Agriculture Reference
In-Depth Information
cross slope, the water migrates in a direction somewhere between the
direction of the main slope and the cross slope, as depicted by the dot-
ted line in Figure 13.2. The dotted line represents water flow diverging to
one side of the walkway.
The 4 percent slope of the walk shown
in Figure 13.2 is somewhat steeper than is
generally found in a high-use public area
such as a large urban space. In this situ-
ation, the public space lies on an existing
sloping site connecting several anchor pub-
lic buildings; a 4 percent slope made sense
because the overall park space slopes close
to this percentage already. A 1 or 2 per-
cent slope may be more common in a large
urban plaza. What may also be common
is to create a slight crown down the cen-
ter of the walk pitched at a .5 to 1 percent
slope to either side of the walk. However,
it is often the practice in an urban space to
pitch paved surfaces with one cross slope.
106
105
104
Slope of
Walk
103
B Cross Slope
102
101
Figure 13.2
Diagram of a sloping walkway at Grand Park
in Los Angeles, CA. The walk has a primary 4 percent slope
and was designed with a cross slope (B) to ease surface
water to the planting area at the left of the walkway. The
contours are diagrammatic to help viewers visualize the
slope conditions.
deSiGn proceSS for GradinG
a pedeStrian ramp
The process for setting slopes described in this section is to some extent
simplistic, but it should serve as a starting point on how to establish the
slope and needed spot elevations for paved or other surfaces. In Figures
13.3-A through 13.3-D, the process for establishing the slope and spot
elevations for a pedestrian ramp is broken down into a series of steps.
Step One: Arrows A, B, and C represent the direction of slope for
three portions of a pedestrian ramp. Slopes A and C can be as steep as 8
percent, while slope B is for a landing and should not be greater than 1
percent to meet wheelchair accessibility standards. In this example the
slopes for A and C are in the range of 2 to 4 percent.
