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Metropolitan Washington Airports Authority
PROCUREMENT AND CONTRACTS DEPT.
AMENDMENT OF INVITATION FOR BID
PAGE 1
Metropolitan Washington Airports Authority
Procurement and Contracts Dept., MA-29
1 Aviation Circle, Suite 154
Washington, DC 20001-6000
Telephone: (703) 417-8660
1A. AMENDMENT OF SOLICITATION NO.
1B. DATED
7-14-C023
October 1, 2014
2A. AMENDMENT NO.
2B. EFFECTIVE DATE
One (0001)
October 23, 2014
The solicitation identified in Block 1A is amended as set forth in Block 3. Hour and date specified for receipt of offers
is extended,
is not extended. Offerors must acknowledge receipt of this amendment prior to the hour and dated specified in the solicitation or as amended, by
one of the following methods: (a) by completing Block 4 and returning copy of the amendment; (b) by acknowledging receipt of this amendment on
the Solicitation Offer and Award Sheet, Block 13. FAILURE OF YOUR ACKNOWLEDGMENT TO BE RECEIVED AT THE PLACE DESIGNATED
FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN REJECTION OF YOUR OFFER.
3. DESCRIPTION OF AMENDMENT
Metropolitan Washington Airports Authority Invitation for Bid No. 7-14-C023, entitled, “Dulles Toll Road
Noise Walls-Package 2” is hereby amended as follows:
1. Specification Section 190423-Drilled Shafts (Caissons) is replaced in its entirety with the attached
Addendum #1, dated October 21, 2014.
2. Specification Section 190519-Noise Walls is replaced in its entirety with the attached Addendum #1,
dated October 21, 2014.
3. Detail Sketch-Dulles Toll Road Package 2 Noise Walls, Addendum #1, dated October 21, 2014.
4. Section III Price Schedule is deleted and replaced with the revised Section III – Price Schedule –
Revised - Amendment One which is available for download at http://www.mwaa.com/7410.htm
5. The deadline for question submission has been extended until October 30, 2014 at 3:00 PM.
6. The deadline for submission of bids has been extended from October 30, 2014 @ 2:00 P.M., to
November 13, 2014 @ 2:00 P.M.
7. All other terms and conditions of the Invitation for Bid remain unchanged.
Except as provided herein, all terms and conditions of the document referenced in Block 1A, as heretofore changed,
remain unchanged and in full force and effect.
4A. NAME AND TITLE OF OFFEROR
MWAA Form PR-06 (Rev. 1/2003)
4B. SIGNATURE
4C. DATE
METROPOLITAN WASHINGTON AIRPORTS AUTHORITY
DULLES TOLL ROAD PACKAGE 2 NOISE WALLS
ADDENDUM #1
DTRR11
October 21, 2014
SECTION 190423—DRILLED SHAFTS (CAISSONS)
Sec. 190423.01—Description
This work shall consist of furnishing and installing Drilled Shafts as indicated in the Plans or as established
by the COTR. If the Contractor revises the wall panel spacing, the furnishing and installing of the drilled
shafts shall be based on the Contractor’s design and details as approved by the Engineer and COTR.
Sec. 190423.02—Materials and Fabrication
(a) Concrete shall conform to the requirements of Section 190217 and those specified herein.
Compressive Strength 3.0 ksi
(b) Reinforcing Steel shall conform to the requirements of Section 190406 and those specified herein.
Deformed bars Grade 60
(c) Steel Casings shall be fabricated A252 Grade 2 or A36 steel.
Sec. 190423.03—Procedures
Refer to 190217 except as modified herein.
For walls on drilled shafts, the soil from the ground surface to a depth equal to the required diameter of the
drilled shaft, but not less than two (2) feet or as required by the conditions, shall not be considered effective
when calculating the required embedment of the drilled shaft. The ground surface slope shall be taken into
account when determining drilled shaft embedment.
An unfactored wind load shall be used in the analysis. Deflections and factors of safety for drilled shafts shall
be determined using actual wind loads not factored loadings.
For axial capacity, the drilled shaft tip elevation shall provide a length of drilled shaft such that at least two
thirds of the total predicted resistance is provided by side resistance. Total vertical deflection of the drilled
shaft head, from settlement and elastic shortening of the drilled shaft, is limited to one (1) inch under service
axial design loads.
The minimum area of longitudinal reinforcement for drilled shaft type foundations shall be one (1) percent of
the gross area of the foundation section. In drilled shafts where the wall post or beam is embedded to the
bottom of the drilled shaft, no reinforcement is required.
The required allowable stresses for steel and concrete in the drilled shaft may be modified by the allowable
overstress permitted in the wind load condition.
