I have a set of plans that I am trying to quote for a new Rite Aid store and the geo tech report say's that the footing of the new buiding should sit on piles because the existing soil is loose fine sand. The specs: For preliminarily design, an allowable load of 30000 pounds for an 8 inch diameter tip, 50 foot long pile is recommended. Piles should be spaced no closer than 4 feet center to center. What is column and grade beam subgrade? Do they poor a footing over the piles? What is a grade beam? If the piles are 50' long do you drive piles in at 10' long pieces? Has anyone done this type of work? if so whats involved? Ho-pac on 200 size machine? Building is around 15,000 sq foot. Any idea on cost? Any info would be very appreciated. John
I don't have all the answers, but I can explain column and grade beam. (Even got a picture. :wink2 ) A grade beam is essentially just a heavily constructed footer. In the cases I've dealt with them the building pad has been brought to rough grade, and then a drilling rig has bored vertical holes, (which are whatever diameter is specified, and reinforced as specified, and sometimes kept in a metal casing, and sometimes not, depending on how stable the soil is.) In this part of the world, we call them caissons. I can't say whether that's the universal term for them or not. I've never dealt with driven piles, but I imagine the end result (at the top of the piles), would be similar. Once the piles are in place, I've had the job of digging for the grade beam. It's essentially like connecting the dots--you dig from one to the other to the other, etc. Rebar is placed both in the top and bottom of the concrete. I'm not sure you could drive piles with a hoepack. How would you keep them plumb while driving them? The pic is of a building I worked on in about 79. I dug the trench for the grade beam. The pic shows flood damage from the aftermath of the hurriicane in Sept 04. You can see the caissons, and the grade beam spanning from one to the next. As you can see, the concrete was just poured into the trench, but there was some formwork in place near the top of the trench to keep it contained. The masonry wall of the building rests on the grade beam. This building has the floor slab right at grade, so there is no basement. One other one I worked on (actually the condo building with the sprinkler system I mentioned in the "confessions" thread) had the caissons drilled and poured to just below basement floor level. The grade beam was then formed and poured on top of them, and is actually the bottom four feet of the basement walls.
Thanks Digger, that helps, sound like something that I would sub out to a drilling rig because the piles go down 50'. The holes would be filled with concrete correct? The job is just in the quoting stages for me to the GC so he hasn't even been awarded the job so until that happens I would not be awarded the job unless my price was the best. I put in a extra 30,000 to my quote, so I think that would be enough to cover the exspense of the drilling sub. I would not be responsible for concrete. The job also includes taking down 7 houses and garages made of brick and wood frame and clearing land for new store, site work, utilities, subgrade, subase, and than taking down old store for parking lot. A very large job for me, infact the largest that I have quoted so far. I think it would keep me going for 3 to 5 months. I have most of the equipment needed except water truck, 200 to 300 size excavator (mine is smaller) and large loader. It is nice to think about such a large project, maybe to large, my biggest fear is finacing so much money for 30 to 60 days, that IMO is the hardest part. If You come across any other info please let me know. John
Again, I have no direct experience with "piles", but the spec you quote, "For preliminarily design, an allowable load of 30000 pounds for an 8 inch diameter tip, 50 foot long pile is recommended. Piles should be spaced no closer than 4 feet center to center", sounds like a driven "pile" rather than a drilled caisson. Whether the engineer will see those two options as being equivalent is something you need to nail down. In my experience, piles are something that exist as one piece already, and are pounded into the ground as such. You need to get clear on which thing meets the specs. In either case, it would seem that the prints should call out specific locations for each pile or caisson--for example, at all the corners, and every so many feet in straight runs of grade beam. I'm not sure what to make of the, "no closer than 4 feet center to center", language. Who decides exactly how far apart they can be? The drilled caissons I described are holes bored into the ground, and then filled with concrete. I've seen them done as a simple hole, with no casing used at all, or as a hole drilled with a casing that's pulled out after the drilling, or as a hole where the casing is left in place. There have also been various rebar systems used in them; some have round cages built out of rebar that's placed and then poured around, and others have simply left a number of bars portruding from the top of the pour, and the bars for the grade beam are later tied on to them. I would NOT, " think that would be enough to cover the expense of the drilling sub." I don't have a clue as to what the cost would be, but I know those drill rigs don't come cheap. Nail that cost down as closely as you can before you make it part of your bid. Also, 50 feet deep in "loose fine sand" sounds like it could require casing--That's a long way down, in material that won't hold itself, especially if there's any water present, and you know steel isn't cheap these days.
i would think that a drilling sub would need a min. of 15k just to mobilize. i would call around and find a contractor that actually does that kind of work.
