This information is intended to
serve as a guide for construction personnel where the Contractor furnishes and
installs traffic control devices and appurtenances. It may also be useful for
maintenance personnel performing the same functions. Inspection procedures for
various types of traffic control devices are outlined, mainly in the form of
checklists to assist project personnel in performing their duties. This
information points out the various important features of each device and
references the applicable specification or standard drawing. Illustrations are
used for easy recognition of the device or feature being discussed.
Sign service shall comply
with SCDs TC-32.10 and TC-32.11 and the plans. Additional
information is provided in TEM
Section 240-7.2 and C&MS Item 631.04.
It consists of cable and equipment to provide a complete electrical service
from either an underground source or an overhead direct drop to separately
furnished disconnect switch with enclosure. The equipment could include a weatherhead, a conduit riser with necessary fittings,
attachment clamps, and cable. A thorough
review of the plans should be made to determine the specific requirements of
the maintaining agency for sign service.
When required, an electric
meter base will be furnished by the applicable utility and installed by the
Contractor as part of the sign service work.
The sign service shall
terminate at the meter base if used; otherwise, termination shall be at the
switch enclosure. Sign service may be:
1. Direct drop by means of a weatherhead
and conduit riser routed to the switch enclosure.
2. Underground conduit and the pole interior to the
enclosure.
3. Underground and structure-attached conduit to the
enclosure (for overpass mounted signs).
The conduit riser shall
comply with Item 725
and the plans, and the weatherhead shall be
threaded aluminum or galvanized ferrous metal 732.16.
The disconnect switch shall
be a single-throw safety switch which meets the voltage and capacity
requirements of the plans. The enclosure shall be a NEMA
Type 4 ICS 1-110.15 with sufficient volume to accommodate an internal
transformer when specified. The enclosure shall contain a solid neutral bar.
A ground wire shall be used
as shown on SCDs TC-32.10 and TC-32.11 leading to a ground rod
installed in accordance with TEM
Section 240-7.3.
Signs should be inspected
when received on the job site if possible, but certainly prior to erection.
The signs should be inspected
for conformance with the plans, certified shop drawings, catalog cuts, and
material specifications.
Flatsheet signs are typically of aluminum sheet cut into
geometric shapes of the size specified.
Dimensions and thickness are
to be as shown on SCDs TC-52.10 and TC-52.20. Bolt holes are to be
drilled or punched (630.04).
Extrusheet signs are fabricated of aluminum sheet and
extrusions, joined by spot welding and assembled by bolts (SCD
TC-51.11). As an alternative, panels extruded in a single operation may be
used (SCD
TC-51.12). Extruded panels and spot welded panels shall not be used in the
same sign. There shall be no appreciable deviation from flatness on the face of
an assembled sign.
Overlay signs are of aluminum
sheet of the specified thickness and used to cover the legend of extrusheet signs. Signs with overlays should be checked for
any loose rivets holding the overlay sign.
All signs shall be
reflectorized by being covered with the appropriate grade of sheeting. The
sheeting shall be of the correct color, firmly attached, and free of tears,
wrinkles, blisters, or blemishes.
Sign legend shall be in
accordance with the plans, certified shop drawings, and the OMUTCD.
The type of copy on extrusheet signs shall be as shown on the certified shop
drawings. Available types of copy are listed in TEM
Table 297-6.
All signs shall be identified
on the reverse side by decals as described in 630.
Extrusheet signs shall also to be identified by information in a
detachable form on the back (see Item 630.04).
TEM
Table 297-6 provides information about the sign copy used, type, material
used, design features, etc.
All signs shall be identified
on the reverse side by decals of Type F white reflective sheeting (730.18)
with silk screened numerals. Information shall be coded by screened-on or
punched-out numerals before decal application and shall include sheeting
manufacturer and year of sign fabrication. At the time of erection, month and
year of erection shall be scratched out by the Contractor. This procedure is
described in 630.04,
which also contains an illustration of the decal. Decals for overlay signs may
be on the front surface.
The
following codes shall be used on the decals to identify the manufacturer of the
sheeting.
0 -
Avery Dennison
1 -
Minnesota Mining and Manufacturing Company (3-M)
2 -
Sakai Trading-New York, Inc.
3 -
Nippon Carbide Industries (USA)
4 -
Morgan Adhesives Company
5 -
American Decal and Manufacturing Company
6 - Stimsonite Corporation
7 - Reflexite North America
Sign support foundations
shall be located so the sign face is at a right angle to the roadway lanes
served, unless the plans specify otherwise. An example of an exception is the
W1-6 Large Arrow sign (black arrow on yellow background), which is located as
shown in TEM
Figure 298-24.
Foundations should be staked
by the Contractor in accordance with the locations shown on the plans.
The stakeout locations should
be checked for:
1. The presence of obstructions which could restrict
motorists' proper visibility of the sign from the point where they are expected
to read the sign. Curved roadway locations should especially be checked.
2. Obvious conflicts with overhead power lines or other
utilities. There should be available a proper safe clearance from overhead
lines for construction operations, in compliance with the National Electric
Safety Code and any local codes.
3. Possible conflict with underground facilities.
Foundation locations may be
adjusted when necessary to overcome difficulties such as those shown in TEM
Figure 298-24 and discussed herein with the concurrence of the project
engineer. Adjustment should not violate minimum clearance dimensions as shown
on SCDs TC-42.10 and TC-42.20 and the OMUTCD.
Foundations shall be placed
only in undisturbed soil or compacted embankment, and excavation shall be by an
earth auger of the specified diameter to the specified depth. See TEM
Figure 298-25 for a diagram of a foundation excavation.
If a minor cave-in should
occur, the Contractor may continue excavation using an increased diameter or
using sleeving, casing, or other method approved by
the Project Engineer. The foundation concrete will be measured as determined
from plan dimensions. The Contractor shall remove all extraneous material from
the excavation before concrete placement.