The Brom’s method may be used for the design of laterally loaded drilled shafts less than twenty (20) feet in
length. For Group II and Group IV where wind is a contributing load, a minimum safety factor of 2.25 shall
be used if soil parameters are based on the results of standard penetration tests. When soil parameters are
based on the results of subsurface exploration and laboratory testing programs as detailed in the current
AASHTO Standard Specifications for Highway Bridges, or are set by the Authority, a safety factor of 2.0
may be used.
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The preferred method of analyses for the design of laterally loaded drilled shafts is the “p-y curve” method
for the design and analysis of drilled shafts under lateral loads, using public-domain computer program such
as COM624P or commercially available software. The drilled shaft embedment shall provide a length where
the second point of zero deflection is reached. The second point of zero deflection may be assumed to be the
point on the deflection curve where the deflection is decreasing and becomes less than 0.02 inch. The total
horizontal deflection at the head of the drilled shaft is limited to 0.5 inch.
Shaft Requirements. Excavate shafts by auguring, drilling, or hand excavation as necessary to reach the
required bearing strata or depth. When earth walls cannot be maintained without spilling into the shaft, install
casings or slurry as excavation proceeds. Ensure that the casings are full length and water tight. The casings
shall be sufficient thickness to withstand compressive, displacement, and withdrawal stresses; and to maintain
the shaft walls. Withdraw casings as concrete is placed unless otherwise specified. All holes shall be
inspected and approved.
Drilled shaft tolerances:
1. Maximum permissible variation of centerline locations is not more than 1/24th of the shaft diameter
or 3 in., whichever is less.
2. Maximum out of plumb is 1.5 percent of the depth, 12.5 percent of the shaft diameter, or 15 inches,
whichever is less.
3. The top of the shaft or concrete cut-off elevation shall be within 1 in. of the design elevation.
If the specified tolerances are exceeded, provide corrective construction to compensate for excessive
eccentricity at no additional cost to the Authority. Submit proposed methods of corrective construction for
approval.
Excavate the bottom of drilled shafts to undisturbed, level plane. There shall be no adverse fractures or soft
zones when the bottom is probed. Remove all loose material prior to placing concrete.
Dewater drilled shafts as required to facilitate excavation, inspection, and concreting.
Ensure that each drilled shaft has been inspected prior to placing concrete.
The minimum length of drilled shaft shall be 18 feet or as shown on the plans. All drilled shafts shall extend
a minimum depth of 3 feet below the bottom of fill soils (into natural residual soils).
If refusal of the auger is reached prior to reaching the minimum depth or length of caisson shown on the
plans, the COTR shall be contacted for direction prior to proceeding. Refusal shall be defined as a
penetration rate of less than 1 inch per 5 minutes of drilling at full crowd force with equipment meeting the
following requirements: Drill rig with a minimum 50,000 lbs. of total weight applied to the augers and a
minimum of 100,000 Ft-Lbs. of torque
Obstructions in fill material, decomposed rock, highly weathered rock or bedrock may be encountered and
will require special excavating methods. Such methods may include coring, jackhammering, hoe ramming,
down-hole hammers, etc. and they shall be provided by the Contractor at no additional cost.
Reinforcing Steel. Fabricate and place reinforcing steel cages for each drilled shaft as one continuous unit.
Place reinforcement accurately and symmetrically about the axis of the hole and keep securely in position
during concrete placement.
Concrete. Fill drilled shafts with concrete immediately after inspection and approval by COTR.
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Place concrete in one continuous operation, in a smooth flow without segregating. Use mechanical vibration
for consolidation. Concrete may be free dropped up to 25 ft. provided that the procedures ensure that the
concrete falls vertically without hitting the inside walls of the hole or falling directly on the reinforcing steel.
When COTR determines that the concrete placement procedures are unsatisfactory, place concrete by means
of bottom discharge bucket, flexible drop chute, elephant trunk hopper, tremie, or pumping. Use chutes,
tremies, or pumping where a drop of more than 25 ft. is required.
Place concrete in the dry insofar as practicable. If excessive water occurs and it is not feasible to dewater the
drilled shaft for concreting, place concrete by tremie method. Control tremie placement operations to ensure
that tremie is not broken during continuous placing from bottom to top. If approved by COTR, other
methods of depositing concrete underwater may be used.
Maintain a sufficient head of concrete to prevent any reduction in the diameter of the drilled shaft by earth
pressure and to prevent extraneous material from mixing with the concrete. Coordinate the withdrawal of the
temporary casings with the concrete placement operations to maintain a head of concrete approximately 5 ft
above the casing bottom.
Where the cut-off elevation is above ground elevation, form the top section to extend the shaft to the required
elevation. Strike off the tops of the caissons level with a rough finish.
