§ 11.3.14. Construction Drawings

The drawings must contain a design summary report listing the design assumptions, material properties and all factors of safety and reduction factors compared to the recommended values or criteria in the AASHTO, NCMA or FHWA design criteria, whichever applies, and in the project geotechnical report.

The retaining wall and any external structural elements, such as geogrid, tie bars or pre-cast units, must be shown on the plan and profile sheets for street, drainage and utility construction and on the site plan for drainage structures so that the location of the retaining wall and related components will be obvious to anyone reading the drawings.

The drawings must contain a separate plan and profile sheet for the wall itself, drawn to a 1 inch = 30 feet (1 to 400), or larger detail plan view and 1 inch = 3 feet (1 to 40), or larger detail profile view. The plan view drawing must show all buried utilities, structures and other constructed features, both existing and proposed, within a horizontal distance of 2 times the wall height. The following must be included: wastewater mains, services and manholes; stormwater drainage pipe, inlets, junction boxes and manholes; water mains, services and hydrants; electrical lines and services; gas mains and services; communications and entertainment lines and services; pavement curb and gutter; sidewalk; guardrail, pull boxes, sign footings, street light footings, and the limits of geogrid, strips, tie bars or nail tendons or rods and other features as required.

The profile view drawing must include the top of wall elevations, footing elevations, locations of changes in top of wall; locations of warning plaques; the elevations of each layer of geogrid, strips or tie bars, if used; the existing ground line at the base of the wall; the proposed ground line at the back of wall; all utilities shown on the plan view, and other features as required. Exact locations of existing utilities must be provided, based on "pot holing" if necessary.

The drawings must contain cross-sections of the wall at points where the wall height is maximum, where drainage structures penetrate the wall, where the utility excavation/backfill zone is most critical and where structures behind the wall fall within the zone of geogrid, strips, tie bars or pre-cast units, if used. The cross sections must be drawn to scale and must show utilities, utility excavation/backfill zone, sidewalks, pavements, wall units, backfill, filter fabric, handrail, guardrail, geogrid, strips, or tie bars, inlets, headwalls, the existing ground line, and other features as required.

Typical sections of the wall must be provided, showing all components necessary to construct the wall and appurtenances.

Details of appurtenances such as handrail, guardrail and headwalls, must be included in the drawings.