When subsurface obstructions are encountered, permission may be granted
by the Project Engineer to replace the excavated material and relocate the
foundation. When bedrock is encountered,
the portion of the specified foundation depth within the bedrock may be reduced
as much as 50 percent.
Anchor bolts and conduit ells
shall be of the correct size and furnished with the support. At least one 2
inch (51 millimeters) minimum conduit ell shall be furnished and capped if
unused. Anchor bolts, conduit ells, and EMT (Electric
Metallic Tubing) shall be oriented in the foundation according to the plans,
conduit runs, and ground rod location.
All anchor bolts shall be provided with standard steel hex nuts,
leveling nuts, and plain washers. The
nuts shall be capable of developing the full strength of the anchor bolts. Reinforcing bars, tie loops, and tie bars
shall be of the correct size and arranged with the anchor bolts into cages
according to the applicable SCD
TC-21.10 or SCD TC-21.20. A special
foundation design will be required when soil with a load bearing capacity of
less than 2,000 pounds per square foot (9700 kg/m˛) is encountered.
Anchor bolts shall be
vertical with their ends projecting the correct distance above the foundation
surface in compliance with the plans.
When the distance the anchor bolts project above the foundation surface
is not specified, a rule of thumb is four times the bolt diameter. The anchor bolts shall be tied to the cage
tie bars according to standard details.
The rebar cage shall be supported
3 to 4 inches (75 to 100 millimeters) above the bottom of the excavation by a
piece of concrete block or similar material. The cage shall be positioned with
a clearance of 3 inches (75 millimeters) from the excavation wall by similar
blocking so that after concrete placement a full thickness cover is
assured. A template and/or frame shall
be used to rigidly hold the anchor bolts and conduit ells in the specified
pattern during concrete placement. A form shall be oriented according to the
plans to shape the foundation into a square from the surface or grade shown to
a nominal 6 inches (150 millimeters) below ground line. The template and form may be combined. Gaps
of 6 inches (150 millimeters) or less between the foundation and adjacent paved
surfaces shall be eliminated by increasing the formed foundation.
Water encountered in the
foundation excavation shall be pumped out before concrete placement.
If this is not feasible,
concrete should be placed by the tremie-tube method.
Concrete conforming to Item 499
and Item 511
shall be placed and vibrated to eliminate voids. Care should be exercised
during vibrating to avoid disturbing the anchor bolts, conduit ells, and
reinforcing cage.
Forms may be removed as soon
as the concrete has hardened sufficiently so as not to be susceptible to
damage, 511.16.
Minor earth caving external
to the hole, which may have occurred during excavation using sleeving or casing should be corrected after concrete
placement by backfilling and tamping in accordance with 203.
Joint filler complying with 705.03
shall be placed between the formed foundation and adjacent paved surfaces.
Supports and poles may be
erected, signs installed, and span wire load applied only after the concrete
has aged sufficiently to be in compliance with 630.
Curing and loading of concrete
for traffic control devices shall comply with 511.17.
Concrete for foundations of
sign supports shall be cured, have bracing removed, and be loaded only when the
concrete has achieved the age shown below:
|
Age of Concrete in Days |
|
|
Without Beam Test |
With Beam Test ** |
Curing |
7 |
5 |
Removing Bracing |
7 |
3 |
Loading* |
14 |
7 |
* No load shall be applied
or other work done that will damage new concrete or interfere with its curing.
** Beam test specimens
shall be poured from the same batch, immediately before, during, or after
foundation pour. Specimen configuration shall be to ODOT requirements. Specimens
when tested shall have at least an average modulus of rupture for two tests of
no less than 650 pounds per square inch (4.5 MPa).
Various general aspects of
overhead sign supports are addressed in this section. TEM
Table 297-7 provides an overall summary of the structure types, allowable
sign area on each, and the span or arm length.
This inspection checklist
covers the general features of strain poles, mast arm type signal supports, and
overhead sign supports. Features pertaining only to specific pole or support
types will be found in the sections of this manual covering exclusively those
poles or supports.
1. When poles and supports of the combination type are
specified, they are to provide extra length for a highway lighting function,
and welded-on bracket arm plate(s) complying with SCD
HL- 10.12 or SCD HL-10.11 for attachment of a separately furnished
luminaire arm. An upper handhole and an additional
internal J-hook are to be furnished.
2. Supports may be of an alternate design utilizing all
non-tapered tubing structural members.
3. If possible, poles and supports should be inspected
when received, but certainly prior to erection.
4. General dimensions should be checked first, including
pole length, base diameter, top diameter, and wall thickness. Similar mast arm
dimensions should also be checked. Wall thickness is most easily measured with
calipers at the end. Caps on poles may have to be removed.
5. Orientations of the various appurtenances should be
checked against the plan’s orientation diagram if such is available; otherwise,
orientations may be determined from certified shop drawings and the
intersection drawing.
6. Base plate dimensions should be checked including thickness,
bolt circle diameter, and bolt hole size. Base plates may be plate or cast
steel according to 730.04.
7. A handhole with ground lug is to be furnished, with a
cover plate complying with 730.05
and a stainless steel chain complying with 730.10.
8. Blind half-couplings shall be provided where required.
Sharp edges shall be rounded to prevent damage to cable or wires. Blind half-couplings
shall be plugged when not in use. Couplings may be for signal or interconnect
cable entrance or for attaching supports for traffic control equipment and for
hubs for controller cabinets. Entrance couplings shall be threaded for use with
threaded weatherheads.
9. An internal J-hook shall be furnished and located as
indicated on the plans.
10. A pole cap conforming with 730.06
shall be furnished and in place before final inspection.
11. An arm cap conforming with 730.07
shall be furnished for chords or mast arms.
