Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020)

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1.16.2

Design Details for Temporary Works

The Contractor shall include the information and details necessary to enable temporary works
construction without reference to any supplemental drawing, calculation sheet, design standard, or
other source document. For falsework, the Contractor shall show all dimensions that control the
design and erection of falsework, including beam lengths, distances between beams, post locations,
distances between posts, vertical distances between connections in diagonal braces, and the heights
of falsework bents (braced frames).

The Contractor shall show the maximum applied dead and live structural loads on each foundation.
Information from the Contractor shall include a drainage plan that describes how work structures will
protect foundations from saturation, erosion, and scouring.

The Contractor shall show anticipated total settlements of falsework and forms, including falsework
footing settlement, joint take-up and elastic deformation. By design, anticipated settlements shall not
exceed 20 mm. Each falsework shall be designed and constructed to elevations that include
anticipated settlement during concrete placement and required camber to compensate for member
deflections during construction.

Temporary waterway bridges shall span the desired water opening and have dimensions that avoid
constricting any stream’s flow while such bridges are in use. To meet basic design criteria, the bridge
system shall be sufficient for a 5-year frequency storm (that is, the worst storm that is anticipated
within  any  five-year  period),  with  allowance  for  150  mm  of  backwater.  The  plans  shall  show  the
minimum bridge lengths between abutment piling and the resultant water elevation caused by a five-
year frequency storm. To determine a minimum low superstructure elevation, the Contractor shall
use the given high water elevation and consider local conditions. A temporary work for structure shall
have  the  minimum  roadway  width  specified  in  the  particular  project  specifications,  as  measured
between the faces of the railings or curbs and at right angles to the centreline. Vertical abutments
shall, by design, prevent spilling fill material into the water. Any temporary crossing over sea water
that  is  subject  to  boating  shall  provide  horizontal  and  vertical  clearance  in  accordance  with  the
appropriate jurisdictional agency.

1.16.3

Materials for Temporary Works

The  Contractor  shall  precisely  describe  all  materials  for  proposed  temporary  works,  including
materials  that  are  not  designated  by  standard  nomenclature  (such  as  AASHTO  or  ASTM
specifications),  based  on  manufacturer‘s  tests  and  recommended  working  loads.  The  Contractor
shall  evaluate  materials  for  temporary  works  and  ascertain  whether  their  physical  properties  and
conditions are sufficient to support the design’s assumed loads.

1.16.4

Concrete Placement for Temporary Works

The Contractor shall provide an outline of the proposed concrete placement operation with a list of
the equipment, labour, and procedures to be used for the duration of each operation. The Contractor
shall include details, such as proposed placement rates and design pressures, etc for each pour.
Information from the Contractor shall include a superstructure placement diagram that shows the
sequence of concrete placements and construction joint locations.

1.16.5

Openings in Temporary Works

The Contract plans shall show the locations of all openings through a falsework that enable public
traffic to pass. The Contract plans shall include all horizontal and vertical clearances and the
locations of temporary railing. For falsework over traffic, the Contract plans shall show the sequence
of falsework erection and removal. The Contractor shall submit separate falsework drawings for each
structure, except for structures with entirely identical falsework designs and details. Construction of
any unit of falsework shall not begin until the project Engineer has reviewed and approved the
drawings for that unit including requirements for height warning structures and locations.

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1.16.6

Requirements for Temporary Works

Temporary works must, by design, support all loads imposed and provide the necessary rigidity to
enable the production of final structures. Temporary work designs shall conform to AASHTO LRFD
Bridge Design Specifications or AASHTO Guide Design Specifications for Bridge Temporary Works.

When a temporary work includes manufactured devices, the design shall ensure that loads on such
devices d

o not exceed the strength load recommended by each device’s manufacturer, and verified

by test certificates.

For equipment where the rated capacity is determined by load testing, the design load shall be as
stated in the generally accepted design code or specification for such work.

Load ratings for special equipment, such as access scaffolding, may be under the jurisdiction of local
regulations. However, in no case shall the load on an item of equipment exceed eighty percent (80%)
of maximum load sustained during its load testing.

When so required or specified in Contract documents, a professional Engineer  shall prepare and
sign designs and drawings for temporary works.  Professional Engineer shall be otherwise licensed
as  a structural  Engineer  or  have  documented  experience  and  training  that  can  be  verified  by  the
Engineer for approval as having the necessary recognized qualifications.

Temporary works shall be constructed in agreement with the approved working drawings.

The Contractor shall verify that materials and workmanship meet or exceed the level of quality
indicated in the designs.

1.16.7

Removal of Temporary Works

Unless otherwise specified, all temporary works shall be removed and shall remain the property of
the Contractor upon completion of their use. The Contractor shall clean the project area and restore
it to its original or planned condition. Final cleanup of a work site includes completely removing all
temporary works, unless the project Engineer directs otherwise, and cleaning the work site of all
debris.

1.16.8

Falsework and Forms

Falsework and forms shall be sufficiently rigid and strong to safely support all loads imposed on them
and to produce in the finished structure the lines and grades indicated in the Contract documents.
Forms shall impart the required surface texture and rustication and shall not detract from the
uniformity of colour of the formed surfaces.

1.16.8.1

Materials for Falsework

Materials  to  be  used  in  falsework  construction  may  be  new  or  used  manufactured  components.
Concrete,  reinforcing  steel  and  structural  steel  that  will  be  part  of  falsework  shall  conform  to  the
relevant  chapters  in  these  standard  specifications,  other  Abu  Dhabi  Owner  specifications  and
standards, and any specific Contractual project requirements. When used materials are proposed,
fatigue shall be considered in design calculations.

If so directed, the Contractor shall supply material certifications for new materials. Concrete tests
should be performed as described in Chapter 4, Concrete Works, and Chapter 21, Concrete
Structures, of these standard specifications. All salvaged and used material and manufactured
components are subject to approval.

a. Salvaged Steel for Falsework

Falsework may include used structural steel for surface imperfections at the allowable working
stresses for new material if the grade of steel can be identified and the used steel meets the criteria
outlined in ASTM’s Standard Specification for General Requirements for Rolled Structural Steel
Bars, Plates, Shapes, and Sheet Piling (ASTM A6 / A6M). Falsework shall not include unidentified
steel.