At the discretion of COTR, if concrete placement operations must be interrupted, a construction joint in the
drilled shaft may be permitted. The surface of the construction joint must be level and roughened. Apply an
approved bonding compound to the surface prior to placing additional concrete.
Defective Drilled Shafts. Repair or replace defective drilled shafts as directed by COTR at no additional
expense to the Authority.
Sec. 190423.04—Measurement and Payment
Drilled Shafts will not be measured and the cost thereof shall be included in the price for Ground Mounted
Noise Walls.
END OF SECTION 190423
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ADDENDUM #1
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DRILLED SHAFTS (CAISSONS)
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ADDENDUM #1
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SECTION 190519—NOISE WALLS
Sec. 190519.01 – Description.
The work shall consist of furnishing and constructing noise walls in accordance with these specifications,
contract plans and approved shop drawings and within the specified tolerances for the lines, grades, and
details shown on the plans or as established by the COTR. Plans were developed using a typical 16’ spacing
for the panel posts. The Contractor has the option of using up to a 24’ post spacing but the Contractor shall
be responsible for all redesign and costs associated with the change. Only one typical post spacing may be
used for the Contract.
Sec. 190519.02 – Materials.
a)
b)
c)
d)
e)
Concrete shall conform to the requirements of Section 190217.
Reinforcing Steel shall conform to the requirements of Section 190406.
Structural Steel shall conform to the requirements of Section 190226
Damp proofing and Waterproofing shall conform to the requirements of Section 190213
Lightweight Coarse Aggregate for use in lightweight concrete shall conform to the requirements
of Section 190206
f) Doors, frames and sills shall be steel with a minimum thickness of 12 gage. Doors shall be hollow
steel type construction with a minimum door size of 36” X 80”. Each door shall include a
commercial grade lever and lockset with six keys. Frames, stills, and doors shall have a three coat
rust inhibitive paint system with the final coat being Taupe Grey to match the wall coating. Paint
coats shall all be from the same paint supplier or shall be certified to be compatible with each
other.
Sec. 190519.03 – Procedures.
A. Products
a) The Contractor shall furnish concrete noise barrier walls, with concrete posts and concrete panels,
for ground-mounted applications. The concrete panels shall use sound absorptive concrete on the
roadway side. Walls shall conform to the requirements of the contract documents, AASHTO
material specifications and the following applicable specifications.
b) Concrete noise walls, including the concrete panels and sound absorptive materials, approved for
use on Authority projects shall be selected out of the products with the following requirements
satisfied:
1) Noise wall systems where the acoustic material facing is cast as integral part of the panel
concrete and other requirements specified in this section and the contract drawings are
met.
2) VDOT’s List of Approved Proprietary/Sole Source Items for Noise Walls, as given
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below, will be considered if the above requirements are satisfied.
Coastal precast Systems – Whisper Wall
Faddis Concrete Products – AcoustaCrete
Smith-Midland Corporation – Softsound
Empire Acoustical Systems – Silent Screen M-90
c) Concrete for noise wall panels or concrete posts shall have a minimum 28-day compressive
strength, f'c, of 5,000 psi. Concrete for drilled shafts, footings, or leveling pads shall have a
minimum 28-day compressive strength, f'c, of 3,000 psi. All other concrete shall have a minimum
28-day compressive strength f'c, of 4,000 psi.
d) Reinforcing steel requiring welding shall be ASTM A706, Grade 60, and shall be welded in
accordance with the current AWS D1.4. All other reinforcing steel shall be ASTM A615, Grade
60, or ASTM A706, Grade 60. Threads on reinforcing steel bars shall be UNC (coarse) Series,
Class 2A as specified in ANSI B1.1. Welded wire fabric used to reinforce panels shall be of
approved quality.
e) Structural steel as well as miscellaneous shall conform to the requirements of Section 190226 and
shall be hot-dip galvanized according Section 190233.
f) Anchor rods, nuts and washers shall conform to the requirements of Section 190226 and shall be
galvanized. Bolts, nuts and washers shall be zinc coated high strength as provided in Section
190226.
g) Elastomeric pads shall conform to the requirements of ASTM D1056 Grade 1B3C1, 1B4C1 or
1B5C1. Adhesives shall conform to the manufacturer’s recommendations.
h) Protective color coating.
1. Protective color coating for concrete panels and concrete posts shall be a semi-opaque toner
containing methyl methacrylate-ethyl acrylate copolymer resins with toning pigments
suspended in solution at all times by a chemical suspension agent and solvent. Color toning
pigments shall consist of laminar silicates, titanium dioxide and inorganic oxides. There
shall be no settling or color variation. The use of vegetable or marine oils, paraffin
materials, stearates or organic pigments in the coating formulation will not be permitted.
