ASB 223 - Buried Civilizations of the Americas - Keith Kintigh

Activity #3, Construction Estimates

Passed Out 10/9; Due in Class 10/16

Archaeologists often find it useful to estimate the amount of labor that it would have taken to build a prehistoric monument (e.g., a mound or pyramid). The amount of labor required to build a monument can be used as a measure of the power of the person(s) who organized the construction; the ability to mobilize large numbers of people to work for extended periods of time suggests that whoever was in charge of the construction had a considerable amount of influence or power.

Because we live in a society in which large-scale construction is done with heavy equipment, we are not very sensitive to the effort that is required to create large structures using only human labor. In this exercise, we want you to estimate the labor that would have been required to build a mound of earth the size of a building here on the ASU campus. Hopefully, after estimating the labor involved in building a monument the size of a familiar building, you will have a better appreciation for the amount of labor that was organized to build less-familiar ancient monuments.

The building you are to use is Wells Fargo Arena. Wells Fargo Arena is the round building just east of Sun Devil Stadium on Stadium Drive. We want you to estimate the labor that would be required to build a mound of earth the size of the Arena. To do this, you will need to follow these steps:

1) Measure the circumference of the Wells Fargo Arena by counting your paces as you walk around it. For the average person, a slightly exaggerated stride will be equal to about 1 yard. You might want to measure your pace with a measuring tape before you pace off the building.

2) Given that the building is 23.3 yards high (67'), calculate the volume of the building. The formula for computing the volume of a cylinder is

V = H p (C/(2 p))2 = HC2/(4 p))

p = 3.14

C = circumference (the number of paces [yards] you counted)

H = height of the building (23.3 yards)

This calculation will give you the volume of the arena in cubic yards (yd3).

3) The preceramic site of El Paraiso was estimated to have 340,000m of fill. The conical pyramid at La Venta may be estimated to have on the order of 4,000,000m of fill. As 1m=1.3yd, this means that El Paraiso is about 445,000yd and La Venta about 5,200,000yd. How many times larger (or smaller) is the arena than each of these monuments?

4) Now that you have a volume estimate for the building, calculate the labor required to build a mound of earth of this size. Archaeologists measure labor in terms of person hours (PH), which is a unit equal to the labor of one person working for one hour.

There are two steps involved in constructing an earth mound: procuring the earth (digging it out of the ground) and moving the earth to the place where you want to build.

It takes 1.5 PH to procure 1 yd3 of earth.

It takes 0.65 PH to move 1 yd3 of earth 100 feet.

5) Assuming that the dirt has to be moved 2000 feet (a little less than half a mile), use these constants to calculate the number of person hours required to build a mound of earth the size of the arena.

6) Finally, calculate how many days or years it would take for 100 people working 8 hours a day to build the mound. Answers must be typed; show your work.

When you have completed your calculations, revisit the Wells Fargo Arena and take a moment to appreciate its size. Make a mental note of the labor involved in building a mound of this size; we will use this mound as a scale to help you appreciate the immense size of some of the prehistoric monuments we discuss in class.