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

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8. Pile bearing capacity design calculations and recommendations

The Contractor shall also provide the following analyses and recommendations, when applicable:

1. Lateral pile load analysis

2. Pile tip protection

3. Pile uplift capacity

d. Haul Bridges

When the Contractor proposes the construction of haul road bridges or other bridges that are not for
public use over any right-of-way that is open to the public or that is over any railroad, they shall
submit working drawings that show complete design and details, including the maximum loads to be
carried, to the Engineer for approval. Such drawings shall be signed by a professional Engineer.
Such designs shall conform to AASHTO LRFD Bridge Design Specification, when applicable, or to
other appropriate standards.

1.16.12.2 Maintenance for Temporary Bridges

Maintenance  of  temporary  bridges  for  which  working  drawings  are  required  shall  include  their
replacement in case of partial or complete failure. In case of the Contractor delays to the project or
makes inadequate progress on repairs and replacement or fails to furnish such labour, materials,
and  supervisions  of  the  work  as  may  be  necessary  to  restore  the  structure  to  a  proper  condition
suitable  for  movement  of  traffic,  the  Owner  will  make  such  repairs  and  the  full  costs  for  such
restoration and repairs shall be charged back to the Contractor.

1.17

Sediment and Pollution Control

1.17.1

Description

Work under this section shall include furnishing, installing, maintaining, removing and disposing of
temporary sediment and pollution control measures such as wind and rain erosion control silt fences,
check  dams,  straw  barriers,  and  other  devices  or  methods  as  otherwise  may  be  required  for  the
Contractors  environmental  sediment  and  pollution  control  plan  as  specified  in  Section  1.15.9,  as
shown in the Drawings as required in the Particular Specifications as may be required by Abu Dhabi
EAD or as directed by the Engineer.

This work also includes the fencing and construction avoidance of areas to be protected as may be
shown on the Drawings, included in the Particular Specifications, directed by the Engineer or
required by Abu Dhabi EAD.

Design requirements on all temporary sediment and pollution control measures shall be in
accordance with Chapter 14 of the Abu Dhabi Road Drainage Manual, AD-D-07,

and as specified

herein.

1.17.2

Protective Fencing

Contractor  shall  install  high  visibility  fencing  around  all  areas  to  be  protected  from  construction
personnel  and  equipment  intrusion  as  shown  on  the  drawings,  included  in  the  particular
specifications, directed by the Engineer or required by Abu Dhabi EAD, which may include vegetated
agriculture,  trees  and  landscaping  areas,  environmentally  sensitive  areas,  historic  areas,
archaeology sites, public access areas, inhabiting species habitats, and protected coral/mangrove
areas. Contractor shall conduct training for all construction personnel about necessity to protect and
avoid those protected sites.

1.17.3

Sediment Controls

Sediment control involves both control of sediment at a dewatering or temporary stormwater
discharge location as well as erosion control caused by wind or rain on open unprotected soils in the

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construction area. Sediment and erosion controls, both temporary and permanent, shall be installed
in accordance with Contractor’s approved staging and phasing plans and coordinated with the
related construction work.

Control of sediment and erosion, caused by both wind and precipitation runoff and dewatering
operations require the Contractor to perform temporary work items including but not limited to the
following items:

1. Providing ditches, berms, culverts, temporary drainage diversions and other measures to

control surface water

2. Building berms, settling basins, diversions, and other measures, to control movement of sand

and sediments to downstream locations carried by the stormwater flows

3. Managing dewatering methods to avoid sediment discharge

4. Covering or otherwise protecting soil slopes and stockpiles until permanent erosion control

measures can be applied

5. Providing measures to control sand movement and dust caused by construction operations

and wind

To the degree possible, the Contractor shall coordinate this temporary work with permanent drainage
and erosion control work the Contract requires.

Engineer may require additional temporary control measures if it appears pollution or erosion may
result from weather, the nature of the materials, or progress on the work.

When natural elements rut or erode the slope, the Contractor shall restore and repair the damage
with the eroded material where possible, and clean up any remaining material in ditches and culverts.

If the Engineer anticipates water pollution or erosion, the Contractor shall schedule the work so that
grading and erosion control immediately follows clearing and grubbing.

Engineer  may  also  require  erosion  control  work  to  be  done  with  or  immediately  after  grading.
Clearing,  grubbing,  excavation,  borrow,  or  fill  within  the  project  limits  shall  never  expose  more
erodible earth than required for the immediate work, without approval by the  Engineer: During the
winter months of 15 October through 15 April, unprotected soil surfaces in a active work area shall
be stabilized by either the permanent erosion control measures or temporary measures, as approved
by the Engineer, prior to opening up another open soil work site.

Contractor shall be responsible for maintaining all erosion control measures in proper functioning
condition at all times.

When deficiencies in the erosion control devices or other elements of work listed herein are noted
by inspection or other observation, corrections shall be made by the Contractor by the end of the
day or work shift when directed by the Engineer.

Work specified herein which is lost, destroyed, or deemed unacceptable by the Engineer as a result
of the Contractor's operations shall be replaced by the Contractor at no additional cost to the
Department.

