948.1DESCRIPTION—This work is the construction of overhead steel sign structures of the type indicated.
948.2MATERIAL—
critical in accordance with AASHTO Specifications ) for all pipe with nominal wall thicknesses greater than 1/2 inch. The actual yield strength for all pipe, per mill test report, is not to exceed 65,000 pounds per square inch.
1.a ASTM A53/A53M, Grade B, Type E or S; or ASTM A500, Grade B; or ASTM A106, Grade B
1.b API 5L, Grades B, X42 or X52; PSL2 with the following characteristics:
• No jointers allowed
• Do not use thermomechanical rolled or thermomechanical formed (grad e suffix M) pipe on monopipe structures.
• Process of manufacture: seamless, electric resistance welded, or longitudinal seam, submerged arc welded.
Section 1105.02(a)2 for structural shapes.
Provide supplemental CVN testing (Zone2, non -fracture critical, in accordance with AASHTO Specifications) for columns with nominal wall plate thicknesses greater than 1/2 inch. Provide a minimum internal surface (concave) bend radius at each press -break that is five times the wall thickness or 1 inch, whichever is larger. (Bends are parallel to direction of mill rolling). The dimension across the flats on fabricated press-break columns may not vary by more than 2% from the specified dimension. The fabricator is responsible for all fabrication adjustments that may be necessary to accommodate any dimensional variation.
non-fracture critical, in accordance with AASHTO Specifications) for tube wall thickness greater than 1/2 inch. If press-break columns are used, provide a minimum internal (concave) surface bend radius that is five times the wall thickness or 1 inch, whichever is larger. (Bends re parallel to direction of mill rolling).
size, process, and nondestructive testing. Shielded Metal Arc Welding (SMAW), Submerged Arc Welding (SAW), Gas Metal Arc Welding (GMAW), and gas-shielded Flux Cored Arc Welding (FCAW) are approved. Galvanize as specified in Section 1105.02(s). If necessary, perform one time weld repair of column to base
plate, column to splice plate, chord to splice plate, and/or circumferential butt welds in chords and columns. If the initial repair fails, seek approval of the Chief Structural Materials Engineer before making any further repairs at the previously repaired location. Column base plates must meet a Class C flatness tolerance, as specified in Section 1111, for structures erected directly on a pre-finished concrete foundation using bridge shoe bedding material. Perform and evaluate all non-destructive testing according to cyclically loaded non- tubular tension criteria.
1.a On monopipe structures, 100% of the length of all CJP groove welds; on other structures, 25% of the length of the length of each weld connecting columns to base plates, cords to splice plates connection plates to columns and chords, welds on truss seat plates, and longitudinal seam welds on cantilever and center-mount sleeves.
• If a rejectable defect is found on a partially tested weld, then test 100% of the CJP weld length on that plate or sleeve.
1.b 100% of the groove weld length on at least 25% of the number of similar type connections of web members to the truss chords.
• If any rejectable defect is found, double the testing frequency until no rejectable defects are discovered.
Penetration (PJP) groove welds.
2.a Intermediate member connections: MT 100% of the weldment length on at least 25% of the total number of connections on trusses and towers, respectively.
• If any rejectable defect is found, double the testing frequency until no rejectable defects are discovered.
2.b Welds on truss seat plates, base plates, cantilever and center-mount sleeves, and alternate press-break members and fillet welds connecting backing rings to base plates and flange splice plates: MT a minimum of 25% of the total length of each weld.
• If a rejectable defect is found, then test 100% of the weld on that element.
2.c Welds attaching handhole frames to columns: MT 100% of the length of each weld.
2.d All other connections: MT 100% of the weldments on at least 10% of the total number of connections
• If any rejectable defect is found, double the testing frequency until no rejectable defects are discovered.
tube structures and on all press-break columns.
than 100% of weld length is required to be tested.
weld. Perform 100% ultrasonic inspection ( UT) of butt welds in rings 5/16 -inch and thicker. Perform 100% MT on rings less than 5/16-inch thick.
Grade 55 only.
per square inch.
stainless steel U-bolts is 3/4 inch Condition B.
• Furnish bolts, nuts, and washers for testing purposes and test as specified in Section 1050.3(c)7.b.
• U-bolts, other than stainless steel, mustl conform to ASTM A449.