I agree with you guys, spoke to GC today trying to nail down what it was they are specifling and he calls me back tells me that the GEO SPEC book is for another site. So that makes it easier. I did not catch was a hydro dynamic seperator. Have you guys installed these before? I plan on leaving the extra money in the bid anyways, at this point I am the only bid for this GC for the site work, I am sure I missed something else that will eat the extra up, it always happens that way. thumbsup
No. Never heard of one before, so to learn, I Googled it. It doesn't look much more complicated to install than a manhole or septic tank. For your convenience, the results of my Googling: http://www.google.com/search?hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=hydrodynamic+separator&spell=1
Piles are drivin into the ground usally in one piece with a pile drive attachment mounted and a crawler crane down to a particular grade. Then a pile cap is poured over the cluster of piles. then the grade is brought up to the top of the pile cap where the grade beams are poured on top of the pile cap the the next pile cap bridging from one to a nother. There should be shopdrawing made for all this work this is not something you can just add a figure to cover your ass. This all had to be priced accordingly.
All I'am used to is marine pile driving but we never drive piles with 50' of penetration usually is only 20' at the most. If the ground is soft piles drive easy if you hit rock then your bending pipe. There are 3 types of pile driving using a set of pile driving leeds and a hammer or Hydraulic hammer or diesel fired hammer. Drilling holes and pouring concrete is easier kinda like drilling holes and using sonotube for Holding up your deck.
I installed one of these a while ago and the thing that stands out in my mind is the cussed tape they use to seal the joints.....:wink2 The pipe was 24" corrugated plastic storm line and they used the same couplings we used to use for joining that pipe together before the days of bell and spigot in plastic corrugated pipe.Those were the couplings that used the wire ties to hold them together. Anyway,their stratagy was to seal those couplings with a wide band of tape after you had them cinched down tight for a perfect seal and the install kit that came with the unit we used had two precut rolls of this heavy duty tape and as it turned out each roll was for a different size pipe that was part of the kit. Be SURE that you use the correct size tape for the joint you are sealing because that tape will NOT come apart or for that matter it is just about impossible to unstick it from anything it touches either.!!! The design we used had two round sumps at different elevations with pipes going back and forth between them at different elevations according to the the design of it and there were instruction sheets that explained everything as you went along. It is funny to me that this was probably 5 years ago and the thing that sticks in my mind was that damn tape,I never saw anything like it!!!LOL Ron G:bouncegri :bouncegri
Pile driving. Hi, Jmac. If they are talking about piles being driven into the sand, you are looking at a piling frame and drop hammer or diesel pile driver mounted on a crane capable of carrying both that rig and the pre-cast concrete pile at a reasonable working radius. I've had to drive 10 metre (33 foot) piles in the past and we used a 50 foot piling frame and a 6 ton diesel hammer mounted on a 28-ton track mounted crane working at around 16 foot radius. With 50 foot piles, you would be looking at a correspondingly bigger set-up with maybe a 50-ton tarck mounted crane. We had an adjustable stringer (Brace) from the front of the crane upper deck to the piling frame. This allowed us to put the piling frame base on the ground and walk the crane back or forward to get the pile vertical or raked as the case may be. Some of our piles were raked as they were in bridge abutments. We had to drive the piles to a certain resistance - till it took a certain number of blows from the hammer to drive the pile a set distance. It usually took about an hour to drive a pile around thirty feet and that included using a high pressure water spear down to around ten feet to start the pile. This water spear treatment was done before the pile was lowered into place and left a hole in the sand about 3" in diameter that helped keep the pile on track for the first few feet, after which it wasn't going to move out of line anyway. Hope this helps. Happy building. You have a wonderful day. Best wishes. Deas Plant.