Page 53 - Pipeline Rules of Thumb Handbook

40 Pipeline Rules of Thumb Handbook

CONCRETE WORK

How to approximate sacks of cement needed to fill a form

To obtain a close estimate of the number of sacks of cement Example. How many 94-pound sacks of cement will be
that will be required, first determine the volume (cubic feet) required to fill a form for a concrete base 10 feet by 10 feet
to be filled in the form. Divide the volume by 4.86 to approx- if it is to be 6 inches thick?
imate the number of sacks of cement needed.
¥
.
10 10 ¥ 0 5
.
= 10 3, or 11 sacks needed.
.
486

What you should know about mixing and finishing concrete

To determine proper mix, divide the constant 44 by the S=6.28 ¥¥ 0 035
2
.
sum of the parts of cement, the parts of sand, and parts of = 044 cubic yard of sand
.
gravel to determine the number of bags of Portland cement G =6.28 ¥¥ 0 035
4
.
required. Multiply the number of bags of cement as deter-
.
mined above by parts of sand and the constant 0.035 to = 088 cubic yard of gravel
calculate the number of cubic yards of sand needed. To deter-
mine cubic yards of gravel needed, multiply bags of cement To increase or decrease slump of concrete, add or subtract
by parts of gravel ¥ 0.035. one gallon of water per cubic yard of mix and subtract or add
20 pounds of aggregate to maintain yield.
Example. Calculate the quantities of cement, sand, and To adjust from no air to air-entrained concrete and main-
1
gravel required for one cubic yard of 1:2:4 concrete. tain strength, reduce water / 4 gallon per sack of cement and
reduce sand 10 pounds per sack of cement for each 1% of
44 entrained air.
C =
++ 4
12
.
= 628 bags of cement

PIPE LAYING

How to determine the degrees of bend in a pipe that must fit a ditch calling for a bend in both
horizontal and vertical planes

Rule. To find the number of degrees in the combination X = 25
2
bend, square the side bend and the sag or overbend; add them
5
together and extract the square root. The answer will be the X =∞
number of degrees necessary to make the pipe fit the ditch.
Example. Determine the bend to make in a pipe whose
ditch has a 9° sag and 12° sidebend. Let X = the unknown
Example. Determine the bend to make in a pipe whose
ditch has a 3° overbend and a 4° sidebend. Let X = the angle:
unknown angle:
2
2
X = 9 + 12 2
2
2
2
X = 3 + 4 2 X = 225
2
916
X =+ X 15∞
=