Work specified herein which is lost or destroyed as a result of natural events, such as excessive
rainfall, which is replaced by the Contractor at the direction of the Contractor, will be paid for in
accordance with the requirements of the bills of quantities.

1.17.4

Pollution Controls

Pollution control measures shall be installed in accordance with phasing provisions in the approved
plans and coordinated with the related construction.

Controlling pollution requires the Contractor to perform work items including but not limited to the
following items:

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1. Provide for dust and wind born sand and sediment controls to control air pollution

2. Implement spill and leak prevention procedures for paints, chemicals and hazardous

substances stored on the job site. Have in place a plan for emergency spill containment and
cleanup, including the providing and convenient access storage on-site of cleanup and
containment materials.

3. Provide positive containment and oil/water separation for stormwater runoff from equipment

maintenance, storage and refuelling yards and depots

4. Manage stormwater on a temporary basis to avoid movement of sediments and roadway

pollutants to downstream locations, in particular where such sediment will cause problems
such as discharge to environmentally sensitive mangrove and coral areas or damaging other
structures or plugging existing storm drain systems

5. Managing dewatering or providing sediment traps or filters prior to discharge to avoid sediment

discharges to sensitive areas or existing storm drains.

In cases of serious or wilful disregard for the protection of protected areas by the Contractor, the
Engineer will immediately notify the Contractor of such non-compliance. If the Contractor fails to
remedy the situation within 24 hours after receipt of such notice, the Engineer may immediately place
the erosion and/or other pollution control elements in proper condition and deduct the cost thereof
from moneys due the Contractor.

1.17.5

Materials

1.17.5.1

Submittals

The Contractor shall provide an environmental, sediment and pollution control (SPC) plan in
accordance with Sections 1.15.1 and 1.15.9, and per the additional requirements as follows:

a. Generally the SPC plan should be submitted at the same time as the Contractors staging and

detour plans, since the SPC plan must be coordinated with the work staging location and
schedule.

b. Contractor shall provide a schedule for SPC plan implementation and incorporate it into the

Contractor’s construction schedule.

Contractor shall obtain the Engineer’s approval of the SPC Plan and schedule before any work
begins.

SPC plan shall cover all areas the Contractor’s work may affect inside and outside the limits
of the project (including all borrow and disposal sites, and haul roads, and staging areas which
shall show:

1. Location of disturbed soil areas, areas to be protected from construction, existing storm

drains and those to be constructed as part of that work stage, dewatering facilities and
discharge locations

2. Show locations of specific sediment and pollution control measures

3. Describe in detail the design, installation, maintenance, repair, and removal of proposed

specific sediment and pollution control measures

4. Describe in detail the design, installation, maintenance, repair and removal of proposed

general site sediment and pollution control measures (i.e. for general dust and spill control
measures)

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5. Show the locations and types of specific temporary sedimentation and pollution control

practices that will be used in the work for each construction phase

6. Show the locations and types of wind and water pollution control practices that will be

installed permanently under the Contract.

7. If dewatering, submit dewatering and discharge work plan. Work plan shall include:

Description of dewatering and discharge activities detailing locations, quantity of
water, equipment, type of dewatering and discharge point

ii.

Estimated schedule for dewatering and discharge start and end dates of intermittent
and continuous activities

iii.

Sediment avoidance measures at discharge, which may include discharge
alternatives, such as infiltration, filtration or sediment traps

iv.

Visual monitoring procedures with inspection log

Obtain approval to discharge into a existing storm drain system

8. Items as otherwise required herein.

Contractor shall amend and resubmit the SCP plan to match any revisions to his program, staging,
detouring and schedule that effects the proper implementation of the approved SCP plan.

Contractor shall submit catalogue c

uts, manufacturer’s installation and maintenance

recommendations and specifications and material test results for all materials and items used for
temporary sediment and pollution control measures. Contractor shall provide samples and specific
testing of the materials if required by the Engineer.

1.17.5.2

Geotextile

Temporary geotextile covering shall meet the requirements of Article 2.7.3.2 of Chapter 2,
Earthworks.

1.17.5.3

Plastic

Temporary plastic covering shall meet the requirements of the NIST Voluntary Product Standard,
PS 17-69, for polyethylene sheeting having a minimum thickness of 6 mils

1.17.5.4

Erosion Control Blankets/Mats

a. Temporary erosion control blankets shall consist of temporary, degradable, rolled erosion-

control products composed of natural fibres mechanically or structurally bound together with
natural or polymer netting to form a continuous matrix. Erosion control blankets are classified
as to two types, as follows:

1. Short

– term duration

2. Extended-term duration

b. Short - term duration blankets shall have a minimum one-year degradation period for both the

netting and fibres, and be composed of 100 % virgin aspen excelsior wood fibres or 100 %
agricultural straw.

c. Extended-term blankets shall have a minimum two-year degradation period for the netting and

fibres, and be composed of heavy-duty excelsior blankets, or a mix of 70 % straw and 30 %
coconut fibres, or 100 % coconut fibres. Heavy-duty excelsior blankets used in the extended-
term category shall have a minimum weight of 0.38 kg/m

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d. All other types of blankets, whether for short - term or extended-term use shall have a minimum

weight of 0.27 kg/m

Fibres for short-term erosion control blankets shall be encased top and bottom with
photodegradable polypropylene or 100-percent biodegradable natural organic fibre netting, as
specified on the plans.

e. Should the plans not specify type of netting for short-term blankets, fibres shall be encased

with photodegradable polypropylene. Fibres for extended-term blankets shall be encased
within either a heavy duty UV stabilized top netting (black) and bottom nettings (green), or two
UV stabilized nettings (black). All nettings for extended-term blankets shall be
photodegradable polypropylene.

