1111HIGH LOAD MULTI-ROTATIONAL BEARINGS

1111.01DESCRIPTION—This work is the fabrication of high load multi-rotational bearings, as indicated

1111.02MATERIAL—Use new material at all times, with no reclaimed material incorporated in the finished

bearing.

bars and shear restriction pins and sleeves. Furnish guide bars and shear restriction mechanisms as specified by the manufacturer and that are approved.

Furnish only virgin, crystallization-resistant polychloroprene (neoprene) or virgin, natural polyisoprene (natural rubber) as the raw polymer for the elastomeric rotational element used in the construction of pot bearings. Use individually molded and one-piece elastomers. Provide neoprene and natural rubber used in these bearings with physical properties, which conform to the following ASTM or AASHTO requirements, with the modification noted:

Compound ASTM Requirement AASHTO Requirement Neoprene ASTM D2000, Line Call Out M2BC520A14B14 AASHTO M 251 Natural Rubber ASTM D2000, Line Call Out M4AA520A13B33 AASHTO M 251

Modification: 1) Prepare samples for compression set tests using a Type 2 die. 2) Shore A durometer hardness = 50 ± 10 Points

Physical Property ASTM Test Method Requirements Compound A Compound B Min. Max. Min. Max. Hardness, Type D Durometer D2240 46 50 60 64 Tensile Stress, psi At 100% elongation At 200% elongation

D412

1,500 2,800

— —

2,000 3,700

— — Tensile Strength, psi D412 4,000 — 5,000 — Ultimate Elongation, % D412 350 — 220 — Compression Set, 22 h @ 158F, % D395 Method B — 40 — 40

and PTFE structures, PTFE -perforated metal composite, back -up materials and all other parts of fixed or expansion bearings containing PTFE materials having the friction, mechanical, physical, and weathering properties specified in 1111.02(c) or indicated.

D4894. Provide resin with specific gravity of 2.13 to 2.19 and Second Melting Peak Temperature of 621F ± 18F.

by weight), carbon (25% maximum filler percent by weight) or fabric containing PTFE fibers, or other approved inert filler materials.

of 385F to 500F when bonding the PTFE to its steel substrate. Provide adhesive material in epoxy resin conforming to the requirements of Federal Specification MMM-A-134 FEP film or approved equal.

Ensure that finished unfilled PTFE sheet conforms to the following requirements:

Tensile Strength (minimum) ASTM D638 2,800 psi Elongation (minimum) ASTM D638 200%

material. Ensure that finished filled PTFE sheets containing glass fiber or carbon conform to the following requirements:

Requirement ASTM Method 15% Glass Fibers 25% Carbon Mechanical Tensile Strength (minimum) Elongation (minimum)

D638 D638

2,000 psi 150%

1,300 psi 75% Physical Specific Gravity Melting Point

D792 D4894, D4895

2.20 ± 0.03 621F ± 18F

2.10 ± 0.03 621F ± 18F

PTFE, fluorocarbon fibers and other fibers as required by proprietary designs. Use PTFE fibers with the following typical physical properties:

Physical Requirement ASTM Method PTFE Fibers Tensile Strength (minimum) D2256 2,400 psi Elongation (minimum) D2256 35%

structures consisting of a phosphor bronze plate with a 0.010 -inch thick porous bronze surface layer into which is impregnated a lead/PTFE compound. Provide an overlay of compounded PTFE not less than 0.001 inch thick. Ensure that the phosphor bronze back plate conforms to ASTM B100 and the porous bronze layer conforms to ASTM B103/B103M.

side and completely through a 1.32-inch perforated stainless steel ASTM A240, Type 304 sheet.

factory treat one side of the PTFE sheet using the sodium naphthalene or sodium ammonia process.

A240, Type 304 with an ANSI 0.02 mil surface finish or less. Attach a stainless steel sheet by an approved welding procedure, which keeps the sheet in contact with the substrate, or weld a stainless steel overlay using Type 309L electrodes. Use 0.05-inch minimum thickness stainless steel.

conform to the requirements of the method of fastening to the structure as indicated.

