Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 2 - ROAD STRUCTURES, 2020)

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21.12.6.3 Sample

Prior to the construction of the pier, wingwall, retaining walls, and abutment rustication, the
Contractor shall submit to the Engineer for approval a full-size sample of a section of each type of
rustication constructed of concrete. These samples

shall be provided at the Contractor’s expense.

21.12.6.4 Construction

No loads shall be placed on the concrete architectural rustication in piers, abutments, wingwalls,
retaining Walls, at any time during or on completion of construction.

Very tight (water-sealed) shutters shall be used. A small mock-up with the approved mix shall be
demonstrated before production.

The Contractor shall submit his proposed construction method, complete with all details and written
description, to the Engineer for approval. The Contractor shall receive written approval of the
Engineer of his proposed construction method prior to the start of construction.

21.13

Precast Concrete Structural Members

Precast concrete structural members shall be constructed and placed in the work in conformance
with the details specified in the Contract documents, as specified herein, and as directed by the
Engineer.

If approved by the Engineer, the Contractor may use precasting methods for elements of the work
that are otherwise indicated to be constructed by the cast-in-place method. When such precasting
is proposed, the Contractor shall submit full design calculations and working drawings showing
construction joint details and any other information required by the Engineer.

21.13.1

Quality Assurance

21.13.1.1 Reference Codes and Standards

Codes and standards shall be as specified herein and the Contract documents.

1. ACI 301-10

“Specifications for Structural Concrete”;

2. ACI 318-08

“Building Code Requirements for Structural Concrete and Commentary;

3. Precast Concrete Institute MNL-116-99,

“Manual for Quality Control for plants and production

of Structural

Precast Concrete Products”;

4. Precast Concrete Institute PCI MNL-120-14,

“PCI Design Handbook – Precast and

prestressed Concrete, 7

Edition

”;

5. Precast Concrete Institute MNL 127-99

, “Erectors’ Manual: Standards and Guidelines for the

Erection of Precast Concrete Products

”;

6. American Welding Society (AWS) - D1.1/D1.1M:2010, Structural Welding Code

– Steel; and

7. American Welding Society (AWS) - D1.4/D1.4M:2011, Structural Welding Code

– Reinforcing

Steel.

21.13.1.2 Qualifications of Precast Prestressed Concrete

Subcontractor

The proposed organization for the performance of the prestressed concrete works under these
specifications shall be certified by the Precast/Prestressed Concrete Institute, Plant Certification
Program, prior to start of production of works.

21.13.1.3 Welder Qualifications

Welders shall be qualified in accordance with AWS D1.1/D1.1M:2010 for all weld operations on the
job.

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21.13.2

Precast Concrete Submittals

21.13.2.1 Working Drawings

Whenever specified in the Contract documents

— or requested by the Engineer — the Contractor

shall provide working drawings for precast members. Such drawings shall include all details not
provided in the Contract documents for the construction and the erection of the members and shall
be approved before any members are cast. Such approval shall not relieve the Contractor of any
responsibility under the Contract documents for the successful completion of the work.

21.13.2.2 Shop Drawings

All shop drawings shall be submitted for review and approval in accordance with the requirements
specified in the Contract documents and these standard specifications. Prints of the final approved
shop drawings shall be furnished by the Contractor for the Engineer's use and as many other prints
shall be provided as may be needed by the Contractor to facilitate and expedite performance of the
Works.

All shop drawings shall show each member location, fabrication details, joint and openings details,
identification markings, reinforcement, connection details, dimensions, embedded items and
relationship to adjacent materials and construction in sufficient detail to facilitate manufacture,
handling, and erection. Identification markings shall include date of casting.

Reinforcement and connection designs shall be accompanied by supporting engineering data,
including all loading details, for review by the Engineer.

The shop drawing submittal shall include erection and handling procedure and sequence for all
precast members.

21.13.2.3 Samples

Samples shall be submitted in the quantity as directed by the Engineer for the following:

1.  Embedded items
2.  Anchorages
3.  Joint materials

21.13.2.4 Full Size Sample

After the Engineer has approved the shop drawings, the precast concrete Fabricator shall produce
full-size typical members for inspection by the Engineer at the production site. If approved,
production of additional members may proceed and the approved samples may be used in the
Project after the production of other such members. If the full-size samples are rejected, required
corrections shall be performed or new full-size samples shall be produced until approval is obtained.

All criteria covered by this article on submittals and approval shall also apply to any subcontractor
conducting any of the respective precast prestressed concrete work.

21.13.3

Precast Concrete Materials and Manufacture

Unless otherwise specified in the Contract documents, all concrete for precast structural members
shall be Class C50/20 concrete, meeting the requirements of Section 4.3 of Chapter 4, Concrete
Works, of these Standard Specifications, and Section 21.3.4. Steel reinforcement shall comply with
Section 21.3.5. Grout in precast works shall comply with Section 21.18.3. The construction of precast
concrete fascia panels shall comply with the requirements of Section 21.16.

Precast concrete shall be as dense, and reach the compressive strengths, as specified herein.
Material gradations and proportions may be varied, subject to the samples submitted by the
Contractor to the Engineer for its approval. All requirements of other articles in this chapter referring
to materials and manufacturing processes for cast-in-situ and prestressed concrete shall apply to
precast concrete, except those requirements that are modified or supplemented by the provisions

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that follow. Additionally, the Contractor

’s work shall satisfactorily ensure the Engineer that the

precast concrete units are not moved or loaded until they have attained the required strength.

When precast members are manufactured in established casting yards, the Manufacturer shall
oversee the continuous monitoring of the quality of all materials and concrete strengths. Tests shall
be performed in accordance with appropriate AASHTO or ASTM methods. All sampling and testing,
and the results of all tests, shall be made available to the Engineer, which shall be allowed to observe
sampling and testing procedures.

Established precast concrete manufacturing plants shall be certified under the Precast/ Prestressed
Concrete Institute (PCI) certification program

— or an alternative equivalent program for the category

of work being manufactured.

Additionally, plant quality control (QC) personnel shall be certified in the PCI QC personnel
certification program, Level II. Plant QC managers shall be certified PCI, Level III. These
requirements may be met by alternative, equivalent experience and certification.

Precast members shall be cast on rigid beds or pallets. When casting the bearing surfaces, the
Contractor shall use special care to ensure that they will join properly with other elements of the
structure.

For prestressed precast units, several units may be cast in one continuous line and stressed at one
time. Sufficient space shall be left between unit ends to permit access cutting of the tendons after
the concrete has attained its required strength.

The consistency of the concrete will be measured by the Engineer by the slump test in accordance
with ASTM C143 / C143M - 10a or BS EN 12350-2:2009. The slump of all concrete shall be as
approved by mix design and as directed by the Engineer.

As soon as their removal shall not cause distortion of the concrete surface, the Contractor may
remove the side forms, providing that curing is not interrupted. Members shall not be lifted from
casting beds until their strength will sufficiently prevent damage.

When cast-in-place concrete will later be cast against the top surfaces of precast beams or girders,
these surfaces shall be finished to a coarse texture by brooming with a stiff, coarse broom. Prior to
shipment, such surfaces shall be cleaned of laitance or other foreign material by sandblasting, or
another approved method.

When precast members are designed to be abutted together in the finished work, each member shall
be match-cast with its adjacent segments to ensure proper fit during erection. As the segments are
match-cast, they shall be precisely aligned to achieve the final structure geometry. During the
alignment, the Contractor shall make adjustments to compensate for deflections.

21.13.3.1 Formwork for Precast Prestressed Members

Formwork for all precast, prestressed members shall comply with the requirements of Section 1.20
of Chapter 01, General Requirements, of these Standard Specifications, and as specified herein.

All  forms  shall  be  constructed  and  maintained  mortar-tight,  of  sufficient  strength  to  withstand
pressures to maintain true to the shapes and dimensions indicated on the Contract plans to provide
completed  members  of  shapes,  lines,  and  dimensions  indicated  within  fabrication  tolerances
specified  herein. The  casting  bed shall  have  a  concrete  deck  to  which  the  bottom forms  shall  be
adequately anchored. Bottom forms shall be placed to provide for camber and to allow for automatic
cambering resulting from transfer of tendon prestress to the concrete, and shall be maintained in
true  alignment  and  of  sufficient  stiffness  to  prevent  excessive  deflection  under  the  load  of  wet
concrete. Self stressing moulds shall not be allowed.

Forms and all related supports shall be designed to anticipate shortening of members due to
concrete shrinkage and the transfer of pre-tensioning or post-tensioning force to the concrete. Forms
shall be constructed to compensate for this shortening so that the centre-to-centre bearing distance
of the completed beam under full dead load will be as indicated on the Contract plans.

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Side forms shall be of steel and shall be supported without resort to ties or spreaders within the body
of the member. They shall be braced and stiffened so that no undesirable deflection or curvature
takes place under concrete pressure. They shall be so designed that proper cleaning of the forms
between uses is facilitated.

The ends and sides of adjacent sections of forms which are butt joined shall match smoothly and
tightly and shall result in proper alignment. The side forms shall be cross-tied above the finished
surface of the member at sufficiently close spacing to maintain true cross-sectional dimensions.

All exposed outside edges shall be beveled or chamfered as indicated on the Contract plans.
Leakage of mortar will not be permitted. Joints between soffit, side forms, and bulkheads shall be
tight and, if necessary, shall be gasketed with rubber. Rubber may also be used to provide the corner
chamfers. Plugging of holes and slots in the forms shall be neatly done so that the finished members
will have a workmanlike appearance acceptable to the Engineer.

Before the concreting operations begin, the forms and casting bed shall be treated with a suitable
form lacquer or oil to prevent bonding of the concrete. The form lacquer or oil shall be of such quality
as to leave no stains or discoloration on the member faces. Extreme care shall be exercised to
prevent the coating of strands and reinforcement steel with such material and any strands or bars
so contaminated shall be satisfactorily cleaned or replaced.

Forms shall be free from paint or other protective substance that may cling to the surface of the
finished precast members. Forms not thoroughly cleaned after prior use shall not be used.

No form ties, spreaders, or forming facilities shall penetrate the body of the member, except those
necessary to provide the ultimate openings as indicated on the Contract plans. Before any forms are
removed, the concrete shall have attained sufficient strength to prevent injury due to such removal.
No forms shall be removed without the approval of the Engineer. Proper care and precautions shall
be exercised in removing forms so that no damage results to the finished surfaces.

In the event that during the casting of members it becomes apparent that forms have deteriorated to
the  degree  that  finished  precast  members  no  longer  can  be  constructed  without  approaching  or
exceeding  the  dimensional  tolerance  limits,  the  Engineer  may  order  production  suspended  with
respect  to  the  use  of  the  unsatisfactory  forms  and  until  they  have  been  completely  renovated  or
replaced by the Contractor.

Built-in items and anchorages shall be accurately positioned and secured to form work. The
Contractor shall locate such items and anchorages where they do not affect the position of main
reinforcement or placing of concrete. Bearing plates shall not be relocated in units unless approved
by the Engineer.

All exposed corners of all precast concrete beams, columns, spandrels, and other members shall
have a 12 mm minimum, 45 degree chamfer unless otherwise indicated on the Contract plans. The
Contractor shall form all recesses, design bevels, and other requirements indicated on the Contract
plans.

21.13.3.2 Precast Prestressed Concrete Deck Panels

The fabrication, handling, storing, transporting and erecting of the precast prestressed concrete deck
panels shall be as indicated on the Contract plans, as specified herein and as directed by the
Engineer.

The Contractor shall provide and install the deck panels, complete, furnishing all materials, labor and
equipment and performing all required work as indicated on the Contract plans, as specified herein,
and as directed by the Engineer.

