Difference between revisions of "Grading"

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==Slope gradient==
==Expressing slope==
===Slope gradient===
Slope gradients are expressed as Y:X where Y is a single unit of rise and X is the corresponding run. It can be calculated by dividing the rise by the run:
Slope gradients are expressed as Y:X where Y is a single unit of rise and X is the corresponding run. It can be calculated by dividing the rise by the run:
e.g.:<math>\frac{rise}{run}=\frac{4\ m}{12\ m}=\frac{1}{3};we\ say\ the\ slope\ =1:3\ or\ 1\ in\ 3</math>
e.g.:<math>\frac{rise}{run}=\frac{4\ m}{12\ m}=\frac{1}{3};we\ say\ the\ slope\ =1:3\ or\ 1\ in\ 3</math>


==Slope percentage==
===Slope percentage===
Slope percentage is calculated similarly by dividing rise by run, but then multiplying by 100 to get a percentage:
Slope percentage is calculated similarly by dividing rise by run, but then multiplying by 100 to get a percentage:
e.g.:<math>slope=\left (\frac{rise}{run}\right )\times 100=\left(\frac{4\ m}{12\ m}\right)\times 100= 33\%</math>
e.g.:<math>slope=\left (\frac{rise}{run}\right )\times 100=\left(\frac{4\ m}{12\ m}\right)\times 100= 33\%</math>


==Slope in degrees==
===Slope in degrees===
Expressing a slope in degrees requires using the ''inverse tangent'' trigonometric function.  
Expressing a slope in degrees requires using the ''inverse tangent'' trigonometric function.  
e.g.:<math>\tan \theta =\left ( \frac{4\ m}{12\ m} \right ); \theta =\tan^{-1}\left ( 0.33 \right )=18.3^{\circ}</math>
e.g.:<math>\tan \theta =\left ( \frac{4\ m}{12\ m} \right ); \theta =\tan^{-1}\left ( 0.33 \right )=18.3^{\circ}</math>


<ref>Ontario. O. Reg. 191/11: INTEGRATED ACCESSIBILITY STANDARDS, 2011. https://www.ontario.ca/laws/regulation/r11191.</ref>
==Accessibility==
The Accessibility for Ontarians with Disabilities Act<ref>Ontario. O. Reg. 191/11: INTEGRATED ACCESSIBILITY STANDARDS, 2011. https://www.ontario.ca/laws/regulation/r11191.</ref> provides a foundation, a bare minimum to which public spaces must be designed.
 


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Revision as of 17:51, 19 October 2018

Theta.jpg

Expressing slope

Slope gradient

Slope gradients are expressed as Y:X where Y is a single unit of rise and X is the corresponding run. It can be calculated by dividing the rise by the run: e.g.:

Slope percentage

Slope percentage is calculated similarly by dividing rise by run, but then multiplying by 100 to get a percentage: e.g.:

Slope in degrees

Expressing a slope in degrees requires using the inverse tangent trigonometric function. e.g.:

Accessibility

The Accessibility for Ontarians with Disabilities Act[1] provides a foundation, a bare minimum to which public spaces must be designed.


Grading Standards and Critical Gradients[2]
Use Extreme range (%) Desirable range (%)
Public Streets 0.5 - 10 1 - 8
Private streets 0.5 - 20 1 - 12
Service lanes 0.5 - 15 1 - 10
Parking areas 0.5 - 8 1 - 5
Parking ramps up to 20 up to 15
Collector walks 0.5 - 12 1 - 8
Entrance walks 0.5 - 8 1 - 4
Pedestrian ramps up to 12 up to 8
Stairs 25 - 50 33 - 50
Game courts 0.5 - 2 0.5 - 1.5
Paved gutters 0.25 - 100 1 - 50
Grassed swales 0.5 - 15 2 - 10
Terraces and sitting areas 0.5 - 3 1 - 2
Grassed banks up to 50 up to 33
Planted banks up to 100 up to 50
  1. Ontario. O. Reg. 191/11: INTEGRATED ACCESSIBILITY STANDARDS, 2011. https://www.ontario.ca/laws/regulation/r11191.
  2. Strom, S., Nathan, K., Woland, J. Site Engineering for Landscape Architects (6th Ed.) 2013, Wiley and Sons