We are getting ready to poor inverts in all our draniage boxes. I asked the new bossman how much he was going to order and he had no clue. He said he was going to order a yard at a time. I've been told before how to figure it, but we never usually do it, so I have forgotten. Can someone please tell me the equation? This is an example, not our actual box sizes.
A cubic yard is 27 cubic feet. A 3' X 3' X 3' box would hold exactly one yard. A slab 3' wide by 9' long by 1' thick would also hold exactly one yard. If the same slab were only 4" thick, it would only hold 1/3 yard, because 4" is one third of a foot. You follow me? In your example, the 150' by 50' slab would be 7,500 square feet, but since it's only 4" thick, you'd divide 7,500 by 3, to get 2,500 cubic feet. Divide that by 27. That gives you 92.59 cubic yards. For the round slab, you need to calculate the area. To find the area of something round you multiply Pi (3.14) times the square of the radius, which in this case is 2 feet. 3.14 X (2 x 2) = 12.56 square feet. Divide that by 3 (cause again, you're only 1/3 of a foot thick), and you get 4.19 cubic feet. Divide that by 27, and you get .15 yard. Orrr... You could just Google something like "concrete calculator" and come up with this really nifty site that lets you figure out a whole bunch of different size pours, and spits out the total for you. http://www.concretecrm.com/calculator.html (I never saw that before just now, but it's nice to know where to find it. It looks handy.) I don't know how it is there, but here you get billed a premium for a "short load" if you only get a little bit at a time. We figured out once that a one yard load costs about the same as four yards.
partial load charges will kill your wallet quick. It is much cheaper to get multiple pours ready before you call for a load. 5 yard min. around here. I am friends with a local redi-mix guy and it is still $50 partial charge.
My question is how this fellow got to be "bossman" in the first place if he can't even figure out how to measure and order concrete. I expect there will always be people who don't know, and they need educated, but to see someone put in charge who has not got a clue boggles my mind. What else does he do that way?? Does he know safety? That would be my first question. If not you and your crew could be at risk. I don't mean to go off on a rant, but what are the owners thinking?? His methods may well have them broke in no time.
That's what I was thinking, but then they probably took this job because of the economy - maybe he doesn't usually do this stuff. Either way - I don't know how he's going to order 1 yard at a time - that's pretty funny, it doesn't work like that.:lmao You'll have a thousand cold joints and the dispatcher will reach through the phone and choke his boss to death, especially if they are busy.
I always a little surprised at the number of experienced people I find in supervisory positions in the industry that can't figure volume. L x B x W...or, as I always try and explain it the area of the surface x the depth. Calculating volume of demo is a real art form.
We have a 3 yard minimum in my area .As far as figuring concrete,on small jobs I break it down to the cubic inch.A yard of concrete is 46,656 cubic inches.On bigger jobs we tell the concrete plant to start bringing concrete then when we get close to the end of the pour we will figure up the yardage for the last truck.On circles,I always square the diameter then multiply it by .785 then multiply in the depth to get the volume.The equation comes from the fact that a circle is 78.5 percent area of a square .48 x48x.785 x4= 7234.56 cubic inches of concrete or .155 of a yard.Dont worry N CarolinaDozer.If you run a little short they will bring you an extra yard to finnish up.On the bigger pour jobs they dont charge any extra for a finnish up yard of crete.Good luck with your concrete pour and stay cool as we are heading in to hot august weather!
I hear ya JD. I could be totally wrong, but it sounds like what we call a "post turtle". Now if your walking down a road, and you happen to see a box turtle sittin' on a fence post, you know he didn't get up on that post on his own. No, somebody had to put him up there. Which may be the case with your bossman, he's a post turtle...it ain't his skill or his knowledge that got him there...somebody put him there. All you can do is stand there an' scratch your head. And don't worry about the turtle, he ain't goin' no where, just do your thing and do it well.
ATCO That is a new term to me, and I like it. I will be on the lookout now for places to use it. Thanks
If you go to your concrete provider they will give you a slide rule to help you figure volume.I was a dispatcher for 12 years,I've had plenty of practice figuring concrete. I used a SR-50 TI calculator which I bought years ago when studying electronics.I still have it and use it after rebuilding the battery pack a while ago.It sure brings back memories although all it does now is figure out my bills.LOL.Ron G
tried it your way but gave up on the feet so did it in meters the way I am used to and came up with 71.118mts converted to yds by this http://joshmadison.com/software/download-convert-for-windows/ (allowing for rounding up at the 4th decimal) got 93 yds I had a different name for these people but the moderators would ban me for life if I tried to use them here ,but once again ATECOEQUIP has come to my rescue, post turtle I really like that. We have a 5mtr min here so even if I only need 3mts I always order the min quantity and it always gets used for some reason...
I was wondering what unit of measurement is used in metric countries. I figured it was probably meters.
a cubic meter is 1.308 yards , down load the convert a great little programme amazing what it does ..
Conversion software: I don't know if that software is still free but it the Duck's Guts for metric/imperial conversions. If anyone really needs it email me. You mean what unit of volume is used in Normal countries:cool2 The golden rule in these calcs is use all the same units...doesn't matter if its yards, metres, Hogsheads or slugs...what you start with you finish.
I thought Normal was a setting on a warshin' machine?