12.a Attachment of PTFE Material. Factory-bond, mechanically connect, or recess into the back- up material PTFE material as indicated.

12.a.1 Bonding. Perform the bonding at the factory of the manufacturer of the fixed or expansion bearings under controlled conditions and according to the written instructions of the manufacturer of the approved adhesive system. Ensure that after completion of the bonding operation, the PTFE surface is smooth and free from bubbles. Then polish filled PTFE surfaces.

12.a.2 Mechanically Fastened. If mechanically fastened, fasten PTFE sheet as indicated with the size, type, and number of fasteners required, taking care to have full bearing of the fastener used in the PTFE sheet and back-up material.

12.a.3 Fabric Containing PTFE Fibers. Bond or mechanically attach the fabric to a rigid substrate. Supply fabric capable of carrying unit loads of 10,000 pounds per square inch without cold flow. Provide a fabric- substrate bond capable of withstanding a shear force equal to 10% of the perpendicular or normal application loading without delamination in addition to the shear force developed as a result of the natural bearing friction shear force.

to ASTM B16, Temper H02, half hard.

for Bronze Castings for Bridges and Turntables, ASTM B22. Furnish alloy C91100 unless otherwise specified. Cast bronze plates according to the indicated details. Plane sliding surfaces parallel to the movement of the spans and polish them unless otherwise indicated.

characteristics as well as lubricating qualities and capable of withstanding long term atmospheric exposure, de-icing materials, and water. Do not use molybdenum disulfide and other ingredients, which promote electrolytic or chemical action between the bearing elements. Do not use shellac, tars and asphalts, or petroleum solvents as binders.

1111.03FABRICATION—

flame-cut shape to a plate. Test all welded areas by the magnetic particle method meeting AWS D1.5/D1.5M, Clause 6 requirements. Welding is as specified in Section 1105.03(m). Machine inside diameter (ID) of pots to a tolerance of ±0.005 inch up to 20 inches ID and ±0.007 inch over 20 inches ID. Pots machined parallel to the inside to Class “A” tolerance. Machined surfaces to an ANSI 125 micro-inch rms finish or better. Elastomeric discs with tolerances as follows:

• Diameters up to 20 inches, ±1/16 inch

• Diameters greater than 20 inches, ±3/32 inch

• Total thickness of all pieces, -0 inch, +1/8 inch

• Mold discs in one piece, do not layer elastomer.

Pistons with tolerances as follows:

• Diameters up to 20 inches, ±0.005 inch.

• Diameters greater than 20 inches, ±0.007 inch.

• Upper side, Class “A” tolerance. Lower side, Class “B” tolerance.

• Diameters up to 20 inches, ±1/16 inch.

• Diameters greater than 20 inches, ±3/32 inch.

• Thickness, -0 inch, +1/8 inch.

• Mold discs in one piece, do not layer elastomer.

Furnish bearing plates for discs with tolerances as follows:

• Diameters up to 20 inches, ±0.005 inch.

• Diameters greater than 20 inches, ±0.007 inch.

• Inside surfaces facing disc Class “A” tolerance and minimum ANSI 125 micro -inch rms finish.

• Outside surfaces, Class “A” tolerance and minimum ANSI 125 micro-inch rms finish.

• Machined diameters, ±0.015 inch.

• Convex radius dimensions, +0.000 inch, -0.010 inch.

• Concave radius dimensions, +0.010 inch, -0.000 inch.

• Mating surfaces to be as indicated, external edges may be “as cast” or flame-cut.

• Lower surface of convex element Class ”C” tolerance.

Furnish masonry and distribution plates with tolerances as follows:

• Plan dimensions up to 30 inches, -0 inch, +3/16 inch

• Plan dimensions over 30 inches, -0 inch, +1/4 inch

• Thickness tolerance, -0.030 inch, +0.060 inch

• Masonry plates used with pot, disc, or spherical bearings, Class “C” tolerance for the underside and Class “A” tolerance for the upper side.