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b. Timber for Falsework

All  timber  shall  be  of  sound  wood,  in  good  condition  and  free  from  defects  that  might  impair  its
strength. If the vertical members are not long enough to cap at the desired elevation for the horizontal
members,  the  Contractor  shall  cap  them  and  construct  frames  to  the  proper  elevation.  The
Contractor shall cut the ends of vertical members so that they are square and support the full bearing
without the use of wedges. If vertical splices are necessary, the abutting members shall be of the
same  approximate  size,  with  square-cut  ends  for  full  bearing,  and  the  Contractor  shall  scab  the
splices in a manner proscribed and approved by the project Engineer.

All wood species for which the National Design Specification for Wood Construction (NDS
ANSI/AF&PA NDS-2005), published by the National Forest Products Association in the U.S., assigns
allowable stresses are acceptable for use in falsework construction for the Owner.

c. Used Lumber for Falsework

Used lumber of known species may be used in falsework construction if the grade is known and the
lumber is in good condition. Owner does not permit the use of lumber of unknown grades, unless
the Contractor performs appropriate standard tests to establish the grade of lumber.

d. Manufactured Components for Falsework

Temporary works may include manufactured components of the following proprietary product
classes:

a. Vertical shoring systems, including tubular welded frame shoring, tube and coupler shoring,

and components thereof

b. Manufactured assemblies, including single-post shores, brackets, jacks, joists, clamps, and

similar devices manufactured for commercial use

1.16.8.2

Materials for Forms

Forms used for concrete shall be wood, steel, or other approved material and shall be cement grout
tight, true to the dimensions, lines, and grades of the structure, and of sufficient strength to prevent
appreciable deflection during placement of concrete. Unless otherwise specified, variations must
comply with the values in Table

1-5

to be permissible.

Table 1-5: Maximum dimensional tolerance for cast-in-place formed concrete(*)

Item

Tolerance (mm)

Deviation from plan line

(

)

±25 mm

Cross-sectional dimensions of columns, piers, beams,
slabs, and walls

+25 - 12 mm

Bridges desk thickness

+12 - 6 mm

* Variations are to be compared with dimensions shown on the Plans or directed by the Engineer.

**Tolerance measurement is perpendicular to the plan line or surface. This tolerance includes
measurement of alignment, plumb, grade and level. Plumb (or batter) of retaining walls will be
inspected both before and after backfilling.

a. Sheathing for Forms

For exposed concrete surfaces, the Contractor shall use class I plywood as defined in the U.S.
Department of Commerce National Institute of Standards and Technology (NIST) Voluntary Product
Standard PS 1, Structural Plywood. Such material produces a smooth and uniform concrete surface.
Form panels to be used should be in good condition without any defects on exposed surfaces. If the
Contractor uses form panel material other than plywood, it shall have flexural strength, modulus of
elasticity, and other physical properties equal to or greater than the physical properties of class I
plywood.

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b. Structural Support for Forms

Materials for structural support of forms shall comply with the materials requirements for falsework.
Owner classifies vertical side forms, wall forms, and column forms, as well as related studs and waler
brackets, as formwork or structural support for formwork.

c. Prefabricated Formwork

If the Contractor uses prefabricated formwork, they shall furnish shop drawings and technical data
that substantiate the formwork’s load-carrying capacity and detail application instructions and
limitations. The Contractor shall use prefab

ricated products in accordance with their manufacturers’

recommendations.

d. Stay-in-place Steel Deck Forms

The  Contractor  may  use  stay-in-place  steel  deck  forms  if  such  are  permitted  in  the  Contract
documents  or  with  the  Engineer’s  approval.  In  such  cases,  the  Contractor  shall  furnish  design
calculations  with  shop  drawings.  Stay-in-place  steel  deck  forms  and  supports  shall  be  fabricated
from  grade  275  or  grade  340  steel  that  conforms  to  the  specifications  in  ASTM’s  Standard
Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed)
by the Hot-Dip Process (ASTM A 653 / A653M). Such forms shall have a coating class of G165 in
accordance with the same specification.

e. Stay-in-place Prestressed Concrete Deck Forms

The Contractor may use stay-in-place prestressed concrete deck forms if such are permitted in the
Contract documents or with the Engineer’s approval. In such cases, the Contractor shall furnish
complete deck design calculations with the shop drawings. Stay-in-place concrete deck forms shall
be fabricated in accordance with the requirements outlined in Chapter 21, Concrete Structures, and
Chapter 22, Prestressing Systems, of these standard specifications.

f. Steel Formwork

Where external vibrators are likely to come into contact with forms, the Contractor shall use steel
formwork. All joints and holes shall be caulked or covered with tape, which shall be firmly fixed by
means of spirit glue or other oil and grease resistant adhesive. All rivets and bolts on the inside of
the formwork shall be countersunk. Steel formwork shall be painted white on the outside.

For precast concrete beams, the Contractor shall use only steel forms that are in good condition.
They should be sufficiently thick and stiff, with effective braces and anchors, to withstand the forces
that result from placement and vibration of the concrete without losing correct alignment. The
Contractor shall thoroughly clean forms and coat them with a bond breaker before each use. Joints
must fit tightly to avoid loss of grout and to avoid rough blemishes on the concrete.

1.16.8.3

Falsework Design and Construction

A falsework shall provide the necessary rigidity to support all loads placed upon it without appreciable
settlement or deformation. When falsework cannot be founded on rock, shale, or thick deposits of
other compact material in their natural beds, wood or metal bases shall support the columns of such
falsework. Falsework shall not be supported on any part of the structure, except the footings, without
written permission from the Engineer. The number and spacing of false work columns, the adequacy
of sills, caps, and stringers, and the amount of bracing in the falsework framing shall be subject to
approval of the Engineer. Engineer may not permit the Contractor to proceed with other phases of
the work if he deems any falsework unsafe or inadequate to properly support all loads to which it will
be subjected.

