bearing appendix

8/2/2019 Bearing Appendix

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APPENDIX

SUPPLY, FABRICATION AND INSTALLATION OF

BEARING ASSEMBLIES

1. General

The details of design and manufacture of bearings shall be in accordance withCAN/CSA-S6-06, Clause 11.6, the Ministrys Supplement to CAN/CSA-S6-06 and theadditional requirements specified herein.

Steel fabrication shall be in accordance with SS 422. All exposed steel surfaces shall begalvanized to CAN/CSA-G164-M or metallized to CSA G189. Shop drawings for allbearing assemblies shall be submitted to the Ministry Representative for review prior tofabrication. Shop drawings shall show all details of the bearing assemblies and of thematerial proposed for use.

Stainless steel shall conform to ASTM A240-00. The face of the stainless steel incontact with PTFE (polytetrafluoretheylene polymer) shall have a bright annealed mirror

finish. The roughness of the contact surface shall be less than 0.2m arithmeticaverage for plane surfaces and 0.4 m arithmatic average for curved surfaces measuredin accordance with CSA B95.

The elastomer shall conform to the requirements of CAN/CSA-S6-06, Section 11.6.6.2.2.

PTFE shall conform to the requirements of CAN/CSA-S6-06, Clause 11.6.3.2.

The Contractor shall submit test results and certificates of compliance to the MinistryRepresentative for all materials incorporated into the bearings.

2. Unreinforced Elastomeric Bearings

Unreinforced elastomeric bearings and bearings cut from cured rolled stock shall betested only for durometer hardness.

3. Steel Reinforced Elastomeric Bearings

3.1 General

Fabrication tolerances shall be in accordance with Clause 11.6 of CAN/CSA-S6-06 and the 17th edition of the AASHTO Standard Specifications for HighwayBridges, Division II Section 18.5. The requirements of Clause 11.6 of CAN/CSA-S6-06 shall govern in the event of a conflict with those of the AASHTOrequirements. For steel reinforced elastomeric bearings the minimum cover ofelastomer over the edges of reinforcing plates shall be 5 mm.

The bearing manufacturer shall conduct compression tests as described below,either by or in the presence of an independent certified testing agency. Thetesting agency shall submit test results to the Ministry Representative.

SCHEDULE 3 - SPECIAL PROVISIONS PROJECT No.

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3.2 Nondestructive Testing - Compression Test

Each bearing shall be tested by the Contractor as follows using a concentriccompression load:

(a) The testing machine used shall have platens at least 20 mm greater in bothplan dimensions than the bearing under test.

(b) At least two dial gauge micrometers shall be positioned at the centres ofopposite sides of the bearing to measure deformation. When bearings are

tested in single vertical stacks, a steel plate shall separate the bearings anda set of dial gauge micrometers shall be installed for each bearing.

(c) The bearing shall be loaded at the rate of 1.5 MPa/minute to a load of 7.5MPa multiplied by the gross plan area. The deformations shall berecorded.

(d) The load shall be reduced at the same rate until the pressure on thebearing is 1.5 MPa, and the deformations recorded.

(e) The load on the bearing shall be maintained at 1.5 MPa for fifteen minutes,and the deformations shall be recorded.

(f) The bearing shall be reloaded to 7.5 MPa, and steps (d) to (e) shall berepeated.

(g) The bearing shall be reloaded to 10 MPa with deformations being recorded

after each 1 MPa increment.(h) A graph of the pressure versus average deformation with data recorded in

(g) shall be developed.

The rates of loading specified in step (c) and (d) also apply to steps (f) and (g).

A bearing shall be rejected based on the following deficiencies:

(a) If it displays bulging patterns under compression load which indicatelaminate placement which does not satisfy design criteria andmanufacturing tolerances or poor laminate bond.

(b) If it has more than two surface cracks which are greater than 2 mm long

and 2 mm deep.(c) If the compressive deformation exceeds 7% of the total elastomeric

thickness of the bearing during the application of the sum of the verticalserviceability loads shown on the Drawings; and

(d) If it does not meet the specified tolerances.

4. Installation

Bearings shall be installed as shown on the Drawings. Bearings shall be set to thedimensions and offsets prescribed by the manufacturer and the Drawings, and shall beadjusted as necessary to take into account the temperature at time of installation andfuture movements of the bridge due to temperature changes, release of falsework and

shortening due to prestressing.

Installation tolerances shall be in accordance with the 17th edition of the AASHTOStandard Specification for Highway Bridges, Division II, Section 18.9.


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5. Pot and Disc Bearings

The elastomer used in disc bearings shall be 100% polymer urethane. The test requiredto satisfy the hardness requirements in Clause 11.6.7.2 of CAN/CSA-S6-06 shall be inaccordance with ASTM D2240. Tensile testing shall be performed in accordance with

ASTM D412, at 500 mm/minute. The tensile stress at 100% elongation shall be at least14 MPa, and at 200% elongation at least 26 MPa. The ultimate tensile stress shall be atleast 34.5 MPa. The ultimate elongation shall be at least 220%. The compression set,

when tested according to ASTM D395 for 22 hours at 70C, shall be 40% maximum.

For pot bearings, the tolerance of fit between the piston and the pot shall be +0.75 mmto +1.25 mm.

Bearings shall be clearly marked to indicate their type and orientation.

All pot and disc bearings shall be plant-assembled and shall not be disassembledwithout special arrangement with the Ministry Representative. The Contractor shallnotify the Ministry Representative at least 7 days before assembly, so that the MinistryRepresentative can arrange for inspection.

6. Payment

Payment for bearing assemblies will be made at the Lump Sum Price(s) bid or UnitPrice(s) bid. Payment shall include quality control, all necessary materials, shopdrawings, submission of test results and certificates of compliance, the supply,fabrication, galvanizing/metallizing and/or painting of steel components as required andinstallation and grouting of the bearing assemblies and anchor bolts.


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