The precast prestressed concrete deck panel work shall include, but not by way of limitation, the
furnishing and installing of the deck panels, the steel shims, the preformed filler strips, the adhesive,
the grout and all appurtenances.

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Materials for Deck Panels

Concrete materials used in the fabrication of the precast deck panels shall comply with the
requirements of this chapter and the following requirements:

•

Concrete shall consist of Class C50/20 concrete that shall meet the requirements of Section

4.3 of Chapter 4, Concrete Works, of these Standard Specifications

—

unless otherwise

indicated on the Contract drawings.

•

Aggregates for the concrete shall be graded as shown in Table 21-8:

Table 21-8: Concrete aggregate size for deck panels

Sieve Size (mm)

Percent Passing (%)

12.5

100

9.5

– 100

4.75

– 60

– 15

1.18

– 5

•

Steel shims shall be constructed of ASTM A36 / A36M - 08 Steel.

•

Preformed filler strips shall be suitable, compressible material

— as approved.

•

Grout shall consist of an approved, flowable, non-shrink, non-metallic grout containing

sulphate-resistant cement. It shall have a minimum compressive strength of 20.6 MPa at an
age of 24 hours, when tested using applicable portions of ASTM C109 / C109M - 11b. Grout
temperature shall be

≤ 30

•

Grouts shall show no expansion after final set takes place, when tested in accordance with

ASTM C827 / C827M - 10. It shall have an initial setting time of not less than 45 minutes.

•

Embedded, threaded inserts shall be manufactured from round or hexagonal, Type 304,

stainless-steel bar that complies with SAE AMS-QQ-S-763; or Type 304, stainless-steel
schedule-40 pipe.

Fabrication of Deck Panels

The fabrication of the deck panels shall comply with the applicable requirements as specified in
Section 21.13.3 and shall be as approved by the Engineer.

Tolerances for Deck Panels

The maximum dimensional tolerances for the deck panels are listed in Table 21-9. It is intended that
the dimensions of all deck panels shall be well within these tolerances and that the maximum values
shall be permitted to be approached or equalled only occasionally. Equipment and methods which
permit an undue proportion of dimensions approaching the tolerance limits shall not be used. Deck
panels having dimensions outside the tolerance limits will be rejected by the Engineer.

Table 21-9: Maximum dimensional tolerances for deck panels

Dimension

Tolerance

Panel depth (thickness)

+ 9.5 mm, -3.2 mm

Panel length (parallel to strands)

± 25.4 mm

Panel width

+ 3.2 mm, - 12.7 mm

Position of strands (vertical)

± 3.2 mm

Position of strands (horizontal)

± 12.7 mm

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21.13.4

Sampling and Testing of Precast Concrete Structural
Members

Sampling and testing shall be in general compliance with this chapter and the provisions of PCI MNL-
117-77. The Contractor shall employ the services of an independent testing laboratory approved by
the Owner to test the cement and aggregates, design the concrete mixes, and make all tests of
concrete, reinforcing steel, and prestressing steel and such other materials as directed by the
Engineer. The laboratory shall have at least five years’ experience in performing the specified tests.

21.13.5

Curing Precast Concrete

Unless otherwise permitted, precast members shall be cured by the water, waterproof cover, or the
steam or radiant-heat methods. Using insulated blankets shall be permitted with the waterproof cover
method. When the waterproof cover method is used, the air temperature beneath the cover shall not
be less than 10 degrees Celsius and live steam or radiant heat may be used to maintain the
temperature above the minimum value; the maximum concrete temperature during the curing cycle
shall not exceed 71 degrees Celsius; and, the waterproof cover shall remain in place until the
concrete’s compressive strength reaches the strength specified for de-tensioning or stripping.

The ends of prestressed concrete members shall be treated with a glass-reinforced plastic lining
(GRP) to protect the strand ends from corrosion. The Contractor shall submit a method statement
for the application of the liner for the Engineer’s approval.

21.13.6

Precast Concrete Storage and Handling

The handling of precast prestressed concrete members from the time of placing of concrete in the
forms until they are in place in the structure shall be in accordance with the standard specifications.
Failure to comply with these specifications may result in damage or destruction of the member by
the internal stresses. Any member damaged during handling, storing, transporting, or erecting shall
be replaced by the Contractor at his expense.

When handling and moving precast, prestressed concrete members, the Contractor shall exercise
extreme care. Girders shall be maintained and handled in an upright, or vertical, position at all times;
and, the directions of the reactions

— with respect to the member — shall be as in the final position.

Support  points  during  transportation  and  storage  shall  be  located  within  750  mm  of  their  final
position;  otherwise,  their  location  shall  be  as  shown  on  the  shop  drawings.  During  lifting,  the
Contractor shall support the girders only by the inserts provided for that purpose.

Proposed methods for handling, lifting, and erecting precast concrete elements; and the details of
any inserts required to be cast into the girders for such purposes shall be included in the

Contractor’s

working drawings

— as required by Article 21.13.2.1.

During transportation, the ends of the girders shall not extend a distance of more than the depth of
the girder and in no case more than 1 m beyond the bolsters or other supports on the transporting
vehicle. Deck beam ends shall not extend a distance of more than 1.5 times their depth and in no
case more than 1 m beyond the supports. Precast girders shall be braced laterally to prevent buckling
during transportation and erection. This bracing shall be securely attached to the top flange of the
girders and shall be of sufficient stiffness to prevent lateral deflection of the top flange during handling
for transportation and erection.

During storage, the supports shall maintain the girders in a level position and without twisting.
Stacking girders while in storage will be permitted only with the approval of the Engineer. If such
permission is granted, the supports of all girders shall be in the same vertical planes and shall be of
adequate thickness to prevent damage to the lifting devices.

Prestressed concrete members shall not be shipped until tests on concrete cubes, manufactured of
the same concrete and cured under the same conditions as the girders, indicate that the concrete of
the particular member has attained a compressive strength equal to the specified 28-day
compressive strength

— except when otherwise specified or approved by the Engineer.

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Precast units shall be so stored, hoisted, transported, and fixed that they shall not be overstressed
at any time or suffer any cracking or damage. Units damaged by improper storage or handling shall
be replaced at the Contractor's expense.

21.13.7

Precast Concrete Erection

During all stages of construction, the Contractor shall ensure the structural integrity of the precast
members.  Lifting  devices  shall  be  used  in  a  manner  that  does  not  cause  damaging,  bending,  or
tensional  forces.  After  a  member  has  been  erected,  but  until  it  is  secured  to  the  structure,  the
Contractor  shall  provide  temporary  braces  to  resist  wind  or  other  loads  and  to  ensure  proper
alignment and safety. If accidental loading is imparted on the precast member, the Contractor shall
prepare  an  evaluation  of  the  accidental  loading  effects,  and  shall  share  this  evaluation  with  the
Engineer  to  ensure  that  the  member  has  not  been  damaged.  Elements  shall  be  rejected  by  the
Engineer if the analysis is not conclusive.

When erecting girders, the Contractor shall take care to keep bridge seats and tops of bearing
devices free of foreign materials. Any shifting of girders shall be done while they are held free of the
foundation.

Placement of, or the use of, erecting equipment supported on the girders or the bridge deck shall
not be permitted by the Engineer.

Precast  concrete  members  shall  be  erected  level,  plumb,  square  and  true  within  the  allowable
tolerances.  They  must  be  positioned  so  that  cumulative  dimensional  error  does  not  occur.  Joints
shall be correctly aligned and uniform joint width shall be maintained as erection progresses. Each
member  shall  be  securely  fastened  in  place  as  indicated  on  the  approved  shop  drawings.
Adjustments or changes in connections, which could involve additional stresses in the products or
connections, will not be permitted without approval by the Engineer.

Precast concrete members shall be lifted and supported during erection operations only at the lifting
or supporting points, or both, as shown on the approved shop drawings. After erection, exposed
locations shall be patched to match adjacent surfaces.

Unless otherwise specified in the Contract plans, installation tolerances of the erected members shall
not exceed following tolerance limits specified in PCI MNL 127-99,

“Standards and Guidelines for

the Erection of Precast Concrete Products

.”

•

Variances from Plumb: 6 mm in 6.00 m run or story height; 12 mm total in 12.00 m or longer

run.

•

Variations from level or elevation: 6 mm in 6.00 m run; 10 mm in 12.00 m run;



12.00 mm

maximum.

•

Variation from position in plan



12 mm maximum.

•

Offsets in alignment or adjacent members at Joint: 6 mm in 3.0 m run; 10 mm maximum.

The Contractor shall be responsible for chipping, spalling, cracking or other damage to the members
until they are erected at the job site. After installation is completed, any further damage is the
responsibility of the Contractor.

No stresses, except for the allowed adjustment in connections indicated above, shall be introduced
into precast members or their connections in order to make connections fit.

The Contractor shall protect members from damage by field welding operations and provide
noncombustible shields as necessary during these operations.

Structural welds shall be made by certified welders in accordance with the erection drawings which
shall clearly specify type, extent, sequence and location of welds. A fire extinguisher of an approved
type and in operating condition shall be located within reach of welding operations at all times.

All work and materials of other trades shall be adequately protected by the erector at all times.

After precast concrete members have been set in place, the work shall be inspected by the Engineer.
Members found to be slightly damaged may be authorized for repair at this time. Repairs shall
conform to the Engineer's requirements and shall be structurally sound. Members that cannot be

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satisfactorily repaired, or that are off-colour in the opinion of the Engineer shall be replaced with new,
undamaged units at no additional cost to the Owner.

Exposed faces shall be cleaned as necessary to remove dirt and stains that may be on the members
after erection. The precast units shall be cleaned only after all installation procedures are completed.
The exposed surfaces shall be cleaned in accordance with the precast Manufacturer's
recommendations.

21.13.7.1 Precast Prestressed Concrete Girders

The Contractor shall verify building structures, anchors, devices, and openings are ready to receive
work of this section.

The Contractor shall check both line and grade in sufficient time before erection is scheduled to
permit any necessary corrections. Corrections, if any, shall be made by the Contractor before
erection begins. Proposed corrections should be submitted to the Engineer for approval.

The Contractor shall submit his proposed method of handling, lifting, erecting and details of any
inserts required to be cast into the members for such purpose shall be included in the shop drawings
required by Section 21.13.2.

Each member shall have proper identification as to number, position in the structure, and date of
casting painted on its top and on one end. Members shall not be shipped to the job site before the
28-day compressive strength data are available except as otherwise specified or approved by the
Engineer.

21.13.7.2 Precast Prestressed Concrete Deck Panels

Precast deck form panels shall be erected and placed so that the fit of mating surfaces shall not
create excessive grout leakage. If such a fit is not provided, joints shall be dry-packed or sealed with
an acceptable caulking compound prior to placing the cast-in-place concrete. End panels for skewed
structures may be sawed to fit the skew.

Deck panels shall be fabricated and placed in such a manner that they will extend approximately
100 mm over the girders. They shall be installed by the Contractor in the following sequence:

•

Shims shall be placed at 1.5 m on centres along girder flanges. Their thickness shall be

determined by the Contractor with survey equipment. These thicknesses shall vary within the
spans of the deck panels to accommodate the girder camber and the roadway profile while
maintaining the depth of the cast-in-place slab.

•

Strips of preformed filler strips shall be placed along the edge of the girder flange and

preformed filler strips shall be glued to the tops of the girder flange using an approved
adhesive. Preformed joint filler heights shall be between 5 percent and 10 percent greater
than the height of the adjacent steel shims. Once installed, and after the deck panels have
been lowered into position, the preformed filler strips shall form a mortar-tight seal.

