(A) Bridges. Minimum criteria for bridges to be built by private interest for future acceptance by the Division of Highways.
(1) Structures which are to span streams shall be designed for hydraulic requirements in accordance with Division of Highways criteria and plans shall be submitted to the Hydraulics Unit for review and approval. Rip rap will be required as recommended by the Hydraulics Unit.
(2) Structures shall be designed for minimum live load of HS-20 as specified in the Standard Specifications for Highway and Bridges of the American Association of State Highway and Transportation Officials, and plans shall be submitted for review and approval by the Structure Design Unit.
(3) Bridge deck widths and clearances shall be in accordance with the State Department of Transportation "Bridge Policy". For bridges with curb and gutter approaches, the clear bridge width shall be the same as the curb to curb approach width, except where bikeways or sidewalks are carried across the structure. Curb and gutter will be transitioned out in 50 feet to line up the face of curb and bridge rail. For shoulder section roadways, the bridge width should be a minimum of 24 feet.
(4) The following materials are acceptable for bridge construction:
(a) For substructures: reinforced concrete, structural steel, pre-stressed concrete, or steel piles or combination of these materials;
(b) For superstructures: pre-stressed concrete, reinforced concrete deck slab structural steel I-beams with reinforced concrete deck or corrugated metal deck with asphaltic wearing surface; and
(c) The type and design of bridge rails shall be as approved by the Structure Design Unit of the Division of Highways.
(5) Guardrails shall be installed at the bridge approaches where required.
(6) All material and workmanship used in construction of the structure shall be in accordance with State Standard Specifications for Roads and Structures.
(B) Roadway dams.
(1) It is the policy of the Division of Highways to discourage the location of roadways on dams. In those cases, where a definite advantage may be gained or a substantial savings in funds may be realized, the utilization of a dam for a roadway may be favorably considered.
(2) Where it is determined that a dam will be utilized as a roadway, the following criteria must be met.
(a) When applicable, the dam must have certification from the State Department of Natural Resources and Community Development pursuant to the "Dam Safety Law of 1967", (as amended by the General Assembly of 1977) being G.S. §§ 143-215.23 et seq.
(b) All pertinent data regarding the design of the embankment as an impoundment structure must be presented to the Division of Highways for review.
(c) The top cross section dimension must be the roadway width required (from shoulder point to shoulder point) for the facility plus a minimum of four feet.
(d) Guardrails will be provided on the impoundment side of the roadway. For safety, the District Engineer may require guardrail on both sides of the roadway.
(e) Spillways will be designed to provide two feet of freeboard at the shoulder for an estimated 50-year design frequency outflow as a minimum.
(f) A means of draining the lake completely will be provided.
(3) Design acceptance or approval by the Division of Highways is limited to the use of the dam as a roadway and is, in no way, intended as approval of the embankment as an impoundment structure.
(4) Responsibility incurred by the Division of Highways when a section of roadway crossing a dam is accepted as a part of the state maintenance system is limited to maintenance of the roadway for highway purposes from shoulder point to shoulder point only. Responsibility for the impoundment, any damage that may result therefrom, and maintenance of the dam or appurtenances as may be required to preserve its integrity as a water impoundment structure, shall remain with the owner of the impoundment. Any maintenance work will be subject to the provisions of G.S. § 136-93.
(5) Impoundment of water on highway right-of-way may be allowed under the following criteria:
(a) The impoundment does not adversely affect the right-of-way for highway purpose; and/or
(b) Adjustment, as required, flattening slopes, installing rip rap, and any others, shall be the responsibility of the developer.
(6) Structures under, over and/or on dams shall be designed and plans prepared under the supervision of a licensed professional engineer.
(Ord. passed 1-1-2000)