ToughButterCup Posted January 10, 2017 Share Posted January 10, 2017 Just a quick post to ask if anyone knows the rough cost of Plate Bearing tests? SPONS doesn't list it. Whats a Plate Bearing test? Why do I need it? The pilers won't come on site without one; and if you are using one of these, you can see why. All 37 tonnes of it.... Link to comment Share on other sites More sharing options...
ProDave Posted January 10, 2017 Share Posted January 10, 2017 So let me get this right. you are using piles because you have poor ground with low bearing capacity. But if you have poor ground with low bearing capacity you can't get the piling rig on your site...... And the "test" seems to be take a heavy wheeled vehicle and drive over a plate and see how far it sinks. If anything is going to bog down on site, that will. I can't see the loading being a big issue, it's only a large digger with something else instead of the normal boom, and the point of tracks is to spread the load. Link to comment Share on other sites More sharing options...
NSS Posted January 10, 2017 Share Posted January 10, 2017 Surely there's more danger of that machine floating skywards than sinking into the ground Link to comment Share on other sites More sharing options...
SteamyTea Posted January 10, 2017 Share Posted January 10, 2017 It is another, non building, cost you can put down in your spreadsheet. it must be close to £80k by now. Link to comment Share on other sites More sharing options...
Declan52 Posted January 10, 2017 Share Posted January 10, 2017 We used to use the old Landover we had to do this test. You are really meant to use a larger machine like a 15t digger. You jacked the back end up and it tested on a stand that had a circular plate on the bottom. How far it sunk was what you used to determine the settlement of the ground. It's a half a day test so shouldn't be that much. Ask can try use your digger for a weight instead of hiring in a larger machine. Ask will dpc testing do instead as it's basically the same thing. All they are looking to know is will their pilling rig sink when they start working. Link to comment Share on other sites More sharing options...
ProDave Posted January 10, 2017 Share Posted January 10, 2017 ^^^ and they could find that out by driving it onto site slowly? This sort of stuff is just madness, money for old rope, the world has gone mad I tell thee. Link to comment Share on other sites More sharing options...
ToughButterCup Posted January 10, 2017 Author Share Posted January 10, 2017 2 hours ago, ProDave said: So let me get this right.[...] you are using piles because you have poor ground with low bearing capacity.[...] But if you have poor ground with low bearing capacity you can't get the piling rig on your site...... Nearly right. The piling mat needs to be right for the machine in terms of the weight it will bear. Also the piling mat needs to be at the correct level. Of course there is an element of common sense to be applied here, but the charges that accrue if I get this aspect of the job wrong are £2500 per day. So for the sake of a couple of hundred quid, why risk the standing charge of £2.5k per day while I get the piling mat sorted out. 2 hours ago, SteamyTea said: It is another, non building, cost you can put down in your spreadsheet. it must be close to £80k by now. Perhaps you could explain your comment in a little more detail, please? I, for one, am not sure how to read it - yet-. Link to comment Share on other sites More sharing options...
Declan52 Posted January 10, 2017 Share Posted January 10, 2017 Can you get the piling company to recommend someone who they know does this test. As you say it's only a few hundred instead of maybe a hell of a lot more of the rig starts to sink to one side. Link to comment Share on other sites More sharing options...
oranjeboom Posted January 10, 2017 Share Posted January 10, 2017 Have you chosen your piling company now? And if so, are you sure they will be sending a 32t rig? The rig that did ours was only about 2-3t, although your pile specs will of course be different for your site. Link to comment Share on other sites More sharing options...
ToughButterCup Posted January 10, 2017 Author Share Posted January 10, 2017 1 hour ago, Declan52 said: As you say it's only a few hundred instead of maybe a hell of a lot more of the rig starts to sink to one side. Exactly. What we're trying to prevent is significant deviation from vertical: the mast is huge; the machine has a limited capacity for self adjustment, though. I've got one informal quote of £400 ish, which to me seems cheaper than the price of having a rig hanging around at £2.5k per day. 5 hours ago, ProDave said: ^^^ and they could find that out by driving it onto site slowly? This sort of stuff is just madness, money for old rope, the world has gone mad I tell thee. The setup cost of the rig is £2.5k per day. So, were the rig to sink just a bit more than allowable, I would have to remediate , test properly (to prevent the same problem occurring again) and do it all again. Bang goes £10k if all goes well following a cock up. And easily double that with a bit of bad luck. 19 minutes ago, oranjeboom said: [...] are you sure they will be sending a 32t rig? [...] Yes. And I've been to see it in action, talked to the rig driver, the company contracts manager and the young engineer in person on site. Contrary to some views expressed in this thread, getting this wrong would be a big deal. Link to comment Share on other sites More sharing options...
swisscheese Posted January 10, 2017 Share Posted January 10, 2017 (edited) Piling Mat specification is a live issue for me now also! The Piling firm now also want to use a 32 tonne rig - at short notice, and because they couldn't be bothered to site visit sooner it wasn't specific on their original estimate( and it's probably what they have available and it will be quicker) The "Piling Mat" - 2 or more layers of rolled in crushed concrete is quite a big deal. Something I hadn't anticipated, I'm expecting a specification soon. Out of interest what were you specified for depth? Good luck with the test. Edited January 10, 2017 by swisscheese Link to comment Share on other sites More sharing options...
