CP 1b vol 5 EN

ii Where the excavation reveals a combination of suitable and unsuitable materials the Contractor shall, unless otherwise agreed by the Employer’s Representative, carry out the excavatio

Tender Documents

For

Ho Chi Minh City Urban Railway Construction Project

Ben Thanh - Suoi Tien Section (Line 1)

CONTRACT PACKAGE-1B: CIVIL (UNDERGROUND SECTION

FROM KM 0+615 TO KM 2+360)

VOLUME 5

Outline Construction Specifications

Tender Documents

For

Ho Chi Minh City Urban Railway Construction Project

Ben Thanh - Suoi Tien Section (Line 1)

CONTRACT PACKAGE-1B: CIVIL (UNDERGROUND SECTION

5.6 Testing of Concrete for Structures 5-7

8.5 Carpenter and Joiner 8-14

In accordance with the Vietnamese regulations, the Contractor shall be also responsible for getting the approval by the Vietnamese competent organizations for the international standards which are not included in the list below and in Appendix 28 to the Employer’s Requirements in Volume 3 but are applied by the Contractor in detailing his specification, additionally

The Contractor is required to review in the first instance the Vietnamese Industrial Standards, Japanese Industrial Standards (JIS), Japan Society of Civil Engineers (JSCE) Standard Specifications, Design Standards for Railway Structures and Commentary (RTRI), the Japanese Geotechnical Society (JGS) Standards and AASHTO & ASTM Standards The specification will be based on the above three standards to the extent that they are applicable

Relevant standards of JIS, JSCE, AASHTO and ASTM are scheduled below:

Section 2: Earthworks

AASHTO T99 The Moisture-Density Relations of Soils using a 5.5lb (2.5kg)

Rammer and a 12in (305mm) Drop AASHTO T193 The California Bearing Ratio

AASHTO T 180 The Moisture-Density Relations of Soils using a 10lb (4.54kg)

Rammer and a 18in (457mm) Drop AASHTO T27 Sieve Analysis of Fine and Coarse Agregate

AASHTO T89 Determining the Liquid Limit of Soils

AASHTO T90 Determining the Plastic Limit and Plasticity Index of Soils

AASHTO T191 Density of Soil In-Place by the Sand-Cone Method

Section 3: Road Works

AASHTO T96 Resistance to Degradation of Small-Size Coarse Aggregate by

Abrasion and Impact in the Los Angeles Machine AASHTO T89 Determining the Liquid Limit of Soils

AASHTO T90 Determining the Plastic Limit and Plasticity Index of Soils AASHTO T180 The Moisture-Density Relations of Soils using a 10lb (4.54kg)

Rammer and a 18in (457mm) Drop AASHTO M81 Cut-Back Asphalt (Rapid-Curing Type)

AASHTO M82 Cut-Back Asphalt (Medium-Curing Type)

AASHTO T245 Resistance to Plastic Flow of Bituminous Mixtures using Marshall

Apparatus AASHTO T209 Theoretical Maximum Specific Gravity and Density of Bituminous

Paving Mixtures AASHTO M29 Fine Aggregate for Bituminous Paving Mixtures

AASHTO M20 Penetration-Graded Asphalt Cement

AASHTO T230 Determining Degree of Pavement Compaction of Bituminous

Aggregate Mixtures AASHTO T167 Compressive Strength of Bituminous Mixtures

Section 4: Piling and Diaphragm Walling

ASTM C150 Standard Specification for Portland Cement

JIS A5372 Precast reinforced concrete product

JIS A5373 Precast Prstressed concrete product

JIS A5530 Steel pipe sheet piles

ASTM D4945 Standard Test Method for High-Strain Dynamic Testing of Piles JGS 1811 Standard Test Method for Vertical Load Testing of Piles

JGS 1816 Standard Test Method for Impact Load Testing of Piles

JGS 1831 Standard Test Method for Horizontal Load Testing of Piles The American Petroleum Institute Standard 13A

JSCE Standard Specifications for Tunneling -2006 (Cut and Cover Tunnel)

Section 5: Concrete

ASTM C150 Standard Specification for Portland Cement

ASTM C260 Air-Entraining Admixtures for Concrete (equivalent with AASHTO

M154) ASTM C309 Liquid Membrane-Forming Compounds for Curing Concrete

(equivalent with AASHTO M148) ASTM C494 Chemical Admixtures for Concrete (equivalent with AASHTO

M194) ASTM C1611 Standard Test Method for Slump Flow of Self-Consolidating

Concrete AASHTO M6 Fine Aggregate for Portland Cement Concrete

AASHTO M80 Coarse Aggregate for Portland Cement Concrete

AASHTO M148 Liquid Membrane-Forming Compounds for Curing Concrete AASHTO M154 Air-Entraining Admixtures for Concrete

AASHTO M157 Ready-Mixed Concrete

AASHTO M194 Chemical Admixtures for Concrete

AASHTO T2 Sampling of Aggregates

AASHTO T11 Materials Finer Than 75-µm (No.200) Sieve in Mineral Aggregates

by Washing AASHTO T21 Organic Impurities in Fine Aggregates for Concrete

AASHTO T22 Compressive strength of Cylindrical Concrete Specimens

AASHTO T23 Making and Curing Concrete Test Specimens in the Field

AASHTO T24 Obtaining and Testing Drilled Cores and Sawed Beams of

Concrete AASHTO T27 Sieve Analysis of Fine and Coarse Aggregates

AASHTO T71 Effect of Organic Impurities in Fine Aggregate on Strength of

Mortar AASHTO T84 Specific Gravity and Absorption of Fine Aggregates

AASHTO T85 Specific Gravity and Absorption of Coarse Aggregates

AASHTO T96 Resistance to Degradation of Small-Size Coarse Aggregate by

Abrasion and Impact in the Los Angeles Machine AASHTO T104 Soundness of Aggregate by Use of Sodium Sulfate or Magnesium