2. Physical properties of the coating shall be as follows:
Weight per gallon
Solids by weight
Solids by volume
Drying time
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8.3 pounds (min.)
30 percent (min.)
21 percent (min.)
Drying time 30 minutes
(max.) at 70°F and 50 percent humidity
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3. Coating material shall not oxidize and shall show no appreciable change in color after 1000
hours when tested in accordance with ASTM D822; shall have excellent resistance to acids,
alkalies, gasoline and mineral spirits when tested in accordance with ASTM D543; shall
allow moisture vapor from the concrete interior to pass through when tested in accordance
with ASTM E398 or D1653; and shall reduce the absorption rate of exterior moisture into
the pores of the concrete surface when tested in accordance with Federal Specification
TTC-555 B.
4. Surface preparation, application rate and application procedures shall be as specified by
the coating manufacturer, using airless spray equipment, having a minimum capacity of
1,000 psi and ½ gallon per minute. Coating shall not be applied when the air temperature
is below 50°F, to damp surfaces or when the air is misty or unsatisfactory for this work as
determined by the COTR.
5. Noise wall color coatings approved for use on Authority projects shall be one of the
products on VDOT’s “Approved List of Absorptive noise wall Color Coatings” list.
6. The basis of design for the stain color selection for the concrete panels and concrete posts
is United Coatings – Wall Coating Systems Architectural Color Selection – Taupe Gray.
7. A list of VDOT approved coatings which will be considered by the Authority for use in
the contract is given below:
Absorptive noise wall Color Coatings:
United Coatings: Canyon Tone Stain
Sherwin Williams: H&C Silicone Acrylic Concrete Stain
Textured Coatings of America, Inc.: Rainstopper Concrete Stain
Tex*Cote 300 Bridge-Cote, Smooth Coating
Tex*Cote XL-70 Bridge-Cote, Smooth Coating
B Acoustic Performance Standards
a. Noise walls shall provide a transmission loss of at least 23 dB(A) when tested in accordance with
the requirements of ASTM E90 using the typical truck noise spectrum and shall have vibrationfree joints and fittings.
b. Absorptive noise walls shall be designed so that the absorptive portion on the highway side has a
minimum noise reduction coefficient of 0.70 when measured in accordance with the requirements
of ASTM C423.
c. Noise walls shall be designed to minimize or eliminate gaps or openings to prevent transmission of
sound through the noise wall.
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C. Design Standards
a. Structural design loadings for noise walls shall be based on a design life of not less than 50 years.
They shall be designed in accordance with the requirements of the current AASHTO Guide
Specification for Structural Design of Noise Walls except as modified herein. References in the
AASHTO noise wall guide specification to “an industry recognized specification” shall not apply.
All concrete, steel, and aluminum members shall be proportioned with reference to the service load
design methods (allowable or working stress design) of the current AASHTO Standard
Specifications for Highway Bridges. Fatigue and traffic impact shall be considered in the design of
these structures. Noise walls subject to lateral earth pressure shall have those portions so loaded,
designed in accordance with the aforementioned AASHTO specifications. In all cases, settlement
shall also be considered.
b. All ground-mounted noise walls shall be designed for exposure category B2, and all bridgemounted noise walls shall be designed for exposure category C. The wind pressure to be applied to
the full height of the wall shall be based on the height to the centroid of the loaded area.
c. Walls designed for the Authority along the Dulles Toll Road corridor shall be designed for a wind
speed of not less than 90 mph (based on a 50-year mean recurrence interval).
d. The Contractor shall design the wall when traversing a grade in such a manner that the finish profile
of the top panels shall be as uniform in height as possible. The top face of the noise wall shall be
aligned to maintain a continuous appearance and shall not deviate from true alignment by more
than ½ inch in 10 feet.
e. The vertical posts shall be proportioned to have a maximum deflection of no more than h/240 due
to wind load, where “h” is the cantilever height of the post from the top of foundation to the top of
the noise wall. The unbraced length of the post for design shall not be less than “h” unless both
flanges are sufficiently braced to allow a reduction of the unbraced length of the section. Post design
shall account for all holes needed for connections. Wall panels and other supporting members shall
be proportioned to have a maximum deflection of no more than L/240 due to wind load, where “L”
is the length of the panel or member.
f.
