Steel Pile, Concrete Deck connection

[Hariharan]

It is common to provide steel piles and concrete decks in Jetty
structures. What kind of connection is commonly detailed ?
Are there many choices for designers? The situation I am
interested in is a connection wherein there is a large bending
moment apart from axial load at the interface.

 

[dik]

I've used both straps welded to the sheet piling and rebar through holes 'burned' through the piling to keep the concrete from 'spreading' due to the lack of bond. Also, depending on the work the concrete capping may be sufficiently massive that bars over the top of the piling may suffice.

Also have capped the sheet piling with a steel member and tied this to the concrete behind.

Bending moment is best accommodated by welding (spec a weldable rebar) to the sheet piling on both sides; one set of bars for compression. A cranked bar can be used to provide a space away from the sheet piling and to develop a 'd' and to develop better bond.

If seawater, concrete should be type 5.

 

[Hariharan]

Thanks, dik. I think I did not make it evident that the pile
I referred to is a steel tubular (driven) pile. The construction
details are expected to be somewhat different. Any ideas,
or past experience?

M. Hariharan

 

[dik]

Not for HSS tubes, but have used H/W sections and have welded rebar to the flange and have also used headed studs, but moments have been small. Also connect to precast piles for small moment values.

Headed studs and rebar matter of designing as regular steel stuff or reinforced concrete. With precast it was a matter of having a sufficient cap to provide reinforcing hoop and rebar development.

HSS should be similar, might drill/burn through for rebar or if wall thickness sufficient, then headed studs near the corners.

 

[Qshake]

Typical for pin-pile application (somewhat similar) is the welded, headed stud connection detail. I have recently used them in conjunction with a seismic retrofit for footing.

The detail that I used was four columns of four 7/8" dia studs welded to the center of of the pipe. The studs were welded on abt. 6" cts.

The project is under construction and I've heard no complaints about the detail either...strange!

There are other details for pipe pile involving rebar not welded to the pipe and I will post them as I return to work.

 

[Riz]

I've had a similar situation and I got round it as follows:

1. Concrete/steel interface
A moment resisting joint is possible if the pile can have enough anchorage in the concrete deck. This can be possible with a pile cap.
You will need to introduce fins that are to be welded on the pile for enabling a robust connection.

2. If above is difficult to achieve, than allow for rebars and concrete within pile that can tie into deck beam reinforcement.

 

[Hariharan]

Riz,

Thanks.

Alternative-1 has the following problems. Pile driving equipment
would normally not permit prewelded fins to protrude. Site
welding is time consuming and expensive. Quality will also be
suspect. Proving adequacy by any rational analysis could be
difficult. Most important, the protruding pile will not allow beam
rebars to pass through! Some minimum negative moment and
bottom rebars will be necessary.

Alternative-2 is what we are adopting. Calculating the many
requirements for load transfer from steel pile to concrete to
rebars results in a number of additional features like massive
shear keys inside piles, huge rebar requirements etc. Details are
quite cumbersome. I wanted to see if anyone had a simpler
design or detail, particularly in US/Europe, where labour costs
are very high.

Hariharan