3. Grading in landscape architectural construction and civil engineering is
the work of ensuring a level base or one with a specified slope for a
road or a railway or landscape and garden improvements or surface
drainage.
Landscape grading adds a gentle slope to the site to encourage proper
drainage and beauty using the contours of the site.
Landscape grading for adequate drainage is not the most visible portion
of the site but starting with these essentials is very important for the
overall health and look of the site.
5. STANDARDS
Abbreviations on Grading Plans
Methods of Expressing Slope
Percentage (of Slope)
Proportion (of Slope)
Degree (of Slope)
Spot Elevations
Making a Contour Map
• Field Survey
• Plotting Contours
6. ABBREVIATIONS ON
GRADING PLANS
Abbreviation - Meaning
CI - Contour interval
TC - Top of curb
BC - Bottom of curb (include spot elevation)
TW - Top of wall (include spot elevation)
BW - Bottom of wall (include spot elevation)
HP - High point (include spot elevation)
LP - Low point (include spot elevation)
TS - Top of steps (include spot elevation)
BS - Bottom of steps (include spot elevation)
7. ABBREVIATIONS ON
GRADING PLANS
BS - Bottom of steps (include spot
elevation)
IE - Invert elevation (include spot
elevation)
RE - Rim elevation
DI - Drain inlet (needs RE and IE)
SD - Storm drain (needs RE and IE)
MH - Manhole (needs RE and IE)
CB - Catch basin (needs RE and IE)
PL - Property line
ROW - Right of way
8. METHODS OF EXPRESSING
SLOPE
Slope is expressed in terms of a percentage,
a proportional ratio, or a degree of slope.
Percentage (of Slope):
Percentage of slope is expressed as the
number of meters (feet) rise in 100 m (100
ft) of horizontal distance, typically referred
to as rise/run . If the slope rises 2 m (2 ft) in
100 m (100 ft), it is considered a 2 percent
slope . The percentage of slope can be calculated
9. by the following formula :
G = (D/L)X100
where D = vertical rise, mm (ft)
L = horizontal distance, mm (ft)
G = gradient,
Proportion (of Slope) :
Slope can also be expressed as a ratio of the
horizontal distance to the vertical rise, such
as three to one (3 :1) . The ratio method is
used typically for slopes 4 :1 (25%) or
steeper.
10. Degree (of Slope):
Slope is expressed in degrees only on large scale
earth-moving projects such as strip mining
and other extractive operations .
Spot elevation :
Spot elevations are used to establish limits
of slope, to locate contour lines, and to
provide detail for establishing control
points that cannot be obtained via contour
lines .
The elevation of any point on an accurately
drawn contour plan may be determined
by interpolation .
11. MAKING A CONTOUR MAP
This process has two steps:
1. Field survey
2. Plotting contour
Field survey is done first.
All intersection points of a grid are marked
on the ground with temporary stakes ; the
elevations of each intersection point are
taken with a transit or level and the elevation
data is plotted on a gridded plan of the
site
12. MAKING A CONTOUR MAP
Plotting Contours :
Once all spot elevations have been determined,
contours at regular intervals [typically
1000 mm, 500 mm, or 250 mm (5 ft,
2 ft, or 1 ft)] can be located and plotted on
a map.
13. GRADING CONCEPTS
Schematic Grading Alternatives for a
Schematic Grading Alternatives for open areas
Preparing a Site Grading Plan
• Site Analysis
• Site Use Concept
•
Schematic Grading Alternatives for a
Schematic Grading Alternatives for
Preparing a Site Grading Plan
• Site Analysis
• Site Use Concept
Schematic Grading Alternatives for a defined area
Schematic Grading Alternatives for
Preparing a Site Grading Plan
• Site Analysis
• Site Use Concept
Schematic Grading Plan
• Grading by Spot Elevations
• Preliminary Cut-and-Fill Calculations
• Final Grading Plan
•
14. Schematic grading alternatives for a defined area :
Slopes of less than about 2 percent in the
open landscape appear flat to the human
eye . However, in areas adjacent to built
structures, even the slightest slope
becomes noticeable because of the relationship
of the grade to mortar joints, roof
lines, and other level architectural features
15. Schematic grading alternatives for open areas:
There are several ways to solve grading
problems when surrounding buildings do
not fully enclose an area to be graded and
there is sufficient peripheral space for transition
to surrounding areas . Such a wide
range of alternatives gives the designer the
opportunity to resolve aesthetic objectives
while solving the engineering problems
involved . These alternatives are especially
applicable to relatively flat surfaces, such
as tennis courts and other types of game
courts .
