Use with Ref Spec 59PJSA

51SPHR_R10-04-06

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Use for PTFE with spherical bearing surfaces. All bearings are to be detailed on the plans and designated fixed or expansion.

Use S8-W04 with this spec; add PTFE spherical bearing to Welding QC specific description item list in S8-W04.

Use with Ref Spec 59PJSA.

Insert in the special provisions as 51526 for PTFE Spherical Bearings in concrete bridges. (Add after SSP55800 for PTFE Spherical Bearings in steel bridges. For PTFE Spherical Bearings in concrete and steel bridges choose one of the above options and put reference in other.)

101.__PTFE SPHERICAL BEARING

PTFE spherical bearings, consisting of polytetrafluoro-ethylene (PTFE) and stainless steel bearing surfaces, structural steel plates and anchors, shall conform to the details shown on the plans, the provisions in Section51, "Concrete Structures," of the Standard Specifications, and these special provisions.

2. Edit if only one type shown on plans.

PTFE spherical bearings shall be of 2types:

A.Fixed type with spherical bearing surfaces.

B.Expansion type with spherical and sliding bearing surfaces.

The manufacturer of the PTFE spherical bearings shall show evidence that PTFE spherical bearings furnished by the same manufacturer and used in conditions similar to this application have had at least 3years of satisfactory service at each of 2projects.

A qualified representative of the manufacturer shall be present during installation of the first bearing and shall be available for advice during any remaining installations.

5. Edit when no PTFE bearing on railroad bridge.

The Contractor shall submit working drawings of the PTFE spherical bearings to the Offices of Structure Design (OSD) for approval in conformance with the provisions in Section51.02, "Plans and Working Drawings," of the Standard Specifications. For initial review, 6sets of such drawings shall be submitted for railroad bridges and 4sets shall be submitted for other structures. After review, between 6 and 12sets, as requested by the Engineer, shall be submitted to OSD for final approval and for use during construction.

6*. Edit to suit. Use "and details of temporary support" for PTFE bearings at locations other than hinges. Plans must show temporary support details at hinges.

The working drawings for PTFE spherical bearings shall include a description of the method of mechanical interlocking of the PTFE fabric to the metallic substrate and details of temporary support for the PTFE bearing sole plate during concrete placement.

Working drawings shall be 279mmx432mm or 559mmx864mm in size and each drawing and calculation sheet shall include the name of the structure as shown on the contract plans, District-County-Route, bridge number, and contract number.

8. Edit when no PTFE bearing on railroad bridge.

Working drawings shall be submitted sufficiently in advance of the start of the affected work to allow time for review by the Engineer and correction by the Contractor of the drawings without delaying the work. The time shall be proportional to the complexity of the work but in no case shall the time be less than 56days for railroad bridges or 42days for other structures after complete drawings and all support data are submitted.

9. Use when PTFE bearing on railroad bridge is on job.

For railroad bridges, approval of the working drawings by the Engineer will be contingent upon the working drawings being satisfactory to the railroad company involved.

At the completion of each structure on the contract, one set of 279mmx432mm prints on 75g/m2 (minimum) bond paper of the corrected original tracings of all working drawings for each structure shall be furnished to the Engineer. Reduced prints of drawings that are common to more than onestructure shall be submitted for each structure. An index prepared specifically for the drawings for each structure containing sheet numbers and titles shall be included on the first reduced print in the set for each structure. Reduced prints for each structure shall be arranged in the order of drawing numbers shown in the index.

The edge of the corrected original tracing image shall be clearly visible and visually parallel with the edges of the page. A clear, legible symbol shall be provided as near to the upper left side of each page as is feasible within the original print to show the amount of reduction and a horizontal and vertical scale shall be provided on each reduced print to facilitate enlargement to original scale.

12. Use when PTFE bearing on railroad bridge is on job.

For railroad bridges, in addition to the reduced prints of the working drawings, the Contractor shall furnish to the Engineer one set of working drawings consisting of either ink tracings on cloth, ink tracings on polyester base drafting film, silver sensitized cloth duplicate tracings, or silver sensitized polyester based reproduction films with matte surface on both sides.

PTFE spherical bearings shall be installed on surfaces prepared in conformance with the provisions in Section553.19, "Bearings and Anchorages," of the Standard Specifications.

The manufacturer shall furnish Certificates of Compliance in conformance with the provisions in Section61.07, "Certificates of Compliance," of the Standard Specifications for all material used in the PTFE spherical bearings. The certification shall be supported by a copy of the results of all proof tests performed on the bearings.

