5-242 SECTIO N 531 – BRIDG E BEARIN G DEVICES 531.0 1 DESCRIPTION . This work shall consist of furnishing and installing bridge bearing devices. 531.0 2 MATERIALS . Materials shall meet the requirements of the following subsection s: Mortar, Type IV ................................ ................................ ................................ ......... 707.0 1(e) Structural Steel ................................ ................................ ................................ ........... 714.02 High -Strength Low -Alloy Structural Steel ................................ ................................ 714.03 High -Strength Structural Bolts and Assemblies, 120 ksi ................................ ........... 714.05 Anchor Bolts for Bearing Devices ................................ ................................ ............. 714.08 Galvanizing ................................ ................................ ................................ ................ 726.0 6 Metalizing ................................ ................................ ................................ .................. 726.0 7 Bearing Pads ................................ ................................ ................................ .............. 731.0 1 Elastomeric Material ................................ ................................ ................................ ..731.0 2 Stainless Steel ................................ ................................ ................................ ............ 731.0 3 PTFE Material ................................ ................................ ................................ ............ 731.0 4 Unless otherwise specified, all materials shall conform to the AASHTO LRFD Bridge Design Specifications , Section 14 ; VTrans Structures Design Manual, Section 14 ; AASHTO LRFD Bridge Construction Specifications , Section 18 ; and a ll AASHTO or ASTM specifications referenced in this section . Substitutions will not be allowed unless approved on the fabrication draw ings. 531.0 3 DESIGN AND FABRICATIO N DRAWINGS . The fabricator of bearings furnished under this section shall submit detailed fabrication draw ings, bonding procedures, welding procedure specifications, and welder qualification test records in accordance with Subsection 105.06 . Fabrication drawings shall identify the number of layers of vulcanized sheets and corresponding sheet thicknesses to be used for fabricating the bearing pad and shall include detailed procedures for bonding these sheets together. When a bearing design is not provided in the Plans or an alternate bearing configuration is proposed by the Contractor, a complete bearing design meeting the requirements of the Plans, AASHTO LRFD Bridge Design Specifications, Section 14 , and VTrans Structures Design Manual, Section 14 shall be provided in accordance with Subsection 105.06 . 5-243 531.0 4 FABRICATION .
a.General Requirements . Material furnished under this section shall conform to all applicable provisions of Section 506 . During any welding, surfaces in contact with the elastomer shall be restricted to 200°F, and surfaces in contact with PTFE shall be restricted to 300°F. Temperatures shall be determined by temperature indicating wax pencils or other suitable means. Bearing devices shall be fabrica ted, assembled, and certified by one supplier. Anchor bolt assemblies may be fabricated and supplied by an alternate supplier. The fabricator may propose minor alterations to the design of each device from that shown on the Plans to conform to the particu lar method of fabrication used at that fabricator’s plant. The general design intent of the Plan s shall be followed with modifications approved on the fabrication draw ings, including minor changes to the overall height of the bearing. If proposed bearing height varies from that shown in the Contract by more than 1/4 inch , the Contractor shall propose a method for accommodating the difference in height, which shall be shown in the submittal.
b.Surface Protection . All bearings shall be galvanized in accordance with Subsection 726.0 6 or metalized in accordance with Subsection 726.0 7.
c.Tolerances . After fabrication and application of surface protection, bearing devices or components shall be within the following tolerances:
1.Plain elastomeric pads and steel reinforced elastomeric pads shall be wit hin the tolerances specified in AASHTO M 251, Table 2 .
2.High -load multi -rotational bearings, external load plates, and guides shall be within the tolerances specified in the AASHTO LRFD Bridge Construction Specifications, Section 18 .
d.Sliding Surfaces .
1.Stainless Steel . Stainless steel used as a mating su rface with PTFE shall conform to the following parameters: 5-244 a. The thickness of the stainless steel sheet shall be at least 14 gauge when the maximum dimension of the surface is less than or equal to 12 inches, and at least 11 gauge when the maximum dime nsion is larger than 12 inches.
b.For bonded applications, stainless steel sheets may be affixed to backup plates with a combination of high -temperature resistant epoxy and mechanical attachment by spot welding or other approved procedures. The fabricator shall demonstrate that any proposed alternate procedure for attachment will maintain adhesion between the backup material and stainless steel under loading, movement, and weather conditions anticipated to be encountered during life of the bearing.
c.For welded applications, stainless steel sheets shall be circumferentially seal welded to backup plates. Procedure qualification will be required for any welding process and welding procedures shall be submitted for approval in accordance with Subsection 5 06.04 and Subsection 506.10 .
d.Prior to adhesion or attachment of the stainless steel to a backup plate, the contact surface of the backup plate shall meet the sliding surface tolerance specified herein and shall be blast cleaned to an appearance equivalent to SSPC -SP 10 . The contact surface of stainless steel sheets to be bonded with epoxy shall be mechanically abraded or etched prior to application of adhesive.
e.High Load Multi -Rotational (Disc) . High load multi -rotational bearings shall be tested in accordance with the requirements of AASHTO LRFD Bridge Design Specifications and the AASHTO LRFD Bridge Construction Specifications , Section 18 , modified as follows:
1.For each structure or pair of structures on a project, one of every ten fixed bearings and one of every ten expansion bearings shall be selected at random from the production lot. Sample or specially -made test bearings will not be permitted.
