Appendix - Supply, Fabrication and Installation of Bearing Assemblies

plantcalicobeansUrban and Civil

Nov 29, 2013 (3 years and 11 months ago)

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SCHEDULE 3
-

SPECIAL PROVISIONS PROJECT No.








1

of
3






APPENDIX


SUPPLY, FABRICATION AND INSTALLATION OF

BEARING ASSEMBLIES



1.

General


The details of design and manufacture of bearings shall be in accordance with
CAN/CSA
-
S6
-
06
, Clause 11.6
, the Ministry’s Supplement to CAN/CSA
-
S6
-
06

and the
additional requi
rements specified herein.


Steel fabrication shall be in accordance with SS 422. All exposed steel surfaces shall be
galvanized to CAN/CSA
-
G164
-
M or metal
l
ized to CSA G189. Shop dra
wings for all
bearing assemblies shall be submitted to the Ministry Representative for review prior to
fabrication. Shop drawings shall show all details of the bearing assemblies and of the
material proposed for use.


Stainless steel shall conform to ASTM

A240
-
00. The face of the stainless steel in
contact with
PTFE

(
poly
tetrafluoretheylene polymer) shall have a bright annealed mirror
finish. The roughness of the contact surface shall be less than 0.2

m arithmetic
average for plane surfaces and 0.4
µ
m a
rithmatic average for curved surfaces measured
in 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 sh
all submit test results and certificates of compliance to the Ministry
Representative for all materials incorporated into the bearings.


2.

Unreinforced Elastomeric Bearings


Unreinforced elastomeric bearings and bearings cut from cured rolled stock shall
be
tested 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 17
th

edition of the AASHTO Standard Specifications for Highway
Bridges, D
ivision 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 AASHTO
requirements. For steel reinforced elastomeric bearings the minimum cover of
elastomer over the edges of reinforcin
g 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. The
testing agency shall submit test results to the Ministry Representative.


SCHEDULE 3
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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 concentric
compression load:


(a)

The testing machine used shall have platens at least 20 mm greater in both
plan dimensions than the bearing un
der test.

(b)

At least two dial gauge micrometers shall be positioned at the centres of
opposite sides of the bearing to measure deformation. When bearings are
tested in single vertical stacks, a steel plate shall separate the bearings and
a set of dial g
auge 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 7.5
MPa multiplied by the gross plan area. The deformations shall be
recorded.

(d)

The load shall be reduced at the same rate
until the pressure on the
bearing 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 be
repeated.

(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 s
pecified 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 indicate
laminate placement which does not satisfy design crit
eria and
manufacturing 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 a
pplication of the sum of the vertical
serviceability 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 the
dimensions and off
sets
prescribed by the manufacturer and the Drawings, and shall be
adjusted as necessary to take into account the temperature at time of installation and
future movements of the bridge due to temperature changes, release of falsework and
shortening due to
prestressing.


Installation tolerances shall be in accordance with the 17
th

edition of the AASHTO
Standard 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 required
to satisfy the hardness requirements in Clause 11.6.7.2 of CAN/CSA
-
S6
-
06
shall be in
accordance with ASTM D2240. Tensile testing shall be performed in accordance with
ASTM D412, at 500 m
m/minute. The tensile stress at 100% elongation shall be at least
14 MPa, and at 200% elongation at least 26 MPa. The ultimate tensile stress shall be at
least 34.5 MPa. The ultimate elongation shall be at least 220%. The compression set,
when tested a
ccording to ASTM D395 for 22 hours at 70

C, shall be 40% maximum.


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


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


All pot and d
isc bearings shall be plant
-
assembled and shall not be disassembled
without special arrangement with the Ministry Representative. The Contractor shall
notify the Ministry Representative at least 7 days before assembly, so that the Ministry
Representative
can arrange for inspection.


6
.

Payment


Payment for bearing assemblies will be made at the Lump Sum Price(s) bid or Unit
Price(s) bid. Payment shall include quality control, all necessary materials, shop
drawings, submission of test results and certifica
tes of compliance, the supply,
fabrication, galvanizing/metal
l
izing

and/or painting

of steel components as required and
installation and grouting of the bearing assemblies and anchor bolts.