Excavation & Grading Handbook Revised Overview
This new trusted reference has been completely updated to keep excavation contractors, operating engineers, and those learning the trade current with state-of-the-art equipment usage and the most efficient excavating and grading techniques.
You'll learn how to read topo maps, set crows feet, install water drain and sewer pipes, lay or remove asphaltic concrete, use a laser level, cut drainage channels, and use GPS and sonar for absolute precision.
Includes a CD-ROM with an interactive study center to help anyone brush up their skills or study for the license exam. Filled with hundreds of tips, pictures, and diagrams and tables every excavation contractor can use.
Explains how to handle all excavation, grading, compaction, paving and pipeline work: setting cut and fill stakes (with bubble and laser levels), working in rock, unsuitable material or mud, passing compaction tests, trenching around utility lines, setting grade pins and string line, removing or laying asphaltic concrete, widening roads, cutting channels, installing water, sewer, and drainage pipe.
Back Cover
This
is the revised edition of the popular reference manual used by over 25,000
excavation contractors and supervisors. It explains how to handle all types of
excavation, grading, paving, pipeline and compaction jobs: reading plans and
topo maps, following crows feet, setting cut and fill stakes, grade pins and
string line (with both conventional and laser levels), and actually doing the
work - whether it's a highway, subdivision, commercial, or trenching job.
Emphasis
is on solving practical problems: working with rock, unsuitable material and in
mud, widening rural roads, building narrow embankments, passing compaction
tests, working around utility lines, cutting drainage channels, trenching and
shoring. Three chapters explain how to lay, remove, or rip and compact asphaltic
concrete. Another four describe the best ways to install water, drain and sewer
pipe and construct manholes.
This
edition has been completely rewritten to cover new materials, equipment and
techniques: filter fabrics, laser levels, slip form pavers, curb machines and
reclaimers. It includes hundreds of tips, pictures, diagrams and tables that
every excavation contractor and supervisor can use.
Nicholas E. Capachi
has
over 30 years' experience as a contractor, foreman and superintendent on all
types of excavation, road and pipeline work, from interstate highways and sewer
trunk lines to subdivisions, industrial and commercial jobs and airport runways.
He's licensed both as a general engineering contractor and a sanitation systems
contractor and has been an active member of Operating Engineers Local 3 for over
20 years. Mr. Capachi and his wife Pat live in Sacramento, California.
Excavation & Grading Handbook Revised
Introduction
Understanding
Road Survey Stakes
This manual is a practical guide to excavation
and grading. It's written for anyone who has to plan, estimate or supervise
excavation and compaction for building sites, highways, drainage channels or
trenching. It also covers installation of water, sewer and drain pipe and the
laying of asphalt concrete pavement.
The first edition of this manual was published in
1978. Since then the book has gone through five printings and has been adopted
as the primary reference by many schools and in many apprentice training
programs. This second edition reflects the changes we've seen in the excavation
business since the mid-1970's. Equipment has changed, materials have changed and
the best way of getting the job done has changed. I had to make changes in every
chapter of the first edition to be sure this second edition describes good
current practice for excavation and grading contractors. In many cases I'm
indebted to readers of the first edition who made suggestions for improvements
or recommended alternate procedures. This second edition also includes new
chapters on using contour line drawings to control excavation, using laser
levels, and trench compaction.
I'm going to start by assuming that you're new to
excavation and grading. The first three chapters cover the basics: reading and
following survey stakes, understanding excavation plans and how excavation
contractors use contour line drawings. If you've been working in the excavation
and grading business for a while, you'll probably be able to skip the first few
chapters. But if you need information on plan reading and stake markings, it's
here for your use.
Now, let's get started at the beginning, reading
and following survey stakes.
Survey Stakes
Excavation for roads, buildings and pipelines
begins with a survey of the area where the excavation will be done. A survey
crew working for the engineering firm that's designing the project will set out
stakes and hubs which identify points that are on the construction plans.
When a precise distance or elevation is needed, a surveyor's tack on top of the
hub establishes the point from which elevations and distances are measured.
Beside each hub there will be an information
stake which explains in surveyor's code the grades at various distances from
the hub or other reference stake or point. It's essential that you know how to
read the markings on these information stakes and follow the instructions they
provide.
