Guidelines from U.S. Army Corps of Engineers

This section outlines the guidelines for selecting pile hammers based on pile material and soil type.

The section discusses how to choose the appropriate pile hammer based on factors such as pile material (concrete, timber, steel) and soil type. It highlights the need for heavier hammers in tough soil conditions and provides specific recommendations for various soil classifications.

Detailed Summary

This section provides comprehensive guidelines on selecting pile hammers, a crucial element in the construction and engineering sectors, specifically from the U.S. Army Corps of Engineers. The selection is intricately connected to both the material type of the piles being used (such as concrete, timber, or steel) and the soil type.

Key Points Covered:

1. Hammer Types and Pile Material:

   • For concrete piles, heavier hammers (drop or single-acting) should be used to minimize the height of the fall, thereby reducing driving stresses.
   • Timber piles may also benefit from drop or single-acting hammers.
   • Steel or sheet piles can utilize double-acting hammers for rapid blow rates.
   • Vibratory hammers are recommended for environments where noise reduction is necessary.

2. Soil Classification:

   • Soil types are categorized primarily into cohesive and non-cohesive soils, roughly determined via standard penetration tests, which measure the number of blows needed for penetration.
   • Non-cohesive soils are classified as loose, medium, or dense based on the blow counts, affecting hammer selection.
   • For cohesive soils, the classification influences the choice of hammer types significantly, emphasizing the use of heavier hammers (single-acting) for stiff or hard conditions.

3. Guidelines Overview:

   • For loose sand, both concrete and wood piles can use double-acting hammers, whereas for medium sand, single-acting hammers are recommended for concrete piles.
   • The choice is conditional upon the density of the soil, requiring more energy to drive piles into more firmly compacted soils.
   • The guidelines provide detailed recommendations for heavy and lightweight hammers according to different verification standards, thus ensuring compliance in engineering practices.

4. Additional Factors:

   • Factors influencing hammer selection also include the weight and length of the piles, along with noise restrictions and productivity needs.
   • Essential guidance on calculating blow energy to define hammer size is also highlighted, emphasizing the relationship between weight, height of fall, and blow energy.