Anchor rod performance shall be evaluated against the net area of the anchor rod after reduction to
account for threads. Anchor rods shall be checked against the effect of combined stresses in
accordance with the following formula from the 2001 AASHTO Standard Specification for
Structural Supports for Highway Signs, Luminaires, and Traffic Signals:
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Where:
Ft = allowable normal stress on the rod = 0.5 x Fy
ft = predicted normal stress on the rod due to direct compression or tension
and bending = fa + fb where:
fa= predicted stress on the rod due to direct compression or tension
fb = predicted stress on the rod due to bending about the rod’s neutral axis
fb shall be included in the computation of ft whenever the clearance between the
bottom of the leveling nuts and the top of the concrete foundation is greater
than or equal to the diameter of the rod
Fv = allowable stress on the rod due to direct shear = 0.3 x Fy
fv = predicted stress on the rod due to direct shear
All stresses shall be based on the applied load acting on the net area after consideration for the reduction
due to the presence of the threads.
Where:
2
Anet = net area = 0.7854(D − (0.9743/n))
3
Sx = section modulus = 0.0982(D − (0.9743/n))
D = the nominal diameter of the rod in inches
n = the number of threads per inch
Anchor rods shall be designed assuming that no mortar, grout or concrete is placed between the bottom
of the base plate and the top of the concrete foundation.
g. Where new noise walls tie into existing barriers, existing noise walls, and other structures, the
existing structures shall be analyzed to determine if they are adequate for the addition of new loads,
if the Contractor chooses to use them for support. The Contractor shall make any field
measurements and observations necessary to analyze the existing structures and detail all
connections. Alternatively, the new wall may be designed independent of existing structures with
details for closing gaps.
h. The Contractor shall submit to the Authority shop drawings and supporting calculations that shall
supplement the Contract Drawings as necessary to adequately control the work.
Shop drawings shall contain all specific details and dimensions (such as post spacings, post sizes,
foundation details, panel sizes, and fabrication and attachment details) necessary for the complete
review, construction and inspection of the work. Shop drawings shall also reflect coordination with
the shop drawings for retaining walls or bridges or other adjacent construction items, such as
drainage structures and utilities, where applicable. Shop drawings and the accompanying
calculations shall be sealed by a Professional Engineer holding a valid license to practice
engineering in the Commonwealth of Virginia. Calculations using computer programs or
spreadsheets shall include a description of the design methodology necessary to validate the results
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of the computer output. Calculations shall also provide the rational for assumed soil parameters
and include the results of additional subsurface investigations and soils laboratory testing necessary
to confirm subgrade conditions.
Any changes to the shop drawings by the Contractor after the initial submittal shall be clearly
identified. Changes shall be identified on the shop drawings and denoted in narrative (e.g. cover
letter) and dated after marking all requested changes. This format shall be followed until all
requested changes are completed to the satisfaction of the COTR. Approval of these shop drawing
shall not relieve the Contractor of the responsibility for accuracy of the drawings or conformity
with the contract and site requirements. Shop drawing approval will not indicate a check of
dimensions.
D. Construction Standards
a. Foundations
Existing ground line elevations shall be established and verified by the Contractor prior to
submitting shop drawings. Existing timber and concrete walls shall be removed to the
limits shown on the plans. Existing foundations may be pulled and completely removed
or removed to a depth 2 ft. below finished ground. Any holes created by post or post
foundation removal shall be filled and the fill consolidated as necessary to prevent
settlement. All portions of existing walls to be removed shall become the property of the
Contractor and shall be removed from the project site and disposed of in a proper manner.
Contractor shall take care to not damage any utilities in the vicinity of his operations.
Noise walls shall be placed on drilled shafts or grade beams constructed for this project.
Grade Beams shall be constructed of concrete to the dimensions shown on the plans and
with the reinforcement, anchor bolts, and other accessories as shown on the plans.
Contractor shall provide dewatering so that grade beams can be cast in the dry. Forms,
curing, and other operations shall conform to Sections 190217 and 190404.
The Contractor shall take all precautions to avoid damage to any utilities and work around
conflicts with pipes or utilities.
b.
Posts
1)
Ground-Mounted Barriers
i. The Contractor shall furnish concrete posts for ground-mounted applications.
ii. Finish on the roadway side and residential side of the concrete posts shall be a
Grade A Finish.
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iii. Concrete posts shall be stained with a protective color coating on the roadway
side.
iv. Anchor rod/base plate connections shall be used to attach all posts to the drilled
caissons and/or the grade beams.
v. All post connection hardware to be embedded in the ground shall be coated with
asphalt mastic.
d. Panels
1)
2)
General Requirements
i.
Where noise wall panels do not occupy the full width between the flanges of
the noise wall posts, panel attachment details shall be furnished with the shop
drawings. Such details shall also include material descriptions. Post flanges
and panels shall overlap at least 1½ inches after installation. The face of the
panel on the roadway side of the barrier shall fit tightly against the post flange
for the full height of the panel after installation. Spacer blocks/wedges will not
be permitted.
ii.