•

Non-shrink grout shall be placed around and between the steel shims and along the

preformed filler strips in such a manner that there are no voids under the deck panels. Grout
may be placed by the Contractor before or after the deck panels are lowered into position.

If the grout is placed before the deck panels are lowered into position, then the height of the grout
shall be slightly greater than the heights of the nearby steel shims to ensure that the placement of
the deck panels will compact the mortar, thus forming a uniform bearing surface for the deck panels.
During this placement method, the Contractor shall ensure that no grout is forced between any steel
shims. Grout shall be mixed and placed in accordance with the grout Manufacturer

’s written

instructions. Rotating drum-type concrete mixers shall not be allowed for mixing the grout.

•

Deck panels shall be lowered into their final positions. If the Contractor chooses to apply the

grout after the deck panels have been lowered, grout shall be placed with a low-pressure
pumping system until all voids under the deck panels have been filled with grout. After the
deck panels have been installed and prior to placing the cast-in-place concrete slabs, the
Contractor shall remove all laitance or flakes by water blasting, which shall be performed by

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experienced personnel with equipment that provides a pressure adequate to ensure the
removal of all laitance and other deleterious materials. Prior to placing the cast-in-place
concrete slabs, the precast deck panels shall be moistened for a period of time approved by
the Engineer.

21.13.8

Precast Concrete Finish

Upon removal from the forms, the precast concrete units shall be examined and all surfaces that will
remain permanently visible shall have a smooth and dense finish or uniform texture that is free from
holes, fins, and shutter staining. Any precast concrete unit found to be defective in any respect will
be rejected.

Surfaces that will be exposed in the completed structure other than architectural precast elements,
will be given Class 1 "ordinary finish" consisting of the removal of fins, rough spots, stains, hardened
mortar or grout, and form lines by rubbing with a No. 16 carborundum stone or an abrasive of equal
quality without materially changing the texture of the surface. The rubbing shall be continued
sufficiently to remove all roughness and projections. When the surface of concrete that will be
exposed to view shows a film of oil left from an excess of oil on the forms, or the concrete is oil-
stained, or is otherwise not of uniform colour, the Engineer shall require the Contractor to employ a
satisfactory cleaning method.

Depressions resulting from holes left by attachments to rod or bolt anchorages shall be carefully and
neatly pointed with a non-shrinkage grout or mortar having equal or better strength than the concrete
used.

Air pockets or rough places larger than 13 mm diameter occurring in any surface shall be pointed as
specified in the foregoing paragraph. Honeycombed areas shall be chipped out by the Contractor
and inspected by the Engineer before being pointed. Pointed areas mentioned in this article shall
then be given an ordinary finish as herein specified.

21.13.8.1 Concrete Fascia Elements

All exposed surfaces of architectural precast fascia elements, shall have a finish equivalent to PCI
finish No. 280 Acid Etched Light (AE-L), as specified in PCI (Precast/Prestressed Concrete Institute)
“Architectural Precast Concrete - Color & Texture Selection Guide”, 2

Edition.

21.13.8.2 Precast Prestressed Concrete Girders

The top surface of beams and girders shall be finished initially with a wooden hand float. Further
finishing shall be delayed until the water sheen appears, but not to the point of rendering further
manipulation ineffective. The surface then shall be finish

ed in accordance with the Manufacturer’s

recommendations to receive the coating system and protection as approved by the Engineer.

21.13.8.3 Precast Prestressed Concrete Deck Panels

The top surface of each deck panel shall be given a rough finish. At approximately the time of initial
set, all laitance shall be removed with a coarse wire brush or with metal tines not less than 3 mm
deep to ensure proper bond with the concrete that will be placed onto the deck panels after the deck
panels have been installed.

21.13.9

Precast Products

All precast units shall be manufactured of diverse sizes by the Contractor with materials as specified
in this chapter. These units shall be transported to the worksite by the Contractor’s own means of
transportation. These materials shall be examined by the Contractor before shipping to ensure that
they are of good quality and comply with these Standard Specifications. Any damage sustained by
this material in the course of transportation, or on the worksite, shall be the responsibility of the
Contractor, including its prices for all costs of labour, haulage, transportation, on-site offloading,
waste, and everything necessary for this work.

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21.13.10 Epoxy-bonding Agents for Precast Segmental Box Girders

21.13.10.1 Epoxy-bonding Agent Materials

Epoxy-bonding agents for match-cast joints shall consist of thermosetting, 100 percent solid
compositions that do not contain solvent or any nonreactive organic ingredient

— except for the

pigments required for colouring. Epoxy-bonding agents shall consist of the following two
components: a resin and a hardener. Each component shall be distinctly pigmented, so that mixing
produces a third colour similar to the concrete in the segments to be joined, and shall be packaged
in proportioned, labelled, ready-to-use containers.

Epoxy-bonding agents shall be formulated to provide application temperature ranges that will permit
erection of match-cast segments at substrate temperatures from 4 degree Celsius to 46 degree
Celsius. If two surfaces to be bonded have different substrate temperatures, the adhesive applicable
at the lower temperature shall be used.

Epoxy-bonding agents shall be insensitive to damp conditions during application and, after curing,
shall  exhibit  high-bonding  strength  to  cured  concrete,  good  water  resistivity,  low  creep
characteristics,  and  tensile  strength  greater  than  the  concrete.  Additionally,  the  epoxy-bonding
agents  shall  function  as  a  lubricant  during  the  joining  of  the  match-cast  segments;  as  a  filler  to
accurately match the surface of the segments being joined; and as a durable, watertight bond at the
joint.

To determine their workability, gel and open time, bond and compression strength, shear, and
working temperature range, the Contractor shall test the epoxy-bonding agents at frequencies stated
in the Contract documents.

Material samples shall be furnished by the Contractor to the Engineer for quality assurance (QA)
testing with a certification from a reputable independent laboratory that indicates that the material
has passed the required tests.

Specific properties of epoxy and the test procedures to be used to measure these properties shall
be as described in the following sections.

Test 1: Sag Flow of Mixed Epoxy-bonding Agent

The sag flow test for mixed epoxy-bonding agent is not directly measured. Table 1 of AASHTO M
235M/M 235 specifies the properties for the various types, grades, and classes of bonding agents.
Table 21-10 presents the testing method and related specification.

Table 21-10: Sag flow test for mixed epoxy-bonding agent

Testing
Method:

No testing is required.

Specification: Mixed epoxy-bonding agents must be an AASHTO M 235M/M 235 Type VI, Grade

3 (non-sagging) consistency at the designated application temperature class for
the bonding agents used.

Test 2: Gel Time of Mixed Epoxy-bonding Agent

Test 2 shall determine gel time on samples mixed and as specified in the testing method. It provides
a guide for the period of time the mixed bonding agent remains workable in the mixing container
during its application to the match-cast joint surfaces. Table 21-11 presents the testing method and
related specification.

Table 21-11: Gel time test for epoxy-bonding agent

Testing
Method:

ASTM D2471-99*, and 1-litre and 4-litre quantities shall be tested.

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Specification:

A 30-minute minimum testing shall occur on 1-litre and 4-litre quantities at the
maximum temperature of the designated application temperature range for gel
time. Note: Gel time is not to be confused with the open time specified in Test 3.

*It is the responsibility of the Contractor to establish appropriate safety and health practices and
determine the applicability of regulatory limitations prior to use this standard.

Test 3: Open Time of Bonding Agent

Open time of bonding agent test measures workability of the epoxy-bonding agent for the erection
and post-tensioning operations. As tested here, open time is defined as the minimum allowable
period of elapsed time from the application of the mixed epoxy-bonding agent to the precast
segments until the two segments have been assembled together and temporarily post-tensioned.
Table 21-12 presents the testing method and related specification.

Table 21-12: Open time test for epoxy-bonding agent

Testing
Method:

Open time is determined  using test specimens, as detailed in Test 4, Three-Points
Tensile  Bending  Test.  Epoxy-bonding  agent,  at  the  highest  specified  application
temperature,  is  mixed  together  and  applied  as  instructed  in  Test  4  to  the  concrete
prisms,  which  shall  also  be  at  the  highest  specified  application  temperature.
Adhesive-coated prisms shall be maintained for 60 minutes at the highest specified
application temperature with the adhesive-coated surface or surfaces exposed and
uncovered before joining together. Assembled prisms shall then be cured and tested,
as instructed in Test 4.

The epoxy-bonding agent shall be deemed acceptable for the specified application
temperature only when essentially total fracturing of concrete paste and aggregate
occurs with no evidence of adhesive failure.

Construction  situations  may  sometimes  require  application  of  the  epoxy-bonding
agent  to  the  precast  section  prior  to  erecting,  positioning,  and  assembling.  This
operation may require epoxy-bonding agents having prolonged open time. In general,
where  the  erection  conditions  are  such  that  the  sections  to  be  bonded  are
prepositioned  prior  to  epoxy  application,  the  epoxy-bonding  agent  shall  have  a
minimum  open  time  of  60  minutes  within  the  temperature  range  specified  for  its
application.

Test 4: Three-point Tensile Bending Test

The three-point tensile bending test performed on a pair of concrete prisms bonded together with
epoxy bonding agent, determines the bonding strength between the bonding agent and concrete.
Bonded concrete prisms are compared to a reference test beam of concrete that measures 150 mm
by 150 mm by 450 mm. Table 21-13 presents the testing method and related specification.

Table 21-13: Three-point tensile bending test for epoxy-bonding agent

Testing
Method:

ASTM  C192  /  C192M  -  07  150×150×225  mm  concrete  prisms  of  41.4  MPa
compressive strength at 28 days shall be sandblasted on one 150 mm by 150
mm side to remove mould release agents and laitance; and shall be submerged
in clean water at the lower temperature of the specified application temperature
range  for  72  hours.  Immediately  on  removing  the  concrete  prisms  from  the
water,  the  sandblasted  surfaces  shall  be  air-dried  for  one  hour  at  the  same
temperature  and  50  percent  relative  humidity  and  each  shall  be  coated  with
approximately  a  1.5  mm  layer  of  the  mixed  bonding  agent.  The  adhesive-
coated  faces  of  two  prisms  shall  then  be  placed  together  and  held  with  a
clamping force normal to the bonded interface of 0.35 MPa. Assemblies shall

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then be wrapped in a damp cloth that is kept wet during the curing period of 24
hours at the lower temperature of the specified application temperature range.

After  the  24-hour  curing  period  at  the  lower  temperature  of  the  application
temperature  range  specified  for  the  epoxy-bonding  agent,  the  bonded
specimens  shall  be  unwrapped,  removed  from  the  clamping  assembly,  and
immediately tested. Tests shall be conducted using the standard AASHTO T
97-10  (ASTM  C78  /  C78M  -  10)  and  the  Contractor  shall  test  for  flexural
strength with third-point loading and the standard MR unit. At the same time,
the two prisms shall be prepared and cured and a companion test beam shall
be  prepared  of  the  same  concrete,  cured  for  the  same  period,  and  tested
following AASHTO T 97-10 (ASTM C78 / C78M - 10).

Specification:

Use of epoxy-bonding agent shall be acceptable if the load on the prisms at
failure is greater than 90 percent of the load on the reference test beam at
failure.

Test 5: Compression Strength of Cured Epoxy-bonding Agent

Compression strength tests of the cured epoxy-bonding agent measures the compressive strength
of the epoxy-bonding agent. Table 21-14 presents the testing method and related specification.

