Grading design shall coordinate with rainwater management design and accessibility. It shall also strive to minimize earthwork. The reduction of fill and the elimination of the need for disposal of excess soil will provide for a cost-effective design. All on-site soils used as part of the proposed design must be deemed suitable and follow all environmental regulations. Consideration shall also be given to any areas of future expansion or improvement. In the event that significant earthwork is required, the location of areas for soil stockpiles shall be
considered as part of the design.
Accessible Walkways
It is key to maintain universally accessible routes between buildings, playlots, athletic fields, and other designed spaces. The identification of primary paths of travel shall occur early in the design process.
- The maximum allowable cross slope for accessible routes, accessible parking, and other ‘level’ areas is 2%, with 1.5% being the CPS preferred design.
- The maximum allowable slope in the direction of travel for an accessible route is 5%, with 4.25% being the CPS preferred design.
- Constructed walking/rolling surfaces shall not exceed maximum slopes and cross slopes above in any accessible location.
- Drainage over walkways is prohibited. Refer to Volume 3 Section 1.10 Site Accessibility for additional information.
Playfields and Athletic Facilities
- Grading for synthetic sports fields may be flat or crowned with a maximum 0.5% slope.
- Slope crossing the full width of the field shall be avoided.
- Natural turf fields must be crowned at 0.5% slope minimum and shall be designed with prepared soils and drainage stone as a base.
- Playlot grading shall have a minimum slope of 0.5% and a maximum slope of 2.0%.
- If athletic fields are functioning as detention storage areas (subsurface), grading around the field shall drain as much area as possible to the field in order to minimize the need for stormwater management infrastructure collection.
- If there is no detention function, areas shall drain away from the fields to minimize the collection of debris.
Curbs and Gutters
Refer to the Chicago Department of Transportation Rules and Regulations for Construction in the Public Way for applicable curb and gutter requirements and details.
- Typical curb heights shall be six inches but may vary from three to nine inches as needed to achieve grading design.
- Reverse gutter may be used to achieve grading design intent.
- Per City of Chicago Department of Water Management grading and drainage requirements, the minimum allowable longitudinal gutter slope shall be 0.4% for straight segments and 0.6% for curves.
- The design of flush barrier curbs at the perimeter of turf fields and play lots is integral to the overall athletic field design.
Parking Areas
In general, parking area design shall minimize slopes across accessible parking spaces and accessible paths of travel to meet minimum requirements while providing positive drainage across the overall area.
- Projects may require a redesign of existing parking areas in order to provide new accessible parking spaces that meet minimum requirements.
- Incorporating flush sidewalks and concrete wheel stops adjacent to accessible parking spaces can aid in achieving ADA required slopes and paths of travel while still allowing rainwater to drain across the parking area.
- In addition to flush sidewalks, curb cuts can also be provided to allow for sheet flow drainage to continue on-site. However, to the extent possible, no sheet flow drainage shall be allowed to flow on to adjacent private property.
- Drainage shall be directed away from any drop-off areas and the collection of rainwater drainage (ponding) in parking areas shall be minimized.
- Crosswalks designed perpendicular to the direction of travel (both vehicle and pedestrian) are preferred.
City of Chicago Department of Water Management grading and drainage requirements state the minimum allowable slope on pavement (e.g. parking lot) shall be 1.0%.