Written in English — pages. Subjects Earthwork , Estimates. Estimating earthwork quantities , Norseman Pub. Not in Library. Libraries near you: WorldCat. Estimating earthwork quantities First published in Subjects Earthwork , Estimates. Edition Notes Includes index.
Classifications Dewey Decimal Class A85 The Physical Object Pagination p. Community Reviews 0 Feedback? Lists containing this Book.
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Professional Estimating. Author : Kimberley Ruth Corp. Professional Estimating Book Review:. Third, even after you've calculated the cost per hour and quantity of soil, you're not finished. You need to estimate the time needed. Usually that's the hardest part. To do it, you have to decide on the equipment method to use. Of course, the quantity of material yardage is a very important part of our cost formula.
But the excavation method type of equipment also has a major influence on cost. The most expensive equipment cost per hour will usually be the most productive move soil at the lowest cost. But the machine with the largest capacity isn't always the best choice for every outhaul. I'll explain why later. For now, just understand that making good equipment selections will help reduce costs. Nearly every significant excavation project that's let out for bid will be based on a set of plans.
Plans are scale drawings that show the finished project. Plans are supplemented with written descriptions called specifications specs for short. Specs explain in words what the plans can't or don't show. Ideally, the plans and specs, read together, should answer every question about the job.
They shouldn't leave anything unclear or subject to interpretation. The better the job done by the engineer or designer, the more likely the plans will be clear and complete. Plan reading is an important skill for every earthwork estimator. But this isn't a book on plan reading.
If you need help with reading plans, if you don't understand the plans and drawings in this manual, pay a visit to your local library. They'll probably have several basic plan-reading texts to choose from. As an excavation estimator, you're expected to understand every detail in the plans and specs for the jobs you bid.
That's why they're worth careful study. Read these documents completely. Note everything that affects your excavation work. Some engineers and architects aren't very well organized. They may put instructions and notes almost anywhere on the plans. Read every page carefully, regardless of what you think it's about.
Pay particular attention to notes that spell out the contractor's responsibility. For example, you may find a note somewhere on plans that relieves the engineer or architect of responsibility for damage to utility lines. The note probably says:. NOTE: While every precaution has been taken to show existing utilities in their proper location, it is the contractor's responsibility to determine their actual location.
No assumption should be made that no other utility lines fall within the limits of construction. If you suspect utility lines may be a problem, ask the utility companies to locate their lines for you. Most will be happy to do that at no cost.
But they may want ample advance notice. Also pay attention to notes on natural obstacles such as rock or anything that's buried on the site. Is there an abandoned underground storage tank or old basement in the area to be excavated?
The plans may also mention drainage problems and unsuitable soil deposits, probably in the cross-section drawings or special provisions of the specs. Search the plans and specs for everything that may affect cost. That's always your starting place. But it's not the end of your search. Many cost items won't show up in either the plans or specs.
For example, you'll have to find out from the city or county building department what permits will he required. Also, city, county or federal law may set minimums for wages, employee benefits and insurance coverage. Here's another pitfall to watch for: Who pays to have the project staked out by a surveyor or engineer? In most cases, the designer will pay for surveying - the first time.
If you knock over any survey stakes during actual work, you'll probably have to replace them at your own expense. Work as carefully around the stakes as possible. But if job layout makes it impossible to avoid moving stakes, allow enough in your bid to pay for another survey.
Make sure you understand how you'll be paid. On larger projects, you're usually paid per cubic yard, based on the difference between the original soil cross section and the cross section when work is finished. We'll talk more about cross sections later in this book. On many smaller projects, your payment may be based on the engineer's estimate of yardage. If that's the case, look for a provision in the specs that gives you an option to have final cross sections made at your own expense.
Experience will help you decide if a final set of cross sections is to your advantage. But I recommend that you always take off quantities yourself. Don't assume the plans are right. Anyone can make a mistake, but you could end up paying the price.
Undercutting is removing additional dirt from an area below the finished grade line. There are several situations where this is necessary. The most common is where a rock ledge is close to, but not above, the finished grade line. Figure shows a typical situation. Most structures can't be built directly on rock.
If the rock weren't there, you would excavate just to the finished grade line and be done. Because the rock is just below finished grade, you have to cut deeper. That's the undercut. Then you have to backfill with suitable material such as compacted dirt. The dirt provides a buffer between the rock and the foundation. Figure Undercutting for Rock.
There's probably nothing in the specifications that gives you the right to collect for undercutting and backfill. But it's expensive work and the cost shouldn't come out of your pocket. Where undercutting may be necessary, include it in your bid item per cubic yard cut.
Undercutting is also needed for underground utilities such as storm drains and sanitary sewer lines. Most plans will show only a designated flow line elevation. Based on the plans and judgment, you'll have to decide how much and what type of bedding to install below the pipe. Each cubic yard of bedding requires a cubic yard of undercutting. Figure shows an example. Undercutting may also be required on roads, parking lots and sidewalks anywhere there's a load on the soil. Overfilling is the opposite of undercutting.
When backfilling a large area, you can usually bring the backfill right to grade without doing any cutting away of excess backfill. But in a small area, it's usually easier to bring the area above the final grade line by 2 to 4 inches, then cut off the excess. This is still called undercutting.
Of course, you can't expect to get paid for removing the 2- to 4-inch excess. But it's still a cost of the job. Figure Undercutting for Pipe Bedding. Accuracy is the essence of estimating. If you can't work accurately, you're in the wrong business. But don't get me wrong.
I don't mean that we're going to account for every spadeful of soil on every estimate. There are times when you can ignore small differences in elevation.
On most jobs these small plus and minus areas will average out to almost nothing. But a 1-inch mistake in elevation over the whole job can cost you thousands of dollars. Here's an example. Assume you're bringing in fill on a city lot that measures feet by feet. Because of a mistake in grade, your estimate of imported soil is wrong. It leaves the entire site 1 inch below the specified finished grade.
How much more soil is needed to correct the 1-inch mistake? In this example, you know the length and width in feet but the depth is 1 inch. To use the formula, convert 1 inch to a decimal part of a foot. Either way, 1 inch equals 0. How many cubic yards is that? Since there are 27 cubic feet in a cubic yard, divide the cubic feet by Trucking in almost 58 cubic yards of soil won't be cheap.
That could make the difference between profit and loss on this job. The more organized and logical your estimating procedure, the more accurate your estimates will be. If you have the tools, papers and information you need close at hand, you're off to a good start. Then you can focus your attention and concentration on producing an accurate estimate.
If you're cramped for space, uncomfortable, and trying to work without all the equipment and information you need, errors are almost inevitable. Start by organizing an efficient work area.
It should be large enough so you can lay out all the plans on a table and still have room to write and calculate. Provide enough light to make reading comfortable, and keep the work area free of shadows.
This is especially important when working with transparent overlays or other light-duty paper where you might mistake shadows for lines. A good calculator is a must.
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