Engineer’s approval of falsework plans or permission to proceed with the project work shall not
relieve the Contractor of the responsibility to successfully erect falsework and to otherwise produce
satisfactory results.

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a. Designs for Falsework

The Contractor shall complete and submit designs for all falsework, with detailed proposals, to the
Engineer or an appropriate representative of the project Engineer for agreement before commencing
any work on the project.

Design loads and allowable stresses for falsework shall conform to the AASHTO LRFD Bridge
Construction Specifications.

Falsework design calculations shall show all of the following details:

1. Stresses, strains and deflections in load supporting members

2. Anticipated total settlements of falsework and forms, which shall not exceed 20 mm, including

falsework footing settlement and joint take-up

3. Details of falsework supporting deck slabs and overhangs on girder bridges that will ensure

consistent settlement between the girders and the deck forms during the placement of deck
concrete

4. Elevations of falsework, including anticipated settlement during concrete placement and

required camber to compensate for member deflections during construction

5. Details of strengthening and protecting falsework over or adjacent to roadways and railroads

during each phase of erection and removal

6. Intended steel erection procedures with calculations in sufficient detail to substantiate that the

girder geometry will be correct

7. Falsework spans that support T-beam girder bridges, which shall be limited to 4.3 meters plus

8.5 times the overall depth of related T-beam girders

b. Manufactured Assemblies for Falsework

For jacks, brackets, columns, joists and other manufactured devices, the ultimate load carrying
capacity of a falsework assembly shall not exceed the manufacturer's recommendations or forty
percent of the ultimate load carrying capacity that has been determined by actual destructive testing.

The Contractor shall furnish catalogue or equivalent data that shows the manufacturer's
recommendations. Otherwise, the Contractor shall perform tests, as necessary, to demonstrate the
adequacy of any manufactured devices proposed for use. The Contractor shall not substitute
components from another manufacturer unless the primary manufacturer's data encompasses such
substitutions or field tests affirm the integrity of such substitutions.

If a component of the falsework system consists of a steel frame tower that is two or more tiers high,
the differential leg loading within the steel tower unit shall not exceed a 4 to 1 ratio. Engineer may
approve an exception, if the manufacturer of the steel frame certifies, based on manufacturer's tests,
that the proposed differential loadings are not detrimental to the safe load carrying capacity of the
steel frame.

c. Foundations for Falsework

Falsework shall be founded on a solid footing, safe against undermining, protected from softening,
and  capable  of  supporting  the  loads  imposed  on  it.  When  so  requested  by  the  Engineer,  the
Contractor shall conduct suitable load test to demonstrate that the soil bearing values assumed for
the design of the falsework footings do not exceed the supporting capacity of the soil. Falsework that
cannot  be  founded  on  a  satisfactory  footing  shall  be  supported  on  piling  which  shall  be  spaced,
driven, and removed in an approved manner, if or  as required. Before designing a falsework, the
Contractor shall verify, in the field, all ground elevations at proposed foundation locations.

Footing edges shall not be closer than 300 mm from the intersection of the bench and the top of a
slope. Unless the excavation for footings is adequately supported by shoring, the edge of the footings
shall not be closer than 1.2 m or the depth of excavation, whichever is greater, from the edge of the
excavation.

When falsework is supported by footings placed on paved, well-compacted slopes of berm fills, such
falsework shall not be strutted to columns unless the column is founded on rock or supported by
piling.

When individual steel towers have maximum leg loads that exceed 130 kN, the Contractor shall
provide for uniform settlement under all legs or each tower under all loading conditions.

For the duration of its use, a falsework’s foundation shall be protected from adverse effects. The
Contractor shall take necessary precautions to protect the foundation of a falsework.

d. Deflections for Falsework

For cast-in-place concrete structures, calculated deflections of falsework and formwork members
shall be limited as follows:

1. Vertical deflection for falsework members shall not exceed 1/360 of the span under the dead

load of the concrete only, regardless of whether deflection is compensated for by camber
strips.

2. Deflections for formwork (other than sheathing) shall not exceed 1/360 of the span under the

dead load of the concrete only or the lateral pressure of fluid concrete only.

3. Deflection for sheathing formwork shall not exceed 1/270 of the centre-to-centre distance

between studs, joists, form stiffeners, form fasteners, or waler brackets.

e. Clearance

Clear horizontal openings for roadways that are to remain open to traffic during construction shall be
at least 1.5 m wider than the travelled approach way, between barriers, and be at least 6.50 m high
to ensure minimum vertical clearance over roads.

f. Construction

Falsework shall be constructed and set to grades that allow for anticipated settlement and deflection.
Falsework shall allow for the vertical alignment and camber indicated on project plans or as ordered
by the project Engineer for the permanent structure. Camber shall be provided for the falsework to
account for the falsework’s deflection and the anticipated deflection of the main structure. To assure
appropriate camber, when so directed by the Engineer, the Contractor shall use variable depth
camber strips between falsework beams and soffit forms.

The  Contractor  shall  use  suitable  screw  jacks,  pairs  of  wedges,  or  other  devices  at  each  post  to
adjust falsework to grade, to permit minor adjustments during the placement of concrete or structural
steel if observed settlements deviate from those anticipated, and to allow for the gradual release of
the  falsework.  The  Contractor  shall  provide  telltales  attached  to  the  forms  and  extending  to  the
ground,  or  other  suitable  means,  to  accurately  measure  settlement  of  a  falsework  during  the
placement and curing of concrete. Screw jacks, if used, shall be adequately braced and secured to
prevent their tipping in any direction.