2.Load measuring instruments used in conjunction with the testing equipment should be calibrated yearly and be accompanied by a certificate indicating their date of calibration.
3.The measured static coefficient of friction shall be less tha n 4%.
4.The measured dynamic coefficient of friction shall be less than 4%. 5-245 (5) The basis for acceptance shall be the following:
a.The coefficients of friction are less than 4%.
b.Acceptable material certifications.
c.Assembled bearings meet requirements and tolerances specified in the Contract.
d.Inspection of tested bearings shows no visual defects, such as extruded or deformed elastomer, polyether urethane, or PTFE, damaged seals or limiting rings, evidence of metal -to-metal contact betwee n the pot wall and the top plate, or cracked steel.
6.Test results and material certifications shall be sent to the Agency’s Materials Testing and Certification Section.
7.Acceptable test results are a prerequisite for certification acceptance. Expense s for performing any testing shall be incidental to the work. 531.0 5 INSTALLATION .
a.General Requirements . Bearings shall be set level and parallel with full and uniform bearing. Pedestals detailed to be on a slope shall be set at the elevation and position specified. The concrete under the bearing device shall be level. Anchor bolts shall be positioned to t he alignment and dimensions specified or approved in the fabrication draw ings. When preset or cast -in anchorages are not specified, the Contractor shall drill holes and set the anchor bolts in a Type IV mortar. Additional aggregates shall not be added to the material during field mixing. Prior to ordering materials and starting the work, the Contractor shall submit a drilling and mortaring proposal to the Engineer for approval, including a premixed mortar material brand name. The drilled holes to be mortare d shall be thoroughly cleaned, wetted, and free of standing water. The mortar shall be mixed in a mechanical mixer in accordance with the manufacturer’s recommendations and shall be readily pourable so that when poured it completely fills the remaining hole cavities. The placement of mortar for each bearing shall be continuous and complete at all hole locations. 5-246 All exposed mortar sh all be cured for a period of not less than three days by the wetted burlap method in accordance with Section 501 . Curing shall commence as soon as practical after mortar placement. The Contractor shall not apply any forces to the anchor bolts during the cu ring period. If allowed in the Contract or ordered by the Engineer, a pre -approved adhesive may be used to set the anchor bolts into the concrete. If an adhesive is used, the manufacturer’s installation requirements for the adhesive shall be followed durin g installation. The Engineer shall be provided with a copy of the safety data sheet (SDS) and a copy of the manufacturer’s installation requirements. Unless otherwise specified on the Plan s, anchor bolts shall have a minimum embedment of 18 inches into the concrete and shall conform to Subsection 714.08 . Anchor bolts to be double nutted shall use the following procedure:
1.Install lower nut in contact with top of sole plate, and then back off 1/2 turn
2.Install upper nut snug tight to prevent lower nuts from loosening Whenever a bridge seat is off by 1/4 inch or more from its designed or adjusted elevation, corrective measures shall be required. If shims are required, they shall be a single thickness plate that meets the requirements of AASHTO M 270, Grade 250 (Grade 36) or Grade 345 (Grade 50), steel, galvanized in accordance with the requirements of Subsection 726.0 6 or metalized in accordance with the requirements of Subsection 726.0 7. Details of shims shall be furnished and approved in accordance with the requirements of Subsection 105.0 6. The cost of any necessary corrective measures, including any costs due to a delay, shall be borne by the Contractor.