Erosion control blankets shall also conform to the following requirements:

Table 1-7: Erosion control blanket requirements

Property

Test method

ASTM

Short-term

duration

Extended-term

duration

Minimum mass per unit area

D6475

271 g/m

271* g/m

Minimum thickness**

D5199

6.35 mm

Minimum tensile strength (kg/m)***

D5035

111

148

*Heavy duty blankets shall have a minimum mass per unit area of 372 g/m

**Numerical value represents total thickness of blanket, including netting.

***Numerical value represents minimum average test result in either direction.

Fibre colour shall be natural unless otherwise specified in the Particular Specifications.

a. Fibres shall be free of weed seed, and shall be locked in place to form a mat of consistent

thickness. Fibres shall remain evenly distributed over the entire area of the blanket after being
placed on the slope.

b. Erosion control blankets shall be furnished in 1.2 to 2.4 m wide rolls, and shall be wrapped

with suitable material to protect against moisture and extensive ultraviolet exposure prior to
placement.

Each roll shall be labelled to provide sufficient identification for quality control purposes.

a. All biodegradable ECPs must be anchored using wire staples.

b. Contractor shall provide certificates of compliance from the manufacturers, for all erosion

control blankets.

1.17.5.5

Anchors

Staples shall be made of 3.05 mm steel wire and shall be U-shaped with 200 mm legs and 50 mm
crowns.

Metal stake pins shall be 5-mm-diameter steel with a 40 mm steel washer at the head of the pin.

All anchors shall be a minimum of 150 mm long and have sufficient penetration to resist pullout.
Longer anchors may be required for loose soils or by the manufacturer’s installation guidelines.

1.17.5.6

Pipe Slope Drains

Pipe materials shall conform to Articles 12.1.3.6 and 12.1.3.7c of Chapter 12, Stormwater Drainage
for corrugated metal and PVC pipe.

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Loose riprap rock and bedding shall conform to Section 7.4.3 of Chapter 7, Incidental construction,
of these standard specifications.

1.17.5.7

Fabric Fence

a. Fabric

Fabric or silt fence fabric shall be supplied in accordance with the material requirements of Section
2.7.2 of Chapter 2, Earthworks.

b. Posts

Posts for silt fence can be wood or steel conforming to the requirements of Article 7.7.2.4. Posts
shall be a minimum of 1 metre plus the burial depth in length and may be made of either wood or
steel. Soft wood posts shall be at least 75 mm in diameter, or nominal 50 mm by 100 mm and straight
enough to provide a fence without noticeable misalignment. If oak posts are used, the size may be
reduced to 38 mm by 38 mm with a minus tolerance of 3 mm, provided that the cross sectional area
is a minimum of 1450 mm

. Steel posts shall have a minimum weight of 1.95 kg/m, and have

projections for fastening the wire and fabric to the fence.

c. Wire Supported Fence

Wire support fence shall be a minimum of 830 mm high composed of 2.8 mm diameter steel wire
mesh fencing material.

Wire staples shall be 1.2 mm diameter and shall have a crown at least 19 mm wide and legs at least
13 mm long. Staples shall be evenly spaced with at least five per post.

Nails shall be 2 mm in diameter, 25 mm long with 19 mm button heads. Nails shall be evenly spaced
with at least four per post.

d. Fabric Packaging, Handling, and Storage

Identification, packaging, handling, and storage of the geotextile fabric shall be in accordance with
ASTM D4873. Fabric rolls shall be furnished with suitable wrapping for protection against moisture
and extended ultraviolet exposure prior to placement.

Each roll shall be labelled or tagged to provide product identification sufficient to determine the
product type, manufacturer, quantity, lot number, roll number, date of manufacture, shipping date,
and the project number and name to which it is assigned. Rolls will be stored on the site or at another
identified storage location in a manner which protects them from the elements. If stored outdoors,
they shall be elevated and protected with a waterproof, light colour, opaque cover.

1.17.5.8

Rock and Aggregate

Geotextile fabric for riprap shall meet the requirements of Article 7.4.3.2 of Chapter 7, Incidental
construction.

Gradation of the loose rock for erosion control shall meet the requirements of Sub-article 7.4.3.2.a
of Chapter 7, Incidental construction, for hand placed riprap and Sub-article 7.4.3.2.c, for pit run or
quarry spalls rock.

Riprap bedding aggregate shall meet the requirements of Article 7.4.3.2 of Chapter 7, Incidental
construction.

Crushed rock or gravel for temporary or permanent ground surface coverings shall consist of hard,
durable rock, with at least two fractured faces of size ranging from 6 to 50 mm nominal diameter.