Sulfate AASHTO T112 Clay Lumps and Friable Particles in Aggregate

AASHTO T113 Lightweight Pieces in Aggregate

AASHTO T119 Slump of Hydraulic Cement Concrete

ACI 304 R Guide for Measuring, Mixing, Transporting, and Placing Concrete

JSCE Standard Specification for Concrete Structures -2002, Construction, Clause 4

Section 6: Prestressed Members

JIS G3536 Uncoated stress-relieved steel wires and strands for prestressed

concrete JIS G3109 Steel bars for prestressed concrete

ASTM A416 Standard Specification for Steel Strand, Uncoated Seven-Wire for

Prestressed Concrete ASTM A421 Standard Specification for Uncoated Stress-Relieved Steel Wire

for Prestressed Concrete ASTM A722 Standard Specification for High-Strength Steel Bar for Prestressed

Concrete AASHTO M235 Epoxy Resin Adhesives

ASTM C940 Standard Test Method for Expansion and Bleeding of Freshly

Mixed Grouts for Preplaced-Aggregate Concrete in the Laboratory

ASTM C942 Standard Test Method for Compressive Strength of Grouts for

Preplaced-Aggregate Concrete in the Laboratory

Section 7: Structural Steelwork

JIS G3101 Rolled steels for general structure

JIS G3106 Rolled steels for welded structure

JIS G3444 Carbon steel tubes for general structural purposes

JIS G3452 Carbon steel pipes for ordinary piping

JIS G4304 Hot-rolled stainless steel plates, sheet and strip

JIS G5101 Carbon steel casings

JIS B1186 Sets of high strength hexagon bolt, hexagon nut and plain

washers for friction grip joints JIS Z3211 Covered electrodes for mild steel

JIS Z3801 Standard qualification procedure for manual welding technique JIS Z3104 Methods of radiographic examination for welded joints in steel JIS Z3060 Method for ultrasonic examination for welds ferritic steel

AASHTO M111 Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products

AWS D1.1/D1.1M : 2008 Structural Welding Code

Section 8: Architectural and Building Works

TCXDVN PROCEEDING OF VIETNAM CONSTRUCTION STANDARDS,

VOL8, VOL10, VOL11 (Vietnamese Standard)

<Pavior>

ASTM C779/C779M-00 Standard Test Method for Abrasion Resistance of Horizontal

Concrete Surfaces

<Steel and Metal Worker>

ASTM D1730-03 Standard Practices for Preparation of Aluminum and

Aluminum-Alloy Surfaces for Painting ASTM B449-93(2004) Standard Specification for Chromates on Aluminum

ASTM D2244-09a Standard Practice for Calculation of Color Tolerances and Color

Differences from Instrumentally Measured Color Coordinates ASTM D4214 Test Methods for Evaluating the Degree of Checking of Exterior

Paint Films ASTM D2247-02 Standard Practice for Testing Water Resistance of Coatings in

100% Relative Humidity ASTM D714 Standard Test Method for Evaluating Degree of Blistering of

Paints ASTM B117 Standard Practice for Operating Salt Spray (Fog) Apparatus ASTM D523 Standard Test Method for Specular Gloss

ASTM D968 Standard Test Methods for Abrasion Resistance of Organic

Coatings by Falling Abrasive ASTM C920 Standard Specifications for Elastomeric Joint Sealant

ASTM A167 Standard Specification for Stainless and Heat-Resisting

Chromium-Nickel Steel Plate, Sheet, and Strip ASTM A480/A480M Standard Specification for General Requirements for Flat-Rolled

Stainless and Heat-Resisting Steel Plate, Sheet, and Strip ASTM A743/A743M Standard Specification for Castings, Iron-Chromium,

Iron-Chromium-Nickel, Corrosion Resistant, for General Application (equivalent with AASHTO M163/M163-00)

ASTM A36/A36M Standard Specification for Carbon Structural Steel

ASTM C509 Standard Specification for Elastomeric Cellular Preformed Gasket

and Sealing Material

JIS G5502 Spheroidal graphite iron castings

JSCE Standard Specifications for Tunneling -2006 (Shield Tunnel) JSCE Standard Specification for Concrete Structures -2002,

Construction

Section 10: Cut and Cover Construction

JSCE Standard Specifications for Tunneling -2006 (Shield Tunnel) JSCE Standard Specifications for Tunneling -2006 (Cut and Cover

Tunnel)

Section 11: (Not Used)

Section 12: (Not Used)

Section 13: Steel Reinforcement

JIS G3112 Steel bars for concrete reinforcement

JIS G3117 Rerolled steel bars for concrete reinforcement

2 EARTHWORKS

2.1.1 Definitions and Classifications

The following definitions of earthworks materials shall apply to this and other Clauses of these Specifications in which reference is made to the defined materials

Shall mean other than suitable material and shall comprise:

(i) material from swamps, marshes and bogs, highly organic clay or silt; (ii) peat, logs, stumps, perishable and toxic materials;

(iii) material susceptible to spontaneous combustion;