Fellas, I think there is more than meets the eye here. The way i see Jeremy's post, they are getting ready to pour flow channels. So this may not be a flat pour. Seems to me, this may be a little more difficult to figure. As not only do you have to figure your flat bottom, but also slopped sides. Not to mention, you have to take into account for loss, or extra material used by the nature of this pour, all hand poured, no forms.
Whos normal, my normal seems to be heavy duty. Even then, the wife still complains about greasy, dirty clothing. :beatsme
I think thats exactly the point. An experienced super wouldn't have a lot of trouble figuring that...because of his experience. Figuring the slump, loss, time, cost, order of trucks, resources required, procedure and all that other stuff (that requires much more than a volumetric calculation) is why the super is on the big bucks. and I'd like to know more about this warshin machine...is that used for compaction?
Normally. :yup
also don't forget they sell it by weight so if it pours rain the night before you could be a tad short no matter how good your math is.
LOL, and I'll spend the rest of my life checking each and every fence post I come across for a perched turtle.....
Huh? They may sell sand and gravel by weight, but when they mix it up together with cement, they call it concrete and sell it by the yard. At least around here. That's right. So if you come up half a yard short, you just have the driver add another half yard of water to the mix. ointhead Yes, yes. My mistake. That's what they use in normal countries, and in Australia. :tong
ointlaugh :exactly :falldownlaugh
They're rare to see. Usually a prank on the poor turtle by kids. You're much more likely to see one at any number of workplaces though...the upright walking version.
Digger The batch plants make up the concrete by weight. They know what each material weighs per yard. If it rains and the sand and rock is wet when it is scaled, the computer will think there is enough product in the drum for 9 yards, but it may only be 8 1/2 due to the extra weight of water. It will also throw the water/cement ratio off, causing rejected loads on some jobs with a tight spec.
Interesting. I'd never considered that. Most of my work has been residential, and truthfully, while I've poured lots of concrete, I've never had to pour something that was subject to possibly being rejected. (Probably fortunately.) The comment about adding another half yard of water, I made with tongue in cheek, but I've worked pouring footers with guys whose philosophy was to back the truck up to one corner of the house and wet it up enough that it ran the whole way around. I never thought that was right...
Ive had a few loads that were close on mud. Most of the time just needed a wheel barrow or two of mud to finish up, have something to screed around with. So I have had the driver add some water to wash mud off the fins giving me that little bit extra needed. Love it when the boss man orders tight to save himself a few buxs
Good batch plants also take the moisture content of the sand and aggregate into consideration and adjust for it.
Of course there is also a calculator that has up to 16 on the pad, http://www.jobbercalculator.com/index.htm , tried to get one even sent them a mail but they never acknowledged me .. maybe they only do local..
Dang I didn't know what I was starting when I asked this question! Turbo is right, we are pouring inverts inside of drainage boxes of all sizes. As far as the bossman, he was a finish grade operator who was turned into a bossman. I won't talk bad about him because he took me under his wing when I started opeating equipment five years ago. It's my fault aswell, because I should have known it to. We just never do this because the pipe crews usually do this before they leave the site. They were in a rush to go to another job, and left us a mess. Some of the boxes are more than 20 foot deep, so we have to crawl down into them. Thanks for all the help, my question is answered, so we can end this thread.
when they batch it here it is by weight so wet sand is heavier hence you get less and could be short. Add water and slump will change.
I know. I was being sarcastic. Well, if you're not experienced at it, here's a little more help--be sure to keep the mix stiff. If you're just pouring something with a flat bottom, it's not such a big headache if it's a little loose, but for inverts, you want to be able to build the sides up higher, and if it's too loose, you'll be really frustrated by the time you're done.
When the material is batched by weight the percentage of moisture is calculated and factored in to the total weight and the water is also adjusted to maintain the desired slump.The sand is the big concern,that is the bulk of the moisture adjustments will be made to the weight of the sand when batching.We considered 2% moisture as pretty wet. Another consideration in the colder climates is frozen material which is generally thawed using steam so moisture content is always a concern and can change several times a day.Ron G
The bit in green is very important.. Water Cement Ratio The relationship between W/C ratio and strength of hardened concrete is expressed by Abrarn's W/C ratio law, which states that, all other factors being equal, the strength of concrete varies as an inverse function of the W/C ratio. This may also be expressed as: the greater the dilution of the paste, the lower the strength of the hardened concrete. Admixtures Admixtures are sometimes used in order to improve certain qualities in a concrete mix. The most frequently used are: air entraining agents, plasticizers, and retarders. Air Entraining Agents: Entrained air reduces the water requirement of concrete mixes and improves the consistence and cohesiveness of fresh concrete. It also improves the frost resistance and general durability of hardened concrete, and its use is therefore recommended for all concrete which will be exposed to destructive weathering agencies. Plasticizers: The water content can be reduced while maintaining the same cement content and consistence; this results in a reduced water / cement ratio by about 10%. and therefore increased strength and improved durability. BETTER STUFF TO HAVE ADDED THAN WATER. Retarders: The length of time concrete remains workable depends on its temperature, consistence class, water / cement ratio and on the amount of retarder used. While the early strength of concrete is reduced by using a retarder which may affect formwork striking times, the 7 and 28 day strengths are not likely to be significantly affected. Note: Trial mixes using the cement, aggregates and admixtures in question, in the proportions to be used in the field, should always be made in order to evaluate the effect of the admixture.