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1.17.5.9

Gravel Bags

Gravel bags consist of a heavyweight fabric (synthetic or canvas materials), sewn sack filled with
gravel and the opening closed with a wrap of twine or wire. Weight of the filled sack shall not exceed
50 kg, so that it can be handled by two people, one on each end.

Bags, when filled shall measure approximately 600 mm long by 400 mm wide by 100 mm thick. Bag
dimensions are nominal and may vary locally but shall not be significantly different. Alternate bag
sizes shall be submitted to Engineer for approval.

Gravel shall be between 10 mm and 20 mm in diameter.

Gravel shall be clean and free from clay balls, organic matter and deleterious material.

Bags shall be manufactured from polypropylene, polyethylene, or polyamide woven fabric with the
following characteristics:

Table 1-8: Gravel bag requirements

Unit weight, minimum

135 g/m

Mullen burst strength, as per ASTM D3786, exceeding

2 mPa

Ultraviolet stability, as per ASTM D4355, exceeding, %

70 %

1.17.5.10 Fibre Rolls

Erosion control blankets used to construct fibreroll shall meet the requirements of Article 1.17.5.4.

Wooden stakes shall be made from wood of type and density to withstand the driving process, as
approved by the Engineer. Stakes shall be 19 mm by 19 mm and maximum 1.2 m long.

Erosion control blankets used to construct fibre rolls shall be between 2 m and 2.4 m wide by
approximately 15 m long. Wood excelsior blankets shall have 80 % of its fibres equal to or greater
than 150 mm. Blankets used to construct the fibre rolls shall have photodegradable plastic or
biodegradable natural netting, with a maximum 25 mm by 25 mm grid, on at least one side.

Contractor shall produce fibre rolls by rolling the blankets along their width to produce 15 m lengths,
and securing the rolls with jute twine spaced at 2 m intervals along the roll for the full length and at
150 mm from each end. If shown on the plans or directed by the Engineer, the Contractor may cut
the blankets before rolling to produce completed fibre roll lengths of between 4 and 15 m as
applicable for the location. Nominal diameter of the finished rolls shall be 220, 300, or 450 mm, as
shown on the plans. Overlapping of more than one blanket may be required to achieve larger
diameters. When overlapping is required, the end of one blanket shall overlap 150 mm onto the end
of the next blanket prior to rolling.

1.17.5.11 Temporary Fence

High visibility fence shall be used by Contractor as temporary fencing to mark protected area
boundaries as shown in plans such as for demarcating areas of vegetation protection.

High visibility fence shall be at least 1.2 m tall UV stabilized, construction orange colour, high-density
polyethylene or polypropylene mesh with mesh openings approximately 50 mm by 50 mm. Colour
shall be construction orange. Fence posts shall be wood or steel and shall meet the requirements of
Sub-article b of Article 1.17.5.7

High visibility fence fabric shall have a minimum tensile strength of 145 kg per ASTM D5735.

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1.17.6

Construction Requirements

1.17.6.1

Preservation of Existing Vegetation and Topsoil

Contractor shall comply with the following requirements:

1. Contractor shall preserve existing vegetation, topsoil and other existing soil covering materials

at areas on a site where no construction activity is planned or will occur at a later date.

2. Temporary fencing shall be provided around areas designated for being maintained from

inadvertent disturbance by the Contractor’s operations.

3. Clearing and grubbing operations should be staged, with the area limited to the area that will

be immediately under construction. Final surface covering (paving, decorative pavers,
landscaping, gravel, etc.) should be provided prior to moving to the next stage of the work.

4. Minimise the disturbed areas by locating temporary roadways to avoid stands of trees and

shrubs and to follow existing contours to reduce cutting and filling.

5. Consider the impact of grade changes to existing vegetation and the root zone.

6. Keep equipment away from trees and shrubs to be retained, to prevent trunk and root damage.

7. Maintain existing irrigation systems.

8. Employees and subcontractors shall be instructed to honour protective fences.

9. No heavy equipment, vehicular traffic, or storage piles of any construction materials shall be

permitted within the drip line of any tree to be retained.

10. Removed trees shall not be felled, pushed, or pulled into any retained trees.

11. Prior to excavation and trenching, remove topsoil to a depth of 200 to 300 mm, and stockpile

it for later re-application per requirements of Article 2.2.2.5 of Chapter 2, Earthworks.

12. Trenching shall be as far away from tree trunks as possible, usually outside of the tree drip

line or canopy. Curve trenches around trees to avoid large roots or root concentrations. If roots
are encountered, consider tunnelling under them.

13. When trenching and/or tunnelling near or under trees to be retained, tunnels shall be at least

450 mm below the ground surface, and not below the tree centre, to minimise impacts to the
roots.

14. Tree roots shall not be left exposed to air. They shall be covered with soil as soon as possible,

protected, and kept moistened with wet burlap or peat moss until the tunnel and/or trench can
be completed.

15. Smoothly cut off the ends of damaged or cut roots.

16. Trenches and tunnels shall be filled as soon as possible. Careful filling and tamping will

eliminate air spaces in the soil that can damage roots.