PTFE surfaces of PTFE spherical bearings shall be unfilled PTFE fabric made from virgin PTFE oriented multifilament and other fibers. The resin in the filaments shall be virgin PTFE material (not reprocessed) in conformance with the requirements of ASTM Designation:D4441.

At the highest point of substrate and after compression, the PTFE fabric shall have a minimum thickness of 1.6mm and a maximum thickness of 3.2mm.

Flat stainless steel surfaces shall be a weld overlay on structural steel plate, or solid or sheet stainless steel conforming to the requirements of ASTM Designation:A240, Type304 with a minimum thickness of 3.2mm.

Curved stainless steel surfaces shall be solid stainless steel conforming to the requirements of ASTM Designation:A240, Type304.

Curved stainless steel surfaces with dimensions shown on the plans exceeding 101.6mm in thickness shall be either a weld overlay on structural steel plate or solid stainless steel conforming to the requirements of ASTM Designation: A240, Type304. Stainless steel sheet will not be allowed.

When a weld overlay is used for stainless steel surfacing, the overlay shall be placed by submerged arc welding using Type309L electrodes. The finished overlay shall have a 2.38mm minimum thickness after welding, grinding, and polishing.

When stainless steel sheets are used for stainless steel surfacing, the sheets shall be attached by perimeter arc welding using Type309L electrodes. After completion of the weld operation, the stainless steel surface shall be smooth and free from waves.

Steel plates, except stainless steel, shall conform to the requirements of ASTM Designation:A709/A709M, Grade36[250], 50[345], or 50W[345W].

Stud connectors shall conform to the provisions in Section552, "Materials," of the Standard Specifications.

Welding of structural steel shall conform to the requirements of AWSD1.1. Welding of structural steel to stainless steel shall conform to the requirements of AWSD1.6.

Convex plate radius dimension tolerances shall be 0.000 to -250µm. Concave plate radius dimensions shall be +250 to 0.000µm.

The bearing manufacturer shall have full size convex and concave metal templates for the 2spherical surfaces of each bearing radius. The templates shall be available to the inspector during all bearing inspections.

The PTFE fabric on spherical or sliding bearing surfaces shall be epoxy bonded and mechanically interlocked to the steel substrate. All bonding shall be done under controlled factory conditions. The mechanical interlock on the spherical concave surface must be integrally machined into the steel substrate. Welded retention grids will not be allowed on the concave surface. Any edges other than the selvage shall be oversown or recessed so that no cut fabric edges are exposed.

After completion of the bonding operation the PTFE surface shall be smooth and free from bubbles.

The surface of the bearing elements shall be controlled such that upon completion of the bearing assembly the PTFE to stainless steel interface shall be in full bearing.

The mating surface of the flat stainless steel with the PTFE surfacing shall have a minimum #8mirror finish as determined in conformance with the requirements in ANSI StandardB46.1. The mating surface of the curved stainless steel with the PTFE surfacing shall have a finish of less than 0.4µm root-mean-square (rms), as determined in conformance with the requirements in ANSI StandardB46.1.

Metal surfaces of bearings exposed to the atmosphere and in contact with the structure of the completed work, except stainless steel surfaces, shall be cleaned and painted in conformance with the provisions in "Clean and Paint PTFE Bearings" of these special provisions.

PTFE spherical bearing assemblies shall be assembled at the factory. Each assembly shall have a minimum of 4temporary steel straps that are bolted to threaded holes in the masonry and sole plates so that the entire assembly is shipped as a unit and remains intact when uncrated and installed. Welding of the steel straps will not be allowed. Straps must be adequate for vertical lifting purposes. Bearing dismantling will only be allowed under the direction and in the presence of the Engineer.

During fabrication, the maximum temperature of bonded PTFE surfaces shall be 150°C.

Damaged bearings and bearings with scratched mating surfaces shall be returned to the factory for replacement or resurfacing.

PTFE spherical bearing sole plates shall be temporarily supported during concrete placement. Temporary supports shall prevent the rotation or displacement of the bearing during concrete placing operations. Temporary supports shall not inhibit the functioning of the PTFE spherical bearing after concrete is placed. Temporary supports shall not restrict the movement at bridge joints due to temperature changes and shortening from prestress forces. Materials for temporary supports within the limits for placing concrete shall conform to the requirements for form fasteners.

36*. Designer to furnish value of first movement static coefficient of friction (usually about 0.06). Different values may be needed if bearing stress varies.

PTFE spherical bearings shall have a first movement static coefficient of friction not exceeding ______.

Prior to proof testing, all bearings shall be permanently die-stamped on 2 of 4sides with markings consisting of bearing number and contract number. Each bearing shall have a unique bearing number and match marks on plate edges to insure correct assembly at the job site.