Table 21-14: Compression strength test for cured epoxy-bonding agent

Testing
Method:

ASTM D695 - 10

Specification:

Compressive strength at 25 degrees Celsius shall be a minimum of 14.0 MPa
after 24 hours of curing at the minimum temperature of the designated application
temperature range and 41.5 MPa at 48 hours.

Test 6: Temperature Deflection of Epoxy-bonding Agent

Temperature deflection tests of epoxy-bonding agents determine the temperature at which an
arbitrary deflection occurs under arbitrary testing conditions in the cured epoxy-bonding agent. It is
a screening test to establish performance of the bonding agent throughout the erection temperature
range. Table 21-15 presents the testing method and related specification.

Table 21-15: Temperature deflection test for epoxy-bonding agent

Testing
Method:

ASTM D648 - 07

Specification:

A minimum deflection temperature of 50 degrees Celsius at fibre-stress loading
of 1.8 MPa is required on test specimens cured seven days at 25 degrees
Celsius.

Test 7: Compression and Shear Strength of Cured Epoxy-bonding Agent

Compression and shear strength test of the cured epoxy-bonding agent is a measure of the
compressive and shear strengths of the epoxy-bonding agent compared to the concrete to which it
bonds. Slant cylinder specimens with the epoxy-bonding agent are compared to a reference test
cylinder of concrete only. Table 21-16 presents the testing method and related specification.

Table 21-16: Compression and shear strength test for cured epoxy-bonding agent

Testing
Method:

A test specimen of concrete is prepared in a standard 150-mm by 300-mm
cylinder mould to have a height at midpoint of 150 mm and an upper surface with
a 30-degree slope from the vertical. Upper and lower portions of the specimen

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with the slant surfaces may be formed through the use of an elliptical insert or by
sawing a full-sized 150-mm by 300-mm cylinder. If desired, 75-mm by 50-mm or
100-mm by 200-mm specimens may be used. After the specimens have been
moist cured for 14 days, the slant surfaces shall be prepared by light sandblasting,
stoning, or acid etching; then by washing and drying the surfaces; and finally by
coating one of the surfaces with a 0.25-mm thickness of the epoxy-bonding agent
under test. Specimens shall then be pressed together and held in position for 24
hours. Assemblies shall then be wrapped in a damp cloth that shall be kept wet
during an additional curing period of 24 hours at the minimum temperature of the
designated application temperature range. Specimens shall then be tested at 25
degrees Celsius, following AASHTO T 22-10 (2011) (ASTM C39 / C39M - 12) or
BS EN 12390-3:2009 procedures. At the same time as the slant cylinder
specimens are made and cured, a companion standard test cylinder of the same
concrete shall be made, cured for the same period, and tested following AASHTO
T 22-10 (2011) (ASTM C39 / C39M - 12) or BS EN 12390-3:2009.

Specification:

Use of epoxy-bonding agent is acceptable for the designated application
temperature range if the load on the slant cylinder specimen is greater than 90
percent of the load on the companion cylinder.

21.13.10.2 Mixing and Installation of Epoxy

As general instructions contained herein cannot cover all situations, specific recommendations and
instructions shall be obtained in each case from the Engineer in charge.

Instructions furnished by the Supplier for the safe storage, mixing, and handling of the epoxy-bonding
agent shall be followed. Epoxies shall be thoroughly mixed until they are of uniform colour. Use of a
proper-sized mechanical mixer operating at no more than 600 revolutions per minute, or as
recommended by the Manufacturer, shall be required. Contents of damaged or previously opened
containers shall not be used.

Surfaces to which the epoxy material is to be applied shall be at least 4 degrees Celsius and shall
be free from oil, laitance, form release agents, or any other material that prevents the epoxy from
bonding to the concrete surface. All laitance and other contaminants shall be removed by light
sandblasting or by high-pressure water blasting with a minimum pressure of 34 MPa. Wet surfaces
shall be dried before applying epoxy-bonding agents and surfaces shall be at least the equivalent of
saturated surface dry, with no visible water.

Mixing shall not start until the segment is prepared for installation. Application of the mixed epoxy-
bonding agent shall be according to the Manufacturer's instructions using trowel, rubber glove, or
brush on one or both surfaces to be joined. These coatings shall be smooth and uniform in thickness
and shall cover the entire surface with a minimum thickness of 1.5 mm applied on both surfaces. A
discernible bead line shall be observed on all exposed contact areas after temporary post-tensioning.
Erection operations shall be coordinated and conducted so as to complete the operations of applying
the epoxy-bonding agent to the segments, erection, assembling, and temporary post-tensioning of
the newly joined segment within 70 percent of the open time period of the bonding agent as
determined in Test 3.

Epoxy material shall be applied to all surfaces to be joined within the first half of the gel time, as
shown on the containers.  Segments shall be joined within 45  minutes after  application of the first
epoxy  material  placed  and  a  minimum  average  temporary  prestress  of  0.3  MPa  over  the  cross
section shall be applied within 70 percent of the open time of the epoxy material. At no point of the
cross section shall the temporary prestress be less than 0.2 MPa.

Joints shall be checked immediately after erection to verify uniform joint width and proper fit. Excess
epoxy from the joint shall be removed, where accessible. All tendon ducts shall be swabbed
immediately after stressing, while the epoxy is still in the non-gelled condition, to remove or smooth
out any epoxy in the conduit and to seal any pockets or air bubble holes that have formed at the
joint.

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If the jointing is not completed within 70 percent of the open time, the operation shall be terminated
and the epoxy-bonding agent shall be completely removed from the surfaces. Surfaces must be
prepared again and fresh epoxy shall be applied to the surface before resuming jointing operations.

21.14

Pre-tensioned Concrete Works

Pre-tensioned concrete members shall be constructed and placed in the work in conformance with
the details specified in the Contract documents, as specified in Section 21.13, as specified herein,
and as directed by the Engineer. Concrete and steel materials shall comply with the requirements
of Section 21.3.4 and Section 21.3.5.

21.14.1

Placing of Reinforcement Steel and Inserts

The reinforcement steel bars shall be accurately cut and formed to the dimensions and shapes as
indicated on the approved shop drawings and bar lists. All bars shall be accurately located and
securely anchored. The Contractor shall provide approved bolsters, chairs, supports, and wire, as
required or directed by the Engineer. The bars shall be free of all loose mill scale, rust, mud, and
other materials that reduce or destroy bonds with concrete. Embed reinforcing steel, anchors,
inserts, plates, angels, and other cast-in items as indicated on approved shop drawings.

Inserts in the concrete shall be accurately installed and secured in place. Where there is interference
with pre-tensioning strands, inserts shall be relocated or modified as directed by the Engineer. In no
case may imbedded inserts be attached to the prestressing strands and care shall be taken so as
not to move the strands out of their designed positions.

21.14.2

Mixing and Placing Concrete

The concrete shall be as specified in Section 21.3.4 and Section 21.13.3. The Contractor shall inform
the Engineer of the tentative amounts of admixtures he proposes to use, and it being understood
that the amounts of these will be adjusted during the progress of the work. The Contractor shall state
the name, source, brand, or type, or otherwise identify each of the materials as per ASTM C494 /
C494M - 12.

The Contractor shall furnish, and have available for the use of the Engineer, approved equipment
for slump and air-content determinations, and sufficient molds for making the specified number of
test specimens. The cube moulds shall be steel and shall comply with the requirements of ASTM
C31 / C31M - 12. Moulds made of cardboard or other expendable material shall not be used.

Tests of the concrete mixture for air content and slump shall be performed on each batch after
delivery to the casting site and before the concrete is incorporated into the girders. The slump of the
concrete shall be no greater than is necessary for proper placement and compaction and within the
limits specified herein.

A  minimum  of  six  test  specimens  shall  be  made  from  the  concrete  mixture  entering  into  each
member.  The  test  specimens  shall  be  cast  from  samples  taken  from  batches  designated  by  the
Engineer,  after  delivery  to  the  casting  site  and  as  the  concrete  mixture  is  being  discharged  for
incorporation into the member. The test specimens shall be compacted by standard rodding, or they
may  be  compacted  by  internal  vibration,  provided  the  Contractor  furnishes  suitable  vibratory
equipment designed for that purpose and approved by the Engineer.

The test specimens shall be placed with and cured in the same manner as the member. The position
of  the  test  specimens  during  curing  shall  be  such  that  no  undue  advantage  is  given  to  them,  as
compared  to  any  part  of  the  precast  members,  with  respect  to  environment  favorable  to  gain  in
strength.  The  test  specimens  shall  remain  with  the  member  until  removed  for  testing  or  until  the
prestress  forces  are  transferred  to  the  concrete  in  the  member.  Thereafter,  the  test  specimens
reserved for the 28-day tests may be cured under standard moist room conditions, or they may be
cured in sand, continuously kept moist, or immersed in water, and the curing temperature shall be
maintained within the range of 18

to 30°C. If immersed in water, a saturated lime solution shall be

used. The Engineer will perform all testing in the testing laboratory. All quality decisions with respect
to the concrete shall be based on the average strength of at least two specimens.

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21.14.3

Placing and Compacting

The  forms,  pre-tensioning  steel,  reinforcement  steel,  and  accessories  shall  be  inspected  and
approved by the Engineer immediately prior to the Contractor placing the concrete. No concrete shall
be  placed  until  such  inspection  has  been  made.  Approval  by  the  Engineer  shall  not  relieve  the
Contractor of responsibility as to the results obtained. Concrete shall be placed in horizontal lifts and
consolidated by internal vibration. Internal vibrators shall have a vibrating head not more than 32
mm in diameter unless otherwise approved by the Engineer. At locations of relative massive concrete
and away from the prestressing strands, where, with the exercise of ordinary care, the reinforcing
steel will not be displaced, the Engineer may approve the use of larger vibrators. External vibration
may be used in conjunction with the internal vibration, if approved by the Engineer. Vibration shall
be  performed  with  care  to  avoid  the  displacement  of  reinforcement,  prestressing  steel,  and
accessories, and to ensure satisfactory compaction.

The concreting operations shall proceed at a rate sufficient to ensure that no seams or cold joints
will exist. Vibration of each lift shall be sufficient to eliminate honeycomb and excess water and air
pockets, and the vibrators shall be inserted completely through the lift and barely into the preceding
lift to ensure proper unification at the junctures of all lifts. The vibrator shall be inserted and removed
slowly but shall not be permitted to remain stationary in the concrete. It shall not be forced between
strands.

21.14.4

Inspection of Completed Prestressed Members

The completed prestressed members shall be inspected while they are still on the casting bed to
determine their acceptability under the standard specification requirements. They shall be inspected
again just prior to and after placement in the structure for possible damage during handling, storing,
transporting, and erecting.

Before the members are removed from the casting bed, all defects visible on the surface shall be
observed, dimensions shall be measured and checked against the shop drawings, and all other
conditions that may have a bearing upon the acceptability of the members shall be noted.

It is the intent of these standard specifications that the members will be cast without cracks or other
defects and true to the dimensions indicated on the approved shop drawings. It is recognized that
certain cracks and surface defects may not be detrimental from the standpoint of structural integrity
and may be relatively harmless if remedied by proper repair as approved by the Engineer. Further
deviations in dimensions from those indicated on the approved shop drawings and within certain
limits as specified herein shall be subject to approval by the Engineer.

The Engineer will determine the kind, type, and extent of cracks and surface defects, such as
honeycomb and chipped edges or corners, that will be tolerated. All such cracks and surface defects
shall be repaired as directed by the Engineer.

