DRIVEN and other pile capacity programs 2

[DaveVikingPE]

Anyone using DRIVEN, the FHWA program for static pile analysis? Or the USACE program CAXPILE?

If so, I've run some examples from Das' book on both programs and the results I get are not at all close to the book answers. I've also got the FWHA 2,000-page manual by Hannigan and, as with the Das problems, am getting answers that aren't close what's in the manual.

Any guidance, etc.?

 

[jdonville]

DaveVikingPE,

I use DRIVEN (version 1.2) on a somewhat regular basis. Would you please indicate the example problem from FHWA HI-97-013/014 (by page references) and include a text dump of your .dvn file and a portion of your output? I will try to 1) verify your result, and 2) assist to track down the discrepancies noted.

Jeff

 

[DaveVikingPE]

Wow! Thanks!

Caveat: I admit that I may not be using the program correctly (thus, I'm asking for help). Also, boy, the numbers sure do look close to what's in the book... But I'm just not sure as this is a new program for me.

I'm trying Student Exercise #2, page 9-183 of HI097-013, that is, volume 1. Answers for depth of pile tip = 15 m are from page G-8, Rs = 1287kN; page G-9, Rt = lesser of 588 kN and 450kN, use 450 kN, Qu = 1287 + 450 = 1737 kN. Results from DRIVEN at depth = 15 m are someting like (forgive the formatting):

Depth Skin Friction End Bearing Total Capacity
=================================================
14.01 m 1073.27 kN 479.23 kN 1552.50 kN

15 m 1225.8 kN higher than 450 kN 1704.99 kN

(interpolated)

17.01 m 1535.37 kN 479.23 kN 2014.61 kN
=================================================

Here's the text dump:

[GENERIC SOIL HEADER : BETA4]

[UNIT SYSTEM: METRIC]
[NUMBER SOIL LAYERS: 2]
[SOIL LAYER: 1]
[SOIL TYPE: COHESIONLESS]
[ANGLE: 30.00]
[CORRECTION: TRUE]
[NUMBER VALUES: 1:FALSE]
[DEPTH: 0.0000 N: 1]
[ANGLE: 30.00]
[CORRECTION: TRUE]
[NUMBER VALUES: 1:FALSE]
[DEPTH: 0.0000 N: 1]
[THICKNESS: 5.0000]
[UNIT WEIGHT: 17.0000]
[SENSITIVITY: 1.0000]

[SOIL LAYER: 2]
[SOIL TYPE: COHESIONLESS]
[ANGLE: 35.00]
[CORRECTION: TRUE]
[NUMBER VALUES: 1:FALSE]
[DEPTH: 0.0000 N: 1]
[ANGLE: 35.00]
[CORRECTION: TRUE]
[NUMBER VALUES: 1:FALSE]
[DEPTH: 0.0000 N: 1]
[THICKNESS: 95.0000]
[UNIT WEIGHT: 18.8000]
[SENSITIVITY: 1.0000]

[END GENERIC SOIL HEADER]
[PROJECT INFORMATION]

[PROJECT NAME: Student Exercise #2]
[PROJECT CLIENT: DaveVikingPE]
[PROJECT MANAGER: DaveVikingPE]
[COMPUTED BY: DaveVikingPE]
[DATE: 01/10/2007]
[WATER TABLE - DRILLING: 5.0000]
[WATER TABLE - RESTDRIV: 5.0000]
[WATER TABLE - DESIGN: 5.0000]
[SOFT COMPRESSIBLE SOILS: FALSE]
[DEPTH: 0.0000]
[NOR]
[SCOURABLE SOILS: FALSE]
[PIER: 0.0000]
[CHANNEL DEGRADATION: 0.0000]
[PILE TYPE: CONCRETE PILE]
[DEPTH: 1.0000]
[SHAPE: SQUARE]
[TIP DIAMETER: 0.0000]
[SQUARE SIDE: 305.0000]

[END PROJECT INFORMATION]

[END OF FILE]

 

[jdonville]

Dave,

Using your inputs, which seem to be correct, I get 1849 kN ultimate capacity at 16 m from Driven rather than 1737 kN from the worked problem.

Looking into the solved example, Rt = 450 kN vs. 479 kN from Driven, Rs1 = 99 kN vs. 103 kN from Driven, and Rs2 = 1188 kN vs. 1267 kN from Driven.

Considering the rounding that needed to be done for the worked example in the book, this is pretty darn close. Don't lose sleep over it.

Jeff

 

[DaveVikingPE]

Jeff,

1. Thanks for your time and assistance.

2. The program that my peers outside of my workplace use is APILE and they eschew the FHWA method in favor of the API method when computing geotechnical capcities for driven piles. APILE is sort of expensive and requires a hardware lock while DRIVEN is "free" (a system admin has to install it on our computers) and there's no silly kind of hardware lock. Thusly, as I anticipate more work with driven piles in the future, my ideal workflow is to work out the easiest situation by hand and then crank out the rest of the pile field (if that's what I'll have) using DRIVEN. I'm going to play with this program some more until I'm confident in using it regularly.

Thanks again!

 

[DRC1]

You should look at Unipile as put out by Unisoft

http://www.unisoftltd.com.

It was developed by Fellenius and others. It is much more analytical than driven, which always seemed kind of black box to me. It is not terribly expensive I think $640. It is very flexible and gives a lot of both printed & graphical output.

 

[IFRs]

Pardon my question, but what does API stand for? In which API publication would I read about the pile method?

 

[DaveVikingPE]

American Petroleum Institute.
API RP-2A
API report 83-42B

Those two, I think (I don't have 'em) expain the API method. The APILE program's User's Manual also has a good outline of the API method.

I'm going to check out Unipile, too.

 

[IFRs]

I looked in the current API publication list and did not find either of those. Well, not exactly - RP-2A is all about Planning, Designing and Constructing Fixed Offshore Platforms, not piles. I could not find the other report, either. Are they different numbers or possibly no longer in print?

 

[DaveVikingPE]

I probably got the numbers wrong... Maybe I see what we have in the office later.

 

[jdonville]

DaveVikingPE,

Happy to help. FYI, the FHWA pile manuals were recently updated (issued late last year), and are available in bound form from the National Highway Institute for about $100 all-in. Unfortunately, they don't appear to be available for download - to the great consternation of many including myself. The reference numbers are FHWA NHI-05-042 and NHI-05-043.

Jeff