Steel Pile to Concrete Grade Beam

[GalileoG]

How would one typically connect a steel pile to a grade beam? We are specifying steel piles for our one storey structure and was wondering if there is anything that I have to keep in mind when I am designing my grade beams or spacing the piles. Grade beam width varies from as narrow as 8" and is currently spaced at 15' o/c. I'd hate to make the pile contractor's life difficult by giving him a design that is very difficult for him to work with.

Thank you.

Clansman

If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.

 

[Teguci]

Pipe, H, Concrete filled...?

 

[GalileoG]

Wouldn't that be up to the contractor? We are showing H piles on our drawings but that is only an illustration.

Clansman

If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.

 

[westheimer1234]

well depends if there is tension then you use tension connectors, if only compression then it is just embedded at a certain depth.

 

[Bobber1]

An 8" wide grade beam sounds too narrow to comfortably accomodate an H-pile (what size?) and allow for construction and pile driving tolereance.

Are you trying to develop moment capacity of the H-pile?

We use steel pipe piles into concrete cap beams all the time in our marine projects. We've been using headed dowels a lot lately since you avoid the need for all that rebar hook developmant length.

How do you intend to structually fasten the pile to the grade beam?

 

[GalileoG]

I do not have any net tension, what tension I have is gone by including the self-weight of the grade beam. I am also not trying to develop a moment capacity. These piles will only take gravity load.

Bobber, I am thinking that the H-pile will be embedded to a certain depth. I am just worried, as you have expressed, that the grade beam width is too narrow to do that.

Clansman

If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.

 

[dik]

If no tension, can you use one or two 3/4" dia headed studs on a plate welded to the steel pile? Centred on the grade beam.

Dik

 

[dirtydude]

As Bobber mentioned, I would think that your GB should be at least 16" or 18" wide to accomodate the H-pile width plus driving tolerance plus concrete cover. As far as a connection, just a plate welded to the top ought to do if it is carrying just gravity load.

 

[Teguci]

Things to chew on:

1st - I don't leave the pile design up to the contractor. I am not familiar with this practice. How is this done?
2nd - The final pile location will not be centered on your grade beam and some moment will need to be developed between the grade beam and pile for torsion, lateral loads, etc...
3rd - I've never seen an 8" wide bucket for earth excavation.
4th - Smallest H-pile is 8" - How are you developing the rebar to either side of this as called for in CRSI?

 

[BAretired]

You could pour a pile cap around the top two feet of the pile, then provide dowels into the grade beam from the cap. U shaped bars within the cap, draped over the pile could carry the vertical load or you could weld projections to engage the pile, avoiding uphand welding.

BA

 

[dirtydude]

Teguci - Sometimes the pile design can be left to the contractor because they have more experience in different ground conditions and can make a better assessment of what the soil can support. Thus, a more efficient pile design will yield savings to you and your client.

BA - no uphand welding would be required for the plate, if it is an 8" H-pile, use a 7 1/2" plate and just put 1/4" fillet weld across both flanges. Should be more than adequate for whatever load is being carried by the pile.

 

[BAretired]

d-dude,

That is true, but if the pile is a little off line, a 7.5" plate doesn't give you much room for error with an eight inch grade beam.

BA

 

[doka1]

As far as tolerance, you would have to go with pile caps as BA mentioned, then the 8" grade beams could run continuous through. Besides, I have always seen a minimum cover around pile be it wood or steel of 1'-3" or around that dimension, so there is no way you could just put an 8" grade beam over it.

 

[GalileoG]

Thanks all for the great help. I've gone ahead with using a pile cap. I've also left the design of the pile cap for the pile contractor. Thanks again all!

Clansman

If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.

 

[IFRs]

Wow - leaving the design of both the pile and the pile cap to the contractor? Who is stamping the drawings? Who is the engineer of record?

 

[GalileoG]

IFRs, leaving the design of the pile for the pile contractor is not unusual. Driven steel pile capacity depend on many parameters that only the pile contractor would know. I have zero information on what equipment they would be using on site.

Clansman

If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.

 

[doka1]

In the states most pile contractors have pe's on staff to sign off on the blow counts, and like clansman referred to-the type of equipment used. Some parameteres are given to the pile driver before he is awardded the project, right? And of course if there a lot of misdrives, doesnt the engineer of record become involved once again?