21.14.4.1 Tolerances

Members shall be produced well within the specified acceptable range. The production process shall
be corrected when members approach or equal a specified limit. If any members are out of tolerance,
the  Contractor  shall  notify  the  Engineer  immediately.  Applicable  dimensional  tolerances  shall  be
checked  before  casting  and  after  removal  from  the  forms.  Time-dependent  tolerances,  such  as
length,  camber,  and  sweep,  shall  be  rechecked  within  three  days  before  shipment.  Camber  and
sweep shall be checked at a time when thermal effects of sunlight are negligible such as on a cloudy
day or early morning. Sweep is defined as the horizontal deviation from a straight line parallel to the
centreline  of  the  member.  Camber  is  defined  as  upward  deflection  of  the  member  caused  by
prestress. The Contractor shall check local smoothness with a 1.5 m straightedge.

Tolerance for precast prestressed members shall be as described in PCI MNL-120-

14 “Precast

Concrete Institute (PCI) Design Handbook 7

Edition (Precast and prestressed Concrete)

”, except

as listed in Table 21-17. It is intended that the dimensions of all members shall be well within these
tolerances and that the maximum values shall be permitted to be approached or equaled only
occasionally. Equipment and methods which permit an undue proportion of dimensions approaching

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the tolerance limits shall not be used. Members having dimensions outside the tolerance limits will
be rejected.

Table 21-17: Maximum allowable dimensional tolerances for precast prestressed concrete

members (General)

Dimension

Tolerance

Depth (flanges, web, and fillets)





Depth (overall)





Width (flanges and fillets)





Width (web)





Length





Square Ends (deviation from square)





Skew Ends (deviation from tangent offset)





Side Insert (spacing between centres of inserts and from the centres
of inserts to the ends of the beams)





Bearing Plates (spacing between the centres of bearing plates)





Bearing Plate (spacing from the centres of bearing plates to the
ends of the beams)





Bearing Plate or Bearing Area (variation from a true horizontal plane
or from a plane surface when tested with a straightedge)





Stirrup Bars (extension above top of the beam)

+ 6 mm, -9 mm

Stirrup Bars (longitudinal spacing, provided that there are not less
than the required number in a given length)





End Stirrup Bars

not more than 50 mm from
the end of the beam

Horizontal Alignment (deviation from a straight line parallel to the
centreline of the beam)





mm per



Max. ± 19 mm

Position of blockouts





mm of centreline

Position of strands





Position of deflection points for deflected strands





Position of plates and inserts





Position of handling devices





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The prestress losses due to creep and shrinkage of concrete, relaxation of prestressing steel and
elastic shortening shall be estimated with reference to Chapter 5 of AASHTO LRFD Bridge Design
Specifications and Road Structures Design Manual (ADQCC TR-516).

The Contractor shall comply with the maximum dimensional tolerances in Table 21-18 for AASHTO
girders and bulb-tees, Table 21-19 for double-tees, Table 21-20 for prestressed piling, and

Table 21-21 for prestressed deck panels.

Table 21-18: Maximum dimensional tolerances for AASHTO girders and bulb-tees

Dimension

Tolerance

Length

(±0.8 mm/m, ±25 mm maximum)

Width (overall)

(+10 mm, -6 mm)

Width(web)

(+10 mm, -6 mm)

Depth (overall)

(+13 mm, -6 mm)

Depth (flanges)

(±6 mm)

Sweep

(1 mm/m)

Variation from end squareness or skew

(±16 mm/m, ±25 mm maximum)

Camber variation from design camber

(±1 mm/m)

For spans of 24 m or less

(±13 mm maximum)

For spans more than 24 m

(±25 mm maximum)

Differential camber between adjacent members

(1 mm/m)

Position of Strands:

Individual

Bundled

Draped strand hold-down point

(±6 mm)

(±13 mm)

(±0.5 m)

Position of plates:

Bearing plates

Other plates

(±16 mm)

(±25 mm)

Tipping and flushness of plates:

Bearing plates

Other plates

(±0.5 percent, ±3 mm maximum)

(±6 mm)

Position of Inserts including diaphragm holes

(±13 mm)

Position of handling devices:

Parallel to length

Transverse to length

(±150 mm)

(±25 mm)

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Dimension

Tolerance

Position of stirrups:

Longitudinal spacing

Projection above top

(±50 mm)

(±19 mm)

Local smoothness of any formed surface

(±3 mm/1,500 mm)

Note 1: To be used when a design camber is specified.

Table 21-19: Maximum dimensional tolerances for double-tees

Dimension

Tolerance

Length

(±0.8 mm/m, ±25 mm maximum)

Width (overall)

(±6 mm)

Width (webs)

(±3 mm)

Depth (overall)

(±6 mm)

Thickness (flanges)

(±6 mm, -3 mm)

Flange Overhang (flange edge to web edge)

(±6 mm)

Distance between Webs

(±6 mm)

Sweep

(1 mm/m)

Variation from end squareness or skew

(±10 mm/m, ±25 mm maximum)

Camber variation from design camber

(±1 mm/m, ±19 mm maximum)

Differential camber between adjacent members

(1 mm/m, 19 mm maximum)

Position of Strands:

Individual

Bundled

Draped strand hold-down point

(±6 mm)

(±13 mm)

(±300 mm)

Position of plates:

Bearing plates

Other plates

(±13 mm)

(±25 mm)

Tipping and flushness of plates:

Bearing plates

Other plates

(±0.5 percent, ±3 mm maximum)

(±6 mm)

Position of inserts including diaphragm holes

(±13 mm)

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Dimension

Tolerance

Position of handling devices:

Parallel to length

Transverse to length

(±150 mm)

(±25 mm)

Position of stirrups:

Longitudinal spacing

Projection above top

(±50 mm)

(±19 mm)

Local smoothness of any formed surface

(±3 mm/1,500 mm)

Note 1: To be used when a design camber is specified.

Table 21-20: Maximum dimensional tolerances for prestressed concrete piling

Dimension

Tolerance

Length

(±25 mm)

Width or diameter

(±10 mm)

Variation from longitudinal axis (bow)

(1 mm/m)

Variation from end squareness or skew

(±6 mm/300 mm, ±13 mm maximum)

Position of individual strands

(±6 mm)

Position of handling devices

(±150 mm)

Longitudinal spacing of spiral reinforcement

(±19 mm)

Local smoothness of any formed surface

(±3 mm/1,500 mm)

Table 21-21: Maximum dimensional tolerances for prestressed concrete stay-in-place forms

Dimension

Tolerance

Length (in direction of panel strands)

(+18 mm, -6 mm)

Width

(+6 mm, -12 mm)

Thickness

(+6 mm, -3 mm)

Variation from end squareness or skew

(±6 mm)

Camber, sweep, and warping

(±2 mm per meter of length)

Position of individual strands:

Vertically

Horizontally

(+0 mm, -6 mm)

(±12 mm)

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Dimension

Tolerance

Position of handling devices:

Parallel to length

Transverse to length

(±75 mm)

(±50 mm)

Local smoothness of any formed surface

(±3 mm/1,500 mm)

Note 1: When measuring panel camber, account for dead-load deflection. Stay-in-place (SIP) form
deck panels are designed to have no camber, only dead-load deflection.

The Contractor shall remedy out-of-tolerance members in one of the following ways:

•

Replacing the member at no additional cost to the Owner.

•

Correcting the member tolerance problem, if possible, using an approved correction

procedure at no additional cost to the Owner.

•

If correction is not possible but the member is considered usable, the Contractor shall submit

the member for review and acceptance at a reduced price acceptable to the Owner. A
description of the problem and any proposed corrective action shall be included. Structural
and physical evaluation by a Professional Engineer shall be provided, as required. If the
submittal is rejected, the member shall be replaced at no additional cost to the Owner.

21.14.5

Rejection of Prestressed Members

Any prestressed member displaying one of the following defects shall be rejected and a new member
shall be cast at the Contractor's own expense.

1.  Strength requirement: Any member represented by cubes not meeting the specified strength.
2.  Exposed prestressing steel: No prestressing strands shall be exposed.
3.  Honeycombing: Honeycombing of the member to such an extent that chipping away of the

honeycombed concrete results in the condition described above, "Exposed prestressing
steel."
All honeycombed areas in a member shall be chipped until sound concrete is detected.
Sound concrete is defined as that point at which chipping causes fracture of the aggregates.

4. Stress cracks: Any member that has a stress crack in the area beginning 100 mm from the

unit end to the centre line of the unit that is greater than 13 mm in depth and five hundredths
(0.05) of a mm in width.

21.15

Post-tensioned Concrete Works

Post-tensioned  concrete  work  shall  be  as  indicated  on  the  Contract  plans,  as  specified  herein,
Chapter 22, Prestressing Systems, and/or in the Contract documents. This work includes, but not by
way  of  limitation,  supplying  and  fixing  formwork,  falsework  and  temporary  works;  supplying  and
placing prestressing steel, ducts and anchors; supplying concrete of the class as indicated on the
Contract  plans  or  specified  herein  and  transporting  and  placing  it  in  prepared  forms;  tamping,
vibrating, finishing and curing the concrete; pointing and jointing with cement mortar; post-tensioning
prestressing steel; pressure grouting ducts; and supplying and installing all joint materials, other than
fixed  and  neoprene  expansion  joints;  all  in  accordance  with  the  specifications  and  Contract
documents.

21.15.1

Standards and Codes

Standards and codes shall be as specified in Article 21.13.1.1, in the Contract documents, if any,
and the following in their latest edition:

•

ASTM A421 / A421M

– 10

Standard Specification for Uncoated Stress-Relieved

Steel Wire for Prestressed Concrete

•

FS MMM-G-650A

Federal Specifications - Epoxy Bonding Agent

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•

FS SS-A-701

Federal Specifications - Bituminous Protective Coating

•

CRD-C-566-64

Grout Fluidifier

21.15.2

Submittals

21.15.2.1 Shop Drawings

Shop drawings shall be submitted to the Engineer for approval in accordance with Section 21.13.2
and as specified herein.

Supplementing the requirements for shop drawings specified in Section 21.13.2, the Contractor shall
include a description of the equipment to be used and the proposed procedure for constructing post-
tensioned concrete work. The type and size of ducts and method of holding the ducts in position,
tendon sizes, jack clearances and procedures, stressing sequences, grout connections and vents,
anchorage details and bonding and grouting procedures shall also be indicated.

In addition the Contractor shall submit to the Engineer for approval calculations of the immediate
deflections and long term deflections for the different construction stages furnished with the required
cambers. A tabulation of these deflections and cambers shall be included on the shop drawings.

21.15.2.2 Certificates

Certificates from the Manufacturers shall be furnished to the Engineer certifying that the materials
and equipment to be provided comply with the requirements of these Standard Specifications.

21.15.2.3 Test Reports

The Contractor shall furnish to the Engineer six (6) copies of test reports and certificates as specified
herein, unless otherwise directed by the Engineer.

21.15.3

Scheduling of Post-tensioned Concrete Works

The scheduling of all post-tensioned concrete work shall be such that construction of each individual
superstructure unit can be completed within a 90-day period commencing with the first concrete pour
through completion of the post-tensioning and duct grouting operations unless otherwise indicated
on the Contract plans, specified in the Contract documents, or directed by the Engineer.

The Contractor shall have sufficient materials on hand prior to commencing work on any given
superstructure unit to ensure completion of the unit within the specified 90-day period.

After a minimum period of 30 days subsequent to the final stressing and grouting of the prestressing
steel, the superstructure ends at expansion bearings shall be raised with jacks, as specified in
Chapter 25, Bearings Devices, to relieve the shear strain in the bearings caused by shortening of
the concrete superstructure due to post-tensioning, shrinkage, creep and temperature change.

