Pile Driving Design (Hand Calculation) Example 1

[rsbmusicguy]

Hey everyone,

I am currently on a job acting as a third party QA/QC (basically inspector) and am in the process of driving piles and have been dealing with the designer of the pile system for some time due to very high blow counts. This is not my area of expertise and do not even have any college books on it from school. Is there anyone that can provide me a hand calculation / design example for a pile? I looked online but had trouble finding anything useful.

RSB

 

[oldestguy]

See if you can come across a printing on the Internet of the US Navy design Manuel NAVFAV DM-7. They have changed designation on these manuals and this one may be changed also is called "Design Manual Soil Mechanics, foundations, and earth structures". It has what you may need.

 

[Retrograde]

See attached.

 

[fattdad]

4N (3N if silty) for tip. N/50 for shaft.
Use N-1-60.
Look at the average N in proximity to the tip when figuring tip. Look at average N along the shaft when figuring shaft.
Equations in TSF and for unit dimension.

For clay, the approach is different. But for sandy soils, that'll get you close.

Use a safety factor of 3 for single pile. 2 or 2.5 for groups.

f-d

ípapß gordo ainÆt no madre flaca!

 

[SlideRuleEra]

rsbmusicguy - See the 13 part series "Pile Foundations: Know-How" on this page of my website: Link
The 1960's info is dated and concerns wood piling, but is useful for steel and concrete piling, too.
Here is an excerpt from the summary: "Review of the Series".

For steel HP and sheet piling, see another website page: Link
In particular, "Bethlehem Steel H Piles".

http://www.SlideRuleEra.net

 

[mchen96]

FHWA also makes very complete guides (including design examples). Search for NHI-16-009, NHI-16-010, and NHI-16-064 (Volumes 1,2, and 3).

 

[BigH]

Good advice as given above. Tomlinson's Pile Design and Construction is a great source for piles. It is commendable that you are seeking to learn about what you are inspecting. That said, in my view, you should be talking with your supervisor in the office for advice. They should not be sending you out to inspect a project without being able to provide backup when you need it.

 

[Settingsun]

Agree with BigH. That said, there are manuals for piling inspectors available on the internet which might help reduce the need to go to others for advice, or help you understand what to observe to assist people who aren't on site. Try the Deep Foundations Institute and several US state bridge departments.

Is the concern small sets at end of drive or total blow count from start to finish? I've only seen computer analysis of the latter (driveability analysis).

 

[SoilRocks]

I think the biggest concern of high blows during driving is the potential for damage to the pile, followed by some assurance that you are achieving the design capacity. Presumably you wouldn't be installing piles without an approved design. It is typical to perform driveability analysis of a pile driving system prior to installation (as referenced above). Typically a program like WEAP is used to get some idea if you might damage the pile during driving, a sense of driving stresses, and a sense of the capacity. You don't mention whether there is any field testing. If you high-strain dynamic testing (PDA), then that will give you actual driving stresses, and perhaps resolve your concern of the high blow counts. Anyway, BigH's note that you should be leaning on a supervisor is absolutely true.