b.Elastomeric Pad with External Load Plate and High -Load Multi -Rotational Bearings . During any welding, surfaces in contact with the elastomer shall be restricted to 200°F, and surfaces in contact with PTFE shall be restricted to 300°F. Temperatures shall be determined by temper ature indicating wax pencils or other suitable means. The welds for the sole plate connection should only be along the longitudinal girder axis. Transverse joints should be sealed with an acceptable caulking material. 5-247 Metal bearing plates shall be placed on a 1/8 inch thick bearing pad conforming to the requirements of Subsection 731.0 1. The bearing pad shall be the same size as the bearing plate with holes to accommodate the anchor bolts. PTFE and stainless steel slidi ng surfaces shall be protected from splatter during welding, grouting, or painting operations if applicable. High -load multi -rotational bearings shall not be disassembled once they have left the manufacturer, since the process coul d result in damage to the components or malfunction of the device. 531.0 6 METHO D OF MEASUREMENT . The quantity of Bearing Device Assembly of the type specified to be measured for payment will be the number of units used in the complete and accepted work. All bearing device components and anchor bolt assemblies will be included as part of the measure d unit. Anchor bolt assemblies include bolts, threaded rods, nuts, washers, and beveled plates required for attachment of bearing devices to the superstructure and substructure. The quantity of Remove and Replace Existing Anchor Bolt to be measured for pay ment will be the number of each anchor bolt removed and replaced in the complete and accepted work. 531.0 7 BASIS OF PAYMENT . The accepted quantity of Bearing Device Assembly of the type specified will be paid for at the Contract unit price for each. Payme nt will be full compensation for detailing, furnishing, handling, transporting, and placing the material specified, including surface preparation, protective coating, testing, anchor bolt assemblies, drilling for anchor bolts, mortar, proprietary anchoring systems, bearing device components, and welding, and for furnishing all labor, tools, equipment, and incidentals necessary to complete the work. Payment for alternate bearing designs and s ubmittals will be considered incidental to the appropriate The accepted quantity of Remove and Replace Existing Anchor Bolt will be paid for at the Contract unit price for each. Payment will be full compensation for removing the existing anchor bolt, removing and replacing the existing bearing assembly, welding, drilling the for new anchor bolt, mortar, proprietary anchoring systems, and for furnishing all labor, tools, equipment, and incidentals necessary to complete the work. 5-248 Payment will be made under: Pay Item Pay Unit
531.15 00 Bearing Device Assembly, High Load Multi -Rotational ......................... Each
531.16 00 Bearing Device Assembly, Plain Elastomeric Pad ................................ ...Each
531.17 00 Bearing Device Assembly, Steel Reinforced Elastomeric Pad ................. Each
531.18 00 Bearing Device Assembly, Elastome ric Pad w/Ext . Load Plates ............. Each
531.19 00 Remove and Replace Existing Anchor Bolt ................................ ............. Each
5-249 SECTIO N 540 – PRECAS T CONCRETE 540.0 1 DESCRIPTION . This work shall consist of manufacturing, transporting, and erecting precast concrete structure components. 540.0 2 MATERIALS . Materials shall meet the requirements of the following subsection s: Portland Cement ................................ ................................ ................................ ......... 701.02 High Early -Strength Portland Cement ................................ ................................ .......701.0 3 Portland -Pozzolan Cement ................................ ................................ ......................... 701.0 4 Portland -Limestone Cement ................................ ................................ ...................... 701.0 5 Portland Blast -Furnace Slag Cement ................................ ................................ ......... 701.0 6 Ternary Blended Cement ................................ ................................ ........................... 701.0 7 Fine Aggregate for Concrete ................................ ................................ ...................... 704.01 Coarse Aggregate for Concrete ................................ ................................ .................. 704.02 Lightweight Fine Aggregate for Concrete ................................ ................................ .704.19 Mortar, Type IV ................................ ................................ ................................ ......... 707.0 1(e) Preformed Joint Filler, Cork, and Asphalt -Treated Felt ................................ ............ 707.0 6 Polyvinyl Chloride (PVC) Waterstop ................................ ................................ ........ 707.08 Bar Reinforcement ................................ ................................ ................................ .....713.01 Mechanical Splices for Bar Reinforcement ................................ ............................... 713.02 Welded Wire Reinforcement ................................ ................................ ..................... 713.0 3 Prestressing Strand and Post -Tensioning Strand ................................ ....................... 713.0 4 Structural Steel ................................ ................................ ................................ ........... 714.02 High -Strength Low -Alloy Structural Steel ................................ ................................ 714.03 Carbon Steel Bolts, Nuts , and Washers ................................ ................................ .....714.04 High -Strength Structural Bolts and Assemblies, 120 ksi ................................ ........... 714.05 Concrete Curing Materials ................................ ................................ ......................... 725.01 Air-Entraining Admixtures ................................ ................................ ........................ 725.02(b) Retarding Admixtures ................................ ................................ ................................ 725.02(c) Water -Reducing Admixtures ................................ ................................ ..................... 725.02(e) Water -Reducing and Retarding Admixtures ................................ .............................. 725.02(f) Water -Reducing, High Range Admixtures ................................ ................................ 725.02(g) Water -Reducing, High Range, and Retarding Admixtures ................................ .......725.02(h) Accelerating Admixtures ................................ ................................ ........................... 725.02(i) Water -Reducing and Accelerating Admixtures ................................ ......................... 725.02(j) Specific Performance Admixtures ................................ ................................ ............. 725.02(k) Mineral Admixtures ................................ ................................ ................................ ...725.0 3 Waterproofing Membrane System, Type III ................................ .............................. 726.08(c) Polystyrene Insulation Board ................................ ................................ ..................... 735.01
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 656–662 of 1,380.