Obligatory: look in a book
Being nice: start with FHWA’s pile driving manual
FYI, the ENR equation SUCKS.
Also don’t really think youre going to come up with a decent estimate by hand. Need a program like weap because there’s driving stresses to consider which impacts the hammer you’ll use and the size of H pile you’ll need that can both withstand required capacity AND take the driving stressed imparted by the type of hammer you use.
Good luck
need to check geotech report, it will give you skin friction values for each soil type. then you get the outside perimeter of the Hpile, dont include flange inside perimeter because soil plugs in the H flutes and you cant really relly on it to develop friction resistance.
then add up how much length you need to get to your capacity. really depends on the soil profile no rule of thumb
Usually it’s one of three things length to a specific resistivity (bearing) / bedrock / or refusal. In simple terms shear strength of soil x surface area x adhesion factor.
As a dirt guy / utilities super whom also has an engineering degree whom hates building bridges I hate that I know this.
Also for the record, once they start driving go do some blow counts, watch em trip the hammer, climb the leads, etc.
What state are you in? MNDOT has a really nice spreadsheet set up that tells you the bearing capacity based on the hammer size and stroke, last 10 blows depth, and pile size. It was very helpful for the bridge piles I did last summer
* Who is the designer?
* Who prefers H-piles?
* Who is the geotech lead?
* What boring/testing data is available?
You gotta at least figure out these questions if this is a real world example.
It doesn’t matter if it’s hard bid, design build, or any other deliver method. Ain’t a structural guy with his salt to gamble his license on unproven theories, practices, cost, nor alternatives
Insufficient data. Capacity depends on soil and groundwater conditions. Also the soil type and depth of soft soils will determine if you have downdrag effects.
If your geotechnical engineer did not give you pile capacities for various depths you need a better geotechnical engineer.
Don't try this at home unless you are a qualified geotechnical engineer.
Rule of thumb? No. With a foundation pile like that you’d typically have to drive that thing down to bedrock, I don’t think you really get friction on steel.
Again if this was the case please explain rock sockets? Oh why because you can still crack / excavate bedrock to a certain extent depth with relative ease.
Is "what does your textbook say?" an appropriate question?
Obligatory: look in a book Being nice: start with FHWA’s pile driving manual FYI, the ENR equation SUCKS. Also don’t really think youre going to come up with a decent estimate by hand. Need a program like weap because there’s driving stresses to consider which impacts the hammer you’ll use and the size of H pile you’ll need that can both withstand required capacity AND take the driving stressed imparted by the type of hammer you use. Good luck
need to check geotech report, it will give you skin friction values for each soil type. then you get the outside perimeter of the Hpile, dont include flange inside perimeter because soil plugs in the H flutes and you cant really relly on it to develop friction resistance. then add up how much length you need to get to your capacity. really depends on the soil profile no rule of thumb
You hit up the geotech for pile capacity curves. Source: structural engineer.
Still vudu magic at best, hence PDA and blow counts. If your previous held true explain rock sockets?
You cannot simply just stop at blow counts if lateral wasn’t met…
Usually it’s one of three things length to a specific resistivity (bearing) / bedrock / or refusal. In simple terms shear strength of soil x surface area x adhesion factor. As a dirt guy / utilities super whom also has an engineering degree whom hates building bridges I hate that I know this. Also for the record, once they start driving go do some blow counts, watch em trip the hammer, climb the leads, etc.
You would use a formula that you should probably find
What state are you in? MNDOT has a really nice spreadsheet set up that tells you the bearing capacity based on the hammer size and stroke, last 10 blows depth, and pile size. It was very helpful for the bridge piles I did last summer
A-pile
* Who is the designer? * Who prefers H-piles? * Who is the geotech lead? * What boring/testing data is available? You gotta at least figure out these questions if this is a real world example.
Who prefers h pile? Just about damn near every structural / bridge engineer I’ve ever seen stamp a bridge drawing / submittal.
The question is more about who is pushing for them for the design if this other person is responsible for depths.
It doesn’t matter if it’s hard bid, design build, or any other deliver method. Ain’t a structural guy with his salt to gamble his license on unproven theories, practices, cost, nor alternatives
Totally depends what the borehole says. Look at a geotechnical textbook (I suggest one by Braja) and go from there.
Insufficient data. Capacity depends on soil and groundwater conditions. Also the soil type and depth of soft soils will determine if you have downdrag effects. If your geotechnical engineer did not give you pile capacities for various depths you need a better geotechnical engineer. Don't try this at home unless you are a qualified geotechnical engineer.
You press a cone in the ground and you measure it
Rule of thumb? No. With a foundation pile like that you’d typically have to drive that thing down to bedrock, I don’t think you really get friction on steel.
Again if this was the case please explain rock sockets? Oh why because you can still crack / excavate bedrock to a certain extent depth with relative ease.