4. Summary of Key Points

Try these first

1. 1.

   What is the primary purpose of cushioning material in pile driving?

   Hint

   Think about what happens when two hard objects collide.

2. 2.

   What should be the minimum thickness of a cushioning material?

   Hint

   Recall the figures discussed for effective cushioning.

3. 3.

   What is the main purpose of cushioning materials in pile installation?

   • To hold the pile upright
   • To protect the pile from impact
   • To speed up the installation

   Hint

   Think about what happens during the driving process.

4. 4.

   True or False: The impact velocity of the hammer should be increased to reduce driving stress.

   • True
   • False

   Hint

   Consider the relationship between velocity and impact.

5. 5.

   Calculate the appropriate hammer weight needed for a pile weighing 720 pounds if the minimum recommending ratio is 1:3 for the hammer.

   Hint

   Think about dividing the pile weight by the ratio.

6. 6.

   If a hammer produces 2000 foot-pounds of energy while driving and encounters 20 pounds of soil resistance, how deep does the pile penetrate according to the formula W.H = R.S?

   Hint

   Work backwards from the given energy and resistance.