Falsework or formwork for deck slabs on girder bridges shall be supported directly on the girders so
that there will be no appreciable differential settlement during placement of the concrete. The
Contractor shall brace and tie girders to resist any forces including uplift that would cause rotation
or torsion of the girders that could be caused by the placement of concrete for diaphragms or
decking. Unless given specific permission from the project Engineer to do so, the Contractor shall
not weld falsework support brackets or braces to structural steel members or reinforcing steel.

The Contractor shall systematically and sufficiently locate telltales and attach them to soffit forms to
enable the Contractor and Engineer to determine, from the ground, the total settlement of a structure
while concrete is being placed.

Unless so authorized, the Contractor shall not apply dead loads, other than forms and reinforcing
steel, to any falsework.

If unanticipated events occur, the Contractor shall discontinue concrete placement and take
corrective action to correct settlements that deviate more than 10 mm from those shown on the
falsework drawings. The Contractor shall remove all unacceptable concrete that results from a failure
to take corrective action before the initial set.

g. Testing and inspection of Falseworks

All falseworks shall be tested and inspected by the Contractor and approved by the Engineer before
any load is placed on it, but such approval shall not relieve the Contractor of his responsibility for the
safety, accuracy or efficiency of the falsework.

1.16.8.4

Formwork Design and Construction

Forms shall be wood, steel, or other approved material and shall be mortar tight and sufficiently rigid
to prevent distortion due to the pressure of the concrete and other loads that are incidental to the
construction, including vibration. Forms shall be constructed and maintained to prevent the opening
of joints due to shrinkage of the lumber; forms shall permit easy removal without damage to the
concrete. Before using a form lining, the Contractor shall submit samples, specifications, and other
pertinent information to the Engineer to secure written permission to use the lining.

Forms for concrete surfaces that are exposed to view shall be new and shall produce a smooth
surface of uniform texture and colour that is substantially equal to that which would be obtained with
the use of plywood that conforms to the requirements outlined in the U.S. Department of Commerce
National Institute of Standards and Technology (NIST) Voluntary Product Standard PS 1, Structural
Plywood.

Form lining material shall not bulge, wrap, or blister. It shall not stain concrete. To minimize joints,
the Contractor shall use form lining in the largest practicable panels. Small panels of the lining
material shall not be permitted. Joints in the lining shall be tight and smoothly cut. Arrangement of
panels that line forms shall ensure that joint lines form a symmetrical pattern that conforms to the
general lines of the structure. Placement of adjacent panels of form lining shall ensure that wood
grain lies in the same general direction (either all horizontal or all vertical). The Contractor shall not
use thin metal form lining. Undressed lumber of uniform thickness may serve as backing for a form
lining.

As an alternative to such lined forms, the Contractor may use wooden ply forms of adequate
thickness and with proper support to meet the requirements outlined in this section.

A single structure shall have the same type of form-lining material throughout. Such forms shall be
sufficiently rigid so that the undulation of the concrete surface shall not exceed 3 mm when checked
with a 1500 mm straightedge or template. The Contractor shall chamfer all sharp corners
approximately by 20 mm x 20 mm.

The Contractor may use metal forms, which are subject to the same requirements and approvals as
wood forms. Metal shall be sufficiently thick to ensure that such forms remain true to shape. All bolt
and rivet heads shall be countersunk. Clamps, pins, or other connecting devices shall hold metal
forms rigidly together and allow removal without damage to concrete. Metal forms shall present a
smooth surface and line up properly. The Contractor shall keep metal forms free from rust, grease,
and other foreign matter. If the performance of such metal is not satisfactory, the Engineer may
require their discontinuance at any time. Engineer will not approve the use of steel panels, panels
with metal frames and wood, or panels with combination facings that leave permanent impressions
or ridges.

a. Designs for Forms

The Contractor shall complete and submit designs for all forms, with detailed proposals, to the project
Engineer or an appropriate representative of the Engineer for agreement before commencing any
work on the project.

Structural design for formwork shall conform to the standards outlined in the American Concrete
Institute (ACI) Guideline to Formwork for Concrete (ACI 347) or an equivalent generally accepted

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standard. In selecting the hydrostatic pressure to be used in the design of forms, the Contractor shall
consider the maximum rate of concrete placement, the effects of vibration, concrete temperature,
and any expected use of set-retarding admixtures or pozzolanic materials in the concrete mix. Form
designers should assume a minimum weight of 2,400 kg per cubic metre when computing vertical
loads and a minimum weight of 1,360 kg per cubic metre when computing horizontal pressure.

When determining lumber widths and thicknesses, the sizes of studs and waler brackets, and the
distances between studs and waler brackets, a form designer shall give due regard to the nature of
the construction work project and shall ensure that forms are sufficiently rigid to prevent distortion
caused by the pressure of concrete.

Bolts, rods, and ties for forms shall be steel and of a type that permits the major part of the tie to
remain permanently in the structure. Devices attached to the waler brackets that can develop the
strength of the ties hold the ties in place. Engineer may permit the use of wire on irregular sections
and incidental construction if concrete pressures are nominal and other means maintain the
alignment of forms.

Fittings for metal ties shall be of such design that, upon their removal, only the smallest possible
cavities remain. Such cavities shall be filled with cement mortar to leave the surface sound, smooth,
even, and uniform in colour.

Forms shall not have form ties that serve as handrails. Pipe spreaders shall not be used unless they
can be removed during the placement of concrete, as determined by the project Engineer. Wood or
metal spreaders shall be removed as concrete is placed. Forms shall not include cofferdam braces
or struts that extend through the forms for any concrete section, except in unusual situations and
with the project Engineer’s explicit approval.

All forms for beams, slabs, and similar members shall have sides that can be removed without
disturbing the bottom boards or related supports.

b. Construction of Forms

Before the placement of concrete, the Contractor shall set forms that mirror the dimensions, lines,
and  grades  of  the  structure  under  construction.  Such  forms  shall  hold  true  to  these  dimensions
throughout  the  placement  of  concrete.  Forms  may  have  bevels  or  drafts  at  projections,  such  as
copings, to ensure easy removal. Before reusing a form, the Contractor shall clean it, inspect it for
damage, and, if necessary, repair it. When forms appear to be defective in any manner, either before
or  during  the  placement  of  concrete,  a  project  Engineer  may  order  the  work  stopped  until  the
Contractor corrects the defects.