21.15.4

Material

21.15.4.1 Concrete

Concrete for post-tensioned works shall be Class C40/20 (unless otherwise indicated on the Contract
plans or in the Contract documents) as specified in Section 4.3 of Chapter 4, Concrete Works, of
these standard specifications, and in compliance with Section 21.3.4.

21.15.4.2 Post-tensioning Systems

Post-tensioning system including strands, ducts, anchorages, couplers, grouting, assemblies, etc.
shall be in compliance with the requirements of Chapter 22, Prestressing Systems.

Epoxy bonding agent shall comply with F.S. MMM-G-650A.

Bituminous protective coating shall comply with F.S. SS-A-701.

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21.15.4.3 Reinforcement Steel

Reinforcement steel shall comply with the requirements of Section 21.3.5, and Chapter 5,
Reinforcing Steel, of these standard specifications.

21.15.4.4 Built-in Materials

The Contractor shall furnish and install all built-in materials and items as indicated on the Contract
plans, as specified herein and as directed by the Engineer.

Built-in materials shall include, but not by way of limitations, all inserts, hardware or similar items as
indicated on the Contract plans or specified in the Contract documents.

21.15.5

Formwork

Formwork, shoring, and removal of forms shall be as specified in Section 1.20 of Chapter 01, General
Requirements, of these Standard Specifications, and as further specified herein and in the Contract
documents.

The deck slab forms and all related formwork for concrete box girder construction, including all
supporting falsework, shall be designed and constructed in order to facilitate removal of all formwork
materials from within the cells of the concrete box girders. The deck forms may be of 18 mm thick
marine plywood and shall be suspended from the girder stems which shall be stripped of all forms
prior to placing the deck forms. The deck slab forms shall in no way interfere with the required
concrete bond between the deck slab and the girder stems.

Stay-in-place deck forms will be permitted for the deck slab of concrete box girder construction,
provided they are galvanized steel or other noncombustible material acceptable to the Engineer
which will not deteriorate in any way. Further, such stay-in-place deck forms shall not increase the
volume of concrete, the depth of the deck slab or reduce the dimension of concrete coverage over
the reinforcement steel. The Contractor shall submit samples of the proposed form material and all
details and design for the use of stay-in-place deck forms. The decision of the Engineer shall be final
for acceptance or rejection of stay-in-place forms.

A 30 mm slip joint shall be placed transversely in the deck forming between each diaphragm to
eliminate resistance of the deck forms to deck shortening during prestressing.

The Contractor shall submit shop drawings and design calculations for the forms to the Engineer for
approval prior to commencing work.

Falsework and forms shall be set to provide the structural camber indicated in the Contract plans for
long term deflection, and shall comply with the required lines and grades.

Where indicated on the Contract plans, the Contractor shall include all formwork required to produce
the concrete surface ornamental pattern on the vertical surface of the box section of the post-
tensioned concrete works as indicated on the Contract plans, as specified herein and as approved
by the Engineer. The plywood forms supporting the bottom slab of the box girder shall be arranged
in a regular brick pattern as approved by the Engineer.

The Contractor shall include in his shop drawing submittal all details and a full description of all
formwork proposed by the Contractor to produce the concrete surface ornamental pattern. All details
and proposed methods and formwork material shall be subject to approval by the Engineer.

The construction of all formwork required to produce the concrete surface ornamental pattern shall
comply with the applicable requirements of Section 1.20 of Chapter 01, General Requirements, of
these Standard Specifications, and as specified herein. All formwork shall produce a smooth, even
surface with clean, straight, true and unbroken lines at the concrete surface ornamental pattern.

21.15.6

Placing Post-tensioning Systems

Anchorage devices, ducts, tendons and other appurtenant post-tensioning equipment and
accessories shall be placed by the Contractor in compliance with the requirements of Chapter 22,

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Prestressing Systems. They shall be accurately positioned in the forms and secured in place as
indicated on the Contract plans and approved shop drawings. Installation of the post-tensioning
system shall be coordinated with the placement of reinforcing steel and embedded items as specified
elsewhere in these Standard Specifications. Care shall be exercised to keep ducts and tendons free
of form coating compounds and other substances which might break or reduce the concrete bond.

Field measurements of vertical locations of centers of gravity of the tendons shall not vary from the
dimensions indicated on the Contract plans by more than the tolerance given in Table 22-6 of
Chapter 22, Prestressing Systems.

21.15.7

Mixing and Placing Concrete

Concrete work for box girder superstructure construction shall comply with the applicable provisions
of this chapter, Sections 4.3 and 4.4 of Chapter 04, Concrete Works, of these Standard
Specifications, and with the Contract documents.

Prior to placing concrete, tendon profiles shall be rechecked to ensure that proper location and
concrete cover will be maintained. Any ducts found to be damaged shall be repaired or replaced as
directed by the Engineer.

Prior to placing forms for box girder deck slabs, the Contractor shall demonstrate, to the satisfaction
of the Engineer, that either the prestressing steel is free and unbonded in the duct or, in the event
prestressing steel has not yet been placed, that all ducts are unobstructed.

The Contractor shall exercise care during concrete placement to prevent concrete from entering
anchorage hardware. Concrete shall be placed in such a manner that tendon alignment and
reinforcement positions are maintained, and concrete shall be vibrated with particular attention at
tendon anchorage locations to ensure optimum compaction and penetration at these points.

Placing sequence of concrete for box girders shall be in accordance with Article 21.7.1.2.

Curing of concrete shall be in accordance with the applicable provisions of Section 21.11, and
Section 4.4.2 of Chapter 4, Concrete Works, of these Standard Specification.

The Contractor shall keep a record showing the date and time of placement of cast-in-place, post-
tensioned concrete in each portion of the structure. This record shall be available for examination at
all times by the Engineer. Upon completion of construction of each structure, two copies of such
records shall be submitted to the Engineer.

21.15.8

Stressing Operations

Post-tensioning of cast-in-place concrete shall be performed as soon as the last placed concrete has
attained a cube compressive strength of 40 MPa, or as specified on the Contract plans, or more
based on the results of two cube tests.

Stressing operations shall comply with the requirements of Section 22.8.4 of Chapter 22,
Prestressing Systems. The Contractor shall employ, at no additional cost to the Owner, a technician
who is skilled in the post-tensioning method to give such aid and instruction in the use of the
prestressing equipment and installation of the prestressing steel as may be necessary to obtain the
specified results.

Prestressing tendons in continuous span post-tensioned structures shall be tensioned by jacking at
each end of the tendon or at one end of tendons as indicated on the Contract plans. Prestressing
tendons in single span post-tensioned structures may be tensioned by jacking from one end only as
directed by the Engineer.

All post-tensioning shall be by means of hydraulic jacks equipped with accurate reading calibrated
hydraulic pressure gauges to permit the stress in the prestressing steel to be computed at any time.
A certified calibration curve shall be furnished with each jack. In the event inconsistencies occur
between the measured elongation and the jack gauge reading, the jack gauge shall immediately be
recalibrated. In the event still further discrepancies occur, the cause shall be determined and
reported to the Engineer. An agreement within five percent shall be satisfactory.

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The Contract plans shall indicate jacking locations of the tendons. Proper allowance shall be made
for friction losses and one tendon shall be checked for friction loss at the very start of the post-
tensioning. In case the friction losses in tests exceed the computed losses, all wires shall be relieved
and lubricated with water soluble oil and re-tensioned. Each tendon shall be stressed until either the
required elongation or the maximum force is reached. Elongation is the preferred method of stress
determination wherever possible. The tendons shall be tensioned by jacking to the total forces
indicated on the shop drawings.

The post-

tensioned prestressing steel shall be anchored at an “initial stress” that will result in the

ultimate retention of working forces or stresses of not less than those indicated on the Contract
drawings, but in no case shall the prestressing steel be tensioned above 80 percent of the ultimate
tensile strength of the wire or strands.

Prior to post-tensioning any member, the Contractor shall demonstrate to the satisfaction of the
Engineer that the prestressing steel is free and unbonded in the duct.

The Contractor shall keep records of the elongation and tension applied to each tendon, and this
record shall be submitted to the Engineer promptly upon the completion of stressing of each member.
At the time of stressing the first member, the stresses in the individual tendons shall be checked to
establish a procedure for ensuring uniform results. At any later time, a recheck may be ordered by
the Engineer if it appears that the design stresses are not being obtained. The Contractor shall have
written permission from the Engineer before capping any prestressing anchorage.

The effective prestress force “P

” indicated on the Contract plans represents the force required after

all losses of prestress have occurred. The prestress losses due to creep and shrinkage of concrete,
and relaxation of prestressing steel and elastic shortening shall be estimated as per AASHTO LRFD
Bridge Design Specifications and Road Structures Design Manual (ADQCC TR-516). Unless
specified otherwise, friction shall be accounted for using wobble and curvature coefficients of k =
0.00066 per meter of tendon

and μ = 0.23. The magnitude of the anchorage set, in case a grip type

anchorage is used, shall be the greater of that required to control the stress in the prestressing steel
at transfer or that recommended by the Manufacturer of the anchorage. The magnitude of the set
assumed for the design and used for set loss calculation shall be shown in the Contract documents
and verified during construction.

21.15.9

Grouting of Tendons

After the tensioning of all tendons has been completed and the total retained stress is equal to or
exceeds that indicated on the Contract plans, for each member, and the steel strands or wires have
been anchored, the annular space between the conduit and the tendons shall be grouted.

Grouting, grout mixture, grouting equipment, mixing of grout, and injection of grout shall comply with
the requirements of Sections 22.7.2 and 22.8.8 of Chapter 22, Prestressing Systems.

21.15.10 Protection of End Anchorages

As soon as possible after tensioning and grouting is completed, the Contractor shall clean exposed
end anchorages, wires and other metal accessories of rust, displaced mortar, grout and other such
materials, then shall apply to all such dry metal surfaces a heavy, unbroken coating of epoxy bonding
agent.

The Contractor shall install tight-fitting forms and hold in place securely against the previously placed
concrete.

After applying epoxy bonding agent, the Contractor shall apply a patching mortar prepared by mixing
one part type V, portland cement to three parts of clean sand (ASTM C33 / C33M - 11a) measured
by volume, and sufficient water to provide a stiff but workable consistency. The Contractor shall apply
the patching mortar, and manipulate, finish and cure as specified in this chapter. After mortar patches
have cured, the Contractor shall apply two heavy brush coats of bituminous protective coating
material, applied as recommended by the Manufacturer, including the recommended thickness.

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21.15.11 Access Doors

Access  doors  shall  be  installed  in  post-tensioned  box  girders  as  located  and  as  detailed  on  the
Contract  plans.  All  access  doors  shall  be  fabricated  of  steel  shapes,  plates  and  accessories
complying  with  Section  30.5  of  Chapter  30,  Miscellaneous  Metal.  All  steel  shall  be  galvanized  in
accordance with Section 23.4.10 of Chapter 23, Steel Structures.

21.15.12 Vent Pipes

The Contractor shall include the unplasticized polyvinylchloride (uPVC) vent pipes in the cells of the
concrete box girders as indicated on the Contract plans.

The vent pipes shall be of the size as indicated on the Contract plans and shall be uPVC extruded
from one hundred percent virgin materials. The pipe material shall be new and homogeneous
throughout and free from visible cracks, holes, foreign materials, blisters, wrinkles and dents.

All vent pipes shall be anchored in an approved manner so as to prevent displacement or movement
during the placement of concrete.

21.15.13 Opening Bridges to Traffic

No equipment or vehicular traffic will be allowed on any bridge superstructure until the post-
tensioning and grouting operation is completed, falsework has been removed, and all concrete has
been cured for the time required in these Standard Specifications, or as further directed by the
Engineer. The Contractor shall carry out the required load tests on the bridge superstructure, as part
of the acceptance process of the bridge, as per Chapter 35, Bridge and Underpass Load Testing,
before opening the bridge to traffic.