(iv) clay of liquid limit exceeding 80 % and/or plastic limit exceeding 55 %; (v) material which contains appreciable amounts of mica, or material with finely

dispersed mica and of liquid limit exceeding 40 %;

(vi) material having a loss on ignition greater than 2.5 % by weight;

(vii) material with a CBR (California Bearing Ratio) value of less than 2 % (when

compacted to 95 % of the maximum dry density determined by AASHTO Test Method T99 and CBR shall be tested in accordance with AASHTO Test Method T193)

Note: Materials that are soft or unstable merely because they are too wet or dry shall not be classified as unsuitable material unless otherwise directed by the Employer’s Representative

(4) Rock

Shall comprise material found in ledges or masses in its original position

(i) Soft Rock

Shall include all excavation except that classified as hard rock or earth

which in the judgment of the Employer’s Representative requires the use of tractor mounted or drawn rippers to loosen the material sufficiently to permit

a bulldozer to remove the material No alluvial or wind blown or transported soils, nor gravels, nor clays which soften when wet shall be classified as soft rock

(ii) Hard Rock

"Excavation of Hard Rock" shall include only excavation which in the judgment of the Employer’s Representative, is not practicable to excavate without the use of pneumatic tools or drilling and blasting Hard rock shall not include boulders less than one cubic meter in volume Hard rock shall not include material which, in the judgment of the Employer’s Representative, can be loosened with a tractor mounted and drawn ripper

of the following description:

- Tractor Unit: Equipment with a minimum weight of 17 tons and net

horse power rating of 150 HP or more The tractor unit is to be in good condition and operated by experienced personnel skilled in the use of ripping equipment

- Ripping Unit: The ripper to be attached to the tractor shall be the

most efficient parallelogram type recommended by the tractor or ripper manufacturer The ripper shall have a single shank in first class condition with sharpened cutting point

(5) Rock Fill

Shall be clean well graded material provided by the Contractor from sources outside the Site or from rock excavation The maximum size particles in the material shall pass through a rigid 200 mm square grid and the largest dimension of any particle shall not exceed 300 mm

(6) Waste

Shall be unsuitable material Waste if not required by the Employer’s Representative shall be the property of the Contractor The Contractor shall dispose waste at the areas outside the Site on his own expenses including claims arising from the use of private land

2.1.2 Plant

The Contractor shall employ only plant which is suited to the soils to be handled He shall

be responsible for maintaining the nature of suitable material so that when it is placed and compacted it remains suitable in accordance with the Contract

2.1.3 Removal of Suitable Material

No excavated suitable material other than surplus to the requirement of the Contract shall

be removed from the Site except on the direction or with the permission of the Employer’s

Representative Should the Contractor be permitted to remove suitable material from the Site to suit his operational procedure, then he shall make good at his own expense any consequent deficit of filling arising there from

2.1.4 Pollution Control

The Contractor shall submit to the Employer’s Representative for his review measures to be undertaken by the Contractor to prevent water pollution of the environment and erosion of earthworks No earthworks may commence until such consent has been given for all pollution and erosion controls as required by the Outline Design Specifications

The Contractor's proposals shall include but not be limited to:

(i) This work shall consist of al clearing and grubbing necessary for the

performance of the work covered by the Contract in accordance with these Specifications

The clearing and grubbing shall consist of clearing the designated areas of all trees, down timber, snags, vegetation, rubbish and objectionable material and shall include grubbing stumps and roots and disposing of all material resulting from the clearing or grubbing It shall also include the demolition, removal and disposal of structures that obtrude into or encroach upon or obstruct the work, removal of all existing utilities remaining within the right-of-way after removal of houses and the removal of existing road surfaces, except where provided for otherwise

(ii) Disposal of debris and foundations remaining after removal of houses or

other structures is considered to be included in the unit rates for clearing and grubbing and no further payment will be made under this Section (iii) Also included in this work shall be the removal of loose pavement material,

road signs, right-of-way markers, kilometer stones, guide posts and all other incidentals within the limit of construction These items shall be removed, if so instructed by the Employer’s Representative, outside of the construction limits but within the right-of-way The Contractor shall exercise care so as not to damage these incidental items during the removal operation All signs, markers and incidentals removed from the project shall be stacked in neat piles so they may be collected by relevant authorities or become the property of the Employer

(2) Preservation of property

(i) Attention is directed to the Contractor’s obligations under law and under this

Contract with regard to damage, particularly with regard to protection of property, forest, and landscape and to responsibility for damage claims (ii) Existing highways, improvements, facilities, adjacent property, utilities,

services, and trees and plants designated for preservation shall be protected from injury or damage which could result from Contractor’s operations

(iii) In order to reduce the risk of erosion no topsoil shall be removed from the

areas outside the limits of earthworks Any topsoil outside these limits, which is inadvertently removed during clearing and grubbing operations or otherwise, shall be replaced immediately by the Contractor and at his own expenses

(iv) Outside the limits of the construction works, certain trees or plants shall be

left undisturbed, if so instructed by the Employer’s Representative, for ecological purposes These trees or plants that are not to be removed shall

be protected from injury or damage resulting from the Contractor’s operations

2.2.2 Execution

(1) General

(i) Clearing and grubbing shall be performed on the areas designated by

staking or on the Drawings If no areas are designated on the Drawings, the areas to be cleared and grubbed will be as directed by the Employer’s Representative