12. All strain poles and overhead sign and signal supports
shall be grounded, even if no power is available.
13. Welding and galvanizing shall be inspected in
accordance with 630.
14. Supports are to include sign brackets, U-bolts, and
clamps. When required by the plans, supports are to include luminaire support
arms, bracing rods, other necessary structural members, and signal hanger
clamps with clevis.
15. The correct number and size of anchor bolts and
conduit ells shall be furnished for placement in the foundation.
16. Anchor bolt diameter and length shall be according to
the plans and SCD
TC-21.10 or TC- 21.20. Anchor bolt ends may have
an L-bend or be fitted with a tapped steel plate. Threaded ends shall not to be
damaged and shall be galvanized at least 2 inches (50 millimeters) beyond the
threads. The galvanizing should be in good condition, and absent or damaged
galvanizing should be repaired by the application of two coats of zinc-rich
paint. Galvanizing thickness should permit the turning of nuts by a wrench
without difficulty. Loose rust on anchor bolts should be removed.
17. All anchor bolts shall be provided with standard steel
hex nuts, leveling nuts, and plain washers. The nuts are to be able to develop
the full strength of the anchor bolts.
All welds of supports shall
be inspected visually, as soon as possible, following support delivery. Welds
should be inspected for flaws and imperfections under good lighting conditions
using a magnifying glass as necessary. Evidence of any of the following faults
or other imperfections, such as warping and misalignment may be cause for
rejection of the support. The following features of welds should be checked:
1. A check should be made for the actual presence of all
welds called for by the certified shop drawings and standard drawings.
2. Welds on tapered tubes, pipe, or structural shapes
shall be continuous around the joint. Welds requiring terminations shall be of
the correct length.
3. Welds shall not exhibit cracks or discontinuities in
base metal or weld material and shall not show evidence of porosity, which
shows up as pitting or pinholes. The galvanizing layer may cover such flaws,
but their existence should be checked.
4. Welds shall be full cross-sections without excessive
concavity or convexity. Required weld terminations shall be filled to full
section without depressions or craters.
5. There should be no evidence of undercut, a condition
where a shallow groove is melted into the base metal adjacent to a weld and
left unfilled by weld metal.
6. Base plates shall be welded to two ply poles with AWS
prequalified welds in conformance with 730.04.
7. Arm attachment plates shall be welded inside and
outside with fillet welds. Each fillet weld shall be equal to the wall
thickness of the respective tubing.
The galvanizing cover of
supports shall be inspected visually, as soon as possible, following delivery.
The galvanizing should be inspected externally and internally for flaws and
imperfections in daylight or strong artificial light. In accordance with 513.26,
supports shall be loaded, transported, unloaded, stored, and erected in a
manner to avoid damage to any feature including the galvanizing. Supports
stored in the field should be kept off the ground to prevent the galvanizing
from contacting water, which may result in a premature oxidation condition. The
galvanizing should have the appearance of a uniform application. Supports
should be checked for assurance that the following flaws or imperfections do
not exist:
1. Loose or bare spots in the galvanizing where improper
preparation has prevented metal adherence in the molten zinc bath. Poles should
be rejected if the point of a penknife can flake off the galvanizing layer.
2. General overall roughness, a symptom of over-pickling
or of excess zinc bath temperature and/or immersion time.
3. Pimples, due to entrapped bath scum particles.
4. Blisters, due to hydrogen gas absorbed during pickling
and coming out at the time of galvanizing.
5. Flux inclusions, picked up from the top of the bath
when dipping and burnt-on during immersion.
6. Ash, usually in course lumps picked up from the top of
the bath.
7. Patches of dull gray coating due to the slow cooling
of heavier cross-sections of supports after immersion.
8. Excess zinc lumps or runs due to delayed molten metal
run-off from surface discontinuities, such as joints, seams, or holes.
9. Rust stains due to the weeping of impurities from the
pickling process at seams and folds.
Excessive galvanizing faults
and imperfections combined with general poor workmanship may be cause for
rejection of the support. Gross imperfections may lead to the suspicion of
inadequate protective cover which may require inspection with a magnetic
instrument. Items 1 through 6 may be cause for rejection. Items 7 through 9, if
extreme, may be cause for rejection because of poor appearance, even if the
protection of the support is not affected.
After erection, supports
should be given a final inspection for any damage to the galvanizing due to
improper handling in the erection process. Damage due to slings, etc., which is
more serious than superficial brightening, is to be repaired by the Contractor
with the application of two coats of zinc-rich paint.
TEM
Tables 297-8a through 297-8f provide information on the weight of various
overhead sign supports. For all structures, the weight of the pipe support has
been given where pipe has been frequently used in place of tapered tubes. In
general, the tapered tube support will be lighter than the pipe support. The
support numbers listed may be preceded by I-129, 815, 844, or other designation
instead of TC.
For estimating purposes, a 10
x 10 foot (3.0 x 3.0 meter) sign, excluding the sign lighting, weighs
approximately 250 pounds (113 kilograms).
Erection procedures
pertaining to specific pole or support types will be found in the sections of
this manual devoted exclusively to those poles or supports. In general, the
following assembly and erection procedure applies:
1. To minimize erection time and the hazard to workers
and road users where traffic is maintained, supports should be erected with
mast arms attached, and horizontal sign support members (over the roadway)
should be prewired for lighted signs or other traffic control devices. See the
notes in plans for traffic maintenance requirements when span-type sign support
members are erected.
2. Support components shall be assembled with their
threaded fasteners tightened in accordance with 630.06.
Fasteners 1/2 inch (13 millimeters) or greater shall have anaerobic adhesive
applied to the threads according to the manufacturer’s recommendations. Nuts
shall be tightened by the turn-of-the-nut method.
3. The turn-of-the-nut method shall be in accordance with
513.20.
