1079BEARINGS AND BEARING MATERIALS

10-159TABLE 1078 -6

TOLERANCES FOR BOX BEAMS (Refer to Figure 1078 -4) Dimension Tolerance Length (A) ± 1" Width (overall) (B) ± 1/4" Depth (overall) (C) + 1/4" Variation from specified plan end squareness or skew (D) ± 1/8" per 12" width, ± 1/2" max Variation from specified elevation end squareness or skew (E) ± 1/8" per 12", ± 1/2" max Sweep, for member length (F) up to 40 ft ± 1/4" Sweep, for member length (F) 40 to 60 ft ± 3/8" Sweep, for member length (F) greater than 60 ft ± 1/2" Differential camber between adjacent members (G): 1/4" per 10 ft., 3/4" max Local smoothness of any surface (H) 1/4" in 10 ft Position of strands (K) ± 1/4" Longitudinal Position of blockout (N) ± 1" Position of dowel holes (o1) ± 1/4" Position of sleeves cast in beams, in both horizontal and vertical plane (o2) ± 1/2" Position of void (P) ± 3/8" Bearing area – deviation from plane surface ± 1/16" Width - Any one span Plan width + 1/8" per joint Width – Differential of adjacent spans in the same structure 1/2"

BEARINGS AND BEARING MATERIALS 2 -1 PREFORMED BEARING PADS 3 Provide preformed bearing pads composed of multiple layers of 8 oz/sy cotton duck 4 impregnated and bound with high quality natural rubber, or equally suitable materials approved 5 by the Engineer, that are compressed into pads of uniform thickness. Ensure that the thickness 6 of the preformed bearing pads is 3/16 inch with a tolerance of ± 1/16 inch. Use cotton duck 7 that meets Military Specification MIL -C-882-E for 8 oz/sy cotton army duck or equivalent. 8 Provide enough pads as to produce the required thickness after compressing and vulcanizing. 9 Ensure that the finished pads withstand compressive loads perpendicular to the plane of the 10 laminations of not less than 10,000 psi without detrimental extrusion or reduction in thickness. 11 Furnish a Type 3 certification in accordance with Article 106 -3 certifying that the preformed 12 bearing pads meet thiss pecification . 13 -2 ELASTOMERIC BEARINGS 14

Provide elastomeric bearings that meet the requirements of AASHTO M251, except as 16 specified herein. 17 Use elastomeric bearings provided by a N CDOT approved as found on the Department’s 18 producer/supplier list . All producer/suppliers must be current with the applicable 19 AASHTO Product Evaluation & Audit Solutions workplan to remain on the NCDOT 20 producer/supplier list. Submit working drawings and manufacturing procedures for 21 approval by the Engineer . Refer to Subarticles 1079 -2(D). Furnish a Type 3 certification 22 in accordance with Article 106-3 certifying that elastomeric bearings satisfy this Standard 23