(ii) Clearing and grubbing of pits, channel changes, and ditches will be required

only to the depth necessitated by the excavation within those areas (iii) All topsoil (including turf) shall be removed from areas of cuttings and

embankments and stockpiled if required for re-use for the soiling to slopes, berms, verges and for the provision of beds for the cultivation of trees and shrubs The following conditions shall apply

- The storage of stripped topsoil shall be to a maximum height of 3

m and shall on no account be consolidated or trafficked by heavy

machinery

- The storage of topsoil shall be kept completely separate from that

of the fill material

- Where natural ground is situated less than 2 m below formation

level or side slopes, topsoil shall be removed to a depth of 150 mm below original ground level

- The use of topsoil shall be restricted to surface layers not subject to

loading by pavements or structures

(2) Clearing

(i) Clearing shall consist of the removal and disposal of everything above

ground level including overhanging branches except those things the Employer’s Representative directs are to be left undisturbed The material

to be cleared shall include but not necessarily be limited to trees, stumps, logs, brush, undergrowth, grass crops, loose vegetable matter, structures (other than those structures where removal or clearance is separately specified and measured)

(ii) Outside the limits of the earthworks, and under embankments more than

1.5 m high, trees and stumps shall be cut to a level not more than 300 mm above ground level and not less than 450 mm below the embankment slopes and everything else to ground level

(iii) In cut areas clearing shall include the removal of stumps and roots

exceeding 80 mm in diameter, to a depth of 450 mm below the finished surface except that in surrounding areas at the tops of cut slopes they may

be cut flush

(3) Grubbing

(i) Grubbing shall be carried out on the area of embankment foundations

where the embankment height is less than 1.5 m Grubbing shall consist of the removal and disposal of topsoil, stumps, and roots to a depth of at least

150 mm below ground level and at least 450mm below the bottom of the lowest subbase or base course of road pavement

(ii) Material thus removed may be used as topsoil for slope protection if it, in the

opinion of the Employer’s Representative, is suitable for this Materials not used as topsoil, if not required by the Employer’s Representative, shall be the property of the Contractor and shall be disposed at the areas outside the Site at his own expenses including claims arising from the use of private land

(iii) Materials more than 150 mm below original ground level within

embankment areas which are removed during the operation of the clearing and grubbing shall be replaced by acceptable fill materials which shall be compacted to the density prescribed for layers at the depths concerned

below subgrade All unsuitable materials shall be wasted, and if not required by the Employer’s Representative, shall be the property of the Contractor The Contractor shall dispose waste outside the Site at his own expenses including claims arising from the use of private land

(iv) Where existing road embankments shall be raised or widened, all

vegetation and topsoil shall similarly be completely removed from shoulders, slopes and ground under the widening before the operations of actual widening can be commenced

(v) Where railway or roadway excavations are made, and where ditches,

streams and rivers are diverted, all vegetation, roots, stumps and the like shall be completely removed and placed outside the excavation area concerned before the excavation works proper can be commenced (vi) At all remaining areas inside the right-of-way, the Works of clearing and

grubbing shall, unless otherwise instructed by the Employer’s Representative, include the leveling of obsolete dikes, terraces and ditches, the neat and complete removal of all remnants from structures and buildings, roots, stumps, untidy vegetation, rubbish, garbage and the like, to such an extent that these matters will not, in the opinion of the Employer’s Representative, obstruct future maintenance by machines of the right-of-way area or access to the works

(v) The clearing and grubbing within areas under embankments shall include

the removal of all vegetation, roots and stumps from trees and palms, garbage, rubbish, etc., remnants from houses and structures and the like Holes left after such removal shall be backfilled with acceptable materials and compacted to the density prescribed for layers at the depths concerned below subgrade, and this backfilling shall be considered incidental to the works of clearing and grubbing and will not be measured and paid for (vi) Ditches, streams and ponds in the embankment areas shall be properly

cleared, drained and dried out prior to being measured for payment of embankment quantities to be filled in

(i) This work shall consist of all the required excavation within the limits of the

right-of-way, except excavation otherwise classified

The excavation shall include the removal, hauling and proper utilization or disposal of all excavated materials, the shaping of excavation and the

preparation of exposed surfaces of excavation in accordance with these Specifications and the lines, levels, grades, dimensions and cross sections shown on the Drawings and as required by the Employer’s Representative (ii) Work Includes:

- Excavation of all materials for formation work, roads, gutters,

ditches, berm ditches, drains and flumes

- The removal and disposal of existing surfacing, footpaths, curbs or

curbs and gutters within the limits of construction

- The demolition, removal and disposal of all foundations, foundation

walls, basement or ground level floors, timber, rubble, masonry pipe, pipe structures and pipe culverts within the limits of construction and otherwise provided for in the Contract

- Excavation for removal of slides, breakages and cave-ins

- Excavation for stream and channel changes

- Excavation required in cuts or under embankments below the

lowest normal limit of excavation indicated on the Drawings or below ground line, for the removal of unsuitable material, and below the ground line under embankments where benching is required, or as otherwise directed

- Prevention of erosion of exposed surfaces

(iii) Unclassified Excavation Shall include all materials to be excavated in accordance with these Specifications above

2.3.3 Execution

(1) General

(i) All excavation and embankment construction shall be performed as

specified herein and in Section 2.6: Embankment, and the complete

earthwork shall conform to the required alignment, levels, grades, and cross-sections

(ii) Where the excavation reveals a combination of suitable and unsuitable

materials the Contractor shall, unless otherwise agreed by the Employer’s Representative, carry out the excavation in such manner that the suitable materials are excavated separately for use in the Works without contamination by the unsuitable materials

