FHWA Resource Center
STRUCTURES TEAM
2001 SCEF Standard Specification
Tooth Dam Expansion
w/Trough
(October 24, 2001)
2.3 GENERAL: This work includes the construction of a tooth expansion joint
with a fabric reinforced drainage trough for highway bridge joints. Provide
materials and workmanship in accordance with individual Department of
Transportation's requirements, AASHTO/AWS Welding Specifications, the Contract
Documents, and this Specification.
2.0 MATERIAL:
2.1 Fabricated Structural Steel: Shall conform to AASHTO M270/ASTM A707 Grade
36, shop coated with approved system, unless noted otherwise.
2.2 High Strength Bolts: Shall conform to AASHTO M164/ASTM A325.
2.3 Flat Washers: Shall conform to AASHTO M293/ASTM F594.
2.4 Stud Anchors: Shall conform to AASHTO M169/ASTM A593.
2.5 Flat Head Countersunk Screws: Shall conform to ASTM F738 Type 304
(Stainless Steel).
2.6 Galvanizing: Shall conform to AASHTO M111 (ASTM A123), with a minimum of
2 oz. of zinc per square foot.
2.7 Polyester Fabric: Shall meet the following requirements:
- Number of Plies 2
- Minimum Fabric Weight (oz./sq. yd.) 7.5
- Minimum Tensile Strength (lbs./in.) (ASTM D378) 425
2.8 Rubberized Trough Material: Shall consist of Neoprene meeting the
following requirements:
- Hardness (ASTM D2240, Shore A) 50+/-5
- Minimum Tensile Strength, psi, ASTM D412 2000
- Minimum Elongation at break, %, ASTM D412 250
- After Oven Aging, 70 hours @ 212º F
Maximum Compression Set 40
Maximum Elongation Loss, % 20
Maximum
Tensile Strength Loss, % 20
Maximum Hardness Points Gain 10
- Brittleness to Heat Aging, ASTM D573 -30º F
- Tear Resistance, (lb./linear in.) Die C, ASTM D624 120
- Resistance to Ozone aging, ASTM D1149 No cracks for 100 hours of exposure
to 20% elongation @ 100º F and 100 pphm ozone
- Oil Swell, 70 hours @ 212º F using ASTM Oil #3. Weight change, % maximum,
ASTM D471 45
2.9 Fabric Composite Properties: Preformed fabric material consisting of multi-ply
polyester fabric and rubberized trough material vulcanized to form a laminate
shall conform with the following properties:
- Thickness, minimum 1/4"
- Minimum composite tensile strength of the Fabric reinforced bridge trough,
(lb./in.) ASTM D378 800
- Maximum Elongation @ Ultimate Tensile Strength, %,ASTM D412 30
- Maximum Resistance to Water Absorption, (less than 10% weight gain for 7
days of water immersion at 150º F) %, ASTM D471 0.75
3.0 Construction:
3.1 Shop Drawings: Shop Drawings shall be prepared and submitted. The joint
shall be fabricated from approved shop drawings and the bridge deck grade and
crown (profile). Joint shop drawings and elastomeric trough shop drawings shall
be coordinated to ensure that joints and troughs will fit when field assembled.
Acceptance of the shop drawings will be required prior to fabrication.
3.2 Welding: All welding permanently incorporated into the tooth expansion
dam shall meet the requirements of the current AASHTO/AWS Bridge Welding
Code D-1.5. All complete penetration welds shall be 100% inspected by
UT or RT using "tension member" acceptance criteria in accordance with
AASHTO/AWS D-1.5.
3.3 Fabrication and Erection: Joint fabrication shall be by an AISC Category
Major Steel Bridges (CBR) certified fabricator. Fabrication and erection of the
expansion dam shall be in accordance with the shop drawings. Expansion joint
system shall be shipped to job site preassembled for lengths up to 50 feet. One
field welded complete penetration splice is permissible for each additional 50
feet Both halves (abutment and superstructure) of all moveable deck joints shall
be fully assembled in the shop to ensure that full joint closure can be attained
without binding of fingers. As necessary, sides of fingers may have to be ground
after cutting to ensure complete closure with continuous fully open 1/8" kerfs.