Formwork arrangements shall facilitate ready dismantling and removal from the cast concrete
without shock, disturbance, or damage. Where necessary, an arrangement of formwork shall enable
retention of the soffit form, properly supported on props only, in position for such period as may be
required. If a component is to be prestressed whilst still resting on the soffit form, form construction
shall resist elastic deformation and variations in the distribution of weight.

The Contractor shall treat forms with form oil or another approved release agent before placing any
reinforcing steel. Forms shall not include materials that will adhere to or discolour concrete. Release
agents shal

l be applied strictly in accordance with their manufacturers’ instructions and shall not

come into contact with any reinforcement. The Contractor shall not use different release agents in
formwork for concrete that will be visible in the finished work. Concrete surfaces shall not have
adverse residual effects from release agents. Release agents shall not leave any residue that is
detrimental to painting or coating concrete.

Other than any specific exceptions described in these standard specifications, constructions of metal
ties or anchorages within forms shall permit their removal to a depth of at least 25 mm from concrete
faces without damage to the concrete. A form may use ordinary wire ties only when concrete will not
be exposed to view and where concrete will not contact salts or sulphates. When removing forms,
the Contractor shall cut such wire ties at least 6 mm from the face of the concrete with chisels or
nippers; for green concrete, the Contractor shall use nippers.

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When a form requires epoxy-coated reinforcing steel, all metal tics, anchorages, or spreaders that
remain in the concrete shall be corrosion-resistant or coated with a dielectric material.

The Contractor shall maintain forms after erection to eliminate warping and shrinkage. Immediately
before placing concrete, the Contractor shall check a form’s dimensions and condition. At any time,
the Engineer may require the revision or reconstruction of forms and may refuse permission to place
concrete within any form until its construction is satisfactory. If at any period of a project during or
after the placement of concrete, forms show signs on sagging or bulging, the Contractor shall remove
concrete to the extent directed by the Engineer, bring the forms to their proper positions, and place
new concrete. The Owner will make no allowance or compensation to the Contractor for such extra
work.

Unless directed to do otherwise, the Contractor shall paint the exterior sides of all forms with an
approved high gloss white oil base enamel of good quality before placing concrete. When one coat
of this enamel does not provide complete coverage, the Engineer shall order additional coats as
necessary to obtain complete coverage. Upon order from the Engineer, the Contractor shall repaint
forms.

To prevent shrinkage cracks, the Contractor shall moisten forms with water before placing concrete.

Forms that are to be reused shall be thoroughly cleaned and reoiled and, if necessary, shall be
reconditioned by revision or reconstruction. Unsatisfactory lumber will be condemned by the
Engineer; the Contractor shall remove such lumber from the project site. The Contractor shall keep
metal forms clean and free from rust to prevent discolouration of concrete surfaces. After each use
with power operated tools, the Contractor shall clean plywood forms before coating them again.

Where the bottom of a form is inaccessible, the Contractor shall leave the lower form boards loose
or make other provisions so that extraneous material may be removed from the forms immediately
before concrete placement. Unless a project plan indicates otherwise or the Engineer directs
otherwise, the Contractor shall use dressed, milcut, triangular moulding with 20 mm sides to level all
exposed edges. All curved surfaces shall be formed with approved plywood or steel.

Concrete shall not be deposited in the forms until all work connected with constructing the forms has
been completed, all dust, debris, loose wire, and other detritus have been removed, all materials to
be embedded in the concrete have been placed for the unit to be cast, and the project Engineer has
inspected and approved the forms and materials.

Further requirements of formworks construction shall be in accordance of Section 4.6.2 of Chapter
4, Concrete Works, of these standard specifications.

c. Testing and inspection of Forms

All formwork shall be tested and inspected by the Contractor and approved by the Engineer before
any concrete is placed in it, but such approval shall not relieve the Contractor of his responsibility for
the safety, accuracy or efficiency of the work.

d. Wrought Formwork

Wrought formwork shall produce a concrete face with a finish that is true, sound, and smooth and
that is free from board marks and other disfigurements. The Contractor shall use wrought formwork
for surfaces that are exposed in the finished work. Panel joint arrangements in wrought formwork
shall match an approved regular pattern. Wrought formwork alignments shall be within a tolerance
of ±3mm along 3 meter line. Plus and minus tolerances will not be permitted in close proximity to
each other.

e. Rough Formwork

Rough formwork shall be grout proof and may be used for surfaces that are not exposed in the
finished work. Rough formwork may be timber, as sawn at a mill. Boards shall have identical widths.
Outer surfaces of walls shall be formed so that the boards shall be vertical.

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f. Tube Forms

Tubes used as forms to produce voids in concrete slabs shall be properly designed and fabricated
or otherwise treated to make the outside surface waterproof. Before concrete placement, such tubes
shall be protected from weather and stored and installed by methods that prevent distortion or
damage. The Contractor shall cover tube ends with mortar-tight and waterproof caps. If the
Contractor uses wood or other material that expands when moist to cap tubes, they shall place 6
mm thick pre-moulded rubber joint filler around the perimeter of caps to permit such expansion. A
polyvinyl chloride (PVC) vent tube near both ends of each tube shall ventilate voids. After removing
the exterior form, the Contractor shall trim the vent tube to within 15 mm of the bottom surface of the
finished concrete.

Anchors and ties for tube forms shall prevent displacement of the tubes during concrete placement.

g. Stay-in-place Forms

The Contractor may use stay-in-place deck soffit forms, such as corrugated metal or precast
concrete panels, if Contract documents indicate such forms or with the Engineer’s approval. Before
using such forms, the Contractor shall provide a complete set of details to the Engineer for review
and approval. Contract documents typically specify the use of removable forms. Any changes to the
dimensions of structures that are necessary to accommodate stay-in-place forms, if approved, shall
be at the Contractor’s expense.

h. Permanent Forms

The Contractor shall not use permanent forms, of any material, that are proposed to remain in place
at the completion of construction unless particular project specifications expressly allow the use of
such forms.

i. Void Formers

All void-forming material shall be expanded polystyrene with the properties indicated in Table

1-6

or extruded polystyrene.