(iii) Where any material under embankment or below formation level in cuttings

is required to be excavated, it shall be removed to such depth and over such areas as are indicated on the Drawings or as directed by the Employer’s Representative and disposed of in a manner depending on its nature and condition at the time The whole of the excavation shall not be carried out in one operation but shall be progressively excavated and filled one width at a time, such that the excavated surface is not left exposed or unsupported during wet weather, or overnight All excavation below embankments shall take place from ground level unless prior consent is given by the Employer’s Representative It shall be the responsibility of the Contractor to ensure the stability and safety of the excavation at all times The resultant excavation shall be backfilled with suitable material as defined in Section 2.1: Earthworks Definitions and Classifications Nevertheless where in these circumstances such backfill has to be deposited below standing water the Contractor shall use only sand as defined in Section 2.6: Embankment Such material may be deposited below water without the associated use of compaction plant

(iv) Where shown in the Contract or directed by the Employer’s Representative,

Rock Fill or suitable material shall be placed directly on the naturally occurring weak material The backfill material shall be deposited in accordance with the requirements of Section 2.5: Excavation and Backfill For Structures and Section 2.6: Embankment for the compaction of fill (v) If after the removal of unsuitable material the Contractor allows the material

so exposed to reach a condition where compaction of backfilling complying with Section 2.6: Embankment is impracticable he shall make good at his own expense either by additional excavation and filling in the manner specified, or by waiting until the condition of the exposed material is fit to receive the consented backfill

(vi) The work shall be carried out by the Contractor in such a way as to avoid

disturbance to the surrounding ground Particular care shall be taken to maintain stability when excavating in close proximity to existing works (vii) The work shall be carried out in a careful manner to ensure that the exposed

surfaces are as sound as the nature of the material permits and that no point shall protrude inside the lines shown on the Drawings except as otherwise specified or consented by the Employer’s Representative In soft excavation which is to remain open permanently, exposed faces shall be

formed accurately to the required slopes and profiles

(2) Excavation in cut

(i) Where cuttings having two or more different slopes are identified in the

Contract, cutting shall commence at the slope indicated for the underlying strata The depth at which a change of slope occurs shall be verified by the Employer’s Representative when sufficient depth has been excavated to enable the full depth of the layer of soft to stiff material to be identified The Contractor shall then re-excavate to the upper slope as indicated in the Contract

(ii) Erosion protection measures shall be carried out immediately after trimming

of the cutting slope

(iii) Where materials having a CBR value (when compacted to 95 % of the

maximum dry density determined by AASHTO Test Method T99 and CBR shall be tested in accordance with AASHTO Test Method T193) lower than

5 % are found in the 150 mm underlying the sub-grade layer, such materials shall be excavated and replaced by materials (which will be paid as embankment fill) having a CBR value of 5 or more

(iv) In cut areas, the "final surface" on which subbase is to be placed shall be

processed as necessary and compacted to a minimum depth of 300 mm to not less than 95 % of the maximum dry density of the materials as determined by AASHTO Test Method T180

(v) The subgrade is the soil on which the sub ballast is placed It must have the

following characteristics for a layer of at least 300 mm: bearing strength CBR 8 % and compacted to 95 % of the maximum dry density determined

by AASHTO Test Method T180 The subgrade layer shall be essentially granular

(vi) The subgrade shall be capable of bearing an imposed local stress due to

live load of not less than 100 kPa

(vii) Any excess depth excavated below the formation level shall be made good

by backfilling with suitable material of similar characteristics to that removed and compacted in accordance with Section 2.6: Embankment, at the Contractor’s expenses

(viii) Hauling of materials from cuttings or the importation of fill material to the

embankments or other areas of fill shall proceed only when sufficient compaction plant is operating at the place of deposition to ensure compliance with the requirements of Section 2.6: Embankment

(ix) Construction traffic shall not use the surface of the bottom of a cutting

unless the cutting is in rock or the Contractor maintains the level of the bottom surface at least 300 mm above formation level (top of sub-grade) Any damage to the sub-grade arising from such use of the surface shall be made good by the Contractor at his own expense with material having the

same characteristics as the material which has been damaged

(3) Channel excavation

(i) Where indicated on the Drawings and where the Employer’s

Representative may so instruct as and when the work proceeds, ditches and streams shall be widened, trained or permanently diverted

(ii) Interception ditches at the top of slopes in cuts, as well as outlet ditches

from railway ditches and culvert outlets, shall be excavated as shown on the Drawings, where required by the Employer’s Representative and as instructed by him

(iii) Channels shall be excavated by methods which will not endanger the

stability of the side slopes

(iv) Existing channels, which are to be reshaped, cleared and trimmed, shall be

cleared of all weeds and growth and the beds graded to the required levels The sides of channels shall be trimmed to the required slope so as to provide widths not less than those shown on the Drawings

(v) Side banks of channels shall be trimmed to a neat appearance and even

surfaces

(vi) Any channels, streams, drains or pipes taking water to or from cultivated

land shall be diverted so as to maintain their flow before being moved or broken into All diversions and their subsequent reinstatement shall be carried out to the satisfaction of the Employer’s Representative

(vii) The Contractor shall control the rates of filling and drawdown of water in

channels so as not to endanger the stability of earthworks

(4) Control of water

(i) The Contractor shall arrange for the rapid dispersal of water, shed on to

earthworks or completed formation during construction, or which enters the earthworks from any source, and when practicable the water shall be discharged into permanent outfall for the pipe drainage system Adequate means of trapping silt shall be provided on temporary systems discharging into permanent drainage systems The arrangements shall be made in respect of all earthwork including excavation whether for pipe trenches, foundations or cuttings