16. Preparing a site grading plan:
Grading of a site should be thought of as a
systematic process that begins with the
analysis and understanding of the existing
site and ends with an overall detailed grading
plan .
Site Analysis :
This process refers to study the general lay of the land by using
topographic maps and site visits .
1 . Determine high points, low points,
ridges, and valleys.
2 . Note natural drainage systems and
directions of flow that exist on the site .
17. Site Use Concept:
Determine how existing landforms would
affect proposed use areas, such as building
locations, roads, parking areas, walkways,
plazas, and lawn areas .
Schematic Grading Plan:
Define general use areas, set building floor
areas by spot elevations, and diagram
drainage flow using slope arrows pointing
along the direction of flow . This will help in
the following procedures :
1 . Developing a general landform concept .
2 . Locating swales and surface water flow.
3 . Locating drainage receptacles .
18. 4. Calculating water runoff for various
areas .
5 . Defining an area that could be altered
(raised or lowered) with limited impact
on drainage or existing trees . This area
could be used to help balance any surplus
cut or fill .
19. GRADING CRITERIA
General Landscape Elements
• Recommended Gradients
• Earth Fill against Buildings
Athletic Fields
Recommended Gradients for Outdoor
Sports
Baseball and Softball
Football/Soccer/Field Hockey
Court Games
20. GRADING CRITERIA
1 . The percentage of slope can be calculated by the following formula :
G=D/L X 100,
where D=vertical rise, L=horizontal distance, and G=gradient (%) .
2 . Grading of outdoor areas is aimed at controlling surface stormwater
runoff while
providing safe and efficient pedestrian and vehicular movement .
Essentially, all surfaces
should have some slope, or pitch, for proper drainage .
3 . Roadway design consists of two major phases : (1) alignment of the
road-giving it
21. GRADING CRITERIA
horizontal and vertical direction-and (2) grading the adjacent landscape to
the
road edge .
4 . Typically, swales are shallow, have a parabolic cross section, and are
very wide,
while ditches are deeper and have a narrower geometric configuration.
5 . Grass swales tend not to erode if velocities do not exceed 1 200
mm (4 ft) per second . If velocities exceed 1 800 mm (6 ft) per second,
then some
form of non vegetative material should be used to construct the swale,
such as
22. GRADING CRITERIA
gravel, crushed stone, or riprap.
6 . Several site grading techniques can be employed to limit the size,
shape, length,
and gradient of these slopes and channels, thereby reducing the volume
and velocity
of runoff 7 . The use of gravel, crushed stone, porous asphalt, or other
types of porous paving
allows either flatter or steeper gradients than bare soil, but their use may
not justify
radical changes from the grading and drainage standards normally used
in a region.
23. EARTHWORK PROCESS
Grading As Part of a Sequential
Design Process
• Preparation of the Site
• Excavation
Earth and Rock Moving Equipment
Information on Soil and Rock Material
• Sources of Information
• Typical Soil Profile
• Rock in Relation to Grading
• Swell and Shrinkage
• Weights of Soil and Rock Material
24. EARTHWORK PROCESS
Estimating Cut and Fill
General Considerations
• Estimating Required Grading
• Quantities
• Grid or Borrow Pit Method
• Average End-Area Method
• Contour Method
25. Grading As Part of a Sequential
Design Process
Preparation of the Site:
Clearing, Grubbing, and Removal of
designated trees and other types of vegetation
from an area to be graded .
Earth and Rock-Moving
Equipment
There are many types of equipment that
can be used to do grading .
Information on Soil and Rock
Material:
The initial site design and the eventual
grading plan should be prepared based
26. upon knowledge of the composition and
other characteristics of the soil and/or rock
to be moved. This data can be obtained in
a variety of ways, depending upon the level
of detail needed.
Sources of Information :
General soil data in the United States is
published by the U.S . Department of
Agriculture (USDA) and the National
Resource Conservation Service (NRCS) for
most states, on a county-by-county basis .
Specific information on soils can be
obtained by borings or test pits at selected
places on a site . These soil profiles can be