The patching of panels will not be permitted without the written approval of the
COTR. Where patching is permitted by the COTR, it shall be performed in
accordance with the manufacturer’s recommendations. Cut, marred, or
scratched surfaces shall be repaired in accordance with the manufacturer’s
recommendations. Panels having deficiencies such as cracking, crazing,
scaling, efflorescence, segregation, mottling of the color coating or stains on
the finish shall be rejected. Irregularities at panel edges that appear broken,
ragged, chipped or dented to the extent that a gap appears once they are stacked
will be cause for rejection.
iii.
Joints and connections shall be secured so as to be structurally sound with no
visible openings for sound transmission and shall not be a secondary source of
noise attributable to vibration.
Ground-Mounted Barriers
i. The Contractor shall furnish concrete panels for ground-mounted applications.
ii. Sound absorptive concrete shall be permanently bonded or attached to the panel’s
core material and have the same service life as the core materials. The absorptive
finish of concrete panels shall meet the requirements of ASTM C666, Procedure
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B, for 300 cycles.
iii. Textured finish on the roadway side of the concrete panels shall be Random Rough
Stake with a vertical orientation. The basis of design for the textured finish on the
roadway side of the concrete panels is Greenstreak Architectural Form Liners
pattern #456 Random Rough Stake.
iv. Textured finish on the residential side of the concrete panels shall be a Scratch
Finish as defined in the plans.
v. Concrete panels shall be stained with a protective color coating on the roadway
side.
vi. Top panels shall be cast with a cap element at the top of the panel that matches the
size and finish of the adjacent concrete posts.
vii. Base panels shall be a minimum height of two (2) feet and shall be embedded in
the ground a minimum of six (6) inches to prevent sound leaks. A non-absorptive
durable finish is required on that portion of the base panels below ground and six
(6) inches above the ground line. Panel height below ground shall match the
existing panels.
viii. When panels are stacked, horizontal joints shall be aligned to create continuous
horizontal lines; however, foundations and/or ground contact panels may be
adjusted within the limits established herein to provide for the continuous
horizontal alignment of joints. Horizontal joints formed where panels mate
together and false or dummy joints (if present) must match in appearance and
alignment. Once installed, the edges of stacked panels shall be neat, and sides that
mate together shall be straight and true.
ix. Concrete noise wall panels shall have all edges chamfered ¾ inch or rounded to ½
3
1
inch radius. V-shaped control joints, /8 to /2 inch deep, shall be scored into one
side of panels less than 8 inches thick and both sides of panels 8 inches or more in
thickness to control temperature and shrinkage cracking. These joints shall be no
more than 8 feet on center.
x. All lifting devices cast into panels shall be hot dip galvanized and flush with the
panel.
xi. All panel connection hardware to be embedded in the ground shall be coated with
asphalt mastic.
e.
Sample Section
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The Contractor shall erect one sample section each for the ground-mounted wall, retaining wall
mounted wall and bridge mounted wall at the job site prior to receiving final written approval
to proceed with panel fabrication from the Authority. The sample section shall be two bays of
panels with posts to show how panels shall be secured to posts with attachment hardware.
Sample panels shall show the attachment area formed in the panel. Sample panels shall show
color and finishes of both sides of the wall.
f.
Drainage Requirements
Ground surface drainage shall be accommodated in the design. Noise walls shall be designed
to deter impoundment and trapping of water. Disturbed areas shall be graded in front and
behind the noise wall to control and dispose of roadway and slope drainage using a graded
ditch or similarly functional drainage. The ground-mounted noise wall posts and bottom noise
wall panel shall be designed with consideration for additional load created by the ditch slope
where it rests against the wall.
Weep holes shall be provided in panels, where necessary, to facilitate proper drainage.
Drainage design shall not create sound leaks.
Disturbed areas of earthwork shall be seeded in accordance with the requirements of Section
190603.
g.
Door Openings and Door Hardware
Doors, where required, shall be located as shown on the noise wall location plans and on the
shop drawings. The lower edge of the door shall be located 12 inches above the finished
grade of the roadway side and residential side at the given location.
Door pulls shall be installed 36 inches above finished grade of the roadway side and
residential side at the given location. Doors shall swing freely on their hinges and close
securely with no visible gaps between the door and frame or door and sill.
Door frame and sill shall be securely attached to precast panel using embedded anchorages or
by drilling holes in the precast panel and using expansion anchors or chemically grouted
anchors.
h.
Other Detail Requirements:
1. Concrete clear cover over reinforcing steel, except precast concrete panels, shall not be less
than 3 inches for primary reinforcement and 2½ inches for ties and stirrups. Concrete clear
cover shall not be less than 1½ inches for precast concrete panels. Concrete clear cover
excludes any sound absorptive concrete finish.
