, and the lateral loading of vertical piles.

Then the chapter turns to a question every contractor asks: will this pile actually go in with the hammer on site? It explains dynamic resistance, pile driveability, dynamic formulas, and the wave equation, and it covers drivability and hammer selection for both impact and vibratory hammers.

A worked sample problem follows the whole process in order, from the statement of the problem through structural capacity, axial capacity in two different soils, group settlement, negative friction, lateral squeeze, and wave equation analysis. The chapter ends with the design of sheet pile walls, including soil pressure, surcharge loads, hydrostatic head, structural aspects, and cellular design.

In this chapter

• Overviewpage 154
  • General Considerations for Foundation Selection
  • Establishment Of A Need For A Deep Foundation
• Basic Load Transfer Concepts for Pile Foundationspage 156
  • General Considerations
  • Load Transfer
  • Overburden Pressure
  • Bearing Capacity of Piles on Rock
• Subsurface Explorationspage 160
  • Subsurface Exploration Phases
  • Guidelines For Minimum Structure Exploration Programs
  • Descriptions of More Common Subsurface Tests for Pile Foundations
• Design Factors and Criteriapage 166
  • Allowable Stress Design (ASD)
  • Load and Resistance Factor Design (LRFD)
• Structural Design of Driven Pilespage 168
  • Allowable Pile Stresses (ASD)
  • Handling Stresses for Concrete Piles
• Static Analysis of Geotechnical Capacitypage 169
  • Axial Compressive Capacity of Piles in Cohesionless Soils
  • Axial Compressive Capacity of Piles in Cohesive Soils
  • Pile Group Capacity and Settlement
  • Negative Shaft Friction
  • Lateral Squeeze of Foundation Soil
  • Lateral Loading of Vertical Piles
• Dynamic Resistance, Drivability, and Hammer Selection: Impact Hammerspage 199
  • Overview
  • Pile Driveability
  • Dynamic Formulas for Static Capacity Determination
  • Dynamic Analysis by the Wave Equation
• Drivability and Hammer Selection: Vibratory Hammerspage 212
• Sample Problempage 214
  • Statement of the Sample Problem
  • Structural Capacity
  • Axial Capacity for North Abutment Piles (Cohesionless Soils)
  • Axial Capacity for the South Abutment Piles (Cohesive Soils)
  • Pile Group Settlement
  • Negative Shaft Friction
  • Lateral Squeeze
  • Wave Equation Analysis
• Design of Sheet Pile Wallspage 229
  • Soil Pressure
  • Soil Properties
  • Surcharge Loads
  • Unbalanced Hydrostatic Head
  • Other Lateral Loads
  • Structural Aspects of Sheet Pile Design
  • General Design Considerations
  • Cellular Design