848-2 MATERIALS
Detectable
warning for curb ramps shall consist of raised truncated domes and must be on
the NCDOT APL.
Use only one type of material per project. The contractor shall submit the assembly or installation procedures to
the Engineer.
848-3 CONSTRUCTION METHODS
The Technician shall check the subgrade under sidewalks and driveways prior to the placement of concrete for proper compaction, stability, typical section, etc. The Technician should refer to the appropriate standard for requirements of joints. The brooming of the concrete surface finish shall be done transversely to the direction of the sidewalk. Joints should not be placed closer than
five feet. Seal expansion joints where sidewalk and curb ramps are placed adjacent to concrete curb and/or gutter. Consideration should be given to the effect of asphalt sealant upon foot traffic prior to its use in sealing expansion joints. Grooved joints shall not be sealed.
All forms shall be sufficiently staked and braced to prevent displacement during construction operations. Flexible forms are normally utilized in sharp radii and are considered acceptable if they will adequately support the section required. Backfill shall be placed no sooner than
threecuring days and no more than
sevencuring days after casting of the sidewalk or driveway. The backfill shall be compacted to a degree comparable to the adjacent undisturbed material.
When driveways are to be constructed leading into populated property, the Technician should contact the property owner and advise him when the driveway will be constructed and when the property owner may expect to use the driveway. The property owner should be contacted prior to placing the driveway to ensure that the planned driveway meets the needs of those utilizing the property. Frequently, there are changes that can be made by the Engineer that are of little consequence to the project expenditure, but create positive experiences for the property owner. It may be necessary to secure a permit of entry from the property owner to perform the work. Properties that are under condemnation should not be altered without the
Division Right of Way Agent’s approval. Contact the Division Construction Engineer for further guidance.
When ingress and egress must be provided to a property and the proposed concrete driveway is of sufficient width, it may be cast in half width sections, if approved by the Engineer. The Engineer should check the plan location of all driveways with right of way agreements to ensure the correct location is obtained. The Technician shall check with the Engineer before moving any driveway from a location originally shown on the plans. No additional driveways other than those shown on the plans shall be placed without the prior approval of the Division Engineer and/or the municipality whose ordinances may govern this section of road. Before the Engineer considers revising the plan width of any driveway, he shall check with the Division Engineer and/or municipality to determine if an increase in width is in accordance with ordinances established. The Engineer shall not add sidewalk without prior consultation with the Division Engineer, because the incorporation of sidewalk through a project is often governed by a municipal agreement.
The location of wheel chair ramps and curb cuts are determined prior to the location of stopbars and crosswalks. As a result, the curb ramps and cut ramps are misplaced in relationship to the stopbars and crosswalks. This should be discussed at the monthly construction meeting held before the work begins. The Technician and the Contractor should consider the location of the stopbars and crosswalks when laying out the wheel chair ramps and curb cuts. Curb ramps will be stationed on the Pavement Marking Plans, do not use the locations shown on the Roadway Plans, as they are shown for quantities. Lay out stopbars as shown on signal plans prior to constructing curb ramps and/or curb cuts. Place curb ramps and/or curb cuts in front of stopbars. Install curb ramps and/or curb cuts where shown on the plans. If the plans do not require sidewalk, install curb cuts only. Please refer to the
May 20, 2009 memorandum from Mr. Kevin Lacey, PE, for procedures to locate curb cuts.
The installation of the Detectable Warnings systems should be installed in accordance with the manufacturer’s recommendations. These instructions should be provided by the contractor prior to installation.
ADDITIONAL RESOURCES