2. Steel reinforcement shall be designed to resist in-service loads and handling loads resulting
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METROPOLITAN WASHINGTON AIRPORTS AUTHORITY
DULLES TOLL ROAD PACKAGE 2 NOISE WALLS
ADDENDUM #1
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October 21, 2014
from manufacture, transport and installation. All concrete elements shall have at least
enough reinforcement to satisfy the requirements in Article 8.20, “Shrinkage and
Temperature Reinforcement,” of the AASHTO Standard Specifications for Highway
Bridges. Mechanical butt spliced connections shall develop at least 125% of the tensile
yield strength of the bar. If welds are necessary, they shall be detailed on the shop drawings.
3. Anchor rods shall be embedded into concrete a distance equal to or greater than the
development length of an equivalent reinforcing steel bar in accordance with Article 8.25,
“Development of Deformed Bars and Deformed Wire in Tension,” of the AASHTO
Standard Specifications for Highway Bridges. Hooked anchor rods shall not be used to
reduce the embedment length. Anchor rods shall be enclosed in reinforcing steel ties over
their full embedded length. These ties shall not be spaced more than 12 inches on center
and shall not be less than #3 in size. A minimum of four anchor rods shall be used per post
if the anchor rods have adequate capacity to resist 150% of the design loads; otherwise a
minimum of six anchor rods shall be used per post. Anchor rods shall not be heated or bent
in the field to accommodate misalignment of anchor rods without approval of the COTR.
Anchor rods, washers and nuts of ground mounted noise walls shall be coated with asphalt
mastic both above and below base plates after installation.
One nut and one washer shall be provided above and below the base plate at the connection
to the anchor rods. The nut against the base plate shall be installed in such a way as to
tension the anchor rod and create adequate friction between the nut and the base plate.
There shall be no play or slack in the connection of the anchor rods to the base plate after
the nuts have been tightened. The distance from the underside of the base plate to the top
of the concrete foundation shall be no more than the diameter of the anchor bolt plus one
inch.
4. Epoxy or adhesive anchors, expansive anchors, split washers, and lock nuts shall not be
allowed. Multiple washers shall not be allowed as spacers for bolted connections or anchor
rods.
5. Base panel leveling pads (support blocks), where needed, shall be cast-in-place reinforced
concrete with steel dowels embedded in the concrete foundation.
6. Precast concrete members, including panels, shall not be lifted from casting beds until their
design compressive strength is sufficient to prevent damage. Concrete shall have attained
the minimum 28-day design compressive strength before members are shipped to the
project site. During storage, stacked members shall be separated from each other by wood
spacing blocks. Curing, storing, transporting, and handling of precast members shall be
done in such a manner as to avoid excessive bending stresses and to prevent cracking,
spalling, chipping or other damage. Units damaged by improper storage or handling shall
be replaced at the Contractor’s expense. Acceptable lifting and support points and
directions of reactions shall be shown on the shop drawings. The Contractor shall be
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METROPOLITAN WASHINGTON AIRPORTS AUTHORITY
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ADDENDUM #1
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October 21, 2014
responsible for the design and safety of the lifting devices used. Embedded lifting inserts
and devices shall be steel and hot dip galvanized in accordance with the requirements of
Section 190233. Computations accompanying the shop drawings shall demonstrate that
stresses in the member are within the allowable range during shipping, handling, and
installation using appropriate impact factors.
7. Mortar, grout, or concrete between the bottom of the base plate and the top of the concrete
foundation shall not be used.
i
Product Warranty
Noise walls shall be guaranteed free from defects due to workmanship and material quality for a
period of one (1) year from the date of Substantial Completion as when only minor or
inconsequential items are remaining and these items cannot be completed for an extended period
of time because of weather or seasonal conditions. Such minor work items may be painting,
mulching, seeding, or plantings. A semi-final inspection shall have been performed and all work
must be satisfactory. Any defects found by the Authority during the one (1) year after Substantial
Completion shall be repaired by the Contractor at no additional cost to the Authority and to the
COTR’s satisfaction.
Sec. 190519.04 – Contractor Quality Control
a) Field Quality Control
1. The Contractor shall follow the requirements in Section 014000 related to the
administrative and procedural requirements for quality assurance and quality control.
2. The following describes the minimum field inspection and testing required in the
Contractor’s Quality Control (CQC) Plan for the work of this section and is for CQC only.
The implementation of the CQC Plan does not relieve the Contractor of the responsibility
to perform the work in accordance with the Contract Documents, applicable codes,
regulations and governing authorities. These elements are provided only as a minimum
starting point for the Contractor to use to general their complete CQC Plan.
3. The Contractor shall establish and maintain quality control for operations under this section
to assure compliance with contract requirements and maintain records of the quality control
activities for all materials, equipment, and construction operations including, but not
necessarily limited to the following:
i.
ii.
iii.
iv.
v.