(ii) The Contractor shall provide where necessary temporary watercourses,

ditches, drains, pumping or other means of maintaining the earthworks free from water Such provision shall include carrying out the work of forming the cuttings and embankments in such a manner that their surfaces have

at all times a sufficient minimum cross fall and, where practicable, a sufficient longitudinal gradient to enable them to shed water and prevent ponding

(iii) Pumping shall not be regarded as meeting the provisions of this Clause

where a blockage temporarily obstructs the free drainage of a cutting In such circumstances the Contractor shall construct temporary drains with a suitable out-fall or install the permanent drainage through the blockage (iv) The Works related to the control of water shall be considered as incidental

to earthworks and shall not be measured or paid for

(5) Disposal of excavated material

(i) General All suitable excavated materials shall be used insofar as practicable in the construction Waste or any excavated material in excess, if not required by the Employer’s Representative, shall be the property of the Contractor The Contractor shall remove and dispose outside the Site at his own expenses including claims arising from the use of private land

(ii) Suitable Material Materials which the Employer’s Representative deems suitable for embankment fill or for topsoil on slope will be ordered by the Employer’s Representative to be:

- used for embankment fill or for topsoil, or

- used for filling parts of the former stream bed lying outside the

embankment areas

(iii) Unsuitable Material Materials which the Employer’s Representative has declared in writing to be unsuitable for embankment fill or for topsoil on slopes shall be placed as ordered by the Employer’s Representative and be:

- used for filling parts of the former stream bed lying outside the

be removed and disposed of as directed

(ii) Subgrade The surface of the finished subgrade shall be neat and workmanlike and shall have the required form, superelevation, levels, grades and cross-section The surface shall be constructed to sufficient accuracy to permit the construction of subsequent layers of materials to the thickness,

cross-section, surface tolerance, and compaction specified The deviation from design level should not exceed 20 mm on the top surface, and the design shape and drainage falls must be constructed correctly

(7) Other right-of way

At locations where the construction is close to irrigation canals and power transmission lines which have their own right-of-way, the Contractor must not without instruction by the Employer’s Representative remove any materials from the right-of-way of other authorities or, by the operation of equipment or otherwise, disturb their installations

(2) Backfill - General

Except around structures, excavations shall be backfilled with suitable excavated material and/or consented material compacted in layers of 300 mm maximum thickness to achieve a density of at least 95 % of the maximum dry density determined in accordance with AASHTO T180 or equivalent

2.4.2 Materials

(1) Fill material

(i) Fill material, other than for road works, shall be evenly graded granular

material to the consent of the Employer’s Representative Clods or large lumps of earth over 75 mm in greatest dimension shall be broken up before compacting the material in embankment

All fill materials shall be free from roots, sods or other deleterious material (ii) The Contractor shall carry out the following initial tests on the proposed

material to confirm that fill materials comply with the design

- Wet sieve analysis

- Dry density/moisture content relationship in accordance with

AASHTO Test Method T180 or equivalent (iii) Thereafter, one set of tests shall be carried out for each 200 m3 of fill,

supplied to Site or as required by the Employer’s Representative

(2) Materials for top layer of fill

(i) In addition to the general requirements for fill material, the material in the

top layer shall not exceed the following test values:

Plasticity index: 6 Liquid Limit (LL): 35 (ii) The laboratory CBR value, at 95 % of the maximum dry density achieved in

AASHTO T180 or equivalent after soaking for 96 hours, shall not be less than 30 %

Tests shall be carried out on fill to determine the degree of compaction achieved, at the rate of one test for either each 1,200 m3 or each layer whichever is the more frequent Compacted layers shall not be covered without consent

The density of individual compacted layers shall be determined by a method detailed in AASHTO T191 or equivalent

The in-situ dry density of fill shall average 95 % of the maximum reached in AASHTO Test Method T180 or equivalent No single result shall be less than 92 % and no more than 25 % of the results on any one layer shall fall between 92 % and 95 % The average shall be computed from the total number of tests on any one layer where the extent of the layer is defined by the Contractor

(ii) Testing of Top Layer Tests shall be carried out on the top layer of fill as follows:

(a) Laboratory tests to monitor the consistency of the consented

material during construction:

Test (not less than one test per …) Test frequency Maximum dry density

1,500 m2Optimum moisture content

Grading Plasticity index

Linear shrinkage

(b) In-situ tests to confirm that the required degree of compaction is

being achieved during construction:

Test (not less than one test per …) Test frequency

Tests shall be carried out in accordance with AASHTO T180 or equivalent, using 4.5 kg rammer methods where applicable or AASHTO T191

2.5.1 General

(1) Scope

This work shall consist of the excavation for structures and subsequent backfilling Works include:

(i) Excavation of foundations for structures and under drains

(ii) Constructing and removing cofferdams and sheeting

(iii) Pumping, dewatering and bailing

(iv) Backfilling around completed structures

(v) Disposal of excavated material

The work done shall meet the requirements as specified on the Drawings

2.5.2 Materials

(1) Material for foundation fill

Material for foundation fill shall consist of suitably graded sand, gravel, or stone as show on the Drawings or required by the Employer’s Representative, or concrete as described below