Figure 1-1 shows the kind of markings you'll find
on an information stake. Usually these are called cut or fill stakes,
depending on the type of excavation required. The front, back and both sides of
a cut stake are shown in Figure 1-1. Below the stake there's a cross section
drawing of the existing grade and final road grades that are described on the
stake. This drawing will help you understand the markings on the stake. Refer to
the drawing as I explain the markings on the information stake in Figure 1-1.
Figure 1-1
Cut Stake Reading
Cut Stakes
Look first at the stake labeled front in
the upper left of Figure 1-1. That's the front of the information stake. The RS
at the top of the stake means that there's a reference stake to be
established, and that reference stake is the point from which measurements and
elevations are taken. Find the reference stake in the drawing. It's labeled RS
and is just to the left of the hub at the right edge. Below the letters RS
on the stake, you see the letter C and a dash followed by some numbers.
Below that you see a diagonal line and some more numbers. These markings above
and below the diagonal line identify the amount of cut and distance needed to
establish the correct grade at the reference stake. The number above the line is
the elevation and the number below the line is the distance. In this case, the
reference stake shows a cut 1 foot and zero tenths of a foot below the
level of the surveyor's hub, 5 feet and zero tenths of a foot from the hub.
Some surveyors may use RP instead of RS.
RP means reference point. Treat it exactly the same as the RS.
Notice that distances and elevations are measured
in feet and tenths (or hundredths) of a foot, not feet and inches. The small
number above the small horizontal line shows decimals of a foot. That's a little
different from what you're probably used to, but you'll appreciate the
difference when adding and subtracting feet and decimals of a foot rather than
feet, inches and fractions of an inch. I'll explain more about this measuring
system, called engineer's measure, later in this chapter.
The two horizontal lines below the first set of
measurements are very important. All measurements above the double horizontal
line are taken from the hub beside the information stake. The double horizontal
line means and then, indicating that all measurements and elevations from
that point down on the stake are taken from the RS point and not the hub. Note
this very carefully: if the double horizontal line were replaced with a single
horizontal line, all measurements and elevations would be taken from the
surveyor's hub rather than a reference stake established. The next information
on this stake shows the elevation and location of the ditch cut. It's to be 10
feet lower than the RS point and 20 feet from it. The grade falls 10 feet over a
horizontal distance of 20 feet, thus creating a 2:1 slope. You'll see this
indicated on the drawing. For every foot of cut, the grade line moves
horizontally 2 feet.
Notice that all measurements are made from the
reference stake. The ditch is cut 10 feet below the reference stake and 20 feet
from that stake. Also note that the 20 foot distance is measured horizontally,
not diagonally, from the reference stake. Glance at the drawing to be sure you
understand how the 20 foot distance to the ditch is measured.
The next reading is the hinge point (HP)
grade and distance. Note the hinge point on Figure 1-1. It's cut 2 feet above
the ditch cut. The HP information indicates the grade must come up 2 feet and
move out 4 feet. By computing the amount the HP rises from the ditch and the
distance it moves towards the center of the road, you can see that it's again a
2:1 slope. Reading down the information stake, the next grade and distance is
the edge of pavement (EP) point. The grade will be 7.9 feet below the
reference stake. Notice the cut at EP is 0.10-foot less than the HP. The reason
for this is that the road grade rises 2% in the 5 feet from HP to EP.
Multiplying 5 feet by 2% gives the amount the shoulder rises in that distance
(5.00 x .02 = .10).
The next markings give the centerline cut. You
can see that the cut is again less than the previous cut at EP. Subtracting the
29 feet at EP from the 49 feet to the centerline leaves 20 feet. So the
centerline is 49 feet from RS and 20 feet from EP. The cut at the centerline is
0.40 foot higher than EP, giving a 2% slope from the centerline to EP. This is
computed by multiplying the 20 feet by 2% (20.00 x .02 = .40).
Look at the back of the cut stake. It's marked 3
+ 50, indicating that this station is 350 feet from station 0 + 00, the point
from which the survey began. Below the station number is the distance from the
surveyor's hub to the center of the road. This includes 5 feet to the RS and 49
feet from the RS to the centerline, a total of 54 feet.
Now note the first stake marked side. This
side of the stake identifies the percentage of slope from the centerline to HP.