Nuts shall be made snug tight by the effort of a person using an ordinary spud
wrench followed by an additional 1/12 to 1/6 turn.
4. Leveling nuts shall be placed on the anchor bolts,
initially clearing the foundation surface by at least 1/4 inch (6 millimeters)
and forming a horizontal plane.
5. Poles or supports shall be raised into position with
equipment of adequate lifting capacity and used in a manner preventing damage
to attached appurtenances (signs, brackets, luminaries, etc.) and to the
galvanizing. The weight of poles or supports is given in TEM
Tables 297-8a through 297-8f for the use of the Contractor in the erection
procedure.
6. With the pole or support’s base plate resting on the
leveling nuts, the plain washers and anchor nuts shall be placed on the anchor
bolts, the support plumbed in a vertical position or raked, and anchor nuts
given a preliminary tightening.
7. After any necessary leveling, nut adjustments are made
to ensure that supports are essentially vertical after attachment of signs,
sign lighting equipment, or signals. The anchor nuts shall have anaerobic
adhesive applied and be tightened in accordance with the instructions for
assembling fasteners given in the foregoing paragraphs, 2 and 3.
8. Anchor nuts are not to be covered with bolt covers or
a cover base regardless of support location (Item 630.06B).
9. Poles or supports which are prewired before erection
should be checked to determine if the erection procedure has disturbed the
wiring. Wire for lighted signs should be supported by looping wire over the
J-hook in the vertical support member (Item 631.05).
Cable supported by cable support assemblies should be checked to determine if
the sling is over the J-hook and if the adjustment is proper to eliminate
strain on the cable jacket.
The previous section addressed
general assembly and erection guidelines for strain poles and supports. The
following sections provide additional information specific to various types of
supports. For the most part, the information is provided in checklist format.
This section provides
additional information, generally in the form of checklists, about various
ground-mounted supports. TEM
Section 221 addresses general guidelines about sign supports and TEM
Section 240-5 provides additional design information about ground-mounted
supports.
1. Ground-mounted sign supports of the post type shall be
U-channels or square posts of the number specified and shown on SCD
TC-41.20.
2. Post lengths appearing on the plans are approximate
and the Contractor is responsible for determining the exact length of required
posts before cutting to length (630.06.A).
3. No. 4 U-channel posts consist of two No. 2 posts
bolted back-to-back. No. 6 U-channel posts consist of two No. 3 posts bolted
back-to-back. Back-to-back posts are assembled by 5/16-inch (8 millimeters)
steel bolts, lock-washers, and nuts on 4-inch (100 millimeters) centers below
the ground line and 16 inch (400 millimeters) centers above the ground
line. No. 4 and No. 6 U-channel posts
cannot be installed in exposed locations.
4. Posts should have a line of paint 48 inches (1.20
meters) from the end, which will be in the earth. The mark when driven to a
distance of 6 inches (150 millimeters) above the ground indicates a post driven
to the proper depth.
5. If it is necessary to cut posts to correct length in
the field, the cut end should be covered with two coats of zinc-rich paint and
the cut end driven in the earth or embedded when required (except for
back-to-back posts).
6. Posts shall yield when hit and shall be driven to a
depth of 42 inches (1.05 meters). Posts are typically not to be embedded in
concrete unless specified in the plans or ordered by the Project Engineer to
overcome problems, such as adverse soil conditions or prevalent bedrock close
to the surface. The driven depth has been established to ensure best yielding
characteristics. Deeper depths are not beneficial in this regard.
7. Caution shall be used when driving posts in areas of
buried cable.
8. Posts shall not to be driven in drainage ditches.
9. Posts shall be installed vertically and at right
angles to the edge of pavement, unless otherwise required. Exceptions may be NO
PARKING signs and STOP signs located at intersections with curved approaches.
In this situation, STOP signs should be placed perpendicular to a line from the
viewing point where they are normally recognized and stopping action would
begin.
10. Posts shall be driven without bending, distortion, or
end mutilation. Mutilation may be prevented by the use of a driving cap. Posts
should be checked to see if the paint mark is 6 inches (150 millimeters) out of
the ground after driving.
11. Posts located in paved areas shall be driven through a
hole provided by sleeving or core drilling. After driving, the hole shall be
patched with asphalt concrete or approved bituminous material.
12. At locations where posts cannot be driven, the post
may be moved at no additional cost to ODOT, when approved by the Project
Engineer.
13. Typical vertical and horizontal clearances of signs
are shown on SCDs TC-42.10 and TC- 42.20.
Square posts, which are
capable of supporting signs at right angles to other signs on the post, are
designated as “One-Way” sign supports for the most common application. This is
shown on SCD
TC-41.50.
1. Ground-mounted sign supports of the non-breakaway beam
type shall be rolled steel, wide flange sections of the size, and weight
specified (from the list on SCD
TC-41.10). Non-breakaway beams shall be protected by guardrail or concrete
barrier installed for another purpose. Inspection of beams of the breakaway
type is covered in 630.
2. Beam lengths appearing on the plans are approximate
and the Contractor is responsible for determining the exact length of required
beams before fabrication (630.06
A).
3. Galvanizing shall be inspected in accordance with 630.
4. Beams shall be embedded in a concrete foundation in
accordance with SCD
TC-41.10.
5. Beams shall be raised into position with equipment of
adequate lifting capacity and in such a manner as to prevent damage to the
galvanizing. The beams shall be braced in a plumb and square position until the
concrete has cured. The age of the concrete before it is considered cured and
before signs are permitted to be erected is to be in accordance with 630.
1. Ground-mounted sign supports of the breakaway beam type
shall be rolled steel, wide flange sections of the size, and weight specified
(from the list on SCD TC-41.10).
2. Beam lengths appearing on the plans are approximate
and the Contractor is responsible for determining the exact length of required
beams before fabrication (630.06
A).
