The " WAVE EQUATION" 3

[ENGMEDINA]

Do somebody knows what wave equation I use and how do I use to evaluate the suitability of the Contractor’s proposed driving system. In this case we are going to build two bridges with prestressed concrete piles and the contractor proposed to use a DELMAG D8-22 Diesel Pile Hammer. Anybody??

William Medina, EIT
Florida

 

[PEinc]

Check out this web site for information on wave equation analysis for piles. GRLWEAP is a very popular program for running WEAP analyses.

http://www.pile.com/pdi/products/grlweap/

 

[Focht3]

[blue]PEinc[/blue] gave you a good starting point.

How big are the piles? How long? Soil conditions? A D8-22 seems to be a pretty light hammer, particularly if you're in the panhandle.

(That may be why you posted your question...)

 

[VAD]

Hello Engmedina:

I do not think that the wave equation will help until you actually are in production. At that time you will be able to get an idea of the feeiciency of the hammer as you will have an energy output which is a function of several things. generally a 40KJ hammer would be a good start. However with concrete piles ther is tha question of pile damage by reflecting waves and as such high energy input may not be totally desirable. I am talking from memory here.

Generally the soil profile a nd depth of embeddment required can give you some ideas along with past experience.
on pile hammer energy output. Rember the rated capacity is not always what is imparted - stroke, improper combustion, cap block, damping etc all come into play in the process.

Good Luck

 

[Focht3]

Hmmm,

I will conditionally disagree, [blue]VAD[/blue]. I've used WEAP and site-specific data to predict driving records - and develop guidelines for when to terminate driving. [blue]ENGMEDINA[/blue] may be trying to determine if the Delmag D8-22 can get the job done (and how long it will take.) PDA has to wait for actual construction in order to be useful.

[blue]ENGMEDINA[/blue]: look for a paper by Roy Olson and Norman Dennis on pile driving formulas - they evaluated them all. A good paper to read.

Be aware that wave equation analyses require a lot of judgement and experience to get right...

 

[PEinc]

ENGMEDINA
Perhaps worse than too small a pile hammer is too large a pile hammer. Care must be taken in chosing the correct hammer to avoid damaging the pile. GRLWEAP will give the maximum driving stresses for the pile based on the chosen hammer.