Provide PTFE sliding surfaces with tolerances as follows:

• Plan dimensions “total design area,” +5%, -0%

• Substrate flatness: Class “A” tolerance for pot and disc bearings, Class “B” tolerance for spherical bearings.

• Thickness, -0 inch, +0.063 inch per AASHTO LRFD Construction Specifications Table 18.1.4.2 -1

Seal weld the stainless steel sheet around the entire perimeter using techniques, which ensure it will remain in contact with the backing plate. Provide an ANSI 20 micro-inch rms finish or better. Flatness to Class “A” tolerance. Furnish sole plates with tolerances as follows:

• Plan dimensions up to 30 inches, -0 inch, +3/16 inch

• Plan dimensions over 30 inches, -0 inch, +1/4 inch

• Center line thickness, -1/32 inch, +1/8 inch

• Flatness of surface in contact with steel beams, Class “B” tolerance; in contact with fresh concrete, none; in contact with stainless steel sliding surface, Class “A” tolerance; in contact with another steel plate, Class “B” tolerance.

• Minimum edge thickness, 3/4 inch

• Machined bevels to an angular tolerance of ±0.002 radians (0.115 degrees)

• Flatness of beveled surfaces, Class “A” tolerance

Provide guide bar with tolerances as follows:

• Length, unless integral with plate, ±1/8 inch

• Section dimensions, ±1/16 inch

• Flatness where it bears on another plate, Class “A” tolerance

• Bar-to-bar, nominal dimension ±1/32 inch

• Not more than 1/32 inch out of parallel

Overall bearing height not more than 1/8 inch or less than 0 inch from nominal dimension. Chamfer all edges.

following method: Place a precision straightedge, longer than the nominal dimension to be measured, in contact with the surface to be measured or as parallel to it as possible. Select a feeler gage having a tolerance of ±0.001 inch and attempt to insert it under the straightedge using the least number of blades. Flatness is acceptable if the feeler gage does not pass under the straightedge. Flatness tolerances are arranged in the following classes:

Class “A” = 0.0005 inch × “Nominal Dimension” Class “B” = 0.001 inch × “Nominal Dimension” Class “C” = 0.002 inch × “Nominal Dimension”

“Nominal Dimension” is defined as the actual dimension of the plate, in inches, under the straightedge. In determining flatness, the straightedge may be located in any position on the surface being evaluated and not necessarily at 90 degrees to the edges.

Ignore a 1-inch wide border around the plate in determining flatness.

If the time of exposure before welding is to exceed 90 calendar days, provide metal surfaces with a protective coating of clear lacquer or other approved coating. Paint all steel surfaces as indicated and according to recommendations of the coating manufacturer.

Representative.

at the manufacturer's plant. A “lot” consists of one of the following:

• No more than 25 fixed bearings of one “load category”

• No more than 25 expansion bearings of one “load category”

One “load category” may consist of bearings of differing vertical force capacity but the bearings may not exceed a range of capacity differing by more than 300 kips.

Test a sample from each lot of expansion bearings. For all guided and nonguided expansion type bearings, measure the sliding coefficient of friction at the bearing's design capacity as specified in Section 1111.03(e)2.a, and on the fifth and fiftieth cycles, at a sliding speed of 1 inch per minute. Calculate the sliding coefficient of friction as the horizontal force necessary to maintain continuous sliding of one bearing, divided by the bearing's vertical design capacity. The test results will be evaluated as follows:

• Measured sliding coefficients of friction not to exceed 3%.

• Visually examine the bearing both during and after the test. Any resultant visual defects, such as bond failure, physical destruction, cold flow of TFE to the point of debonding, or damaged components will cause rejection of the lot.

2.a Test Method. Obtain approval of the test method and equipment and comply with the following requirements:

• Arrange the test so that the coefficient of friction on the first movement of the manufactured bearing can be determined.