3. Beams shall use a slip base design. Alternate designs
of breakaway connections are permitted.
4. Base plates shall be fabricated to standard details
and welded-on with a bead equal to the beam flange and web thickness
respectively, but not less than 1/4 inch (6.4 millimeters).
5. Welding and Galvanizing shall be inspected in
accordance with 630.
6. All portions of beams should be shop assembled in
accordance with SCD
TC-41.10.
7. The beam upper portions shall be joined by the bolts
attaching the fuse and hinge plates. The plates shall be fabricated to standard
details with the fuse plate having notched holes at the bottom and the hinge
plate having unnotched holes. The steel hex head bolts, with washers under both
head and nut, shall be tensioned in the shop to the final specified value. For S4x7.7 (S100x11.5) beams only, malleable
iron beveled washers are used under bolt head and nuts.
8. Torque limiting nuts may be used instead of
conventional nuts on the fuse and hinge plates (SCD
TC-41.10, Note 5).
9. The beam lower portions should be joined by steel hex
head bolts inserted with their nuts uppermost. A galvanized bolt retainer plate
shall be sandwiched between the base plates. Flat washers shall be used under
both bolt head and nut as well as under the bolt retainer plate. Bolts shall be
snug tightened for delivery to the site with final torqueing to be done after
erection.
10. Torque limiting nuts may be used instead of
conventional nuts on the base plates (SCD
TC-41.10, Note 5). The nuts shall be snug tightened, but not to the point
where the upper area shears away.
11. Base plate skewed notches should point toward the
roadway along the path of typical vehicle collision. The skewed notches of both
base plates should match.
12. For beams located in medians, the base plates should
be welded-on upside down as compared with those of beams located on the right
side of the roadway, so the base plate skewed notches will point toward each
roadway along the path of vehicle collision from either direction of traffic.
13. For beams located in medians, fuse plates shall be
used on both sides of the beam.
14. For beams located on the right side of the roadway,
fuse plates shall be on the side of the beam facing traffic.
15. For the alternate design, special foot brackets shall
be bolted to the upper beam portion, and four couplings incorporating a
breakable reduced section are connected between the foot brackets and threaded
anchor inserts embedded in the foundation. The couplings permit use of the
design in medians where collision can occur in either direction of traffic.
16. The alternate design uses four hinge/fuse plates
incorporating a thinned section and bolted where the beam is cut through just
under the sign. The pair of plates on the impact side of the beam and a pair on
the opposite side bend severs upon impact to allow the beam to swing upward out
of the path of the impacting vehicle.
17. Beams should be erected in a single unit because they
are easier to plum, square, and brace when the entire assembly is raised and
set in concrete.
18. Beams shall be erected in accordance with the
procedure given for non-breakaway beams in 630.
19. A sloping concrete foundation top surface is required
on the high ground side to prevent a water pooling pocket and permit drainage
as per SCD
TC-41.10. For the alternate design, the foundation top shall be level in
the area of the breakable couplings.
20. When a supplemental panel is required below an
extrusheet sign, the panel is fastened by sign backing assemblies to the parent
sign. The panel shall be separated from the sign by the width of the fuse
plate, plus 1 inch (25 millimeters). This is to permit unhindered hinge plate
bending in the event of a vehicle collision.
21. After the foundation concrete is cured, base plate
nuts shall be loosened in turn and retightened with a torque wrench in a
systematic manner to the specified maximum torque shown in the table on SCD
TC-41.10, also shown in TEM
Table 297-9. Torque wrenches used should be calibrated daily.
22. When torque limiting nuts are used on base plates, the
nuts shall be loosened in turn, and tightened in a systematic manner until the
upper area shears away and ensures that the correct torque has been applied.
23. At least 4 weeks following the erection of signs on
breakaway beams, the breakaway feature shall be inspected by the Contractor for
evidence of shifting or loose fasteners.
24. All loose fasteners shall be re-torqued to specified
values. Base plate fasteners shall be loosened and re-torqued even if no
shifting or looseness is detected. If the base plate connection was made with
torque limiting nuts, re-torqueing will only be required if looseness can be
detected. Re-torqued conventional nuts shall have anaerobic adhesive applied,
or as an alternate, new torque limiting nuts of the proper range may be used.
1. Single arm supports shall comply with certified shop
drawings, SCD
TC-16.20, and the plans.
2. Welds, galvanizing, and general features of the
support shall be inspected in accordance with 630.
3. For arms of two telescoping pieces, a 15 inch (400
millimeters) overlap is required. The overlapped arms shall be secured with a
stainless or galvanized steel hex head through bolt with nut.
4. Arm caps shall cover at least 50 percent of the end
area (Item 730.07).
5. A minimum of two brackets shall be provided for each
sign, each attached to the arm by steel clamps with carriage bolts. The clamps
should be able to be tightened in a manner to firmly grasp the arm so as to
prevent sign rotation.
6. If signs are lighted, disconnect switch enclosure
mounting brackets may be required on the support.
7. Erection shall be in accordance with the general
procedure given in 630,
except as hereafter noted.
a. The Contractor may choose to attach the signs and any
sign lighting items before erection.
b. Signs are installed at the same elevation. For this
purpose, adjustment is provided by two pairs of slotted holes in the sign
bracket for attachment of the arm clamp.
c. Contact between galvanized clamp flanges and aluminum
sign brackets shall be prevented by the use of chloroprene gaskets.
d. Initial rake shall be adjusted so that under the load
of signs, the pole will assume an essentially vertical position and the arm rise
will be within the limits specified on the standard drawing, 3 inches (75
millimeters) minimum and 12 inches (300 millimeters) maximum.
1. Cantilever supports shall comply with certified shop
drawings, SCD
TC-12.30, and the plans.
2. Welds, galvanizing, and general features of the
support shall be inspected in accordance with 630.