Table 1-6: Properties of expanded polystyrene for forming materials

Property

Value

Cross breaking strength

– kN/m² minimum

140

Compressive stress kN/m² minimum at 10% compression

Water vapour transmission at 38 Co and 90% relative Humidity, microgram
metres/Newton hour, maximum per 50 mm sample thickness

Thermal conductivity W/m² C at 10 Co mean temperature, maximum

0.037

Dimensional stability at 80 C per cent maximum

0.5

j. Forms for Beams and Slabs

All forms for beams, slabs, and similar items shall enable removal of such forms’ sides without
disturbing the bottom boards or related supports.

k. Forms for Precast and Prestressed Girders

Each casting bed shall have a concrete deck to which the bottom forms shall be adequately
anchored. Placement of bottom forms shall provide for camber and allow automatic cambering that
result from the transfer of tendon prestress to the concrete. Bottom forms shall remain in true
alignment and be sufficiently stiff to prevent excessive deflection under the load of wet concrete.

Forms and all related supports shall, by design, accommodate the shortening of members due to
concrete shrinkage and the transfer of pre-tensioning or post-tensioning forces to the concrete.

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Forms shall compensate for this shortening so that the centre-to-centre bearing distance of a
completed beam under full dead load will be as indicated on the Contract plans.

Side forms shall be steel. Support for side forms shall not require ties or spreaders within the body
of the member. The Contractor shall brace and stiffen side forms to ensure that no undesirable
deflection or curvature takes place under concrete pressure. Side form designs shall facilitate proper
cleaning between uses.

For adjacent sections of forms that are butt-joined, ends and sides shall come together smoothly
and tightly with proper alignment. Side forms shall have cross-

ties above any member’s finished

surface with spacing that is sufficiently close to maintain true cross-sectional dimensions.

The Contractor

shall bevel or chamfer all of a form’s exposed outside edges as indicated on the

Contract plans. Forms shall not leak mortar. Joints between soffit, side forms, and bulkheads shall
be tight; as necessary, forms shall include rubber gaskets to prevent leakage. The Contractor may
use rubber to provide the corner chamfers. Plugging of holes and slots in the forms shall be neat
and shall ensure that finished members have a workmanlike appearance that is acceptable to the
Engineer.

Before beginning concreting operations, the Contractor shall treat forms and casting beds with a
suitable form lacquer or oil to prevent bonding of the concrete. Such form lacquer or oil shall leave
no stains or discoloration on concrete. The Contractor shall be careful not to coat tendon conduits
or reinforcement steel with such form lacquer or oil. The Contractor shall either clean any tendon
conduits or bars that are so contaminated to the satisfaction of the Engineer or replace them.

Forms shall be free from paint or any other protective substance can cling to the surfaces of finished
precast members. The Contractor shall not reuse any form without cleaning it thoroughly.

No form ties, spreaders, or forming facilities shall penetrate the body of a member, except when
doing so is necessary to provide openings that are indicated on the Contract plans.

If, during the casting of members, any forms have deteriorated to the degree that finished precast
members cannot be constructed without approaching or exceeding the dimensional tolerance limits,
the Engineer may suspend production of structures related the unsatisfactory forms until the
Contractor has completely renovated or replaced the deficient forms.

l. Lined Formwork

The Contractor shall use sawn tongued-and-grooved timber boards to make formwork. Such boards
shall have the same thicknesses and same widths, unless the Contract documents specify otherwise
or in accordance with additional requirements in these standard specifications.

Boards on the visible outer surfaces of piers and walls shall be vertical, except where formwork is
lined as specified in this section.

Unless  the  Contract  plans  indicate  otherwise,  exposed  faces  of  wing  walls,  retaining  walls,  and
abutments shall have lined forms that will achieve the surface textures that have been approved by
the  project  Engineer.  Before  ordering  form  liners,  the  Contractor  shall  submit  sample  form  liner
panels  to  the  project  Engineer  for  approval;  such  liners  shall  be  at  least  50  cm  by  50  cm  and
otherwise in accordance with Contract requirements. Form liners shall produce surface textures that
match  the  textures  approved  by  the  Engineer.  Form  liners  shall  be  elastomeric  material  in
accordance with their manufacturer’s recommendations and approval from the project Engineer.

m. Sawn Formwork

Formwork for unexposed concrete surfaces may be of timber as sawn at the mill. Boards shall be
of the same width. Outer surfaces of walls shall be formed so that the boards shall be vertical.

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n. Special Formwork

The Contractor shall include all special formwork that is required to produce surface ornamental
patterns on all concrete surfaces, including the fronts of wing walls, piers, abutments, and parapets,
as indicated on the Contract plans and as approved by the Engineer.

o. Slip-form Formwork

The Contractor shall receive Engineer’s approval of slip-form formwork prior to fabrication or bringing
the slip-form equipment to the site of the works. Slip-form formwork shall comply with the
requirements of Section 4.6.1 of Chapter 4, Concrete Works, of these standard specifications.

p. Damage to Concrete

The Contractor shall make good any damage to concrete work and any damage caused by or from
the removal and striking of forms and supports. The Contractor shall notify the project Engineer of
any such damage, who shall inspect and evaluate the Contractor’s proposals for remedial works.
Engineer may reject any concrete surfaces that have been remedially treated in any way before such
inspection and approval from the project Engineer.

q. Openings in Formwork

Formwork may have openings to facilitate internal inspection and to allow wash water to escape.
Such openings, by design, shall be easy and convenient to close before concrete placement.

Access openings into hollow substructures and box girders shall be formed at locations and in
accordance with the details shown on the Contract plans.

