10-72 1044 -5 Corrugated Steel Pipe and Fittings
Non-perforated corrugated steel pipe and pipe fittings shall meet Subarticle 1032- 3(A). Perforated corrugated steel pipe shall meet AASHTO M 36. Fabricate the corrugated steel pipe from steel sheets having a minimum thickness of 0.052 inch. 1044 -6 PVC PIPE Solid Wall PVC pipe shall meet ASTM D1785. Perforated Solid Wall PVC pipe shall meet AASHTO M 278. 1044 -7 CORRUGATED PLASTIC PIPE AND FITTINGS Corrugated HDPE pipe and fittings shall meet AASHTO M 252, except that the maximum stretch resistance shall be 10 %. 1044 -8 OUTLET PIPE Outlets constructed of PVC Schedule 40 pipe shall meet ASTM D 1785. HDPE pipe shall meet AASHTO M 252. 1046 -1 GENERAL Use guardrail materials meeting requirements of the Department ’s Brand Registration Program for guardrail and are listed on Department ’s approved producer/suppliers list or NCDOT APL . The producer/supplier and products must be current with the applicable AASHTO Product Evaluation & Audit Solutions workplan to remain on the NCDOT producer/supplier list and NCDOT APL. The following types of guardrail materials and all associated accesso ries may be accepted under this program: rail elements, posts and offset blocks, terminal sections, anchor units, transition sections and hardware. 1046 -2 RAIL ELEMENTS The ra il element and terminal sections shall meet AASHTO M 180 for Class A, Type 2. 1046 -3 POSTS AND OFFSET BLOCKS
A.General
1.The Contractor may furnish any one of the following types of steel guardrail posts. Only one type of post will be permitted at any one continuous installation. Use structural steel posts throughout the project, unless otherwise directed by the Engineer or detailed in the plans.
a.Steel W6 x 8.5 or W6 x 9.0 posts
b.Steel 4.5 inches x 6.0 inches C-shape posts
2.The Contractor may at his option furnish either of the following types of treated timber posts if specifically directed by the Engineer or detailed in the plans. Only one type of post will be permitted at any one continuous installation.
a.Timber 6 inch x 8 inch posts
b.Timber 8 inch x 8 inch posts
10-73 (B) Structural Steel Posts
Fabricate steel posts for guardrail of the size and weight shown in the plan s from structural steel complying with Section 1072. Metal from which C -shape posts are fabricated shall meet ASTM A1011 for any grade of steel except mechanical requirements that shall meet ASTM A36. Punch or drill the holes for connecting bolts. Burning will not be permitted. After fabrication the posts shall be galvanized in accordance with Section 1076.
C.Treated Timber Posts Timber guardrail posts shall be of treated southern pine meeting Section 1082. Bore bolt holes to a driving fit for the bolts. A minus tolerance of 1% will be allowed in the length of the post. Perform all framing and boring before the posts receive preservative treatment.
D.Offset Blocks Provide 8 inch deep recycled plastic or composite offset blocks approved for use with the guardrail shown in the plans. Only one type of offset block will be permitted at any one continuous installation. Treated timber offset blocks with stee l beam guardrail will not be allowed unless directed by the Engineer or detailed in the plans. Steel offset blocks with steel beam guardrail will not be allowed. Recycled plastic or composite offset blocks shall be made from no less than 50% recycled plastic or composite and shall meet the requirements in Table 1046 -1. TABLE 1046 -1 COMPOSITE OFFSET BLOCKS Property Requirement Minimum Specific Gravity 0.950 Min. Compressive Strength in Lateral Direction 1,600 psi Maximum Water Absorption 10% by weight Maximum Termite and Ant Infestation 10% Approval Approved for use on the NCDOT APL 1046 -4 HARDWARE Provide all hardware as indicated in the plan s that is galvanized in accordance with ASTM A153. 1046 -5 ANCHORS AND ANCHOR ASSEMBLIES Each shipment of guardrail terminal end sections, anchors and anchor assemblies shall be shipped from the manufacture with a current parts list and installation guide. Units not having the abo ve documents will be rejected by the Engineer . Articles 1046 -1, 1046- 2 and 1046 -3 are applicable to rail elements, terminal sections, posts, offset blocks and hardware. Reinforcing steel shall meet Article 1070 -2. Steel plates shall meet ASTM A36. Anchor rods shall meet ASTM A663 for Grade 65. Anchor cable shall be 3/4 inch wire rop e having a minimum breaking strength of 21.4 tons and galvanized. Use commercial quality galvanized steel cable thimbles. Use commercial quality drop forged galvanized steel cable clips. The fitting and stud for the anchor cable shall be suitable for co ld swaging and be galvanized. After being swaged on the cable, the fitting and stud assembly, including swaged joint and cable, shall have a minimum breaking strength of 21.4 tons.
Source: North Carolina Standard Specifications for Roads and Structures, 2024 Edition. Pages 488–489 of 857.