21.16

Precast Concrete Fascia Panels

This section contains the requirements for the precast concrete fascia panels and the materials and
hardware for fastening the precast concrete fascia panels to the deck slab.

The Contractor shall be responsible for the construction of precast concrete fascia panels as
included in the Contract documents and as shown on the Contract plans.

The precast concrete fascia panels shall be constructed to the dimensions and details indicated on
the Contract plans. The construction of the precast concrete fascia panel for the curved portions of
the roadway shall be in curved sections. The curvature of the precast concrete panel shall match the
curvature of the roadway. The construction of the precast concrete fascia panel for the straight
portions of the roadway shall be in straight line segments.

21.16.1

Materials

Unless otherwise specified in the Contract documents, precast concrete fascia panels shall be
constructed of Class C40/20 concrete. Materials for concrete, preformed joint filler, and sealant shall
comply with the requirements of the applicable provisions of this chapter and Section 4.3 of Chapter
4, Concrete Works, of these Standard Specifications, and as described herein.

The embedded sleeves and the steel plates and hardware for fastening the precast concrete panels
to the cast-in-place bridge decks shall be manufactured of hot-dip galvanized ASTM A36 / A36M -
08 steel. The steel galvanization shall conform to the requirements of Section 21.3.5. The setting
grout and the grout cant shall meet the requirements of Section 21.18.3.

21.16.2

Moulds

The precast concrete fascia panels shall be cast in mortar-tight metal or metal-lined special moulds
that shall give a smooth, dense finish to the precast concrete parapets. The Contractor shall submit
to the Engineer for approval shop drawings of his proposed moulds. The mould release oil shall be
nonstaining.

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21.16.3

Shop Drawings and Method Statement

The Contractor shall submit complete shop drawings and method statement in accordance with the
Contract documents and provisions of Section 21.13.2, detailing his proposed method of fabricating,
transporting, and installing the precast concrete fascia panels. Further, the shop drawings shall
include details of the dimensions and lifting inserts. The shop drawings shall contain a schedule of
the quantities of each of the various types of precast concrete fascia panels.

21.16.4

Sample Panel

The Contractor shall fabricate one complete full-sized precast concrete fascia panel in accordance
with the Contract documents and provisions of Section 21.13.2, and as specified herein. This sample
unit shall be constructed in a location directed by the Engineer, and shall be protected and properly
stored in a secure place for reference. The sample unit, as approved by the Engineer, may be
installed in the works later if so directed or approved by the Engineer.

All precast concrete panels shall match the approved sample moulding panel in colour and quality.
Any precast concrete fascia panel not matching the approved sample parapet in colour and quality
or as rejected by the Engineer shall be replaced by the Contractor.

21.16.5

Fabrication

The Contractor shall provide a roughcast texture where indicated on the Contract plans in order to
provide a bond with the members to be constructed after the precast concrete fascia panels have
been installed. The dimensions of all precast concrete fascia panels shall be verified in the field
before they are cast.

The precast concrete fascia panels shall be constructed of a concrete mixture of cement, water, fine
aggregate and coarse aggregate having a maximum size of 10 mm. The concrete mixture shall meet
the requirements of Class C40/10 concrete as specified in Section 4.3 of Chapter 4, Concrete Works,
of these Standard Specifications. The Contractor shall submit to the Engineer for approval, a
proposed mix design proportioned by weight and based on trial mixes conducted with approved
materials. The mix design shall be accompanied by all relevant data.

The sand shall be specifically selected for colour and grading in order that the colour and texture of
the precast concrete fascia panels shall match the colour and texture of the adjacent precast facing
panels. Only sufficient water shall be used in mixing to permit the removal of the precast panel
segments from the moulds as soon as practical. The precast concrete fascia panels shall be kept
damp for a period of at least ten (10) days. During this period they shall be protected from the sun
and from wind. Any segments that show checking, soft corners, or soft surfaces shall be rejected.
The method of storage and handling shall be such as to preserve true and even edges and corners.
Any precast concrete fascia panels that become chipped, marred, or cracked before or during the
process of installation shall be rejected.

21.16.6

Surface Finish

Finishes shall be to shapes, lines and level as shown on the Contract plans and as approved by the
Engineer. Surface texture, smoothness or roughness and appearance shall be as approved by the
Engineer and shall be achieved by:

1.  Maximum aggregate size selection.
2.  Regulating the grading and workability of the mix.
3.  Aggregate type and colour.
4.  Addition  of  standard  appropriate  polypropylene  fiber  reinforcement  at  a  rate  of  between

700g/m

- 1000g/m

5. Use of special liners for patterned surface of type and motives approved by the Engineers

proposals and trials.

6. Use of specialized textile shutter liners for smooth finish.
7. Application of suitable surface retarders approved by the Engineer.

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8. Application of proper surface blasting, hacking grinding etc. techniques approved by the

Engineer.

The surfaces shall be free from cracks, blowholes, honeycomb, blemishes and similar effects. No
concrete surface repair system adversely affecting the quality and uniformity of the finish shall be
allowed. No additives or surface applications affecting the quality of finish or integrity of subsequent
coatings shall be used. A detailed concrete surface repair system including coatings (if any) shall be
submitted to the Engineer for approval. The finish quality, texture and general final appearance shall
be approved by the Engineer based on sample panels of other suitable pieces which shall be
inspected, approved and tagged by the Engineer. These tagged samples will serve as a reference
to document the approved finish and for use in subsequent quality control works.

21.16.7

Installation

The precast concrete fascia panels shall be installed after the bridge deck has been constructed.
The precast concrete fascia panels shall not be placed on the superstructure (bridge deck) until the
complete superstructure is in place and all post-tensioning works has been completed. The precast
concrete  facing  panels  shall  be  installed  on  the  superstructure  in  accordance  with  the  details
indicated  on  the  Contract  plans.  The  recessed  areas  at  the  lifting  inserts  shall  be  sealed  with
approved  grout  after  the  installation  of  the  precast  concrete  panels  has  been  approved  by  the
Engineer.

21.17

Cast-in-place Concrete Works for Bridge, Tunnel &
Underpass Structures

This section contains the cast-in-place concrete requirements for the following structural elements:

•

Bridge superstructure: diaphragms and slabs.

•

Bridge substructure: abutments, piers, wingwalls, retaining walls, and footings.

•

Tunnel and underpass structures: roof solid slab, roof voided slab, retaining walls, base slab,

monolithic barriers and curbs.

•

Associated structures: Lift stations, storm water reservoirs, and generator rooms.

21.17.1

Materials

Cast-in-place  bridge  superstructure  and  substructure,  tunnel  and  underpass  structures,  and
associated structures shall be made of Class  C40/20 concrete. All materials shall comply with all
applicable  requirements  of  this  chapter,  and  Section  4.3  of  Chapter  4,  Concrete  Works,  of  these
Standard Specifications.

21.17.2

Shop Drawings

The Contractor shall submit to the Engineer for approval shop drawings including all formwork, as
required by the Contract documents.

21.17.3

Construction

The construction of cast-in-place bridge superstructure and substructure, tunnel and underpass
structures, and associated structures shall comply with the applicable requirements of this chapter
and Section 4.4 of Chapter 4, Concrete Works, of these Standard Specifications, as specified herein,
and as per the lines, shapes, dimensions and details indicated in the Contract plans.

Junction boxes and electrical conduits shall be embedded as indicated in the Contract plans.

21.17.4

Formwork

The Contractor shall include all special formwork required to produce curved and decorative walls
and elements and the pattern on the surfaces of the cast-in-place bridge superstructure and
substructure, tunnel and underpass structures, associated structures, and other surfaces, as

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indicated on the Contract plans, as specified in Section 1.20 of Chapter 01, General Requirements,
of these Standard Specifications, and as approved by the Engineer.

Tie rods used in the formworks for areas below the ground water table should incorporate special
water-stops. Special water-stops shall be an accessory to the formwork. The Contractor shall show
water-stop details in the shop drawings.

21.17.5

Expanded Polystyrene Board

Tunnel  and  underpass  voided  slabs  shall  be  constructed  using  commercially  available  expanded
polystyrene  board.  Expanded  polystyrene  shall  have  a  minimum  flexural  strength  of  240  kPa,
determined  in  conformance  with  the  requirements  of  ASTM  C203  -  05a(2012),  and  compressive
yield strength of ≥ 200 kPa, at 10% compression, as per ASTM D1621 - 10. Surfaces of expanded
polystyrene  shall  be  faced  with  hardboard  or  similar  material.  The  facing  layer  shall  be  1.5mm
minimum  thickness.  Expanded  polystyrene  shall  have  maximum  water  absorption  of  2%  after  24
hour immersion, and maximum density of 25 kg/m³ as per ASTM D1622 - 08. Thermal conductivity
at 10

C mean temperature shall be 0.037 W/m² C maximum complying with ASTM E96/ E96M-10,

and the dimensional stability at 80

C shall be 0.5 maximum complying with BS 4370-2:1993. The

water vapour transmission at 38

C and 90% relative humidity, maximum per 50 mm sample

thickness, shall be 25 Mgm/m

/h, complying with BS 4370-2:1993.

Boards shall be held in place by a combination of nails, straps, waterproof adhesive or other means
approved by the Engineer. The expanded polystyrene shall be considered as an accessory to the
formwork.

Any special formwork and accessories for the formworks shall be

at the Contractor’s expense.

21.18

Mortar and Grout

This work makes and places mortar and grout for use in concrete structures and precast works other
than in prestressing ducts. Such uses include mortar for filling under masonry plates and for filling
keyways between precast members, where shown in the Contract documents; mortar used to fill
voids and repair surface defects; grout used to fill sleeves for anchor bolts; grout for sealing bolt
pockets and the insides of the coil anchors; and mortar and grout for other such uses, where required
or approved.

21.18.1

Mortar and Grout Materials and Mixing

Materials for mortar and grout shall conform to the requirements of Section 21.3, Materials Used for
Concrete Structures. Grading of sand for use in grout or for use in mortar, when the width or depth
of the void to be filled is less than 20 mm, shall be modified so that all material passes the No. 8,
2.36-mm sieve.

Unless otherwise specified in the Contract documents, or later in this section, or ordered by the
Engineer, the proportion of portland cement to sand for mortar shall be one-to-two and for grout shall
be one-to-one. Proportioning shall be by loose volume.

When non-shrink mortar or grout is specified, either a non-shrink admixture, or expansive hydraulic
cement conforming to ASTM C845 - 04 of a type approved by the Engineer, shall be used.

Only sufficient water shall be used to permit placing and packing. For mortar, only enough water
shall be used so that the mortar will form a ball when squeezed gently in the hand.

Mixing shall be done by either hand methods or with rotating paddle-type mixing machines and shall
be continued until all ingredients are thoroughly mixed. Once mixed, mortar or grout shall not be re-
tempered by the addition of water and shall be placed within one hour.

Alternatively, proprietory, nonshrinkable, prepacked, flowable grout material having strength greater
than 1.5 times characteristic strength of surrounding concrete and with slant shear greater than or
equal 25 percent of its compressive strength may be used, provided the colour and texture are
approved by the Engineer.

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21.18.2

Placing and Curing of Mortar and Grout

Concrete areas to be in contact with the mortar or grout shall be cleaned of all loose or foreign
material that would in any way prevent bond, and the concrete surfaces shall be flushed with water
and allowed to dry to a surface-dry condition immediately prior to placing the mortar or grout.

