Franki Pile Design 1

[dirtguy4]

Ok, I've done several searches on this site over the last four years for Franki pile design and have always returned empty handed.

Every once in a while, in my travels, I come across a site that would be ideal for Franki piles.........a very competant bearing strata located approximately 35 to 40 feet below ground surface with the upper strata very soft, saturated and provides little or no skin frictional contribution for pile capacity. Footings are a waste due to excess settlement and groundwater infiltration.....etc.....etc.

Usually in these situations we recommend driven piles (steel or timber)....but just once I would like to do a franki pile comparison as there are times when extending pile length due to welding and splicing is quite time consuming and expensive.

Does anyone have a really good reference for franki pile design? Building and designing the bulb as well as the complext shaft resistance components.

Thanks in advance and Happy New Year

 

[hokie66]

Franki is a big international piling company and these days does lots of different types of piles. But I assume by your post you mean cast in place expanded base piles which they call Frankipiles.

In my experience, you need to involve Franki for selection of the pile type, and the design, installation, and certification is by Franki. That is the way it has worked on projects I have been involved in.

 

[dirtguy4]

hokie66,

Thanks for your comments. You are correct, that they are expanded base piles, but not to be confused with belled piles. These are cased and the pile consists of a gravel and portland cement mixture.

There has got to be some design data out there for this..........I have seen AMEC design these before, so I am sure the information is out there......just getting my hands on it seems to be the tricky part.

 

[PSlem]

Look for papers by William J. Neely, their engr., such as

http://cedb.asce.org/cgi/

http://WWWdisplay.cgi?9000017

 

[dirtguy4]

Thanks PSlem

 

[aeoliantexan]

I have a paper by Rey Nordlund delivered at Lehigh University in 1970, in which he presents the dynamic formula used by Franki to install the PIFs. It does not present a static design approach. His paper includes references to papers by Demcsak 1968, Meyerhoff 1959 and 1960, and O'Neill 1963. I can send you a copy if you wish.

I believe the approach was mostly art for a long time, based on the thickness and density of the bearing layer and how well the soil was expected to densify during compaction of the bulb. Franki would look at the boring logs, suggest a capacity, and back it with their performance bond. I haven't dealt with Franki for a long time, but my first thought would be to give them a call.

 

[BigH]

I've seen papers - in the past (early DFI papers??) that detail the design of "expanded base piles" (which might be a better search than Franki piles. They have "capacity" vs volume of concrete extruded. Sorry, am on vacation and have nothing in front of me to be more specific.