SECTION 710 - FENCE AND GUARDRAIL
710.01 Barbed Wire Barbed wire shall conform to the requireme nts of AASHTO M
280. The Design number shall be 12-4-5-14R with, coating Type Z, metallic coating Class 3 if zinc coated or coating Type A, (0.30 oz/ft²) if aluminum coated.
710.02 Woven Wire Wire and stays shall conform to the require ments of AASHTO
M 279. The Design number shall be 1047-12-11,Grade 60,coating Type Z, coating Class 3 if zinc coated. The Design number shall be 1047-12-11, Grade 60, coating Type A,if aluminum coated.
710.03 Chain Link Fabric Chain Link fabric shall conform to t he requirements of
AASHTO M 181, Type I, Class D if zinc coated, or Type II if aluminum coated, or Type IV, Class B if PVC coated. The wire shall be 9 gauge and the mesh shall be 2 inch unless otherwise noted on the plans. Tension wire shall be seven gauge (0.177 inch diameter) steel coil spring wire and have a zinc coating or an aluminum coating. Zinc coating shall be Class 3 and aluminum coating shall be a minimum of 0.4 oz/ft².
710.04 Metal Beam Rail Galvanized steel rail elements shall c onform to the
requirements of AASHTO M 180, Class A, Type II. When corrosion resistant steel is specified, rail shall conform to AASHTO M 180, Class A, Type IV. Beams of corrosion resistant steel shall not be painted or galvanized. They shall be so handled and stored that the traffic face of these beams, used in a continuous run of guardrail, shall not show a distinctive color differential. 7-23 When metal beam rail is to be installed on a curve having a radius of curvature of 150 ft. or less, the beam sections shall be fabricated on an arc to the required radius and permanently stamped or embossed with the designated radius. The Department may take one piece of guardrail, a backup plate , and end or buffer section from each 200 pieces in a lot, or from each lot if less than 200 pieces are included therein for determination of compliance with specification requirements. If one piece fails to conform to the requirements of this specification, two other pieces shall be tested. If either of these pieces fails to conform to the requirements of this specification, the lot of material represented by these samples shall be rejected. A lot shall be considered that quantity of material offered for inspection at one time that bears the same heat and coating identification.
710.05 Cedar Rail Fence Rails and posts for cedar rail fence shall be of cedar,
reasonably straight, machine or hand peeled and branch stubs cut flush.
710.06 Fence Posts and Braces Wood posts shall be of cedar, w hite oak, or
tamarack, of the diameter or section and length shown on the plans. Round wood posts shall be of seasoned stock straight and sound and shall have been cut from live growing trees with the outer and inner bark removed and all knots trimmed flush with the surface of the post. Rotted, loose or hollow knots, plugged or open holes will not be permitted. Sound knots will be permitted if the diameter of any one knot or the combined diameter of 2 or more knots occurring in the same cross section is not greater than one-third of the circumference of the post at that cross section. Posts shall be of uniform taper from top to bottom not to exceed 1½ inches of taper in 7 feet. The minimum diameter of heartwood in line posts at their small end shall be no less than 3 inches. The minimum diameter of line posts at the small end shall be no less than 3 inches. The maximum diameter of line posts at the small end shall be 6 inches. The minimum diameter of heartwood in end, corner, gate, and barway posts shall be 4½ inches at the small end. The minimum diameter of end, corner, gate, and barway posts at the small end shall be 4½ inches. The maximum diameter of end, corner, gate, and barway posts shall be 8 inches. That portion of wood posts to be set below ground shall be imm ersed to a depth of 4 feet in a tank or barrel containing an approved commercial timber preservative solution for a minimum of 60 minutes. All wood posts so treated, unless otherwise specified by the Resident, shall have been peeled and air seasoned to permit thorough drying for at least 3 months before treatment. After being treated, the posts shall be piled to permit thorough drying before being set in the ground. Braces shall be of spruce, eastern hemlock, Norway pine, pitch pine, or tamarack timbers or spruce, cedar, or tamarack round posts of sufficient length to make a diagonal brace between adjacent posts. If other than cedar, white oak, or tamarack, braces shall be treated as described above for posts except that they shall be immersed full length. 7-24 Metal posts and braces for woven wire fence shall conform to t he requirements of AASHTO M 281. Posts and post assemblies shall be galvanized according to the requirements of AASHTO M 111. Assembly hardware shall be zinc coated in accordance with AASHTO M 232M/M 232. The type of post furnished shall be channel or U unless otherwise noted on the plans. Metal posts, rails, and bracing for chain link fence shall be as specified in AASHTO M 181. Type I, Grade 1 or Grade 2 posts shall be used with zinc coated chain link fabric. Type II, Grade 1 or 2 shall be used with aluminum coated chain link fabric. End and corner posts shall be 2 inch inside diameter. Line posts shall be 1 ½ inch inside diameter. Top and brace rails shall be 1 ¼ inch inside diameter. Expansion sleeves, turnbuckles and other fittings and hardware shall be galvanized in accordance with the applicable requirements in AASHTO M 181.
710.07 Guardrail Posts Posts shall be of wood or steel.
a.Wood posts shall be of Norway pine, southern yellow pine, pi tch pine, Douglas fir, red pine, white pine, or eastern hemlock. They shall be of straight and sound timber cut from live growing trees, free from loose knots or other structurally weakening defects, including shake, holes and heart rot over 1 inch in diameter. The posts shall be free from season checks that exceed ¼ inch in width. A tolerance of 1 inch in length and ¼ inch in width or thickness is permitted in the dimensions of rectangular posts. They shall be well sawn and have square edges except that wane not more than 1½ inches wide and extending not more than ½ the length of the piece will be allowed on that portion of the post to be placed below ground. Sound, tight, well spaced knots to 2½ inches or less in diameter will be permitted. Wood posts and offset brackets shall be preservative treated in accordance with the requirements of AASHTO M 133 and AWPA U1, UC4A Commodity Specification A: Sawn Products. Treatment shall be according to the Standards of AWPA C5. Composite material blocks tested and meeting the requirements of the National Cooperative Research Program Report 350 and approved by the FHWA may be used as offset brackets.
b.Galvanized steel posts shall conform to the requirements of AASHTO M 270 Grade 250 (36) if a rolled section or ASTM A 769Grade 36 if a welded section. Fabrication will be in accordance with Section 504 - Structural Steel. Galvanizing shall be in accordance with Section 506, Shop Applied Protective Coating- Steel.
c.Corrosion resistant steel posts shall conform to the require ments of ASTM A 769, Grade 50W if a welded section. Fabrication will be in accordance with Section 504 - Structural Steel. The portion of the post that is underground shall meet the galvanized steel post requirements in Section b. above. 7-25
710.08 Guardrail Hardware Guardrail hardware shall conform to the applicable
standards contained in the latest ARTBA Bulletin No. 268B, "A Guide to Standardized Highway Barrier Rail Hardware", approved by the AASHTO-ARTBA-AGC Joint Cooperative Committee, Technical Bulletin Number 268-B. All galvanized fittings, bolts, washers, and other accessories shall be in accordance with the requirements of AASHTO M 111, M 232 or AASHTO M 298, Class 50, Type I, whichever applies. All galvanizing shall be done after fabrication. Hardware for corrosion resistant guardrail shall be in accorda nce with ASTM A 325M/A 325, Type 3, except the 16 inch bolts and nuts for attaching the metal beam rail to the posts, which may be galvanized as specified above.
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Sections that cite this one
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Source: Standard Specifications — Highways and Bridges, 2020 Edition. Pages 727–730 of 817. View official source ↗