Whenever the concreting of narrow members has to be carried out within formwork of considerable
depth, the Contractor shall consider making temporary openings in the sides of forms to facilitate
concrete placement and consolidation. The Contractor shall provide small temporary openings, as
necessary, at the bottom of forms of narrow members to permit the expulsion of water, wire, rubbish,
and other deleterious materials.

r. Shutters for Forms

To enable the proper placement of concrete, forms shall include shutters for all slopes that exceed
15 degrees to the horizontal. Formwork shall be constructed so that the side shutters of members
can be removed without disturbing the soffit shutters and, if the Contractor wishes to leave some of
the props in place when the soffit shutters are removed, these props shall not be disturbed during
the striking. Detailed arrangement of the props shall be submitted to the Engineer in advance for his
approval.

s. Chamfers for Forms

Unless otherwise specified or shown on the Contract plans, all exposed arises shall have 20 mm x
20 mm chamfers.

1.16.8.5

Removal of Falsework and Forms

The Contractor

shall not remove falsework or forms without the Engineer’s approval. Removal of

falsework and forms shall be in accordance with the requirements of Section 4.6.3, Chapter 4,
Concrete Works, and Section 21.7.10, Chapter 21, Concrete Structures, of these standard
specifications.

1.16.9

Cofferdams

Cofferdams are temporary structures that provide the following functions:

a. Keep water and soil out of excavations in which substructures are to be built

b. Protect adjacent property and facilities during construction of permanent works

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c. Give workers a dry work environment

Usually, cofferdams are dewatered so that the substructures can be built under dry conditions. After
the substructures have been completed, the cofferdams are removed.

To design cofferdams and dewatering systems, as specified above, the Contractor shall engage a
professional Engineer who specializes in such design to prepare and sign such plans. Engineer shall
approve both the professional Engineer and the designs. Engineer’s approval of designs and shop
drawings, however, shall not relieve the Contractor of responsibility for the adequacy and
performance of such temporary works.

A cofferdam shall be sufficiently deep and high to seal of all water. Cofferdams usually have depths
that  are  well  below  the  bottom  of  an  excavation.  The  Contractor  shall  design  and  construct
cofferdams to be safe and as watertight as is necessary for the proper performance of the permanent
works.  They  shall  be  sufficiently  large  to  give  easy  access  to  all  parts  of  a  foundation  form  and
pumping equipment, with dimensions equal to or greater than the related excavation. If cofferdams
are  tilted  or  moved  laterally  during  the  process  of  sinking,  the  Contractor  shall  right,  reset,  and
enlarged them as needed to provide the necessary clearance. Such correctional adjustments shall
be solely the Contractor’s expense.

The  Contractor  shall  ensure  that  a  cofferdam  prevents  the  penetration  of  water  to  ensure  the
placement of footing concrete in a dry environment. When a cofferdam’s bottom is of sandy or porous
material that, in the opinion of the project Engineer, will not permit a concrete footing to be poured
in  a  dry  environment,  it  shall  be  sealed  with  sufficient  Class  C28/20  concrete  so  that  it  may  be
pumped dry. If a seal is required, the Contractor shall determine the depth of seal and the required
cure time. Engineer may approve other satisfactory methods of sealing out water.

Under ordinary circumstances, Class C28/20 concrete for a cofferdam shall have 10 % more cement
content and the slump of the concrete shall be approximately 150 mm. A cofferdam shall not use a
seal course unless such is shown on project plans or is authorized in writing by the Engineer. If the
Engineer deems that a cofferdam’s construction is inadequate or improper, the Engineer may order
the removal or reconstruction of the cofferdam or permit the Contractor, at their own expense, to
place  a  seal  course.  After  such  a  seal  has  cured,  the  Contractor  shall  pump  all  water  out  of  the
cofferdam and place the balance of the masonry in the dry environment. When the Contractor use a
weighted  cofferdam  to  partially  overcome  hydrostatic  pressure  that  acts  against  the  bottom  of  a
foundation seal, special anchorages, such as dowels or keys, shall transfer the entire weight of the
cofferdam  onto  the  foundation  seal.  During  the  placement  and  curing  of  a  foundation  seal,  the
elevation of the water inside a cofferdam shall be controlled to prevent any flow through its seal; if a
cofferdam is to remain in place, it shall be vented or ported at or below low water level.

Cofferdams shall be adequate to support all loads imposed on them and shall comply with any
applicable safety regulations.

1.16.9.1

Protection of Concrete by Cofferdams

Cofferdams shall protect green concrete against damage from any sudden rising of water and shall
prevent damage by erosion. Timber or bracing in cofferdams shall not extend into the permanent
work except where permitted, in writing, by the Engineer.

1.16.9.2

Removal of Cofferdams

Unless an alternative has been approved by the Engineer, the Contractor shall remove cofferdams
and shoring, with all sheeting and bracing, after the completion of the substructure, without disturbing
or marring finished works.

1.16.10

Shoring

Shoring involves the use of excavation support structures to allow the excavation and backfilling of
trenches or excavations for the installation of sanitary or storm sewers, watermains, forcemains, and
their associated appurtenances.

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The Contractor shall provide, place, and maintain shoring and bracing at the necessary locations
and elevations to meet the following requirements:

a. Support and protect the sides and bottom of an excavation

b. Prevent undue disturbance or weakening of the supporting material below or beside project

works

c. Prevent ground movement that may disturb or damage project works, adjacent pavements,

property, structures, or other works

Shoring and bracing shall be driven and placed so that it can be removed as backfilling takes place
without damaging pipeline or appurtenances and without settlement of or damage to adjacent
pavements and structures.

The Contractor shall remove all shoring and bracing as the excavation is backfilled, unless a project
specifies that such shoring and bracing is to remain in place.

The Contractor

’s procedure for extracting shoring and bracing and placing backfill shall ensure that

the backfill load is applied gradually and avoids disturbing works or foundation materials.

