Grading A, B, C for Landscape Architects

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Intro/TOC

• The Basics of Grading
• Determining Slope
• Communicating Slope as Percent or Ratio
• Grading Techniques
• Contour Interpolation
• Strategies for Using the Land F/X Tools on a Plan

0:00 – 6:25: Intro/TOC

Importance of an accurate grading design (2:58)

• Accessibility
• Opportunities for universal access, not just wheelchairs but also limited mobility or children, can ensure the longevity of a design.
• Safety
• Impact of ice on a design
• Planning for accidental falls
• Drainage
• Positive flow
• No pooling (unless desired)
• Interest and aesthetics
• Flat park vs. rolling hills
• Loss in profits
• Extras for mistakes or impossible plans
• Future jobs

Other grading resources (5:46):

• Site Engineering for Landscape Architects by S. Strom, K. Nathan, and J. Woland
• Grading by Peter Petschek

6:26 – 25:27: The Basics of Grading

Determining Slope (6:26)

Grading is determining and communicating a slope equation.

Slope = Rise / Run

Other common terms:

• Grade
• Pitch
• Fall

Communicating Slope as Percent or Ratio (8:25)

Communicating slope as percent (8:25)

Slope percentage = Rise / Run x 100%

Run = Rise / Slope

Rise = Slope x Run

Example:

40% = 4 / 10 x 100%

10 = 4 / 0.4

4 = 0.4 x 10

Communicating grading as ratio (12:15)

Run : Rise (10 : 4, 5 : 1)

What about Land F/X? (14:15)

• Land F/X grading tools automate this calculation in our communication tools.
• Use them to get initial slopes, help make decisions, automate the scale and standards of your grading callouts, and check your design.
• It’s a tool. You still need to know how to grade.

Common percentages and rations while grading (15:53)

• 0%: Doesn’t drain. Areas with a contained material, such as mulch or sand in a playground, need subsurface drainage at one of the following grades.
• 0.5%: Drains flat concrete, commonly used for ball play surfaces.
• 1%: Drains asphalt, other hard surfaces.
• 2%, 3%, 4%, 5%: Drains grass, other soft surfaces, or aggregates. Over 5% (1:20) usually denotes when a walkway is considered a ramp and needs landings.
• 8.333% (12:1): Common max slope for walking/chair ramps with landings.
• 10% – 33% (10:1 – 3:1): Common slopes for soft areas, grass/planting.
• 33% (3:1): Typically max slope for mowed grass area.
• 40% – 100% (2.5:1 – 1.1): Slopes only for vegetated or otherwise reinforced slopes. Use caution, and design according to the slope.

(Note that these are just general guidelines. Check your local regulations for official grading standards.)

Grading Techniques (19:35)

It’s about moving people or water. Your job is to be creative, accurate, effective, and efficient.

• Pitched slopes
• Crowned
• Hipped crown
• Hipped funnel
• Soft crown

Summary:

• Use pitches, funneling/ channeling to your advantage to move water around the site while respecting the needs of people/cars.
• Respect the constraints of your site.
• Elevation at property line needs to stay the same.
• You usually can’t change the flow of water off your property.
• Know the limiting factor – existing house, or pinch point along property line?
• Look up local by-laws. Is the max ramp slope 8% where you are? How high can retaining walls be before you need a railing?

Contour Interpolation (23:37)

• If you were to slice the land horizontally, the line would show where the slice intersects the land.
• Interpolation is choosing the elevation of that slice and determining where it slices the land between two elevation points.

25:28 – end: Strategies for Using the Land F/X Tools on a Plan

Think about:

• Existing flow.
• Drain away from buildings and pools.
• Minimums and maximums.
• No pooling against garden walls.
• Cross/sheet or crown?
• Swales? Catch basins / drains?
• No change to property line.

Grading in CAD with Land F/X (30:47)

Grading tools (Spot Elevation and Slope Callout) (30:58)

Placing a Spot Elevation callout (32:07)

Placing a Slope Callout (33:00)

If your drawing includes contours that don’t include elevations, we recommend clicking on them and adding the correct elevations in the Properties panel. (33:54)

If you click on a polyline that has an elevation and snap to it while creating a Spot Elevation, the Spot Elevation tool will assign that elevation automatically. (34:21)

Creating a contour interpolation (36:10)

Calculating the slope between two Spot Elevations using our Slope Callout tool (38:00)

Placing a Spot Elevation callout relative to an existing one (38:50)

Changing the Spot Elevation style (example: proposed vs. existing) (40:12)

Grading/draining around a building (42:00)

Putting additional elevation points into a Spot Elevation (45:35)

Grading between contours using relative callouts (46:40)

Grading a swale (49:00)

Confirming that a grading design fits the intent and needs of the site design (51:00)

Placing Spot Elevations at a set distance from each other automatically throughout the design (51:10)

Overview of the grading of the rest of the site (52:40)

Sheet draining (troubleshooting to eliminate pooling) (54:26)

Preparing the site to move into 3D (56:00)

WBLOCKing the design (56:40)

Using the FX_SPOTELEVATIONZALIGN tool to assign the blocks with Z elevations (57:07)

Importing the design into SketchUp (57:30)

More on the FX_SPOTELEVATIONZALIGN feature (1:01:10)

Importing linework into SketchUp (1:03:00)