(2) Concrete for foundation fill

Concrete shall be Grade 15 and conform to the requirements of Section 5: Concrete for Structures of these Specifications

(3) Backfill material

(i) General

Backfill shall be consented compatible material It shall be obtained from the structure excavation if such material is consented by the Employer’s Representative as suitable Any additional material needed shall be obtained from excavation or borrow unless otherwise directed by the Employer’s Representative

(ii) Culverts Shall be sand complying with the requirements of Selected Material Type

B of Section 2.6: Embankment or consented well graded granular material (iii) Porous Backfill

Shall be hard durable material composed of gravel, crushed rock or sand free from organic material, clay balls and other deleterious material Laterite or concretionary materials shall not be used Porous materials to

be used shall conform to followings:

Shall confirm to the following particle-size gradation:

*Sieve Designation (AASHTO T27) square mesh

% by weight passing Type A

% by weight passing Type B Type C Type D Type E

Where one or more of the gradings shown above are indicated on the Drawings or other Contract Documents, materials conforming

to the gradings indicated on the Drawings shall be used, otherwise the Contractor may select any one of the above gradings

- Gravel filters Shall confirm to the following particle-size gradation:

*Sieve Designation (AASHTO T27) square mesh

(i) The Contractor shall notify the Employer’s Representative sufficiently in

advance of the beginning of any excavation so that cross section elevations and measurement may be taken of the undisturbed ground The natural ground adjacent to the structure shall not be disturbed without consent of the Employer’s Representative

(ii) Trenches and foundation pits for structures and structure footings and

under drains shall be excavated to the lines, grades and elevations shown

on the Drawings

(iii) The sides of pits and trenches shall be adequately supported at all times

Alternatively, except where the Contract expressly requires otherwise, they may be suitably battered to such slopes consented by the Employer’s Representative

(iv) Boulders, rocks under beams, logs and other objectionable materials

encountered in excavation shall be removed

(v) After each excavation is completed the Contractor shall notify the

Employer’s Representative to that effect and no footing, bedding material

or structure shall be placed until the Employer’s Representative has consented the depth of excavation and the character of the foundation

material

(vi) Rock and other hard foundation material shall be cleared of all loose

material and cut to a firm surface, either level or stepped or serrated, as specified or shown on the Drawings or directed by the Employer’s Representative All seams and crevices shall be cleared out and grouted with Portland cement grout at the time the footing is placed All loose and disintegrated rock and thin strata shall be removed

(vii) If fill with suitable material is required it shall be placed and compacted in

layers not more than 150 mm thick or as directed by the Employer’s Representative The degree of compaction shall be equivalent to that of the surrounding foundations

(viii) In the excavation for foundations, the Contractor shall take particular care

during construction to avoid deterioration of the ground due to weather or the use of Contractor’s equipment, and the last 150 mm of excavation above foundation levels shall be carried out by hand immediately before blinding layers or structural concrete are placed

(ix) If required, before any concrete for a foundation is placed, the bottom of all

excavations, where blinding layers shall be cast, shall be re-compacted to achieve a smooth and level surface Subject to consent of the Employer’s Representative sand layers shall be placed and compacted to at least 90 %

of the maximum dry density as determined by AASHTO Test Method T99,

in layers not exceeding 150 mm thick

(x) The excavation for foundations shall be kept free of water, and sheet piling

and/or pumping or temporary dewatering by well points or pumping wells may be required

(xi) All excavation surfaces and surfaces of backfill material against which

concrete is to be placed shall be smooth and firm and true to line and level (xii) The Contractor shall allow for sufficient time between the excavation and

execution of the foundations for the Employer’s Representative to carry out supplementary soils investigations and subsequent tests

(3) Disposal of excavated material

(i) All excavated material so far as suitable, shall be utilized as backfill or

embankment The waste material or any excess material derived from excavations if not required by Employer’s Representative shall be the property of the Contractor The Contractor shall dispose outside the Site at his own expenses including claims arising from the use of private land (ii) Excavated material suitable for use as backfill may be deposited by the

Contractor in storage piles at points convenient for re-handling of the material during the backfilling operation

(iii) Excavated material shall be deposited in such places and in such a manner

as not to cause damage to the highway, roads, services or property either

within or outside the right-of-way and so as to cause no impediment to the drainage of the site or surrounding area The location of storage piles shall

be subject to the consent of the Employer’s Representative who may require that the survey center line and the transverse or hub line of any part

of the structure be kept free of obstruction

(4) Cofferdam

(i) The term “cofferdam” denotes any temporary or removable structure,

constructed to hold the surrounding earth, water, or both, out of the excavation, whether such structure is constructed of earth, timber, steel, concrete or any combination of these The term includes earth dikes; and timber cribs, sheet piling, removable steel shells and all bracing; and it shall

be understood to include excavation enclosed by pumping wells and well points

(ii) The Contractor shall submit upon request drawings showing his proposed

method of cofferdam construction Consent of the drawings by the Employer’s Representative will not in any way relieve the Contractor of the responsibility for the adequacy of the design for strength and stability or for the safety of the people working therein

(iii) The interior dimensions of cofferdams shall be such as to give sufficient

clearance for the construction and removal of any required forms and the inspection of the interior and to permit pumping outside the forms

(iv) If practicable cofferdams shall be so designed that no cross bracing shall be

left in place If this is not practicable bracing left in place shall be of structural steel The end of such structural members that would be exposed when the structure is completed shall be boxed back at least 150

mm behind the concrete face The resulting holes shall be completely filled with concrete