3. Supports with arm lengths 18 feet (5.5 meters) and
over shall have truss members. Truss members may be angles or pipe.
4. One blind half coupling shall be welded to the top
chord approximately 12 inches (300 millimeters) beyond or outside of the first
sign bracket for a sign less than 20 feet (6.1 meters) long. A second blind half
coupling shall be welded near the second sign bracket for signs 20 feet (6.1
meters) or longer.
5. Erection shall be in accordance with the general
procedure given in 630,
except as hereafter noted.
a. The Contractor may choose to attach the signs and any
sign lighting items before erection.
b. Signs are centered vertically on the chords.
1. Center-mount supports shall comply with certified shop
drawings, SCD
TC-9.30, and the plans.
2. Welds, galvanizing, and general features of the
support shall be inspected in accordance with 630.
3. Sign clearance above the roadway shall be a minimum of
17 feet (5.2 meters).
4. Arms may be either square or round tube. The arm
attachment design shall be in accordance with standard details for either
square arms or round arms with separate cradle.
5. A blind half coupling shall be located on the pole.
6. Erection shall be in accordance with the general
procedure given in 630,
except as hereafter noted.
a. Signs are centered vertically on the arms.
b. Signs may be mounted laterally on the support in an
eccentric position. However, a minimum of 2 feet (0.6 meter) of sign length
shall remain to one side of the pole centerline.
c. The Contractor may choose to attach the sign and any
sign lighting items before erection.
1. Semi-overhead supports shall comply with certified
shop drawings, SCD
TC-9.10, and the plans.
2. Welds, galvanizing, and general features of the
support shall be inspected in accordance with 630.
3. Sign clearance above the ground shall be at least 10
feet (3.0 meters) unless a lower height is approved by the Project Engineer to
provide sign visibility through preceding overpass structures.
4. Arms may be either square or round tube. The arm
attachment design shall be in accordance with standard details for either
square arms or round arms with separate cradle.
5. A blind half coupling shall be located on the pole.
6. Erection shall be in accordance with the general
procedure given in 630,
except as hereafter noted.
a. Signs are centered vertically on the arms.
b. Signs may be mounted laterally on the support in an
eccentric position. However, a minimum of 2 feet (0.6 meter) of sign length
shall remain to one side of the pole centerline.
c. The edge of the sign shall be back at least 2 feet
(0.6 meter) from the edge of the curb.
d. The Contractor may choose to attach the sign and any
sign lighting items before erection.
1. End frames for span truss supports shall comply with
certified shop drawings, the plans, and SCD
TC-7.65 for aluminum trusses and SCD
TC-15.115 for steel trusses.
2. Welds, galvanizing, and general features of the
support shall be inspected in accordance with 630.
3. Handholes shall be oriented on the end frame
downstream vertical member on the side away from the direction of traffic.
4. The size of truss members shall be in accordance with
standard details. Truss member joints may be of two different designs.
5. Switch enclosure mounting brackets shall be in place
and a chase nipple installed on both end frame vertical members, which are away
from the direction of traffic.
6. An angle shall be furnished and welded onto the end
frame, near the top, to support the lower chords of the span box. Stainless
steel U-bolts shall be used with aluminum trusses and galvanized steel U-bolts
with steel trusses.
7. End frame vertical members shall be furnished with
steel clamps and a separate tee or angle (alternate) for supporting the upper
chords of the span box. Stainless steel U-bolts shall be used with aluminum
trusses and galvanized steel U-bolts with steel trusses.
8. An internal J-hook shall be in each end frame in the
downstream vertical member.
9. When using an aluminum truss, the following shall
apply:
a. Aluminum trusses shall comply with certified shop
drawings, SCD
TC-7.65, and the plans.
b. Welds shall be inspected according to 630.
c. End caps shall be on each end of chords. The top front
end caps shall be tapped for wiring.
d. A blind half coupling shall be welded to the front top
chord of the truss approximately 12 inches (300 millimeters) beyond or outside
of the first sign bracket for each sign. Sharp edges shall be rounded to
prevent damage to wires.
e. Span length shall be in accordance with shop drawings
and the plans.
f. Span box camber shall be in accordance with standard
details.
g. Flanges between span box sections may be cast or
fabricated with forged flanges as an alternate.
h. Flange attachment hardware shall be stainless steel
bolts and nuts.
i.
Supports shall be
furnished with necessary sign brackets, U-bolts, luminaire support arms,
bracing rods and other necessary structural members
10. When using a steel truss, the following shall apply:
a. Steel trusses shall comply with certified shop
drawings, SCD
TC-15.115, and the plans.
b. Steel truss checking instructions are the same as
those for aluminum trusses, except as hereafter listed.
i.
The galvanizing
shall be inspected according to 630.
ii.
Flanges between
span box sections shall be forged.
iii.
Flange attachment
hardware shall be galvanized steel bolts and nuts.
11. See the notes in the plan for traffic maintenance
requirements when span type sign support members are erected.
12. The base plates of end frames shall be placed on
anchor bolt leveling nuts, plain washers and anchor nuts placed, the frames
plumbed into a vertical position in both longitudinal and lateral directions,
and nuts made tight in accordance with 630.
13. Truss camber shall be correct. The various truss sections
shall be assembled in the arrangement and sequence shown on the shop drawing.
14. Trusses may be assembled into a total span while lying
on blocks with wedges. Flanges on truss section ends may be aligned by driving
in the wedges as necessary. All flange bolts are then assembled and made tight.
15. Two cranes may be necessary when lifting very long
trusses or the heavier steel trusses. For reference, truss weights are given in
630.
16. Care should be taken in the attachment of slings.
Trusses should be lifted at positions of a quarter to a third of the total
span. Slings should be attached to the top chords and the horizontal diagonals.
17. Trusses may be easily overstressed by poor handling,
and care should be taken when moving assembled trusses for temporary storage, during
transportation to the erection location, and in the erection procedure.