17. Remove any trees intended for retention if they are damaged seriously enough to affect their

survival. Such trees shall be replaced as directed by the Engineer at the Contractors expense.

18. After all other work is complete, temporary fences shall be removed last, because protected

trees may be destroyed by equipment operator carelessness during the final cleanup and
landscaping.

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1.17.6.2

Soil Surface Coverings

This measure involves the placement of geotextile, plastic covers, erosion control blankets or gravel
to stabilise disturbed areas and protect soils from erosion by wind or water.

These measures are used as a temporary surface covering for the following situations:

1. Steep slopes, generally steeper than 1:3 velocity to height (V:H) in areas to be landscaped to

hold the soil until the plant root zone is established.

2. Slopes of cuts and compacted embankments to be protected during the rainy season until the

permanent slope protection measures can be installed.

3. Stockpiles of topsoil or other fine-grained construction materials to avoid erosion by rain or

wind.

4. Temporary channels with flow velocities exceeding 1 m per second.

5. Slopes adjacent to environmentally sensitive areas.

a. Geotextile, Plastic and Blanket Installation

Prior to laying of the covering, Contractor shall:

1. Grade and shape the area of installation.

2. Remove all rocks, clods, vegetation, or other obstructions so that the installed blankets or mats

will have complete, direct contact with the soil.

3. When using a fabric or mat that is designed to be used in conjunction with seed or vegetation,

follow the manufacturer’s guidelines for proper installation. Prepare the planting bed by either
loosening the existing 50 to 75 mm of topsoil or placing new 150 to 200 mm thick topsoil per
requirements of Article 13.1.3.10 of Chapter 13, Landscaping and irrigation.

Installation should be in accordance with the manufacturer's recommendations. In general, these
shall be as follows:

1. Begin at the top of the slope and anchor the blanket in a 150 mm deep by 150 mmwide trench.

Backfill the trench and tamp the earth firmly.

2. Unroll the blanket down slope in the direction of water flow.

3. Overlap the edges of adjacent parallel rolls 50 mm to 75 mm and staple every 1.0 m.

4. When blankets must be spliced, place blankets end over end (shingle style) with 150 mm

overlap. Staple through overlapped area, approximately 300 mm apart.

5. Lay blankets loosely and maintain direct contact with the soil. Do not stretch.

6. U-shaped wire staples, metal stake pins, or triangular wooden stakes can be used to anchor

mats and blankets to the ground surface

7. Staple blankets sufficiently to anchor the blanket and maintain contact with the soil. Staples

shall be placed down the centre and staggered with the staples placed along the edges. Steep
slopes, 1:1 to 2:1 require a minimum of two staples per square meter. Moderate slopes, 2:1 to
3:1, require a minimum of one-and-a-half staples per square meter, placing one staple per
meter on centres. Gentle slopes require a minimum of one staple per square meter.

8. Seed (if specified); fill turf reinforcement matting with soil; and insert plantings.

9. Do not drive tracked or heavy equipment over matting.

10. Avoid any traffic over matting if loose or wet soil conditions exist.

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11. Use shovels, rakes, or brooms for fine grading and touch up.

12. Smooth out soil filling, just exposing the top netting of the mat.

When no longer required, Contractor shall remove and dispose of all non-degradable temporary
coverings in a manner approved by the Engineer.

b. Aggregate Installation

Crushed aggregate shall be spread over the sand to increase the surface roughness and prevent
sand movement and erosion. It may be applied as a temporary wind and water erosion control
measure or as shown on the Drawings as the permanent soil covering method. Unless otherwise
shown on the Drawings or approved by the Engineer, crushed aggregate shall be installed as follows:

1. Prepare ground surfaces as described in Sub-article a above. Take care to avoid compaction

of the final ground surface to maintain as much surface soil permeability as possible for
precipitation infiltration.

2. Minimum gravel thickness should be 150 mm . Where shown on the drawings for permanent

gravel coverings, provide and install a geotextile filter fabric under the gravel surfacing.

3. Do not use crushed rock or gravel in areas of pedestrian or vehicle traffic, which will disperse

the rock. Provide temporary paved walkways and paved driveways through the gravel area.

4. Rock or gravel should be clean, free of weeds, debris, and trash.

5. Slopes on which gravel covering is placed shall not be steeper than 3:1 slopes, unless

otherwise approved by the Engineer. Provide an blanket type covering for steeper slopes.

1.17.6.3

Concentrated flow diversions

This measure consists of temporary ditches, swales, and dikes that intercept, divert, and convey
surface runoff to provide protection from flooding and sedimentation of the Contractors works and
provide for the public safety in the case of rainfall. These temporary measures shall be constructed
and maintained for the winter season of 15 October through 15 April of configurations as appropriate
for the Contractor’s staging and detour plans during that time period. The Contractor shall design
and construct concentrated flow diversions in accordance with Chapter 14 of the Abu Dhabi Road
Drainage Manual, AD-D-07, and as follows:

a. Care shall be applied to correctly size and locate earth dikes, swales, and ditches. Excessively

steep, unlined dikes and swales are subject to erosion and gully formation

b. Refer to Chapter 4 of the Abu Dhabi Road Drainage Manual, AD-D-07, for the hydraulic design

of ditches and swales

c. Conveyances shall be stabilised

d. Use a lined ditch for high-flow velocities

e. Select flow velocity based on a careful evaluation of the risks due to the erosion of the measure,

soil types, over-topping, flow backups, washout, and drainage flow patterns for each project
site

f. Compact any temporary dike fills to prevent unequal settlement

g. When possible, install and use permanent stormwater facilities early in the construction

process for the collection and conveyance of construction site runoff and dewatering flows

h. Provide stabilised outlets.

