I'm working on a house pad, coming up short on dirt. My question to you all is; what is the "best" way to estimate a fill quantity on a slope? Including swell/compaction. Are you guys pulling out your tape? Or are you shooting from the hip? This is a small house pad, split level. The extra cost is not in my bid by the way!
Can you calculate the area of a triangle? The cross section of a slope is just that. Measure the rise and the run. Divide the rise by 2 and multiply by the run. Then muliply by the length of the fill area. (this is assumiing a consistent slope. If the slope varies, you need to calculate multiple sections and take the average.) Do you calculations in cubic feet. Convert to cubic yards and then multiply by the swell factor to figure out how many yards of loose fill you need. What do you mean "extra cost is not in your bid"? Who's picking up the tab on this? Did you have an exclusion on bringing in material or specify working with onsite material only?
Ok, that's what I was going to start with as well. I'm going to base my swell at about 25% The extra cost means, I'm not responsible for any additional expense if additional fill is needed. Joispoi, you're quite knowledgeable, and have helped me out in the past. Keep it up my friend!
Another question, when an architect or engineer states soil quantities on a set of plans, BUT then states " grading contractor to confirm all soil quantities needed" how would you proceed with a bid? Would you hold the engineer to his numbers? Or put in your own numbers and hope there right.
The engineers like to add stuff like that to cover their butts. If they're way off base, then they can point the finger towards the contractor and say "...well he should have known better". And the truth is you do have to know better. You never know if an intern did the calculations or if they were performed by an ace. Best way to go about it is to list quantities. CY moved, sq. yds graded, miles trucked etc. If you get into additional work it cuts down the grey area and the customer's illusions of "I thought that it was included".
Set up your laser and take a few shots to see how much fill you need in certain areas. Then add them up and divide by the number of shots to get a avg. fill depth. Then multiply by length and width and divide by 27 to get cu. yds. Then multiply by your shrinkage.
Yup they do the same thing on state highway jobs. They give you the quanties with same stipulation. We usually go and cross section the whole job before we break ground to make sure they are right.
This is why it's a good idea to include a unit price schedule of values in any bid you submit. Often times on public projects, the bid form is based on a list of quantities provided by the engineer, you put a unit price to each line item and then add them all together for you "Total Base Bid". During the course of the project the actual quantities may vary, but you will be paid for each unit based on the unit price you bid. Sometimes it saves you, some times it bites you, but it typically keeps things pretty fair, and it provides the contract administrator with assurance that they are looking at "apples and apples" when reviewing the bids. I have learned from this practice, and always provide a schedule of values on private projects, that way everything is up front and if something changes there are no surprises for anyone.