Minimum shear spacing at LAP in bored pile 1

[windkiss]

Do we need to apply the minimum shear spacing at LAP according to EN 1992-1-1:2004 (C8.7.4.2) for the Bored pile? (the spacing should be lesser than 150mm (Fig. 8.9)
I saw many practices drawing this principle is not applied
Is there any Code of practice or guideline that says we can ignore this principle in bore pile LAP?

 

[kostast88]

The structural detailing of piles, is one of the most overlooked aspects by structural engineers.

Piles are generally identified as pure compression elements. Largely wrong, but for most buildings in the UK, that's the case. So figure 8.9b applies.

Most CFA piles I've seen nowadays use a superlatch connector, but this would come from the fabricator drawings or the pile contractor. The designer wouldn't specify something like that. Technically it avoids this requirement.

For the deeper and bigger piles I've seen couplers, it's the only possible solution for H40's or bigger. Which avoids this requirement.

Theoretically speaking the code should be followed. But a lot of piles have spiral reinforcement and it's not practical to locally increase the spacing. Which is why this is often overlooked. Instead they add 1-3 single links at the end of the cage.

This rule could be more relevant in micropiles (say 300mm diameter).Which almost always is the pile contractor's job.

150mm spacing shear links along the pile, is perfectly normal. 200 is optimum for ease of concreting and reduced weight.

 

[windkiss]

Thank you for the reply
The situation is the Contractor prefers to apply Lap splice with the helical pitch is 300 throughout the non-required shear rebar zone.
If we follow the Contractor's instructions, the independence check may reject the design so I need some Code of practice or guidelines commonly apply in UK.
To me this :"Instead they add 1-3 single links at the end of the cage." could be a considerable solution

 

[kostast88]

You can terminate the helix and transition to circular links with 1/2 the spacing, or as required.

You can reduce the half spacing of the helix locally, for the length required. Also provide a circular link at the end.

The next rebar cage will follow suit.Specify Construction Joint in the drawing!

There is the lengthy BS8004 - Code of practice for foundations - Chapter 6: Piles. But I've never seen anything relatd to this issue. The issues I've seen are in practice. Your best bet is to address with contractor properly. Of course the contractor will not never want to increase spacing. You don't have to follow him down this road.