The minus sign indicates that the centerline slopes down to the HP. If it were a
plus sign instead, the centerline would be sloping up to the HP. The
second stake marked side first gives the rate the cut slope falls from RS
to the ditch. In this case, it is 2 feet out for every foot downward. The second
group of numbers is the elevation of the hub above sea level.
Figure 1-2
Comparing Inches and Decimals of a Foot
Comparison of inches and decimals of a
foot- Notice that all measurements are in feet and tenths of a
foot rather than feet and inches. Setting grades requires many additions and
subtractions. Using decimals speeds the work and makes errors less likely.
Figure 1-2 compares inches with decimals of a foot.
If you're
uncomfortable reading distances in tenths and hundredths of a foot, think of one
foot as being like a dollar bill. One dollar is the same value as 100 pennies;
one foot is the same distance as 100 hundredths of a foot. One dollar is the
same value as 10 dimes; a foot is the same distance as 10 tenths of a foot.
Pennies are hundredths. Dimes are tenths or ten hundredths.
Fill Stakes
Figure
1-1 shows a cut stake where material must be excavated to reduce the existing
grade to the finish grade. Figure 1-3 shows a typical fill situation where soil
has to be deposited to build up the existing grade. Again, the illustration
shows four sides of the stake and the road cross section. The RS means
that the reference stake (to the right of the hub) is the starting point and the
place from which all measurements and grades are measured. The cuts and fills
given for the RS point will be measured from the hub. Here, the RS is located
1.8 feet above the hub and 3 feet from it. The grade setter will have to set the
reference stake the indicated horizontal distance from the hub and draw a
horizontal line on the stake at the elevation given on the surveyor's
information stake. Or he may elect to place his own hub there.
Reading
down the stake, the two horizontal lines mean and then, indicating that
the grade setter must measure from the RS point for the next fill and distance
given instead of measuring or shooting grades from the original hub. For the hinge
point (HP), measure 10 feet from the RS hub or lath. At this point a fill of
5 feet must be made to obtain the required grade. The hinge point is the place
where the fill slope stops and the road grade begins. It's sometimes called the catch
point. Next, reading down the stake, is the EP. This is the edge of the
pavement and has a F-5.12 fill 14.0 feet from RS.
Below the
EP data is PG. This is the projected centerline grade. In most cases, the
surveyors will mark it as the centerline and not PG. From the RS, measure 32
feet and fill 5.66 feet. This will put the PG or centerline 18 feet from the EP
and 0.54 of a foot higher.
Figure
1-3
Fill Stake Reading
The
stake marked back has a 25 and a little worm line standing for + 00. Some
jobs might have an A, B, C line with one being at the centerline. Check the
plans to learn what these lines mean. The 25 + 00 identifies this stake as being
2,500 feet down the line from the point where the measurements started. The
point the surveyors start from is most likely marked 0 + 00, but may not be in
all cases.
Next,
reading down, notice a C and an L, one over the other. This means centerline.
The number 35 below that means that the center of the road is 35 feet from
that point. Look back to the stake
marked front and notice that when the RS distance of 3 feet is added to
the PG distance of 32 feet, the total is 35 feet, the same distance as marked on
the back.
The stake labeled side is marked SE-3.00%.
This is the percentage that the road bed slopes from the centerline to the hinge
point. On the far right stake marked side. the first reading is 2:1 (two
to one). This is the rate the fill slope will rise from RS to HP. Notice that
the first stake has a 5 foot fill over a 10 foot distance. This is what the 2:1
indicates. The next item down the stake is EL 96.6. This is the elevation of the
hub at the information stake. All cuts or fills were computed from that hub by
the surveyors.
What I've described so far in this chapter is
more or less standard procedure for indicating elevations and distances on road
stakes. However, surveyors in some counties and cities follow slightly different
procedures. Some surveyors provide more information on the stakes. The stakes in
Figure 1-4 show what you might see on some county or city road stakes.
The top of the stake has a 2 with a circle around
it. This indicates that the first cut starts 2 feet out. The next markings
indicate that the cut is 4 feet at 10 feet from the stake. The slope will again
be 2:1 because the first 2 feet are not cut and the cut over the next 8 feet is
4 feet. Look at Figure 1-4 again. Notice that there is no double and then line.
