Quantity Take Off Methods

[passpepasspe]

I am studying for the AM portion of the PE exam, an I can't find where in the CERM are quanity take off methods?? what is that anyways? please let me know where is this material in the CERM?

 

[maryannette]

I don't know where in the CERM, but it refers to estimating quantities required for a construction project. For example, paving a mile of road would require so many CY of removal, so much area grading, an amount of fill, stone, asphalt, etc. That is very basic as an example, but that gives you an idea.

 

[passpepasspe]

I don't know where in the CERM, but it refers to estimating quantities required for a construction project. For example, paving a mile of road would require so many CY of removal, so much area grading, an amount of fill, stone, asphalt, etc. That is very basic as an example, but that gives you an idea.

I looked through my material and its not clear where these problems are, i know there are tons of examples in materials for cut and fill but not any other types of quantiies, any idea where the Concrete Masonry Unit problems might be.

 

[mallen]

I agree with you. I've been having a hard time finding problems for concrete quantity take off related problems.

 

[Dexman PE]

The only types of materials that have different take-off methods are earthwork quantities. There is the "average end" method in which you take 2 known cross-sectional areas, average them, then multiply by the distance between them. To use this method, you have to assume that the transition from one end to the other is a relatively smooth transition. For example, you have a 100' long roadway excavation. One end you have to cut down 5 feet for a width of 30 feet, and the other end you only have to cut 2 feet for a width of 50 feet. So you average the end areas ((5x30)+(2x50))/2 = 250/2 = 125, then multiply by the distance: 125x100' - 12,500 cubic feet. Now you just check the units to see what they want (typically cubic yards).

There are a few other methods for earthwork discussed in the CERM, and unfortunately I don't have my copy in front of me to go into more detail into the other earthwork takeoff methods.

Pretty much the rest of the quantity takeoff stuff you need to know would be things like: You have to build a concrete footer for a bridge that measures 2'high x 5'wide x 10'long. How many SF of forms are needed (obviously you just add up the outside areas, not including top and bottom)? Assuming a 5% waste, how many cubic yards of concrete (find the volume in CY, then multiply by 1.05)?

Thats pretty much it.

 

[andyrich]

I did not see much in the CERM on this point, though the Kaplan manual actually has a section on it. They merely note that earthwork is the most commong item requiring takeoff in construction. I actually disagree, because almoast everything in construction requires takeoff. But the previous poster makes a good point in that earthwork is the main item having multiple methods for takeoff.

* You may need to calculate roadway excavation volume. Here is a clarification regarding the two ways.

Average end area : Vol = (A1+A1)/2 x Length ; Where A1 and A2 are two end areas and length is distance between two.

Prismoidal Area : Vol = (A1 +4Am +A2)/6 x Length ; Where Am is the area at the midpoint of the length.

Here are a few other quatitiy takeoffs related to earthwork:

* Calculate the volume of a pile of soil. Which, by definition a pile is a conical shape based on the angle of repose.

* Calculate loose volume of soil

Other than earthwork, it seems the other takeoff methods should require logic moreso than formulas.

Anyone else have other thoghts about the takeoff requirement section on the morning exam?

 

[Patrick1441 PE]

An important skill to be prepared to exercise for quantity take-off problems is the ability to read and interpret plans. It's more than likely that the problem will be presented in the form of a typical cross-section of a footing, wall, or road surface.

They could ask you to compute the volume of concrete for a given cross-section and length. Basic base x width x length type stuff.

They could ask you to compute the weight of steel given a certain number of reinforcing bars spaced off center at a given length. Make sure you tab the reinforcing steel standards section of the CERM (Page 48-8 Table 48.2 in the 12th edition). They might not provide you with the unit weight of the different bars used in a problem, and this information is much easier to pull from that table than to compute manually.

They could ask you to compute the weight of steel given a length of W12x26 structural members. Know that the weight of any such structural member is the second number multiplied by the length (in this case, 26 x length).

If they ask any earthwork quantity questions, they could also ask for the number of trucks required to transport the required material. Remember to take into account any shrinkage or swell in the soil during excavation, loading, transport, and placement.

 

[Jayman_PE]

The CERM is almost void on this topic. Some of these problems can get pretty involved in the PM portion. Since you are asking about the AM only, I would not worry about it. The takeoff questions you will see on the AM will be elementary.

Jason

 

[desantmf]

Quantity Take off is the first step required when estimating costs for a project. As stated before you need to review plans/or narratives and be able to figure out how many CYs of soil must be moved, how many lbs of steel is required, how many CF of mortar is required, what is the square footage roof, etc, etc. Also it is not true; the Quantity take off on the AM could be the same difficulty as in the PM. However, the good news is that for the PM and AM portion it really is not that difficult, you just need to use a little bit of common sense. If you need some help or have questions please let me know below is a link to some information.

http://www.learncivilengineering.com/wp-content/uploads/2012/08/Quantity-Take-Off-Problems-and-Solutions.pdf

Mark

www.learncivilengineering.com

“Know where to find the information and how to use it – That’s the secret of success.” – Albert Einstein

 

[Jayman_PE]

Also it is not true; the Quantity take off on the AM could be the same difficulty as in the PM.

I wouldn't bank on it. The AM questions will be common sense. Definitely not something worth focusing on.

 

[desantmf]

Also it is not true; the Quantity take off on the AM could be the same difficulty as in the PM.

I wouldn't bank on it. The AM questions will be common sense. Definitely not something worth focusing on.

I would agrue that the Quantity take off in the PM is also just common sense. But then again, common sense is not that common :2cents:

 

[Jayman_PE]

Also it is not true; the Quantity take off on the AM could be the same difficulty as in the PM.

I wouldn't bank on it. The AM questions will be common sense. Definitely not something worth focusing on.

I would agrue that the Quantity take off in the PM is also just common sense. But then again, common sense is not that common :2cents:

So then you agree the AM takeoffs are likely common sense? That doesn't follow your first assertion. Confused.

 

[ptatohed]

Agreed that the quantity take-offs in the AM were a joke. Those were the "gimmees". Not much more difficult than calculating how many gallons of paint you need to repaint your house or how many tiles you need for your kitchen/bath or how much sod/sprinklers you need for your backyard, etc., etc...

 

[desantmf]

I always stated that the Quantity take-offs are relatively simple (common sense) however, I would still recommend for an engineer to review the topic for the AM portion before the exam. But definitely agree don’t spend more than an hour studying it…just understand a couple points and move on.

 

[Dexman PE PMP]

The important thing to remember when doing quantity take-offs is to read the entire question to get what they are actually asking for. One example is something along the lines of concrete formwork. Say you need to figure out how many sheets of plywood needed to build the concrete forms for a wall that is 5 feet high and 20 feet long and 1' thick. You will need to remember that sheets of plywood are 4'x8' and that you will need forms for both the front and back of the walls as well as forms for the ends. You won't need forms for the top or the bottom (unless otherwise stated in the problem).

These types of problems are not designed to confuse or trick you, they are just making sure you are thinking through the entire construction process.