Mortar or grout shall completely fill and shall be tightly packed into recesses and holes, on surfaces,
under structural members, and at other locations specified. After placing, all surfaces of mortar or
grout shall be cured by the water method as provided in Section 21.11, Curing Concrete, for a period
of not less than three days.

Keyways, spaces between structural members, holes, spaces under structural members, and other
locations where mortar could escape shall be mortar-tight before placing mortar.

No load shall be allowed on mortar that has been in place less than 72 hours, unless otherwise
permitted by the Engineer.

All improperly cured or otherwise defective mortar or grout shall be removed and replaced by the
Contractor at the Contractor's expense.

21.18.3

Grout in Precast Works

The grout for sealing bolt pockets and the insides of the coil anchors, the grout cant, and the setting
grout for the precast members shall be a nonmetallic, nonshrink grout containing a mixture of sulfate
resistant cement and sand approximately in the proportions of one part of cement to two and one-
half parts of sand. The sand shall be specifically selected for colour and grading in order that the
colour and texture of the grout shall match the colour and texture of the precast members. The sand
shall be sieved through a screen having 3.715 mm square meshes. All over-sized sand particles
shall be discarded. The grout shall show no expansion after final set takes place when tested in
accordance with ASTM C827 / C827M - 10. It shall have an initial setting time of not less than 45
minutes.

The grouting shall be performed in accordance with the recommendations of the American Concrete
Institute and with the grout Manufacturer's published literature for site preparation, product mixing,
and placing. An adequate number of metal shims shall be placed before the grout is placed.

The Contractor shall furnish, from an Owner’s approved independent laboratory, test results verifying
that the grout shows no shrinkage from the time of placement and no expansion after set, has a one-
day compressive strength of not less than 20 MPa, and has an initial set time of not less than 45
minutes.

21.19

Application of Loads

Loads shall not be applied to concrete structures until the concrete has attained sufficient strength
and, when applicable, sufficient prestressing has been completed, so that damage shall not occur.

21.19.1

Earth Loads

Whenever possible, the sequence of placing backfill around structures shall be such that overturning
or sliding forces are minimized. When the placement of backfill will cause flexural stresses in the
concrete, and unless otherwise permitted by the Engineer, the placement shall not begin until the
concrete has reached not less than 80 percent of its specified strength.

21.19.2

Construction Loads

Light materials and equipment may be carried on bridge decks only after the concrete has been in
place at least 24 hours, providing curing is not interfered with and the surface texture is not damaged.
Vehicles needed for construction activities and having a mass between 450 kg and 1,800 kg, and
comparable materials and equipment loads, shall be allowed on any span only after the last-placed
deck concrete has attained a compressive strength of at least 20 MPa. Loads in excess of the above
shall not be carried on bridge decks until the deck concrete has reached its specified strength.

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Additionally, for post-tensioned structures, vehicles weighing more than 2,000 kg, and comparable
materials and equipment loads, shall not be allowed on any span until the prestressing steel for that
span has been tensioned.

Precast concrete or steel girders shall not be placed on substructure elements until the substructure
concrete has attained 70 percent of its specified strength.

Otherwise, loads imposed on existing, new, or partially completed portions of structures due to
construction operations shall not exceed the load carrying capacity of the structure, or portion of
structure, as determined by the Strength II Load Combination in Table 3.4.1-1 of the

AASHTO Load

and Resistance Factor Design (LRFD) Bridge Design Specifications

. Compressive strengths of

concrete (

fc'

) to be used in computing the load-carrying capacity shall be the smaller of the actual

compressive strength at the time of loading or the specified compressive strength of the concrete.

21.19.3

Traffic Loads

Unless otherwise provided in the Contract documents, traffic shall not be permitted on concrete
decks until at least 14 days after the last placement of deck concrete and until such concrete has
attained its specified strength.

21.20

Special Requirements for Segmental Bridges

21.20.1

Geometry Control

21.20.1.1 Deflection and Camber Data

Deflection or camber data shall be submitted by the Contractor for each stage of construction, as
required to construct the structure to its final grade. Procedures used shall account for the effect of
the time-dependent prestress losses and creep that will occur during the construction phase. Data
for the entire bridge, based on the Contractor's proposed erection sequence, method, and schedule,
shall be submitted to the Engineer for review prior to commencing pier shaft construction.

Structure cambers will be monitored by the Contractor at each stage and corrective actions, as
approved by the Engineer, shall be performed by the Contractor to assure proper erection of the
structure to its final grade.

21.20.1.2 Geometry Control

A geometric control plan that indicates, in detail, how the survey is to be performed shall be submitted
by the Contractor for the Engineer’s approval. These proposed actions shall assure proper erection
of the structure to the final grade shown in the working drawings. This plan shall provide for regular
monitoring  of  the  superstructure  deflections  beginning  with  the  addition  of  the  first  cantilever
segments  and  concluding  with  the  last  cantilever  segment.  It  shall  also  include  the  adjusting
procedure to be utilized,  shall the cantilever, as erected, deviate from the predicted alignment by
more than 25 mm.

Elevations and alignments of the structure shall be checked by the Contractor at every stage of
construction and the Contractor must maintain a record of all these checks and of all adjustments
and corrections made. All surveying shall be performed at a time that will minimize the influence of
temperature. Corrections by shimming shall be done only when approved by the Engineer.

For precast segmental construction using short-line forming techniques, the Contractor shall provide
precision surveying systems so that levels and horizontal alignment during precasting are measured
to an accuracy of ±0.3 mm. For all other types of segmental construction and for erection of
segmental bridges, surveying shall be provided to an accuracy of ±3 mm.

For precast segmental construction using match-cast segments, careful checks of both
measurements and computations of geometry shall be made by the Contractor before moving
segments from their casting position. Computed coordinates of all sections cast shall be completed
before casting a new segment. In addition to the computed as-built casting curves for vertical and

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horizontal deflections, a cumulative twist curve shall be computed using the measured cross slopes
of the individual units as a check on the extrapolated deflections. In computing set-up elevations in
the match-cast process, priority shall be given to correcting twist errors by proper counter rotation.
Segments in the match-cast position shall not be subjected to a stress-inducing twist.

21.20.2

Segmental Bridge Tolerances

Unless otherwise specified, reinforcement shall be fabricated and placed within the tolerances
specified herein as recommended by the Concrete Reinforcing Steel Institute [CRSI] 1990.

•

For specified effective depth (d) and the minimum clear concrete protection in flexural

members, walls, and compression members, Table 21-22 illustrates the admissible
tolerances.

Table 21-22: Tolerances on effective depth and minimum cover

Effective depth d

Tolerance on d

Tolerance on
minimum mover

200 mm or less

±10 mm

-10 mm

More than 200 mm

±12 mm

-12 mm

•

However, tolerances on the clear distance to formed soffits shall be -6 mm, and in no case

shall the tolerance on cover exceed minimum one-third of the minimum cover stipulated on
the structural drawings or in the specifications.

•

For longitudinal location of bends and ends of bars: ±50 mm, except at discontinuous ends

of members where tolerance shall be ± 12 mm.

•

As long as the total number of bars specified is maintained, a reasonable tolerance in spacing

individual bars is ±25 mm, except where openings, inserts, and embedded items might
require some additional shifting of bars.

Embedded ducts for all types of segmental bridge construction shall be positioned to tolerances as
specified in Chapter 22, Prestressing Systems, Article 22.8.4.2, Placement of Ducts.

Tolerances for completed segments shall be taken, as shown in Table 21-23. For bridges without an
overlay, the flatness of the top slab shall be 3 mm in 3 m in the direction of traffic.

Dimensions from segment-to-segment shall be adjusted to compensate for any deviations within a
single segment so that the overall alignment of the completed structure will conform to the
dimensions shown in the Contract documents.

When cantilever construction is used, the tolerances for the alignment of the opposing cantilevers in
a span shall be stated in the Contract documents. Forces up and down that can be placed on the
end of the cantilever shall also be stated on the design drawings and shall consider the allowable
tensile stresses for construction load combinations, as stated in Table 5.14.2.3.3-1 of the

AASHTO

LRFD Bridge Design Specifications

After erection, final post-tensioning, final corrections, and adjustments are complete and the
structure has been placed on its permanent bearings, the superstructure shall conform to the grade
and alignment shown in the Contract drawings, with due consideration of creep and superimposed
dead-load deflections within tolerances as specified in the Contract documents.

Finished segment tolerances shall not exceed those listed in Table 21-23.

Table 21-23: Completed segment tolerance for segmental box girder bridge construction

Dimension

Tolerance

Length of Match-Cast Segment (Not Cumulative) (10
mm/m +25 mm max)

±10 mm /m

Length of Cast-in-Place Segment

±12.5 mm but not greater than +50
mm per span

Web Thickness

±9.5 mm

Depth of Bottom Slab

±9.5 mm

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Dimension

Tolerance

Depth of Top Slab

±9.5 mm

Overall Top Slab Width

±5 mm/m, ± 25 mm. max.

Diaphragm Thickness

±12.5mm

Grade of Form Edge and Soffit

±3 mm in 3 m

Tendon Hole Location

±3 mm

Position of Shear Keys

±6 mm

21.20.3

Shop Drawings and Design Calculation for Construction
Procedures

Sufficiently in advance of the start of superstructure field construction operations, so as to allow the
Engineer not less than a 30 day-review period, the Contractor shall submit complete details and
information concerning the method, materials, equipment, and procedures it proposes to use in
constructing that portion of the superstructure for which the information is furnished. This submittal
shall include step-by-step erection procedures.

More than one method or technique of erection may be permitted in the overall scope of work. Any
subsequent deviation from the approved materials or details shall not be permitted unless details are
submitted by the Contractor and approved by the Engineer in advance of use.

Submittals for approval shall include calculations, drawings, and information outlined in Article
21.20.3.1, Design Calculations for Construction Procedures, and Article 21.20.3.2, Shop Drawings.
Two sets of all required drawings and calculations shall be submitted and resubmitted until approved
by the Engineer. A specified number of distribution copies shall be furnished after approval.

21.20.3.1 Design Calculation for Construction Procedures

Design calculations shall be submitted for falsework, erection devices, formwork, or other temporary
construction that may be required and that will be subject to calculated stresses.

Design of the falsework or erection devices for all superstructure concrete shall be done under the
direction of and sealed by a specialty engineer. Calculations shall also be submitted to substantiate
the system and method of stressing proposed by the Contractor. Such calculations shall include the
required jacking force and elongation of tendons at the time of tensioning, tendon stress level at
stressing ends after seating, stresses in anchorage zones and distribution plates, stress-strain
curves typical of the prestressing steel to be furnished, seating losses, temporary overstresses, and
reinforcement required to resist anchor block stresses.

In addition to the above, computations shall be submitted for approval for the following:

•

Computations of deflections and required camber due to dead loads, post-tensioning forces,

creep, and shrinkage. A tabulation of deflections and camber dimensions shall be included
on the shop drawings.

•

Computations of jacking forces required at joints during temporary post-tensioning.

21.20.3.2 Shop Drawings

Detailed shop drawings shall be submitted by the Contractor for approval in accordance with the
Contract documents. These drawings shall include, but not necessarily be limited to, the following
information:

•

Fully and accurately dimensioned views showing the geometry of the segments, including all

projections, recesses, notches, openings, block outs, and other pertinent details.

•

Details of non-prestressed steel reinforcing shall be clearly shown as to size, spacing, and

location

— including any special reinforcing required but not shown in the Contract plans.

•

Size and type of ducts for all post-tensioning tendons and their horizontal and vertical profiles

shall be clearly detailed. Duct supports, grout tubes, vents, and drains shall be shown

—

including size, type, and locations.

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