Kerf openings between fully closed finger joints shall be tested by passing a
3/32" diameter cylindrical gage, held vertically within kerf openings, from one
end of completely assembled joints to the other without binding. After joint
segments have been fully assembled to nominal joint dimensions and approved,
they shall be match marked and scored (the upper surface of the finger plates
shall be permanently scored to provide two or more parallel lines in both
directions) to aid in proper field installation. Trough clamp bars and trough
fastening hardware shall be provided assembled in their planned location by the
deck joint fabricator.
After joint assemblies have been made, match marked, and approved, the
fabricator shall make and provide the contractor with template drawings
showing the transverse dimensional relationship between the abutment anchor
bolt holes and the mating superstructure joint segments (hole spacing
relative to superstructure joint segment field splices) so that the abutment
anchor bolts can be installed at the proper location while only the superstructure
joint segments are in place. Fabricator to provide a chart showing joint
openings for temperatures between -10º F to +110º F for steel structures
and +10º F to +100º F for P/S concrete structures in 10º intervals on
shop drawings.
Dam openings shall be preset prior to shipment and assembled with temporary
shipping angles. Temporary L's 4x3x1/2 at maximum 5'-0" centers shall
be shop welded. After erection and adjustment, bolts shall be tightened.
After concrete has been set, temporary attachments shall be removed by
chipping connection welds and grinding surfaces smooth. Fabricator to
show detail of all shipping and erection temporary attachments on the
shop drawings. Areas in which welds have been removed and the surfaces
ground smooth shall receive the same coating as was applied in the shop
to the adjacent areas.
The Contractor shall place concrete under the expansion dam and vibrate until
the concrete is forced through the 7/8" diameter air holes. Strike off excess
concrete. After concrete has cured inspect the holes and remove ¼" depth of
concrete. Clean the holes with an air jet and fill with an approved sealer.
Top roadway surfaces of finger plates shall have 3/8" diameter ball studs ¼"
high welded to the plate at 2½" on centers transversely and 2" on centers
longitudinally, in a staggered pattern.
Anchor bolts shall be cast in place. When a block out area is shown in the
Contract Documents set the dam end block out after the adjacent deck concrete
has been placed. Before placing block out concrete apply epoxy bonding agent to
transverse deck construction joints.
Provide ASTM A615 Grade 60 epoxy coated reinforcing steel bars. Do not weld
Grade 60 reinforcing steel bars unless specified.
3.4 Coatings: Apply one coat of asphalt cement paint to steel surfaces
sliding on concrete. Steel shall be coated as specified in the Contract
Documents. The intermediate and finish coats of paint shall be applied in the
shop to all areas that are inaccessible after the drainage trough is installed.
Areas embedded in concrete shall receive a prime coat only and it is to be
applied in the shop.
3.5 Drainage Trough: The drainage trough shall be installed using 3/8"
diameter stainless steel studs with self locking nut and washer @ 12" centers.
The drainage trough shall not be spliced, unless indicated in the contract
documents. When splices are indicated, they shall be shop vulcanized by the
manufacturer. No field vulcanization is to be allowed. Longitudinal splices are
not permitted.
Control the maximum depth of the trough such that it does not come into
contact with the substructure of the bridge.
An independent laboratory, to ensure compliance with these provisions,
shall test each lot of neoprene sheeting. Two certified copies of the
qualification test data indicating that the tested materials comply with
these provisions shall be submitted to the Department's Testing Laboratory.
The sample from each lot shall be one 6-inch piece, 2-foot long.