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1.17.6.4

Pipe slope drain

Slope drains are pipes used to intercept and direct surface runoff or groundwater into a stabilised
watercourse, trapping device, or stabilised area. Slope drains are used with ditches, swales, and
dikes to intercept and direct surface flow away from slope areas to protect cut or fill slopes. Slope
drains may also be used at construction sites where slopes may be eroded by surface runoff. Slope
drains shall be hydraulically design in accordance with the requirements of Chapter 4 of the Abu
Dhabi Road Drainage Manual, AD-D-07, and as follows:

a. When using slope drains, limit the drainage area to 4 ha per pipe.

b. Direct surface runoff to the entrance of a slope drain with interceptor dikes, swales, or ditches.

c. Slope drains may be placed on or buried underneath the slope surface.

d. When installing slope drains:

1. Install slope drains perpendicular to slope contours.

2. Compact the soil around and under the entrance, outlet, and along the length of pipe.

3. Securely anchor and stabilise pipe and appurtenances into soil.

4. Check to ensure that pipe connections are watertight.

5. Protect the area around the inlet with geotextile fabric or erosion control blanket. Protect the

outlet with riprap. Ensure that high velocities/energy are dissipated at the outlet.

6. Protect the inlet and outlet of slope drains with a standard flared-end section at the entrance

for pipe slope drains 300 mm and larger.

1.17.6.5

Sediment trapping

Sediment trapping measures function by slowing water velocities thereby allowing soil particles to
settle out or by attenuating the peak flow by detaining flow and releasing water at a slower rate.

a. Fabric fence

Fabric fence or silt fence is a temporary linear sediment barrier of permeable fabric designed to
intercept sediment laden runoff. Silt fences may consist of a wire supported geotextile silt fence or a
self supporting geotextile silt fence.

Contractor shall place fabric fences at the following general locations, or as otherwise shown on the
Drawings or required by the Engineer:

1. Between the perimeter of a project and an environmentally sensitive area

2. Below the toe of exposed and erodible slopes

3. Along slope contours for longer slope lengths

4. Downslope of exposed soil areas

5. Around temporary stockpiles

Installation shall meet the following requirements:

1. At the time of installation, the fabric will be rejected if it has defects, rips, holes, flaws,

deterioration, or damage incurred during manufacture, transportation, storage or installation

2. Fence height shall not exceed 900 mm above ground surface.

3. Geotextile fabric shall be attached on the upstream side of the posts by wire, cord, button head

nails, pockets, staples, or other acceptable means

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4. Geotextile fabric shall be installed in such a manner that 200 to 250 mm of fabric is left at the

bottom to be buried. The fabric shall be installed in the trench such that 150 mm of fabric is
against the side of the trench and 50 to 100 mm of fabric is across the bottom of the trench in
the upstream direction. The trench shall then be backfilled and compacted so that no flow can
pass under the barrier

5. A minimum overlap of 450 mm shall be provided at all splice joints with posts at the ends of

each fabric roll.

6. Contractor shall be responsible to maintain the integrity of silt fences as long as necessary to

contain sediment runoff or as directed by the Engineer

7. Sediment deposits shall be removed when the deposit reaches approximately one-half of the

height of the silt fence.

8. Silt fence shall remain in place during the duration of the Contractors work and that winter

season or until the Engineer directs that it be removed. Upon removal, the Contractor shall
remove and dispose of any excess silt accumulations, grade the area to leave a generally
smooth appearance.

b. Sediment traps

A sediment trap is a temporary basin formed by excavating and/or constructing an embankment so
that sediment-laden runoff is temporarily detained under quiescent conditions, allowing sediment to
settle out before the runoff is discharged. Contractor shall design and install sediment traps as
needed for control of downstream sedimentation, as may be shown on the drawings or where
directed by the Engineer. Design shall meet the applicable requirements of Chapter 14 of the Abu
Dhabi Road Drainage Manual, AD-D-07, and as follows:

1. Limit the contributing area to the sediment trap basin to only the runoff from the disturbed soil

areas. Use temporary concentrated flow conveyance controls to divert runoff from undisturbed
areas away from the sediment trap basin.

2. Provide the minimum surface area required for the sediment basin as per the formulas and

procedure in Chapters 6 and 14 of the Abu Dhabi Road Drainage Manual, AD-D-07.