• Stainless Steel U-bolts as specified in Section 948.2(i) may be substituted for ASTM A449 U-bolts for bolt diameters of 3/4 inch and smaller.
trusses and chord sections to verify geometry and camber. If distortion occurs after galvanizing, re -verify.
948.3CONSTRUCTION—As indicated, as shown on the Standard Drawings, and as follows:
directed by the Structure Control Engineer conforming to Section 105.02. Material and workmanship not previously inspected will be inspected on the work site. Remove rejected material from the work site. Restore the site to its original condition, including the disposal of excess or unsuitable material.
the applicable parts of Section 1001.3. Use steel templates provided by the fabricator to accurately set tower base anchor bolts to the correct elevation and alignment. Securely brace the bolts against displacement before concrete is placed. Provide conduit sweeps when required. After constructing the concrete foundations, backfill the excavation around the foundation using acceptable material, in uniform loose layers, not exceeding 4 inches in depth. Compact to the necessary density by means of mechanical tampers.
position. Provide full bearing under bases. Place bedding material for bridge shoes, if indicated.
sign panels and lighting are installed, to make the signs level.
the anchor bolts in strict conformance with the following procedure:
top and bottom surfaces of column base plates to the satisfaction of the Representative; remove any burrs or excessive surface galvanizing in the area of th e anchor bolt holes that would prevent proper seating of the washers in the snug tightened condition.
to the bottom of each in-place leveling nut, and can then be backed off the bolt by the effort of one person using a 12-inch long wrench or equivalent without employing a pipe extension on the wrench.
bearing surfaces of all nuts. Re -lubricate the anchor bolts and the nuts if more than 24 hours has elapsed since earlier lubrication, or if the bolts or nuts h ave become wet since they were first lubricated.
Place one hardened washer on top of each leveling nut.
Support the column with the crane as necessary and adjust leveling nuts to align the column into its proper upright position. Bring all leveling nut washers into contact with the bottom of the base plate.
NOTE: Upon subsequent completion of any column installation and the tightening of all nuts, the clear dimension between the bottom of each leveling nut and the top of the concrete pedestal or caisson must not exceed approximately 1 inch as shown on the Standard Drawings. In no case will this clear dimension ever exceed the diameter of the anchor bolt unless substantiated by design bending calculations for the bolts.
onto the anchor bolts and into contact with the washers on the base plate.
NOTE: If for any reason, the slope of an anchor bolt from vertical, or the slope of the base plate from horizontal, results in a deviation of greater than a 1:40 slope at the bolt/plate intersection, or if a nut cannot be brought into full contact with the base plate after final tightening, a fabricated -to-fit beveled washer must be used in place of a flat washer under each nut at t hat location.
as the maximum nut rotation resulting from the full effort of one person using a 12-inch-long wrench or equivalent (no pipe extensions). A star tightening pattern is one in which the nuts on opposite or near opposite sides of the bolt circle are successively tightened in a pattern resembling a star.
nuts. At this point, verify that the clear distance between the bottom of each leveling nut and the top of the concrete is compliant with maximum allowable requirements.
snug-tight condition with a suitable marking on one flat, and a corresponding reference mark on the base plate at the same location. Then, using a star tightening pattern and at least two tightening cycles (passes), incrementally turn the top nuts until achieving the total required nut rotation as specified in the table below. After tightening is completed, verify proper rotation at each nut by observing the reference marks, and verify that the nut and washer are in full contact with the top surface of the base plate.
Top Nut Rotation Beyond Snug Tight Anchor Bolt Diam. (in.) F1554 Grade 55 ≤ 1 1/2 1/3 Turn > 1 1/2 1/6 Turn Note: The top nut rotation tolerance is -0, +20 degrees (1/18 turn) from the specified value.
the jam nut.
installation, as follows:
leveling nut as stipulated in Paragraphs 7 and 8 above. If any nut rotates by any amount, carefully document the location and approximate degree of rotation of that nut, in writing, and report the information to the Chief Structural Materials Engineer as soon as possible upon completion of the verification.
walls. Hand-tighten the nuts on the U-bolts at expansion points on such structures, and then install jam nuts.
948.4MEASUREMENT AND PAYMENT—
The price includes removal of existing signs.
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