Driving H-pile with Vibrotory Hammer or Any Acceptible Alternatives 2

[GGGGeo]

Instead of installed caisson per plan, the contractor proposed alternatives to install steel H-piles. What's more, they dont want to bring large enough crane with hammer. They have been fighting with us stating that these H-piles can be installed by their vibratory hammer mounted on their excavator.

These piles are designed for friction pile and friction around pile is expected to be reduced by the vibrotory hammer (we are not driving sheet pile).

Since the pile is not deep (about 10 feet), is there any other hammer (1) smaller than diesel one (2) similar to geoprobe (downward direction only) but still pick-up the needed friction (I was told that "ABI Mobilram" may be considered).

Thank you for your opinion.

 

[140lbHammer]

There was a history case I had read that ARMY used vibratory hammer to install h-pile on a dam face but losing 20 to 30% of design value...

You are right, not too many paper or restriction to forbid the use of vibratory hammer to replace diesel one. Interesting....

 

[GGGGeo]

Here is the case study link:

http://140.194.76.129/publications/eng-manuals/em1110-2-2906/a-c.pdf

 

[TDAA]

Tell them if they wish to install H piles, especially with a vibratory hammer, that they must perform (a) load test(s) to verify the design loads have been achieved.

 

[GGGGeo]

Thank you TDAA! Could you please comment on "Push-In" or "Guided hydraulic hammer"? My small web/flange is only need 10 feet deep.

Thank you!

 

[BigHarvey]

GGGGeo

Your piles can be designed with two methods :
1 ) using soil parameters ( SPT, lab tests, etc )and in this case your piles must be installed to the design depth whatever method is used ( ie if vibratory hammer can do it, then it is acceptable )

2) using a pile driving formula and in this case the last meters at least must be installed with a hammer delivering blows and not vibrations.

The ABI rigs are using vibratory hammers but can be used with a Delmag D 19 hammer.

 

[GGGGeo]

Thanks BigHarvey!

Vertical is not only major player. Now there are also installation speed (there 200+), lateral, and uplift from wind load now. So we are really looking into some alternatives....

Any comments, any hydraulic hammer can drive downward only you can suggest?

Thank you!

 

[BigHarvey]

GGGGeo

Best hydraulic hammers are IHC hammers ( I would say S35 model for your site) . They have pretty accurate software to determine the right hammer size as a function of pile and soil characteristics.

You also have small diesel hammers but installation speed is higher with a hydraulic hammer.

 

[vulcanhammer]

I've got more detailed information on the Army's experience in this regard at

http://www.vulcanhammer.info/vibro/vibro-technology.php

As far as "push-in" vs. "guided" is concerned, the only thing that comes to mind with vibratory hammers is whether the hammer is free-hanging (the usual case) or run in leaders (the unusual case.) For 10' piles, using leaders (unless there's a serious support problem with the piles) seems a bit much.

Vibrated piles still have the axial capacity conundrum, i.e., you don't have a reliable method of correlating their axial capacity with the performance of the hammer.

IHCWAVE is at

http://www.vulcanhammer.info/drivability/tno.php

http://www.pz27.net

 

[GGGGeo]

Thank you Vulcanhammer. However, each time I saw soils settle on surface around the H-pile/sheetpiles for shoring installed by vibratory hammer. Somehow they give me the impression that impact hammer and vibratory hammer at certain degree may not simply comparable.

Is there any studies by FHWA and/or State DOT that you can refer?

Much appreciated to your precious suggestion BigHarvey!!

 

[BigHarvey]

GGGGeo

Settlements observed with vibratory hammers are due to soil compaction. It happens mainly in granular materials where the vibrations cause a densification of the soil. A steel tube or a pair of sheetpiles driven with a vibratory hammer is a very good ground improvement method down to depths of about 10 m max. Sometimes it can be an undesired effect !

 

[vulcanhammer]

GGGGeo, I am unaware of FHWA or state DOT studies.

Vibratory and impact driving are, in many respects, difficult to compare. The dominant frequencies of the two are very different. Impact driving's frequencies, for example, are high enough to induce wave propagation in the pile while vibratory frequencies are not for "normal" length piles.

http://www.pz27.net