3. Basin length shall be more than twice the dimension as the width

4. For safety purposes, the maximum depth shall be no greater than 1.5 m unless otherwise

protected from public access

5. Outlet structures shall be placed on a firm, smooth foundation, with the base securely anchored

with concrete, or by another means, to prevent floatation

6. Discharge from the basin shall be accomplished through a corrugated metal or a high-density

polyethylene riser pipe. A riser is sized so that the top opening acts as an overflow weir of total
circumference to accommodate the design storm frequency flows. A riser should also be
perforated and wrapped with a geotextile filter fabric around the base to allow for low-flow
dewatering

7. Perforated sections should be designed to drain the basin within 72 hours after a storm

8. Attach the riser pipe with a watertight connection, to a horizontal pipe which outlets to a

stabilised outfall or to a storm drain system

9. Cleanout level shall be clearly marked on the riser pipe

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10. Remove accumulated sediments when the depth reaches one-third the depth of the sediment

storage in the basin.

c. Check dams

Check dams shall be used where applicable to reduce scour and channel erosion by reducing flow
velocity and encouraging sediment settlement. Check dams are small devices constructed of rock,
gravel bags, sandbags, fibre rolls, or other proprietary products, placed across small open channels,
in steep channels where stormwater runoff exceed 1.5 m per second and in temporary ditches.
Contractor shall place check dams per the following guidelines:

1. Check dams shall be placed at a distance and height to allow small pools to form behind them.

Install the first check dam approximately 5 m from the outfall device and at regular intervals
based on slope gradient and soil type.

2. For multiple check dam installation, spacing shall be such that backwater from the downstream

check dam shall reach the toe of the upstream dam.

3. High flows (typically a two-year storm or larger) shall safely flow over the check dam without

an increase in upstream flooding or damage to the check dam, channel, or bank.

4. Rock should be placed individually by hand or by mechanical methods (no dumping).

5. Fibre rolls may be used as check dams (more temporary than rock)

6. Gravel bags may be used as check dams

7. Install check dams along a level contour, placed approximately perpendicular to the centreline

of the ditch or drainage line

8. Tightly abut and stack rock, gravel bags or fibre rolls using a pyramid approach

9. Check dams shall not be any higher than 1 m. Midpoint of the rock check dam shall be a

minimum of 150 mm lower than the sides in order to direct across the centre and away from
the channel sides. Base of the check dam shall be entrenched approximately 150 mm

10. Where the check dam is constructed of rock, the rock shall be placed so that it completely

covers the width of the channel. Stone placement shall be performed either by hand or
mechanically as long as the center of check dam is lower than the sides and extends across
entire channel. Side slopes of the check dam shall be no steeper than 2:1.

11. Where gravel bags are used, upper rows of gravel bags shall overlap joints in lower rows

12. If a temporary check dam is to be placed in the same area as an erosion control blanket,

install the blanket before placing the dam.

13. Check dams shall remain in service until the permanent stabilization work commences or

until they are no longer needed, as approved by the Engineer. When a rock check dam is
discontinued, the materials shall be removed and disposed of as approved by the Engineer

d. Fibre rolls

Fibre rolls are placed on the toe and face of slopes to intercept runoff, reduce its flow velocity, release
the runoff as sheet flow, and provide a removal of sediment from the runoff. Fibre rolls may also be
used for inlet protection and as check dams. Fibre rolls shall be installed at the following general
locations

1. Located along the toe, top, face, and at-grade breaks of exposed and erodible slopes to

shorten slope length and spread runoff as sheet flow

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2. Place below the toe of exposed and erodible slopes

3. Place around storm drain inlets to trap sediment before entering the inlet

4. Use downslope of exposed soil areas

5. Place around temporary stockpiles and along the perimeter of a project

6. Installation shall meet the following guidelines:

Slope inclination of 1:4 or flatter: fibre rolls shall be placed on slopes 6 m apart

ii.

Slope inclination of 1:4 to 1:2: fibre rolls shall be placed on slopes 4.5 m apart

iii.

Slope inclination 1:2 or greater: fibre rolls shall be placed on slopes 3 m apart

iv.

Stake fibre rolls into a 50 to 100 mm deep trench

Drive stakes at the end of each fibre roll

vi.

Use wood stakes 19 mm by 19 mm and a minimum length of 600 mm

vii.

If more than one fibre roll is placed in a row, the rolls shall be overlapped, not abutted

7. Removal:

viii.

Fibre rolls are typically left in place and will degrade and compost in areas used for
landscaping or other agricultural plantings

ix.

If fibre rolls are removed, collect and dispose of sediment accumulation, and fill and
compact holes, depressions, or any disturbance to blend with adjacent ground.

e. Gravel bag berms

A gravel bag berm consists of a single row of gravel bags that are installed end-to-end to form a
barrier across a slope to intercept runoff, reduce its flow velocity, release the runoff as sheet flow,
and provide some sediment removal. Contractor shall use gravel berms at the following locations:

1. Where flows are moderately concentrated, such as ditches, swales, and storm drain inlets

2. Where control or redirect runoff on detour pavement is needed to avoid concentrated flow

across adjacent traffic lanes

3. When site conditions or construction sequencing requires adjustments or a relocation of the

barrier to meet changing field conditions and needs during construction

4. At grade breaks of exposed and erodible slopes to shorten slope length

5. As check dams using stacked bags

When used as a linear control for sediment remova, berms shall be installed as followsl:

1. Install along a level contour

2. Install with ends tightly abutting each other to eliminate gaps

3. Turn the ends of the gravel bag row upslope to prevent flow around the ends

4. Install with a setback of at least 1 m from the toe of a slope

5. Bags in the vicinity of curbs and inlets shall be installed to 50 mm below the height of the

adjacent curb to allow drainage into the inlet. When sediment depth behind the bags reaches
75 mm the sediment shall be removed

When used for concentrated flows, such as for a check dam, berms shall be installed as follows:

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1. Stack gravel bags to the required height using a pyramid approach

2. The upper rows of gravel bags shall overlap joints in the lower rows

Sand or gravel bag features shall remain in service until disturbed areas have been stabilized, as
directed by the Engineer. During removal, all sediment shall be disposed of, and the area restored
to a finished condition as shown on the plans, or as directed by the Engineer.

f. Storm drain inlet protection

Storm drain inlet protection measures are used at storm drain inlets that are subject to runoff from
construction activities. These devices are used to detain and/or to filter sediment-laden runoff in
order to allow sediment to settle and/or to filter sediment prior to discharge into storm drainage
systems. Installed protection shall not be used where ponding may encroach into highway traffic.
Storm drain inlet protection shall be installed and maintained during the winter season of 15 October
through 15 April for the following conditions:

1. Sediment-laden surface runoff may enter an inlet.

2. Disturbed drainage areas have not yet been permanently stabilised.

Inlet protection shall consist of one of the following types:

1. Inlet protection Type 1

– fabric fence: Filter fabric fence protection is similar to constructing a

fabric fence. Do not place filter fabric underneath the inlet grate because the collected sediment
may fall into the drain inlet when the fabric is removed or replaced.

2. Inlet protection Type 2 - excavated drop inlet sediment trap: Applicable for existing inlets in

open areas, where a sediment trap can be excavated adjacent to the inlet, using the inlet as
the open top overflow structure. Refer to the requirements for sediment traps, in the subsection
above.

3. Inlet protection Type 3

– gravel bag: Install gravel bags in accordance with the requirements

for gravel bag berm described in the subsection above, around the inlet opening. Gravel bags
are generally used due to their high permeability.

4. Inlet protection Type 4

– fibre rolls: Fibre roll is placed around the inlet and keyed and anchored

to the surface. Fibre rolls are intended for use as inlet protection where the area around the
inlet is unpaved and the fibre roll can be secured to the surface by staking.

1.18

Basic Product Requirements, Product Options

This Section specifies general requirements for materials and equipment and includes, but is not
limited to, the following:

1. Products

2. Transportation, delivery, receiving, and handling

3. Storage and protection

4. Products list

5. Substitutions

6. Product acceptance

1.18.1

Products

Term “product” shall mean any material, including proprietary goods, equipment or services that are
incorporated into the final works.

Products do not include materials, machinery, or equipment that is used for the preparation,
fabrication, conveyance, or erection of works.

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If possible, products of a similar nature shall be standardized, interchangeable and supplied by the
same manufacturer.

All products shall comply with the specifications and referenced standards, unless otherwise
approved by the Engineer.

1.18.2

Transportation and Handling

All products shall be transported, stored and handled at all times in accordance with the requirements
of Sections 1.18.5 and 1.18.6.

1.18.3

Products List

Products shall be delivered according to the construction schedule in order to avoid construction
delays or undue storage requirements. Submit four copies of a list of all products which are proposed
for installation, not later than 30 calendar days after the start of the Contract. The list shall include
the following items:

1. Include the name of manufacturer and supplier, the trade name, and the model number of

each product.

2. List shall identify products that are specifically listed by manufacturer or product model, those

which are not referenced and those that are proposed as a substitute to a listed product
model or manufacturer.

3. The Contractor shall ensure that the listed products comply with the requirements of the

Contract documents.

4. Product list shall be arranged according to specification section number.

5. Include the specification title and the paragraph number.

Engineer will notify the Contractor in writing of any product deemed to be unacceptable. Notification
shall be made no later than 30 days after submission of the products list. Engineer

’s objection or

failure to object to a listed item shall not constitute a waiver of the requirements of the Contract
documents.

1.18.4

Product Substitutions

Substitution requests shall be in conformance with the requirements of Section 1.19 and the
requirements in this section.

The Contractor must submit requests for substitution within 60 days of starting the Contract. After
that date, substitutions will only be considered when a product becomes unavailable, due to no fault
of the Contractor.

Document each request with complete date substantiating that the proposed substitution complies
with the Contract documents. Substitutions will not be considered in either of the following situations:

1. Substitution is indicated or implied on shop drawings or product data submittals without

separate written request complying with the above requirements.

2. When acceptance will require substantial revisions to the Contract documents.

1.18.5

Product Acceptance

All products shall be tested as required by the specification, as follows:

1. Product testing shall be by an approved site laboratory, independent laboratory or a recognized

testing organization

2. The Contractor shall be responsible for all costs associated with product testing including

labour, transportation and the cost of the test itself, except as specified elsewhere in the
specifications.

Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020) - page 16