NOISE WALLS
Performing survey layouts.
Obtaining and verifying dimensions, lines and grades as provided on plans.
Performing clearing and grubbing operations.
Method of integrating acoustic material layer with the concrete core of the panel
Fabrication of posts and panels
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METROPOLITAN WASHINGTON AIRPORTS AUTHORITY
DULLES TOLL ROAD PACKAGE 2 NOISE WALLS
ADDENDUM #1
vi.
vii.
viii.
ix.
x.
xi.
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October 21, 2014
Performing and checking layouts of anchor bolts and providing verification of
layouts to the Authority prior to ordering of materials.
Erecting posts and panels.
Applying protective color coating.
Protecting finished surfaces.
Repairing post and panels with damages or defects.
Performing final site grading, seeding, and cleanup.
b. The CQC Plan shall include, but not be limited to, the following inspections, sampling, and
testing elements.
1. All field inspections, sampling, and testing as required in referenced sections of the
specifications.
2. Sample Section of the ground-mounted wall erected at the job site.
c.
Submittals
1. All submittals as required in referenced sections of the specifications.
2. Design calculations sealed and signed by a Professional Engineer registered in the
Commonwealth of Virginia.
3. Shop Drawings with the complete details of noise wall system including foundations, posts,
panels, panel finishes, protective color coating, connection details, construction details,
sequence of construction, and coordination of stages of work sealed and signed by a
Professional Engineer registered in the Commonwealth of Virginia.
4. Maintenance of traffic plans, if required by the project.
Section 190519 - 05– Measurement and Payment
A
Method of measurement
a. Ground Mounted Noise Wall will be measured in square feet of the surface facing the
highway, from bottom of the panel to the top of wall coping as shown on the plans or to
the actual elevation as approved and constructed and from end to end of the wall, completein-place.
b. Noise wall color coating will be measured in square yards of coated surface from the
finished grade or from the top of the parapet or mounting structure to the top of wall coping
as shown on the plans and from end to end of the wall.
c. Demolish and Remove Walls will be measured in linear feet of existing wall removed.
Walls shall be measured from centerline of foundation post to centerline of foundation post
and from top of wall panel to bottom of wall panel or existing ground, whichever is higher.
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METROPOLITAN WASHINGTON AIRPORTS AUTHORITY
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ADDENDUM #1
B.
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October 21, 2014
Basis of payment
a) Noise walls will be paid for at the contract unit price per square foot.
b) These prices shall include, designing, furnishing, and installing the walls, including drilled
caissons, grade beams, sound absorptive treatment, complete-in-place; providing textured
finishes; providing doors, frames, and hardware; providing modifications to avoid utility,
Right-of-Way, foundation exposure, and tie-back conflicts; grading and seeding; disposing
of surplus and unsuitable material; restoring property; and working outside the grade or
sound attenuation lines depicted on the plans. Excavation of tree roots, existing limited
access fence and other clearing and grubbing items required for the placement of walls
shall be included in the unit price per square foot bid. Costs for ultrasonic and radiographic
testing and all other quality control measures required by the specifications shall be
included in the unit price per square foot bid.
c) Payment for noise walls shall be made incrementally as construction progresses in
accordance with the following percentages: 20 percent of the contract unit price per square
foot after completion of the shop drawing submission and acceptance; 65 percent of
contract unit price per square foot price after installation of drilled shafts and panels; and
15 percent of contract unit price per square foot after completion of noise wall and color
coating. Where multiple walls are specified in the contract, incremental payments will
apply to all walls included in the specific, individual pay items listed.
d) Noise wall color coating will be paid for at the contract unit price per square yard, which
price shall be full compensation for furnishing and applying the noise wall color coating,
preparing surfaces, and providing all materials, labor, tools, equipment and incidentals
necessary to complete the work.
e) Payment for Demolish and Remove Wall shall include demolition , removal of all or
portions of the foundation, removal from site, and proper disposal of all portions of the
existing walls; backfilling any holes from the removal of the foundations; and all labor,
material, tools, equipment and incidentals necessary to complete the work.
Payment will be made under:
Item No.
Pay Item
Pay Unit
190519-1
Ground mounted noise wall
Square foot
190519-2
Noise wall color coating
Square yard
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METROPOLITAN WASHINGTON AIRPORTS AUTHORITY
DULLES TOLL ROAD PACKAGE 2 NOISE WALLS
ADDENDUM #1
DTRR11
October 21, 2014
190519-3
Demolish and Remove Concrete Wall
Linear Feet
190519-4
Demolish and Remove Timber Wall
Linear Feet
END OF SECTION 190519
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