Heavy construction experts: Anyone familiar with this kind of pile driving?

[Cruzan]

I've never seen this before and can only guess at what's happening, but I watched a crane lifting and positioning a huge metal pipe or tube that was hanging off one edge of a large, flat metal box. The metal box in turn had what looked like a bundle of heavy electrical cables coming out of it and leading to apparently a big generator. After lowering the pipe by one end to where they wanted it driven, the metal box attached to the upper pipe end and in less than 10 minutes sunk the entire pipe all the way into the ground in a fairly smooth and not too noisy fashion.



How is the pipe driven into the ground? Is the flat box some kind of electro-magnet and uses a high frequency repelling force to push the pipe down?

[Richard Steele]

1. No, but you're on the right track with your "electromagnet" guess.

That "box" does run on electricity, and I think
it uses opposing electromagnets to move the internal hammer,
but it's still jut HAMMERING the piling down into the ground.

It's a rapid, short-stroke hammering device;
the internal hammer only rises and falls a few inches
to strike the piling, but it does it hundreds (thousands?)
of times per minute.

Basically, it's like a 3000-pound VIBRATOR, and it
works like a charm, doesn't it?

Saw one of those back in '93, working power line construction.

An old bridge was being replaced in the Blackwater Wildlife Refuge,
and we had to build a temporary line AROUND the construction site.

They floated a crane up to the bridge on a barge,
and were using one of those big vibrators to drive interlocking
steel plates to form a dike around the bridge abutments so they
could pump the water out and work on the riverbed.

[Cruzan]

3. Thanks for the explanation!

On the construction project next to it -- both in back of my apartment building and in full view from my balcony -- a six story building is being put up with pilings that not only weren't driven even half as deep but were done so with the traditional falling weight hammer, suspended from just a basic tripod at that. The noise of the pile driving that followed is probably for me the most irritating construction sound, particularly to be woken up by it in the morning. With the big iron equipment they've been laying out on the new site, I was dreading the inevitable pile driving, and am quite relived it won't be near as loud as before. But from the size of the pilings on this new one, it looks like they might be building a little bit higher.

[MilesColtrane]

2. The mods lock sex threads you know. n/t

[Hubert Flottz]

4. What you saw was a vibratory pile driver/extractor

The "cables" you saw are 4 or 5 hydraulic hoses and the unit on the ground that the other end of the hoses were connected to was a diesel powered hydraulic control/pump unit that drives the vibratory hammer that was clamped on to the piece of shell pile in that picture. The same system will also drive or extract sheet piles or H piles. I have worked with those types of pile-drivers on many jobs during my 30 years time working in and around the pile-driving bidness. Dragging those hoses around is VERY hard work...tying the hoses off about halfway up the crane boom takes most of the dragging out of the job.

Working around water is pretty tricky because if a hose comes loose or is cut or broken and the hydraulic fluid gets in the water the EPA will be on your case in no time flat. We always carried big bottles dish liquid out on the rivers to quickly disperse the rainbow colored oil slick that a hydraulic fluid spill produced before the EPA would nail us. Now that was indeed a TRICK...but it wasn't magic.

Nothing magic about pile-driving...just hard dangerous work.

here is what you saw...

http://www.apevibro.com/asp/products/chinaquad.asp

http://en.wikipedia.org/wiki/Pile_driver

http://images.google.com/imgres?imgurl=&imgrefurl=http://www.hammersteel.com/pile_driving_equipment.html&h=160&w=130&sz=13&hl=en&start=4&um=1&tbnid=rbmZrAQVaMtZyM:&tbnh=98&tbnw=80&prev=/images%3Fq%3Dvibratory%2Bpile%2Bhammer%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DN

[Richard Steele]

5. Ah, so it's hydraulic?

Thanks Hubert! :thumbsup:

[Hubert Flottz]

6. You're welcome dicksteele

Re.."drive interlocking steel plates to form a dike"

"interlocking steel plates" = Sheet Piles

http://images.google.com/imgres?imgurl=&imgrefurl=http://www.tracosteelproducts.com/Home.html&h=236&w=359&sz=25&hl=en&start=52&um=1&tbnid=wz4Y7lJy2vdSVM:&tbnh=80&tbnw=121&prev=/images%3Fq%3Dcofferdam%26start%3D40%26ndsp%3D20%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DN

"dike" = Cofferdam



http://images.google.com/imgres?imgurl=&imgrefurl=http://www.highfield-tunnelling.co.uk/id2.html&h=2112&w=2816&sz=2801&hl=en&start=37&um=1&tbnid=acJYA_Ogu9J4sM:&tbnh=113&tbnw=150&prev=/images%3Fq%3Dcofferdam%26start%3D20%26ndsp%3D20%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DN

[Cruzan]

7. Great info, thanks!

From other pictures I took, the vibrator appears to be a PVE brand, possibly a 38M: http://www.pve-equipment.com/uploadedfiles/downloads/download.php?file=38M.pdf