Ground Slab edge thickening and Pile Cap / Pad interaction

[liam1369]

Good evening all,

I have a general query for a detail I am developing and this is for the interaction between a ground bearing slab edge thickening, which is going to be supporting masonry and a pile cap which is supporting a steel column.

Most general details (see attached a couple of examples) show the ground edge beam thickening sitting directly on top of the pile cap / pad where applicable? I would have thought it would be more beneficial to allow for a similar build up below the slab edge thickening before the pile cap / pad starts. As opposed to casting the new ground slab edge thickening directly on top of it?

In addition, between the caps / pads the edge thickening will be on compacted stone and wherever there is a pad/cap the edge thickening will be on the pad/cap. Surely this will effect the deflection, at least theoretically.

Does anyone else have a similar view from a general detailing view? I currently think the top of the pile cap / pad should stool down around 500mm below the bottom of the edge thickening before the top of the cap/pad starts.

Please see attachments for clarification.

Many thanks all,

Liam

 

[liam1369]

Also see proposal.

 

[liam1369]

Any opinions on this?

 

[Enable]

I'm a little confused on the coincidence of pile caps and slab thickenings. Is there a regular spacing where they are coincidental? If so, I would go with the traditional detail but reinforce the thickening between them to act as a beam. If they occur together much less frequently then that or are not at regular intervals, I would probably prefer to separate them in some way for the deflection reason you've identified. Your approach seems reasonable in that case.

Though I would be concerned about resting brick on a SOG in any event. Is that typical in Britain? I would probably be up at night wondering if the contractor did a good job of compaction or if they had bubba with his big shoe do it!

FYI if you lower the cap by 500mm you may want to check the unsupported length of your column. I wouldn't rely on the top to provide any lateral restraint.

 

[liam1369]

Hi Enable, it will be where the columns occur, therefore every 5-10m say.

Yes brick and masonry sitting on a slab edge thickening is typical.