Full sized PTFE spherical bearings shall be proof tested and evaluated for compression and coefficient of friction in the presence of the Engineer. The proof tests shall be performed on samples randomly selected by the Engineer from the production bearings to be used in the work. Proof testing shall be performed by the Contractor at the manufacturer's plant or at an approved laboratory. If proof tests cannot be performed at the specified load, the Contractor shall submit to the Engineer for review and approval a testing plan listing additional physical tests. These tests shall be performed in the presence of the Engineer and shall demonstrate that the requirements for proof testing at the specified load are satisfied. The Contractor shall give the Engineer at least 7days notice before beginning proof testing. Proof testing of PTFE spherical bearings shall conform to the following requirements:

A.One bearing per lot of production bearings shall be proof tested. A lot is defined as 25bearings or fraction thereof of the same type, within a load category. Bearings in 2load categories with vertical load capacities within 800kN of each other will be considered in oneload category for testing.

Para38B1 or 38B2, edit if only one type shown on plans.

B.The bearing types and proof tests required for each type shall be as follows:

1.Fixed type bearings shall be proof tested for compression.

2.Expansion type bearings shall be proof tested for compression and coefficient of friction.

C.A load category shall consist of bearings of differing vertical load capacity within a range defined as follows:

1.Bearings with less than or equal to 2225kN maximum vertical load capacity.

2.Bearings with greater than 2225kN but less than or equal to 8900kN maximum vertical load capacity.

3.Bearings with more than 8900kN maximum vertical load capacity.

38D. The maximum vertical load and design rotation of bearing shall be shown on the plans.

D.Proof tests for compression: The bearing shall be held at the design rotation or 0.02radians, whichever is greater, for one hour at 1.5times the maximum vertical load shown on the plans for the bearing. The device shall be in a rotated position during the test. The rotation may be imposed on the bearing by inserting a beveled plate between the bearing and the restraining surface prior to loading.

38E. Use only if Para38B2 is used.

E.Proof tests for coefficient of friction: The tests shall be performed at the minimum vertical load shown on the plans for the bearing with the test load applied for 12hours prior to friction measurement and the following:

1.The tests shall be arranged to allow measurement of the static coefficient of friction on the first movement of the bearing.

2.The first movement static and dynamic coefficients of friction shall be measured at a sliding speed not exceeding 25millimeters per minute and shall not exceed the specified coefficient of initial static friction.

3.The test bearings shall be subjected to a minimum of 100 movements of at least 25mm of relative movement at a sliding speed not exceeding 300millimeters per minute. After cycling, the first movement static and dynamic coefficients of friction shall be measured again at a sliding speed not exceeding 25millimeters per minute and shall not exceed the specified coefficient of initial static friction.

F.The bearing surfaces shall be cleaned prior to proof testing.

G.Proof testing of bearings shall be done after conditioning specimens for 12hours at 21°±8°C.

H.The proof tested bearings shall show no visible sign of: (1)bond failure of bearing surfaces, (2)separation or lift-off of plates from each other or from PTFE surfaces, or (3)other defects. When a proof tested bearing fails to comply with these specifications, all bearings in that lot shall be individually tested for acceptance.

I.Proof test results shall be certified correct and signed by the testing laboratory personnel who conducted the test and interpreted the test results. Proof test results shall include the bearing numbers of the bearings tested.

Quantities of PTFE spherical bearings will be determined as units from actual count in the completed work. A PTFE spherical bearing with more than onePTFE surface shall be considered a single PTFE spherical bearing.

The contract unit price paid for PTFE spherical bearing shall include full compensation for furnishing all labor, materials, tools, equipment, and incidentals, and for doing all the work involved in constructing the bearing, complete in place, including masonry and sole plates, anchor bolts and sleeves, mortaring of bolts, temporary supports, proof testing, and cleaning and painting of PTFE spherical bearings, as shown on the plans, as specified in the Standard Specifications and these special provisions, and as directed by the Engineer.

41. Increase reduction in payment to $10,000 for more than 480km and $10,000 ($20,000 total) for more than 4800km when quantity of bearings exceeds 2lots.

If a portion or all of PTFE spherical bearings are either fabricated or tested at a site more than 480air line kilometers from both Sacramento and Los Angeles, additional shop inspection expenses will be sustained by the State. Whereas it is and will be impractical and extremely difficult to ascertain and determine the actual increase in such expenses, it is agreed that payment to the Contractor for PTFE spherical bearings will be reduced $5,000 for each fabrication or testing site located more than 480air line kilometers from both Sacramento and Los Angeles and an additional $10,000 ($15,000 total) for each fabrication or testing site located more than 4800air line kilometers from both Sacramento and Los Angeles.