Declan52 Posted January 10, 2017 Share Posted January 10, 2017 (edited) Put it this way if that 32t rig sinks and topples over as it will be very top heavy when the boom is up imagine the size of the crane or cranes you will need to get it back up. Sign the cheque for £400 and get the ball rolling. Edited January 10, 2017 by Declan52 2 Link to comment Share on other sites More sharing options...
ToughButterCup Posted January 10, 2017 Author Share Posted January 10, 2017 1 hour ago, swisscheese said: Piling Mat specification is a live issue for me now also! OK @swisscheese, to help you, I'll go into detail; Here are the calculation for the depths of the working platform thickness provided by TC Vibro (I'm working with Dan and John Ashton the Contract Manager) PilingMatCalcs.pdf The numbers which interest us are the Required Working Platform Thickness (bottom of page 1). There's one for 'raw' thickness of 0.48m and the other for a piling mat with Geosynthetic Reinforcement , 0.30m What constitutes a piling mat if you need new fill? Here's the answer - again from TC Vibro Specification for Upfill Materials.pdf Are there any guidelines for Piling mats? Of course there are. BR470t.pdf In preparation for this exercise we had a topographical survey done (5 locations) soil sampling 5 locations and a site visit done by Dan from TC Vibro. He asked me to dig a three meter hole in front of him so that he could hold the clay that I dug out. He needed that done in front of him so he could judge the water content. The charges for the rig set up are eye watering (£2.5k per visit) but after that each stone column of stone is relatively cheap. As I explain above -broadly- there's probably no need to get the mat tested. But on balance, why would I not demonstrate good faith to the company when they have visited me three times (Dan twice and the Contracts manager once) to make sure the risk of failure is as low as we can reasonably get? I also visited a site on which TC Vibro were working. In addition I have called out the water board to survey the water pipes (compulsory when piling within 15 meters of a water pipe here), but more honoured in the breach than the observance I think. Luckily, our pipes are cast iron, and a meter below ground level. 1 hour ago, swisscheese said: The Piling firm now also want to use a 32 tonne rig - at short notice, and because they couldn't be bothered to site visit sooner it wasn't specific on their original estimate( and it's probably what they have available and it will be quicker) The "Piling Mat" - 2 or more layers of rolled in crushed concrete is quite a big deal. Something I hadn't anticipated, I'm expecting a specification soon. Out of interest what were you specified for depth? Can I suggest a bit of care with the crushed concrete spec (see the Up-fill spec attached). Dan informally talked me through some of the poor practice that some contractors do in preparation for the piling mat: the end in mind is making sure the piler (or in our case the 'poker') can get through the mat and the substrate. If the area hasn't been dug to the correct depth, the risk increases. @John Ashton, you may want to comment on the above. @swisscheese, I'd be interested in a bit more detail if you can bear it..... 1 Link to comment Share on other sites More sharing options...
swisscheese Posted January 10, 2017 Share Posted January 10, 2017 9 minutes ago, recoveringacademic said: Can I suggest a bit of care with the crushed concrete spec (see the Up-fill spec attached). Dan informally talked me through some of the poor practice that some contractors do in preparation for the piling mat: the end in mind is making sure the piler (or in our case the 'poker') can get through the mat and the substrate. If the area hasn't been dug to the correct depth, the risk increases. @swisscheese, I'd be interested in a bit more detail if you can bear it..... Thanks for info, I'm currently going through much of this. background: We had the topological and soil surveys done, report, engineers loadings etc. We are on a gault clay, at about 5-6 metres we hit very dense/hard Blue Clay, the average pile length will be 8m over 39 piles. (Since when we have been waiting/haggling with Planners over material submission - another story) I had the site meeting today with the Piling Firm when the requirements were discussed. As a result I contacted a local crushed concrete guy who assured me he had provided fill of suitable granularity for Piling, though whether he has enough for my requirements I don't yet know. in excess of 100m3@0.5 for example In brief what the piling firm require is a scrape back, lay the rolled piling mat in unspecified layers to as yet an unspecified depth. Requirement for 8 tonne excavator+man to remove spoil from piling area. Estimate 3-4 days on the Job. That is all I know at the moment. I can't bear it.... oh and then most of the piling mat is scraped back and taken away.....for the excavations for a ground beam. Financial complications of piling and groundbeam..... Link to comment Share on other sites More sharing options...
