erical) will be shown or specified.

(b) Elastomeric
Bearings -
Design, fabricate, test and install
elastomeric bearings
according to
AASHTO LRFD Design Specifications and Section 02571
.
Select elastomeric bearings from the QPL.

(c)

Rockers and Hangers - Furnish and install bearings, such as rockers and hangers, which consist
entirely of structural steel, according to Section 00560.


00582.02 Definitions:

Composite Bearing - Bearing having a rotational element between an upper and a lower unit. This
includes disc bearings, fabric pad bearings, pot bearings and spherical bearings.

Disc Bearing - Composite bearing whose rotational element is comprised of a polyether urethane disc with
an upper and lower unit.

Elastomeric Bearing - Bearing consisting of a single layer of elastomer (plain) or of several layers of
elastomer alternated with steel plates (reinforced).

Fabric Pad Bearing - Composite bearing whose rotational element is a preformed fabric pad.

Fixed - Restrained against all horizontal structural movement.

Guided - Able to accommodate structural movement in a specified horizontal direction.


Guide Bars - The elements that restrain the lateral movement of a sliding bearing.


Nonguided - Able to accommodate structural movement in all horizontal directions.

Pot Bearing - Composite bearing whose rotational element is a piston supported on an elastomeric disc,
totally confined within a base pot cylinder.

Spherical Bearing - Composite bearing whose rotational element consists of an upper plate with a
spherical concave bottom surface and a lower plate with a spherical convex top surface.

Materials

00582.10 General - Use materials meeting the requirements of Sections 02570 and 02571, as
applicable.

Composite Bearings

00582.20 General - Unless otherwise shown, use only one type of composite bearing per bridge
,

subject to the following requirements:

(a)
Make composite bearings, including all plates except distribution plates and masonry plates,
removable and replaceable.

(b)
Design rotational elements between upper and lower units to meet the following:

(1) Upper Unit - The upper unit shall consist of a distribution plate that is permanently attached to the
superstructure and a sole plate attached to the distribution plate with cap screws. For a guided or
nonguided bearing, a stainless steel sheet shall be welded to the bottom surface of the sole plate.
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6-20
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selected
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Furnish and install
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as shown or specified
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¶
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¶
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Design of
Deleted:
.
Deleted:
Design according to the
current AASHTO Standard
Specifications for Highway Bridges,
(2) Lower Unit - The lower unit shall consist of a masonry plate permanently anchored to the structural
support and a base plate attached to the masonry plate with cap screws. A separate masonry plate and
base plate are not necessary for fabric pad bearings fabricated as outlined in 00582.27, third paragraph.

(3) Bearing-to-Base Connection:

The base pot of a pot bearing, the lower bearing plate of a disc bearing, or the convex plate of
a spherical bearing shall be welded to the base plate.
For guided or nonguided bearings, a polytetrafluoroethylene (
PTFE
) sheet shall be recessed
into and bonded to the top surface of the piston of a pot bearing, the upper bearing plate of a
disc bearing, the top surface of the concave plate of a spherical bearing, or a steel backing
plate bonded to the top surface of a fabric pad forming a sliding surface with the stainless steel
surface of the sole plate.
For fixed bearings, the piston of a pot bearing, the upper bearing plate of a disc bearing, or the
concave plate of a spherical bearing shall be welded to the sole plate.

Design for loads, movements, and rotations as shown
in the contract documents
.

Use schematic drawings, and/or details of bearings shown, to describe the attachment of the upper unit to
the superstructure, and the attachment of the lower unit to the substructure.

00582.21 Disc
Bearings - Design disc bearings according to

the following:




(

The shear restriction mechanism shall allow free rotation but prevent any shear being applied to the
rotational element.

Each guided bearing shall resist the total horizontal load at the bent or hinge where it is located.




00582.25
Composite Bearings with Polytetrafluoroethylene (
PTFE
) Sliding Surface:



(a)
PTFE
Sliding Surfaces -
Use only woven PTFE.



Recess
PTFE
1/16 inch into the material it is bonded to for all composite bearings
.

Bond
PTFE
to the steel substrate sufficiently to develop a horizontal force equal to a minimum of 10% of the
vertical design capacity shown, in addition to the shear force developed as a result of the natural bearing
friction shear force.


