TM5-803-14
Figure 4-12. Building Orientation to Topography.
maintain a smooth grade line with gradual
aisles and 1.5% for the transverse slope. For areas
changes. Vertical curves should be sympathetic to
laid out for 60- and 45-degree parking, 5% is the
and balance the severity of horizontal curves. On
maximum desirable grade along the aisles with
up or down slopes, particularly at intersections,
1% for the transverse slope. Steeper grades create
sufficient flattening of the vertical curve should be
problems with opening and closing car doors and
provided to allow adequate sight distance and to
increase the potential of cars rolling.
(3) Sidewalks. Gradients for sidewalks can
avoid bumps at the crest or hidden dips. TM
5-822-2 provides additional guidance on the de-
range from 0.5% to 15%. Gradients depend upon
sign of roads. Good grading for vehicular circula-
the quantity and types of pedestrians, the width of
tion should:
the pathway, and the surface. The normal mini-
(a) Relate the roadway profile as closely as
mum grade is 1 to 2%. Entrance areas or court-
possible to existing topography.
yards require a slightly steeper grade to ensure
(b) Allow adequate vertical and horizontal
that runoff moves rapidly away from doors as well
sight distances.
as locations where people sit or stand. Long,
(c) Provide safe and smooth intersections.
vertical climbs should be broken by short spans.
(2) Parking Areas. A relatively constant grade
The spans should continue upward movement at a
should be maintained across parking areas. Slight
gentler grade to reduce exertion. Ramps and steps
changes in the slope interval should be made at
can access steeper topography (where grades are
intersections to provide a gradual transition into
greater than 5%) and minimize regrading. TM
the main traffic flow. Changes may also be made
5-822-2 provides additional guidance on grading
at interior and exterior corners to direct or collect
walks. Grades are critical to barrier-free accessibil-
ity. Careful thought is needed to make all facil-
runoff. For areas laid out for 90-degree parking,
5% is the maximum desirable grade along the
ities, not just buildings, accessible. "FED STD
4-12
Previous Page