• Clean the bearing surface before testing.

• Conduct the test at maximum working stress for the TFE surface with the test load applied continuously for 12 hours before measuring friction.

• Determine the first movement static and dynamic coefficient of friction of the test bearing at a sliding speed of less than 1 inch per minute, which is not to exceed the coefficient of friction for design in Article 14.7.25 of the LRFD specification.

• Subject the bearing specimen to 100 movements of at least 1 inch of relative movement and, if the test facility allows, the full design movement at a speed of less than 1 foot per minute. Following this test, determine the static and kinetic coefficient of friction again, which is not to exceed the values specified in Section 1111.03(e)2.a, fourth bullet. Verify that the bearing or specimen shows no appreciable sign of bond failure or other defects.

Bearings represented by test specimens passing the above requirements will be approved for use in the structure subject to on-site inspection for visible defects. Bearings not damaged during the testing of performance characteristics may be used in the work.

a test bearing to 150% of the bearing's rated design capacity and simultaneously subject it to a rotational range of 0.02 radians (1.146 degrees) or design rotation, whichever is greater, for a period of 1 hour. Visually examine the bearing both during the test and upon disassembly after the test. Any resultant visual defects, such as extruded or deformed elastomer, polyether urethane or TFE, damaged seals or limited or cracked steel, will cause rejection of the lot. During the test, for pot bearings maintain continuous and uniform contact between the steel bearing plate and steel piston for the duration of the test. For disc bearings maintain continuous and uniform contact between the polyether urethane element and the bearing plates and between the sliding steel top plate and the upper bearing plate for the duration of the test. Any observed lift-off will cause rejection of the lot.

to LTS for material testing to ensure compliance with appropriate material specifications.

fabricator, shipped to the job site, and stored without relative movement of the bearing parts or disassembly at any time. Wrap bearings in moisture resistant and dust resistant material to protect against shipping and job site conditions. Match mark the bearings to indicate normal position of each bearing. Take care to ensure that bearings are stored at the job site in a dry sheltered area free from dirt or dust until installation. Inspect bearings within one week after arriving on the project. Do not disassemble unless the fabricator's representative is present. Following inspection, rewrap the bearings to keep them clean until installation. Do not remove the sole and top plates of bearings for separate attachment to the structure except under the direct supervision of the fabricator. Do not remove the sole and top plates of bearings for separate attachment to the structure except under the direct supervision of the fabricator. With each shipment, enclose a copy of the materials, fabrication, and testing compliance certifications.

• The total quantity of each kind of bearing required (fixed, guided-expansion, or non-guided expansion), grouped first according to type (load range) and then by actual design capacity.

• Plan view and section elevation including all relative dimensions.

• Details of all components and sections showing all materials incorporated into the bearing.

• All ASTM, AASHTO, and other material designations.

• The maximum design coefficient of friction as indicated.

• Clearly describe and detail any welding process used in the bearing manufacture that does not conform to the approved processes of the AWS code.

• Vertical, horizontal, rotation, movement, and load capacity.

• A schedule of all bearing offsets, if required by the project.

• Alignment plans.

• Paint or coating requirements.

• Installation scheme.

• Complete design calculations verifying conformance with the provisions of this specification. Stress analysis and the mechanics of standard bearing details are not required.

• Anchorage details.

• Bearing pre-set details.

• Location of the fabrication plant.

• The manufacturer's name and the name of its representative responsible for coordinating production, sampling, and testing.

106.03(b)3 and containing the following:

• Material test reports for all steels used except AISI C1018 and C1020 for which a mill conformance certificate is acceptable.

• Certificate of Compliance for all non-ferrous metals.

• Material test reports for any elastomeric components.

• Certificate of Compliance for PTFE and any adhesive used.

• A Certificate of Compliance for the bearings, executed by an officer of the manufacturing company.

• Certificate of Compliance for any dowels or bolts supplied.

• Test reports for the performance tests.