Construction Channel Posted January 10, 2017 Share Posted January 10, 2017 and i thought underpinning was a PITA. I can't help with any of your questions, but this is definitely an interesting read Link to comment Share on other sites More sharing options...
ToughButterCup Posted January 10, 2017 Author Share Posted January 10, 2017 @swisscheese - have you noticed we are using 'ground improvement columns' NOT piles, but they appear to most people to be piles so we call them piles - in error. Have a look at this However, the piling mat is the same for both: I think. Notice the difference in the calculations for the depth needed if you use Polypropylene Geogrid Tensar SS20. You might like to ask for the calculations they have done showing the difference made by the grid: in our case 280mm instead of 480mm I do not wish to be seen to be advertising. Stone columns and piles are different beasts. Stone columns are significantly cheaper than steel piles. We have about 52 columns to insert. Start 0930. Finished - off site by 15:00 same day. Link to comment Share on other sites More sharing options...
Stones Posted January 10, 2017 Share Posted January 10, 2017 I take it the various different temporary tracks you can get wouldn't be suitable? Just thinking back to several events that I had the misfortune to be working at and how effective metal track was at keeping 40 ton articulated lorries from sinking into the mud. Link to comment Share on other sites More sharing options...
ToughButterCup Posted January 10, 2017 Author Share Posted January 10, 2017 3 minutes ago, Stones said: I take it the various different temporary tracks you can get wouldn't be suitable? No, @Stones, I imagine they wouldn't probably because the mat needs to take a dynamic stress . And the mat needs to be penetrable by the poker (stupid term for a humungous vibrating crane-mounted ramrod) Link to comment Share on other sites More sharing options...
Stones Posted January 10, 2017 Share Posted January 10, 2017 Sorry, should have picked up on that bit in your earlier post. Link to comment Share on other sites More sharing options...
swisscheese Posted January 11, 2017 Share Posted January 11, 2017 16 hours ago, recoveringacademic said: @swisscheese - have you noticed we are using 'ground improvement columns' NOT piles, but they appear to most people to be piles so we call them piles - in error. Have a look at this However, the piling mat is the same for both: I think. Notice the difference in the calculations for the depth needed if you use Polypropylene Geogrid Tensar SS20. You might like to ask for the calculations they have done showing the difference made by the grid: in our case 280mm instead of 480mm I do not wish to be seen to be advertising. Stone columns and piles are different beasts. Stone columns are significantly cheaper than steel piles. We have about 52 columns to insert. Start 0930. Finished - off site by 15:00 same day. @recoveringacademic - Yes I did spot you are using 'ground improvement columns' - these were never discussed for our project by engineers or contractors, possibly an oversight on our part, but you kind of only know what you know. - given ground conditions/trees piles were "recommended" I will check the mat calcs if they arrive- but I am also checking mat less piling solutions - smaller rigs etc and comparing prices against the cost of installing and the removing the engineered mat over what is a significant area for us. Link to comment Share on other sites More sharing options...
ToughButterCup Posted January 11, 2017 Author Share Posted January 11, 2017 Yes, exactly, you need to go through that exercise. 'Known unknowns and unknown unknowns' (God, how I loathed that bloke) We are on a small, but noticeable slope. That means that we can accommodate all our post-piling spoil. Might that work for you? Link to comment Share on other sites More sharing options...
swisscheese Posted January 11, 2017 Share Posted January 11, 2017 7 minutes ago, recoveringacademic said: Yes, exactly, you need to go through that exercise. 'Known unknowns and unknown unknowns' (God, how I loathed that bloke) We are on a small, but noticeable slope. That means that we can accommodate all our post-piling spoil. Might that work for you? Any actual clean soil/pile spoil I can "loose" over a farmers field, he has bit of a dip in it I can fill, but I would not be able to put any of the removed mat in the field, it would contain too much rubbish, the site is fairly odd shaped/tight so I don't really have space to hold it for reuse, that is a problem. Link to comment Share on other sites More sharing options...
Triassic Posted January 11, 2017 Share Posted January 11, 2017 (edited) I was wondering why you've gone down the stone column route, considering the rig mat requirements. in a previous life I manage a project where we installed poured concrete piles in difficult ground conditions using a mini rotary drilling rig, because of its smaller size no ground mats were required. Have you looked at alternative piling approaches and the total costs of each method? Edited January 11, 2017 by Triassic Link to comment Share on other sites More sharing options...
ToughButterCup Posted January 11, 2017 Author Share Posted January 11, 2017 Yes. It boils down to a combination of price, rig size, and piling design (in terms of kN per pile). Ian Link to comment Share on other sites More sharing options...
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