Sample vulcanized splices, if used on the project, shall be submitted
to the laboratory for testing. Samples shall consist of two pieces 3-inches
wide by at least 12-inches long, with a 6-inch by 3-inch long vulcanized
lap splice at the center. When subjected to a room temperature of 180º
peel test (ASTM D413), splices shall yield a peel strength of at least
30 ppi. Troughs fabricated with splices that are partially unbonded will
be cause for rejection. Holes in elastomeric troughs for trough fasteners
shall be ¾" diameter and shall be drilled after troughs have been match
marked with the deck joint fasteners either in the shop or field.
4.0 Basis of Payment: The payment will be full compensation for furnishing,
fabricating, placing, etc., of structural steel, roadway joint seals, drainage
troughs, catch basins, downspouts, cleaning, painting, and all material, labor,
equipment, tools and incidentals necessary to complete the work as specified in
the Contract Documents.
Commentary
The rubberized trough material noted in the Specification is one of the major
problem areas in a toot expansion dam. The subcommittee is looking into
alternatives to the material specified. This may be a coated neoprene trough, a
metal type trough (aluminum or some other material), an FRP type material, or
some other material.
There is some discussion on the requirement of a Major Steel Bridge (Cbr)
certified shop being the required fabricator. Should AISC develop the
new category that is being discussed for bridge components the new category
may be the one to require. There is also the possibility of not having
any AISC certification requirement in the Specification. In this case
it would be stated that the shop would have to be pre-approved by the
individual State or other governing body (the owner).
The coating of a joint expansion dam with paint is also one of those items
that requires further discussion. The idea of galvanizing, metalizing, or some
other coating was discussed, with paint being the preference of most
subcommittee members. The discussion of when the steel is to be coated has also
been a discussion item. Some feel the entire system should be shop applied,
others feel only those areas inaccessible after erection should receive the full
shop coat. In addition the areas in contact with concrete are not felt to
require a full three coat application of paint.
The Basis of Payment is a topic for which there are several opinions as well.
At this time it looks like most states include the cost in their lump sum
structural steel item for bidding purposes. There is some logic in having this
cost broken out as a separate pay item for the expansion dam itself, either as
lump sum or linear feet.
Upon discussion and/or approval of the written Specification the subcommittee
will tackle the actual tooth expansion joint details. As presently done in the
states represented on the subcommittee there is much similarity of details. It
was felt that the criteria should be established in the written Specification
and that criteria then be incorporated into the details. Each state has design
notes, either as a separate document or as plan notes, which accompany the
detail drawings. The subcommittee tried to avoid design notes in the
Specification as it was felt the Specification should be more material and
fabrication related. Any design notes can be incorporated into a separate
document or incorporated into the detail plan sheets, as determined by the
subcommittee, when we develop the details. Some of this information is included
with this document as Design Information and Instructions and is provided at
this time for general information.
(To be placed on Detail Plan Sheet)
Design Information
- Normal temperature = 68º F
- Temperature range = -10º F to +110º F for steel and +10º F to +100º F for
P/S
- Temperature change = 42º F rise, 78º F fall for steel and 32º F rise and
58º F fall for P/S
- Design Live Load = 100 psi + 60% impact = 160 psi
- Deflection of tooth shall not exceed l/300 where l = cantilever span of
tooth
- Expansion: D0 = 0.00672L @ 68º F (See Table)
- Contraction: D = 0.00953L @ 68º F (See Table)
- D0 and D are in inches and L = Total Expansion Length in feet
Instructions
- Dimensions and details are shown in section or plan are typical.
- For dimensions D, D0, T, A, B, X, and Y refer to design drawings. A =
distance from top of deck slab to top of stringer at c/l bearings and B =
distance from top of diaphragm to top of stringer.
For Steel
Beam Bridges
L 251 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000
r0 (see
table FHWA Region 3 Large Movement Expansion Joints 4/11/94)
For P/S bridges use ¾of D0 and D values in this table.
TRAINING
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