Are all QS mental?
This isn’t directly aimed at Greg Tripp, but maybe he can help me understand why I find myself wanting to dispose of all QS at the bottom of a rotary bored concrete pile!
During piling activities a byproduct of the process is pile arisings, or spoil. In our case this is sandstone (more like builder’s sand). This needs to be removed from site and we have a sub-contractor who is paid to do this.
My first assumption was that when a tipper lorry collects spoil from site and then leaves through the gate, the ticket they leave will be used to quantify how much spoil has been removed. This will then be used to complete the valuation each month for the sub-contractor removing the spoil.
I have been asked by the QS for details on the volumes of the piles as this is actually the quantity they use to complete valuations (not what actually leaves site). I have a number of issues with this:
- What bulking factor is being used – 1m^3 of bank is not 1m^3 of loose.
- Not all material from piling is being taken off site. A large amount is used on site to improve underfoot conditions and the working areas for sub-contractors.
- Other sub-contractors also use the spoil to back-fill in their own areas (where the SES allows)
So I believe the SC is getting paid to remove spoil that is staying on site. When I discussed these issues with the junior QS, he asked me to quantify how much is being left on site – I had a look up my sleeve but was still found wanting on this figure – it’s like trying to quantify the amount of icing sugar in my cocaine.
I see the issues with paying for tickets:
- The tipper lorry may not be full
- The spoil may have come from another location or task
- Tickets get lost
But these issues can be easily controlled; the gate man can confirm the lorry is full (or 1/2 etc). Spoil on site is separated in the tasks it has come from in case of localised contamination. The gate man also keeps a register of vehicles entering and leaving site which will back up lost tickets.
I am yet to consult the QS Pocket Book, but this is my next step. I have so far given in to the QS and delivered the information they have requested.
I have another QS rant where they have specifically gone for a day-works contract over lump sum, because it was initially cheaper – again I argued against this but the QS insisted she wanted all of the risk and none of the security (facetious)…
From the Standard Methods of Measurements 7th Edition, the item highlighted in green states:
The volume of disposal of surplus excavated materials is calculated from the nominal corss-sectional size of piles and their lengths measured in accordance with 1 & 2.1.2. The volume of enlarged bases is added to this calculation.
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Chris, not sure on the scale of volume, but have you done a cost benefit analysis of using a scale to weigh the lorries when they arrive and depart from site to get an accurate volume of material removed?
Daz,
Just looking at it objectively, a weigh bridge would be the golden solution for measuring what is leaving site, but the cost of implementing this wouldn’t be worth it and the logistics on a site this tight would be a nightmare.
Chris, As Daz mentioned. Here we have a weigh bridge just to weigh the incoming muck from the other NLE sites. Its all the same project but allows cost to be attributed.
I would assume that the total volume of material in the piles is pretty negligible overall, but it could be useful at a later date.
To you original question, the QS we have here are all pretty good and are very knowledgeable (most have come from crossrail). Difficulty comes when our QS and the sub contractors QS get into the same room and try to out QS eachother. It not safe to be in the same room when they get going.
I don’t want to turn this thread in to QS bashing, but I do hear that the snr QS sleeps upside down from a rafter.
I don’t wish to steal Greg’s thunder but,…… were this a civil’s contract using CESSM the P item, item coverage includes the disposal of spoil in the pile item coverage … makes life Sooooooo simple
If the contractor then makes something from the arisings…..whooopeeedo for him!
But the answer QS or not is what’s the measurement item coverage…..simples!
The Standard Methods of Measurements (7th Edition) corroborates the idea that the pile arisings are quantified from the pile volume (in-situ). This is also mirrored in the New Measurement Rules (2nd Edition). To me this is still crazy and puts even more emphasis on the QS actually being on site or actively using the Engineers diaries to assess what material qty should be deducted for material staying on site.
I will add the page from the SMM7 shortly.
Chris, sorry about the belated reply but I have been having a well earned break (and not upside down from a rafter either…) Taking your second point first, any QS who agrees to pay daywork over a lump sum to a contractor is breaking one of Quantity Surveying’s cardinal rules regarding commercial risk management. It is at its best naive and could be at is very worst corrupt. Regarding the first point it sounds like your junior QS has wilted under pressure from the sub-contractor and his own inexperience and picked on you to solve his dilemma. He should be capable of calculating a gross disposal figure allowing for a reasonable bulking factor and then make some very generous notional deductions for the onsite disposal and then present the gross figures to the subbie with a request to him substantiate any extra money he thinks he is entitled to. Anyway, if you know the sources of this information why can’t he work something out? Regards Greg