making sense of concrete pile caps

[redtop]

so we have the design for the pile caps, need to decide whether to do ourselves or contract out. on top of the caps will be steel posts which lift the building off the ground; all designed by a SE. In the meantime can anyone explain in idiot speak the process for fitting these?

 

I assume:

 

• put some hardcore around pile
• shutter and lay binding layer, let it go off
• fit formwork for cap
• fit steel re-enforcement inside formwork
• pour concrete
• fit 4 bolts using template so they will fit steel posts later
• leave to go off
• rinse and repeat 41 times ?

 

we are getting levels, etc properly marked out, but does the above sound right and does anyone know what the term 'dishing' means?  Also any idea re the hardcore depth?

 

cheers all

 

Edited July 31, 2019 by redtop

[redtop]

 

 

Edited July 31, 2019 by redtop

[redtop]

in particular what does 'locally dish' mean?

[Russell griffiths]

Get a quote, see how much it makes you sweat. 

I had a quote of £12,000 to do my ringbeam, I new I could do it my self for half that, depends how you value things. 

 

 

[redtop]

had a quote for 7k, but this is just for the caps not the steels / ring beam. i can do it for less than half and will have time to do a few at a time as wont be onto main building until the spring

[Russell griffiths]

I wouldn’t do a few at a time, it will drag on, get them all boxed up, get a ready mix truck and a pump and pour them all in one hit. 

 

Do they have to be pretty, are they going to be on show. 

[redtop]

no, will be under final soil level

[Russell griffiths]

7 minutes ago, redtop said:

no, will be under final soil level

In that case buy pre formed shuttering that stays in place, buy your re bar pre bent, saved me absolutely days in labour. 

[redtop]

have had quote for pre-formed rebar which i was going to use, but couldnt really understand drawing.  I get 51 shape, easy to google. But is it 3 per cap and are tey connected via bars?  Just want to make sure i order right ?

 

Pre-formed shuttering.... never heard of such a thing

[Russell griffiths]

Have a look at  SWIFTFORM from total construction supplies, mention me if you talk to them, it’s my footings on their website. 

Have you got a steel layout drawing and a bar bending schedule. 

 

If you have the bar bending schedule it will make your drawing make more sense 

 

for example. 

You have 41 caps, 

if your schedule says 123 links then it sort of gives the idea that you have 3 links per cap, if it lists straight bar then that will give you a rough idea that they may be joined with bars, go back to your drawing and it might get clearer. 

 

If you are casting bolts into the top of the cap are you aware of all the products you can use that allows bolt placement with a degree of movement so you can line up your steel before you grout. 

[Russell griffiths]

Just looked at the drawing you put up it shows links with 6 bars in them, this might just be an example so look at the exact pile cap drawing. 

[redtop]

so it says:-

 

[Russell griffiths]

You will need a drawing to confirm this but looking at that schedule 

bar mark 01. Is 350 x 250

bar mark 02. Is 350x225. 

 

i am presuming here as I cannot see everything but I would think the 3 smaller links insert into the 3 bigger links, at 90 degrees to them

so 3 links one way and 3 links the other, they will all need tying on the corners to keep it square. 

You finished rebar will look like a box or like a very very poor example of a bird cage. 

Edited August 1, 2019 by Russell griffiths

[redtop]

i cant even see where bar mark 1 and 2 are lol.  SE is away until end of aug so i guess it will have to wait. there are 41 piles and they are all the same

[PeterW]

9 hours ago, redtop said:

had a quote for 7k, but this is just for the caps not the steels / ring beam. i can do it for less than half and will have time to do a few at a time as wont be onto main building until the spring

 

Not wanting to curb the enthusiasm but if this isn’t something you’ve done before then you need to ask if the saving is worth the hassle or the cost of any error rectification later down the line. 

 

Ideally the caps need to be within +\-10mm tolerance in all planes - that’s square to each other and also the levels need to be correct. That probably needs a total station, so add in £2-300 for hire of that. Rebar placement has to be done accurately as if you’re drilling caps at a later date (some show a resin bolt..?) then the rebar has to be out of the way of the holes. 

 

I would focus on cutting cost elsewhere and get this done by a contractor and give them the problems if it’s wrong. 

[redtop]

getting the level right should be easy as they are being marked out by Nationwide. Getting them square to each other is another matter, need to have a think.  I am planning on getting the rebar cut and shaped.  I just want to fully understand the job before i make the decision ?  The bolts have an option of drill and resin or embed in the concrete before its set, which seems easier to me

[Russell griffiths]

5 hours ago, redtop said:

i cant even see where bar mark 1 and 2 are lol.  SE is away until end of aug so i guess it will have to wait. there are 41 piles and they are all the same

Bar mark is in the first column of your steel schedule

 

[Russell griffiths]

What are the piles made of. 

I think what your structural engineer is proposing could be simplified. 

[redtop]

steel posts, 100SHS 5

[Russell griffiths]

1 minute ago, redtop said:

steel posts, 100SHS 5

Ok thought so. 

So why not a steel pile cap. .?

or why not extend the pile up to the underside of your steel frame, replacing the need for the little bolt down legs. 

[redtop]

i know the answer to the second option was due to twisting forces in the piles as they are quite narrow. no idea re steel pile cap.  I have gone through the drawings and still have no idea of where the bar marks can be found in the drawings. As there are only 41 piles why do i have bar 01 and 02  each with 41 piles and a slight dif in the rebar lengths...

[Russell griffiths]

Pm sent.