This means that you must take all measurements and grade shots from the hub set
by the surveyors rather than from an RS or RP point as on the previous stakes
shown.
Reading down the stake at the left in Figure 1-4,
we find a second group of numbers that shows the top of the shoulder cut. This
was referred to as the HP, or hinge point, on previous stakes. Notice there's no
EP distance or elevation on the stake. In this case, you must look at the plans
for the distance from shoulder to edge of pavement, and the elevation.
Engineering companies follow different
conventions when marking their stakes. But the plans should clarify what is
intended and which points are actually indicated. If something isn't clear,
don't guess. Call the engineering company that created the drawing and marked
the stakes. They should be eager to help.
The
second illustration in Figure 1-4 is the back of the stake. It shows the rate of
fall of the cut slope (2:1) and the station number (8 + 00). The far right
illustration is the side of the stake. It gives the elevation above sea level
(EL 82.56). In some cases the hub elevation will not be on the stake at all. It
may be replaced with the percentage of slope on the road or both may be omitted
entirely. The back of the stake in Figure 1-4 will still have the station number
but no centerline distance because all the front measurements are from the hub
and not an RS or RP point.
Many
stakes have very little information. They have just the details required to
allow you to set the grades. These stakes always have the station number on the
back, though the percentage of slope and hub elevation may be absent.
Miscellaneous Information Stakes
Curb stake- Note Figure 1-5.
The stake at the left is what you'd expect the surveyor to set for cutting and
setting curb grades. From the hub at the base of this information stake, move
out 5 feet and down 1.50 feet to the top of the curb to set the curb forms.
In some cases, the surveyors will give the front
lip grade or even the flow line grade. If not, you 'II have to determine the
distance from the back of the curb to the lip. This information is available in
the plans. When setting curb subgrade, determine the thickness of the curb plus
any aggregate base, if it's called for under the curb. The thickness of one or
both must be added to the cuts and subtracted from the fills to find the
subgrade rather than the finished grade level.
Street stake- The center
stake in Figure 1-5 is a stake you would expect to find in a subdivision for the
first road cut. The front of the stake indicates the centerline of the street,
and the cut or fill to the finished grade. In this case, there's a 2 foot cut to
the finished grade (F.G.). The plans should show the road width, percentage of
slope or crown, and the thickness of the road section. Remember to add the
thickness of the road to this cut. The station number will be on the back of the
street stake.
Ditch channel stake- The
stake at the far right in Figure 1-5 is a grade stake for a ditch or small
channel. The 3 in a circle is the distance from the hub where the first cut
starts. The west toe grade indicates the first slope and the bottom of
that slope. The east toe is the bottom of the slope on the opposite side
of the ditch. Both toe cuts are the same, so the bottom is flat. The east top
cut is where the cut will be started on the opposite side. Subtracting the 3
foot offset from the 23 feet distance to the east top cut gives the distance
across the top of the ditch, 20 feet. Subtract the small toe distance from the
larger. This gives the width of the ditch bottom, 4 feet.
To find the rate of slope from the top cut to the
toe of the channel, subtract the distance given to the top cut from the distance
given to the toe cut. The 3-foot offset must be subtracted from the west side
distance of 11 feet. This will make the distance 8 feet from top cut to toe on
each side. Dividing the cut of 8 feet into the 8 foot horizontal distance gives
an answer of 1. This indicates that for every foot cut vertically, the slope
moves out 1 foot horizontally. That's a 1:1 slope.
A stake with only a few markings will usually
provide all the information you need to do the excavation. If something is still
unclear, the plans should have the answer you're looking for.
In this chapter we've described grades by either
a ratio of run to rise, or as a percent above the horizontal. Most grades in
excavation work are expressed as a ratio of horizontal distance (run) to
vertical distance (rise). Figure 1-6 illustrates the four most common slope
rations, and should help you visualize most of the slopes you work with in
excavation.
If you’re still confused about the work
required after reading the surveyor’s stakes and checking the plans, ask the
survey crew about it if they’re still on the job.
If they’ve left, call the engineer and have him clarify the problem or
send the survey crew out for a field meeting. Be sure you know what’s
required before beginning the work.
Figure 1-6
Slopes 1:1 to 4:1
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