18. Trusses shall not be erected unless at least one sign
is in place within 8 hours or the trusses are fitted within the same period
with damping devices approved by the Project Engineer (630.06
B).
19. Attachment of the box truss to the end frames shall be
by four U-bolts. Aluminum trusses shall be attached by 5/8-inch (16
millimeters) stainless steel bolts according to SCD
TC-7.65 and steel trusses shall be attached by 3/4-inch (19 millimeters)
galvanized steel bolts according to SCD
TC-15.115.
20. The Contractor may choose to attach the signs and any
sign lighting items before erection.
21. Signs are centered vertically on the chords (not
considering the height of Exit Panels).
Span Wire sign supports shall
comply with SCD
TC-17.10 and the plans. These sign supports consist of strain poles,
messenger wire with accessories, and sign hangers. Strain pole size and type,
anchor base, or embedded shall be as specified.
1. Strain poles shall be inspected in accordance with 632
and general features of the poles shall be inspected in accordance with 630.
Welds shall be inspected according to 630
and the galvanizing shall be inspected according to 630.
2. Erection shall be in accordance with the general
procedure given in 630,
except as hereafter noted.
a. For the initial rake of strain poles of the anchor
base type or embedded type poles, see 632.
b. The upper messenger wire shall be assembled with its
accessories according to the standard drawing. Preformed guy grips are not
permitted because wind loads on the signs can cause failure of the grips. Alternate
methods of attaching messenger wire to strain poles may be used.
i.
Span wire clamp
with clevis, anchor shackle and thimbles on the messenger wire, or
ii.
Messenger wire
wrapped twice around the strain pole and secured with a 3 bolt clamp of the
proper size.
c. The upper messenger wire shall be fitted with its
signs, furnished under other items of work, and the vertical clearance to sign
bottoms adjusted within clearance limits over the roadway. The sag of the upper
messenger wire shall be between 4 and 5 percent.
d. It is essential that the lower messenger wire have
more slack than the upper wire. The sag should be approximately 3 inches (75
millimeters) greater than the upper wire. This sag adjustment shall be made
before the sign hangers are attached to the lower wire.
e. Sign hangers shall be clamped snugly to the lower wire
by U or J bolts. In the case of back-to-back signs, the lower messenger wire
running in between the sign hangers is clamped between bolted spacers that are
slightly thinner than the messenger wire (see SCD
TC-17.10).
1. Overpass structure-mounted supports shall comply with
the plans and SCD
TC-18.24 for flush type supports and SCD
TC-18.26 for skewed type supports.
2. Overpass structure-mounted supports include sign
brackets and two different kinds of steel Z-bars which are fastened to bridge
concrete. For steel beam bridge mounting, aluminum angles at the bottom are to
extend between sign brackets and short galvanized steel angles bolted to the
bridge steel. For overpass structures essentially perpendicular to the roadway
underneath, sign brackets are flush mounted to Z-bars for direct sign viewing.
For overpass structures skewed to the roadway underneath, a wedge-shaped box
structure is inserted between the sign brackets and Z-bars to provide for
direct sign viewing.
3. The number of sign brackets will vary according to the
bracket spacing as required by SCD
TC-22.20. Bracket details are also shown on the standard drawing.
4. The number of aluminum frames in skewed supports shall
equal the number of sign brackets. Frame details shall be in accordance with
standard details and are to include two angles placed diagonally.
5. Front upper and lower members of skewed supports shall
be aluminum angles with a length equal to the sign length.
6. The skewed support structure shall be internally
braced by two aluminum angles extending diagonally and horizontally through the
interior.
7. For bridge clearance above a roadway of less than 17
feet (5.2 millimeters), the sign clearance above the bottom of the bridge shall
be 3 inches (75 millimeters) minimum without or 15 inches (400 millimeters)
minimum with sign lighting fixtures on the lower edge of the sign.
8. Supports shall be mounted on the overpass structure so
the sign is horizontal regardless of bridge slope (630.06
D).
9. Expansion double wedge steel anchor bolts shall be
used to fasten the support’s Z-bars to the overpass structure concrete parapet.
Intended locations of anchor bolts are to be approved by the Project Engineer
before any field drilling. Z-bars “A” are used at the top and Z-bars “B” at the
bottom of parapet concrete.
10. For a steel beam bridge mounting, aluminum angles at
the bottom shall be fastened to short galvanized steel angles bolted to the
bridge steel.
11. Chloroprene gaskets shall be used to prevent contact
between aluminum sign brackets or support frames and steel Z-bars or bolted-on
angles.
12. If the sign extends more than 4 feet (1.2 meters)
above or below the attaching Z-bars, intermediate sign brackets shall be
provided.
13. For precast beam bridges, aluminum angles at the
bottom shall be fastened to short steel angles and two expansion double wedge
steel anchor bolts shall be used.
14. After sign erection, the sturdiness of the support to
bridge attachment should be checked.
This section provides
information on erection of the signs. Assembly and erection of various types of
overhead sign supports are addressed in 630.04
and 630.05
and ground-mounted supports are addressed in Section 630.06.
When erecting ground-mounted
flatsheet signs, the following provisions apply:
1. Typical vertical and lateral clearances of
ground-mounted flatsheet signs are shown on SCD
TC-42.20.
2. Flatsheet signs shall be fastened to posts by
5/16-inch (8 millimeters) hex head steel bolts with a 3/8-inch (10 millimeters)
ID x 1-1/4-inch (32 millimeters) OD wide washer under the bolt head and using a
lock washer and hex nut. For U-channel posts, at each bolt, a bearing plate
shall be used behind the sign to reinforce the sign, as indicated on SCD
TC-41.20. The hardware and bearing plates are furnished with the signs.
