Pile Installation Plan

Once the Contractor has been awarded the contract, there are several steps to go through before they can actually start driving production piles.

The Pile Installation Plan is the first step in the process. It is a shop drawing describing in detail the Contractor's tools and methods of installing piles.The idea behind having the Contractor submit this item is to cause him to put thought and planning into the project rather than taking a "wait and see" attitude.

The Contractor must provide this document no less than 30 days prior to beginning pile driving operations.

The Pile Installation Plan will contain the Contractor's:

• List of all equipment to be used and a completed FDOT Form 700-020-01-A.
• Methods for determining hammer energy in the field.
• Details on followers, Templates and Load Test Equipment.
• Sequence of driving piles and schedule, including test piles.
• Details to protect existing structures in the vicinity.
• Required shop drawings for piles, cofferdams, etc.
• Methods to prevent displacement of plumb and battered piles.
• Details on proposed splices.

Other information required:

• Included here would be any special information required in the plans or by the Engineer.

This is the Contractor's plan, which must be approved by the Department. You, the Inspector, will have certain responsibilities for verifying that certain items, such as the hammer, are as specified in the plan.

The Inspector must have a copy of this plan during the project.

Test Pile Program

The Test Pile Program is the second step in the process. It is performed prior to production driving so that actual, on-site, in the field data can be gathered to determine pile driving requirements for the project. This also is the manner in which the Contractor's proposed equipment and methodologies identified in their Pile Installation Plan are put to the test.

Test piles are driven harder and deeper than the production piling because they are exploratory in nature. Test piles are generally longer than the production piling but are of the same type and size.

Data is gathered to assist in determining:

• The safe bearing value of the piles
• The nature of the subsurface soils and driving resistance characteristics of the various strata
• The lengths of piles required for the permanent piles
• The amount of work it takes to obtain the minimum penetration
• The ability of the driving system to do the job
• The need for point protection on the piles

Typically a geotechnical engineer is on site monitoring the test pile driving with Pile Driving Analyzer (PDA) equipment.

Based upon the results of the test pile program, the geotechnical engineer, following PDA data evaluation, will generate the "Driving Criteria Letter".

The Driving Criteria Letter, issued by the Department, establishes the criteria for the driving of the piles. The information obtained during the test pile program was used to develop this letter. The Driving Criteria Letter will set the required blow counts based on hammer energy (stroke). It will also set parameters for initial driving, such as using a reduced fuel setting to control stresses in the pile during early driving and Practical Refusal.

Additionally, this letter should also specify the hammer and cushion equipment and materials used for the test pile program and that these materials should continue to be used for the production pile program. Guidelines for replacement of the pile cushion along with replacement of the hammer cushion are generally presented.

When concrete piles are to be used, another letter is issued by the Department upon the completion and evaluation of the test pile program. This letter is the Pile Lengths letter, which presents the authorized pile lengths. The Pile Lengths letter is usually issued as soon as practical after the end of the test pile program to permit the Contractor ample time to order the correct length concrete piles from the prestress yard. These are the lengths the Department authorizes and will pay for. If the Contractor orders longer lengths, they are not paid for the additional length, except under certain circumstances. The same goes for shorter piles. If they order shorter piles that must be spliced to achieve the "authorized length", there is no Contractor compensation for the splice. Let's take a look at the following Driving Criteria letter:

You have completed the chapter on the Pile Installation Plan and Test Pile Program.

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