Bracing shall not be removed until backfill has reached the level of the bracing. Shoring shall be
removed in 150 mm increments until safely clear of project works.

The Contractor shall cut off all shoring that remains in place, as specified for the project or as directed
by the Engineer.

1.16.11

Temporary Water Control Systems

A temporary water control system can include one or more of the following components:

1. Dikes

2. Bypass channels

3. Flumes and other surface water diversion works

4. Cut-off walls

5. Pumping systems, including well point and deep well systems, that prevent water from entering

excavations for structures

1.16.11.1 Working Drawings for Water Control Systems

Working drawings for temporary water control systems, when required, shall include details of the
design and the equipment, operating procedures to be employed, and the locations of points of
discharge. Design and operations shall conform to all applicable water pollution and erosion control
requirements.

1.16.11.2 Operation of Water Control Systems

Pumping from the interior of any foundation enclosure shall prevent the movement of water through
fresh concrete. Engineer will not permit pumping during the placement of concrete or for a period of
at least 24 hours thereafter, unless it is done from a suitable sump that is separated from concrete
work by a watertight wall or other effective means, and only with the approval of the Engineer.

The Contractor shall not pump water from a sealed cofferdam until the seal has set sufficiently to
withstand the associated hydrostatic pressure.

The Contractor shall regulate pumping from wellpoints or deep wells to avoid damage by subsidence
to adjacent property.

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1.16.12

Temporary Bridges

Temporary bridges include detour bridges for use by the public, haul road bridges, and other
structures, such as conveyor bridges, used by the Contractor. The Contractor shall design, construct,
maintain, and remove temporary bridges in a manner that does not endanger project works or the
public.

1.16.12.1 Detour Bridges

A design for a detour bridge shall provide the following elements:

1. Bridge length

2. Bridge width

3. Bridge surface type

4. Bridge clearances

5. Alignment

6. Load capacity

7. Bridge railing type

8. Design speed

9. Road surface type

10. All project specific requirements (such as utilities and sidewalks)

11. Other design parameters specified or approved in Contract documents

To design temporary detour bridge, the Contractor shall follow all the required steps for designing a
permanent bridge. Detour bridges shall carry all anticipated loads and forces and resist lateral loads
caused by hydraulics, debris, wind, and other intermittent forces. Detour bridges over waterways
shall apply scour depths and design flood in accordance with the project’s particular specifications.

Any detour bridge design shall conform to the AASHTO LRFD Bridge Design Specification. If design
live

loads are not otherwise specified in Contract documents, a temporary bridge’s design load must

match that of a permanent bridge.

The Contractor shall submit working drawings and design calculations that have been sealed by a
professional Engineer to the Engineer for review two weeks before on-site construction of a detour
bridge is scheduled to commence. After constructing a detour bridge, the Contractor shall provide a
letter signed by a professional Engineer that states that the detour structure has been constructed
in accordance with its design.

During the design, installation, maintenance, and removal of a temporary detour bridge, the
Contractor shall strictly adhere to all environmental guidelines and the requirements of relevant
environmental agencies.

Temporary detour bridges shall be constructed according to the applicable sections of these
specifications and the requirements of applicable permitting agencies. Structural steel welding shall
comply with the welding specifications outlined in Sections 23.4.11 and 23.6.10 of Chapter 23, Steel
Structures. Welding shall not begin until all of the following have been approved:

1. Welding Procedure Specification (WPS)

2. Procedure Qualification Records (PQR)

3. Welder Qualification Test Records (WQTR)

4. Material Test Report (MTR)

5. Certified Welding Inspector (CWI-AWS)

Engineer will not permit field welding to girders, beams, stringers, crossbeams, or floor beams.

ENERAL

Construction of a bridge’s end fill shall match the approved working project drawings and comply
with the material, placement, and compaction requirements of these specifications. The Contractor
shall perform all quality control, sampling, and testing that is needed to verify that a completed
bridge’s end fill meets the specified requirements. At a minimum, such verification shall include
materials sampling, sieve analyses, laboratory proctor density testing, and in-situ density testing.

The Contractor shall maintain the detour throughout the period of its use and shall provide interim
inspections by a professional Engineer for long-term detour bridges. Signs confirming load capacity
shall be erected prior to opening to traffic.

After traffic has been routed onto the new permanent road or bridge, the Contractor shall remove
the detour bridge and restore the detour area to its natural condition to the satisfaction of the
Engineer.

When temporary detour bridges are no longer needed, the Contractor shall remove them according
to applicable specifications herein. Unless Contract documents show or specify otherwise, all
temporary bridge materials shall remain the property of the Contractor. The Contractor shall satisfy
all requirements of applicable permitting agencies during bridge removal, and shall restore all areas
occupied by the temporary bridges to original condition or as shown in project plans.

a. Materials for Detour Bridges

The Contractor shall furnish new material for temporary detour bridges according to the applicable
requirements in these standard specifications.

b. Spread Footings for Temporary Bridges

For temporary bridges supported on spread footings, the Contractor shall provide the following
information:

1. Soil or rock properties, ground water levels, and all assumptions used to characterize the

subsurface conditions for footing design

2. Estimated global and local scour depths used in the analysis

3. Bearing capacity design calculations and recommendations

4. Recommended footing elevations

5. Estimated footing settlements and differential settlement, if applicable, based on the service

conditions

6. Global stability analysis of spread footing locations

7. Method of providing adequate footing scour protection

c. Driven Piles for Temporary Bridges

For temporary bridges supported on driven piles, the Contractor shall include the following
information on project drawings:

1. Pile type, size, and steel grade

2. Pile layout and spacing

3. Required ultimate bearing capacity (nominal resistance)

4. Method for field determination of ultimate (nominal) bearing capacity (dynamic formula, wave

equation, or dynamic load test)

5. Minimum pile tip elevations

6. Subsurface material properties, ground water levels and all assumptions used to characterize

the subsurface conditions for pile design

7. Estimated global and local scour depths used in the analysis

Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020) - page 15