3. Posts supporting groupings of flatsheet signs in
multiple arrangements will require the use of sign backing assemblies made up
of bolted together short sections of posts. Sign backing assemblies are
furnished with the signs unless separately itemized.
4. Flatsheet signs mounted so as to be read by motorists
using bridges shall be erected on special steel posts in accordance with SCD
TC-41.40.
5. Street Name signs shall be erected on square supports
in accordance with SCD
TC- 41.40.
When erecting ground-mounted
extrusheet signs, the following provisions apply:
1. Typical vertical and lateral clearances of
ground-mounted extrusheet signs are shown on SCD
TC-42.10.
2. Mounting clips and other attachment hardware shall conform
with SCD
TC-51.11.
3. Supplemental panels erected underground-mounted
extrusheet signs mounted on non-breakaway beams shall be fastened directly to
the beams. The panel shall be separated from the parent sign by 1 inch (25
millimeters) to conform with SCD
TC-42.10. When the panel is too short to reach between the beams, the panel
may be fastened to the parent sign by sign backing assemblies.
4. Supplemental panels erected underground-mounted
extrusheet signs mounted on breakaway beams shall be fastened to the parent
sign by sign backing assemblies. The panel shall be separated from the parent
sign by the width of the fuse plate plus 1 inch (25 millimeters).
5. Exit Panels erected above extrusheet signs shall be attached
by sign backing assemblies furnished with the Exit Panel.
6. The signs should be checked after erection to verify
that the beams extend to the top of the signs and that the signs are horizontal
and the clearances satisfactory.
When erecting overhead signs
the following provisions apply:
1. The clearance above the roadway for the bottom of
overhead signs shall be a minimum of 17 feet (5.2 meters) or as shown on the
plans.
2. Overhead signs shall be vertical or horizontal
regardless of the sag of supporting messenger wire, mast arm rise, chord
camber, or overpass slope.
3. Signs erected on span wire supports shall be attached
in accordance with SCD
TC- 17.10.
4. Signs erected on single arm supports (SCD
TC-16.20) shall be installed so their bottom edge is at the same elevation.
Sufficient adjustment for this purpose is provided by the two pair of slotted
holes in the sign brackets for the attachment of the arm clamps. The clamps
shall be tightened sufficiently to prevent sign rotation about the arm.
5. Signs mounted on semi-overhead supports (SCD
TC-9.10) shall be erected so that their edge clearance from the curb line
is at least 2 feet (0.6 meter).
6. Extrusheet signs over 8 feet (2.4 meters) in height
may be delivered in two pieces for assembly in the field (630.08).
7. Extrusheet signs erected on supports with two arms
shall be centered vertically.
8. Mounting clips and other attachment hardware for
extrusheet signs shall conform to SCD
TC-51.11.
9. Signs mounted on center-mount supports (SCD
TC-9.30) may be mounted laterally on the support in an eccentric position
when required by the plans. However, a minimum of 2 feet (0.6 meter) of sign
length shall remain to one side or the other of the vertical member centerline.
10. Overlay signs erected in the field over existing
extrusheet signs shall be attached by blind rivets at spacings as required in 630.04.
11. Flatsheet signs used in connection with signals
supported by span wire shall be fastened to the messenger wire by special
attachments in accordance with SCD
TC-41.41.
12. Flatsheet signs used in connection with signals
supported in a swinging condition on mast arm supports shall be fastened to the
arm by a special attachment in accordance with SCD
TC-41.41.
13. Exit Panels erected above extrusheet signs shall be
attached by sign backing assemblies furnished with the Exit Panel.
14. Extrusheet signs shall be attached to rigid overhead
supports using sign brackets in accordance with SCD
TC-22.20. Signs extending more than
4 feet (1.2 meters) above or below an attachment point require the use of
intermediate sign brackets.
Signs shall be suitably
protected and identified for shipment and storage. Extrusheet signs shall be
kept rigid by backbracing or crating and the sign face covered with protective material.
The backbracing shall extend sufficiently below the sign lower edge to keep the
sign off the ground.
Extrusheet and flatsheet
signs shall be stored in a vertical position.
Signs must be stored in such
a manner that the packaging paper or cardboard material does not get wet. If
the packaging material or slip sheeting should become wet, the paper should be
removed immediately from contact with sign faces to prevent damage to
reflective sheeting on the faces.
In the case of signs
furnished by ODOT for erection by the Contractor, the Contractor shall be
responsible for the storage and care of the signs after their transfer (630.08).
After sign erection, the
Contractor shall inspect all signs under both day and night conditions. Any
necessary adjustments in lateral position or orientation to correct visibility
deficiencies shall be made to the satisfaction of the Project Engineer (630.13).
Overhead Guide Signs should
typically be centered over the lane(s) to which they apply. Down arrows on the
signs should normally be centered over the proper lane as viewed by the road
user.
The maximum displacement of a
down arrow from the center of a lane should not be more than 2 feet (0.6
meter).
Overhead Guide Signs situated
on curved roadways and incorporating down arrows may have the arrow(s) adjusted
within the sign and/or the entire sign moved laterally so the arrows, when seen
from a typical viewing distance on the curve, will appear to be over the proper
lane(s).
Night conditions inspection
is to assure that each sign has visible and uniform reflectivity. Any signs not
having proper reflectivity should be noted and cleaned or replaced by the
Contractor.
1. Ensure signs and supports are in compliance with plans
and approved catalog sheets.
2. Document depth, diameter, or foundations.
3. Document steel and clearance maintained (if used).
4. Document support stubs (if placed).
5. Document anchors: diameter and depth (if used).
6. Document size and depth driven of drive post used.
7. Document curing used on concrete.
8. Measure appropriate units for foundations and/or
supports used and turn in for pay.
9. Document type, size, background sheeting, and legend
sheeting for signs.
10. Measure signs and turn in for pay as per 630.14.