(b)
PTFE
Rotational Surface for Spherical Bearings -


PTFE
sheet minimum thickness shall be 1/8 inch, and the sheet shall be recessed 1/16 inch into the
spherical element.

PTFE
fabric minimum thickness shall be 1/16 inch when measured according to ASTM D 1777.

(c)
Stainless Steel Sliding Surfaces -
Provide a flat stainless steel sliding surface which completely covers the
PTFE
surface in all operating
positions, plus at least 2 inches more in every direction of possible movement.

Design a spherical stainless steel rotational surface attached to the convex surface of the spherical convex
plate of each spherical bearing so that it completely covers the convex surface of the plate.

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TFE
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(a) Upper and Lower
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Provide a limiting ring by
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The thickness of the plate
Inserted:
The thickness of the plate
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¶
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<#>The depth of the
Deleted:
(b) Polyether Urethane
Deleted:
36 MPa (
Deleted:
5,250 psi
Deleted:
)
Deleted:
at the vertical design
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c) Central Shear
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00582.22 Fabric Pad
Inserted:
Provide fabric pad
Deleted:
Design fabric pad bearings
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¶
Deleted:
The average maximum
Deleted:
00582.23 Pot Bearings -
Deleted:
Design
Deleted:
Provide pot bearings
Inserted:
Provide
Deleted:
the following:
Deleted:
the requirements in the
Inserted:
the requirements in the
Deleted:
(a) Pot - Provide a pot
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00582.24 Spherical
Inserted:
Provide sperical bearings
Deleted:
Design spherical bearings
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¶
Deleted:
TFE
Deleted:
BDDM
Deleted:
TFEDesign bearings so
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The maximum average
Deleted:
TFE
Deleted:
PTFE surface for fabric pad
Inserted:
PTFE
Deleted:
8 MPa (
Deleted:
1,200 psi
Deleted:
)
Deleted:
at the vertical design load
Deleted:
The maximum thickness of
Deleted:
TFE
Deleted:
PTFE bonded to the flat
Inserted:
PTFE
Deleted:
<#>2 mm (
Deleted:
<#>3/32 inch
Deleted:
<#>)
Deleted:
<#>¶
Deleted:
<#>3 mm (
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... [10] 00582.26
Guide Bars for Composite Bearings - Provide
a

sliding surface
between the guide bars
and the guide element
made of
polished stainless steel against virgin
PTFE
. The virgin
PTFE
shall be
bonded and mechanically fastened to the guide bars.
Design:

The guide bars and their connections to the sole plate for the horizontal forces on the bearing, but
not less than 10% of the vertical design load of the bearing, unless otherwise shown

Each guided bearing to resist the total horizontal load at the bent or hinge where it is located. Do
not include the resistance due to bearing friction as part of the horizontal load capacity of guided
bearings and fixed bearings.
Integral guide bars machined from a solid plate, or attached by welding or with cap screws, or
fabricated from a single steel plate

The space between the guide bars and the guided member equal to 3/16 inch plus or minus 1/16
inch

Guiding arrangements so the guided member is always within the guides at all points of translation
and rotation of the bearing. Avoid guiding the member off the fixed base or any extension of it
where transverse rotation is anticipated.

00582.27
Sole, Base, Distribution and Masonry Plates for Composite Bearings - Make the
bottom surface of sole plates flat and level. Make the top surface flat, and sloped as required to mate with
the bottom surface of the distribution plate.

Use 3/4 inch minimum plates, except sole plates may taper to 5/8 inch at the thinnest edge.

For fabric pad bearings, keeper bars at least 1/4 inch thick shall be fastened to the top surface of the base
plate, around the perimeter of the fabric pad, with high-strength cap screws. Provide a gap at all bar ends to
allow drainage.

Provide studded anchors or threaded bolts, as shown or specified, to anchor the masonry plates to the
supported and supporting members. Locate anchoring devices to avoid conflict with metal reinforcement
and prestressing systems.

Fabrication

00582.30 General - Fabricate bearings according to the reviewed working drawings and these
Specifications.

(a) Working
Drawings - Submit working drawing