(v) In general, sheet piling cofferdams shall extend well below the bottom of the

footing and shall be well braced and as watertight as practicable

(vi) When foundation piles are to be driven inside a cofferdam and it is judged

impracticable to dewater the cofferdam before placing a concrete seal, the excavation may be extended below the designed level to a depth sufficient

to allow for swell of the material during pile driving operations Any material that rises to a level above the design level shall be removed

(vii) Where it is possible to dewater the cofferdam the foundation materials shall

be removed to exact grade after the foundation piles are driven

(viii) Backfilling in a foundation to compensate for excavation which has been

extended below the required design level shall be at the expense of the Contractor Backfilling shall be with concrete or foundation fill material as indicated on the Drawings, or as directed by the Employer’s Representative

If no material is indicated, backfilling shall be concrete Grade 15 complying the requirements of Section 5: Concrete

Unless otherwise permitted no excavation shall be made outside of cofferdams or sheet piling and the natural stream bed adjacent to the structure shall not be disturbed without consent from the Employer’s Representative If any excavation or dredging is made at the site of the structure before cofferdams are in place the Contractor shall, after the foundation is in place, backfill all such excavation to the original ground surface or stream bed with material satisfactory to the Employer’s Representative

Material deposited within the stream area from foundations or other excavations or from the filling or cofferdams shall be removed and the stream area freed from obstruction

(ix) Cofferdam which tilt or move laterally during construction shall be corrected

as necessary at the expense of the Contractor

(x) Unless otherwise provided cofferdams shall be removed after the

completion of the sub-structure The removal shall be effected in such a manner as not to disturb or mar the finished work The Employer’s Representative may order the Contractor to leave any part or the whole of the cofferdam in place

(xi) When conditions are encountered which, in the opinion of the Employer’s

Representative, render it impracticable to dewater the foundation before placing the footing, the Employer’s Representative may require the construction of a concrete foundation or seal of such dimensions as he may consider necessary, and of such thickness as to resist any possible uplift The concrete for such seal shall be placed as shown in the Drawings or required by the Employer’s Representative The foundation shall then be dewatered and the footing placed

When weighted cribs are used and the weight is used to overcome partially the hydrostatic pressure acting against the bottom of the foundation seal, special anchorages such as dowels or keys shall be provided to transfer the entire weight of the crib to the foundation seal When a foundation seal is placed under water the cofferdam shall be vented at low water as directed Cofferdams shall be constructed so as to protect newly cast concrete from sudden rising of the water and to prevent damage to the foundation by erosion

(5) Pumping and bailing

(i) Pumping or bailing to dewater a sealed cofferdam shall not be started until

at least 36 hours after final set of sealing concrete

(ii) Pumping and bailing from the interior of any foundation enclosure shall be

done in such a manner as to preclude the possibility of the movement of

water through or alongside any concrete being placed No pumping or bailing will be permitted during the placing of concrete or for a period of at least 24 hours thereafter unless it is done from a suitable sump separated from the concrete work by a watertight wall

(iii) Excavations shall be as dry as possible prior to and during placing concrete

Placing concrete under water will only be permitted if indicated on the Drawings or consented by the Employer’s Representative

(6) Backfilling

(i) All spaces excavated under these Specifications and not occupied by the

permanent structure shall be backfilled Backfilled material shall be free from large lumps, wood and other extraneous material

(ii) The Contractor shall not backfill around structures until the structural

elements have attained adequate strength consented by the Employer’s Representative

(iii) Backfill not within the embankment area shall be placed in layers not more

than 300 mm in depth (loose measurement) and shall be compacted to a density comparable with the adjacent undisturbed material

(iv) Backfill within the embankment areas shall be made with suitable material

placed in uniform layers not to exceed 300 mm in depth (loose measurement) and each layer shall be constructed and compacted in accordance with Section 2.6: Embankment

(v) Backfill for culverts shall be placed in layers not exceeding 300 mm and

shall be compacted to at least 95 % of the maximum dry density according

to AASHTO Test Method T99 The in-place dry density shall be tested in accordance with AASHTO Test Method T191

(vi) In placing backfill and embankment the material shall be placed insofar as

possible to approximately the same height on both sides of the structure If conditions require backfilling appreciably higher on one side, the additional material on the higher side shall not be placed until consent is given by the Employer’s Representative nor until the Employer’s Representative is satisfied that the structure has enough strength to withstand any pressure created

(vii) Backfill for embankment shall not be placed behind the walls of bridges or

box culverts until the top slab is placed for the required time and not less than three days Backfill and embankment behind abutments held at the top by superstructure shall be carried up simultaneously behind opposite abutments and side walls

(viii) No backfilling shall be placed against any structure until consent shall have

been given by the Employer’s Representative Jetting of fill or other hydraulic methods involving, or likely to involve, liquid or semi-liquid pressure shall be prohibited

(ix) Special care shall be taken to prevent any unduly high pressures against

the structures

(x) The placing of embankment and the benching of slopes shall continue in

such a manner that at all times there will be a horizontal berm of thoroughly compacted material for a distance at least equal to the height of the abutment or wall to be backfilled

(xi) Adequate provision shall be made for drainage and to allow for porous

backfill material to be placed in accordance with Sub-Clause 2.5.2 herein

2.6.2 Materials

(1) Embankment shall be constructed of materials with a CBR value not lower than the

design values stated on the Drawings

(2) These required CBR values shall be on soaked samples compacted to 95 % of the

AASHTO Test Method T99 The use of materials with a CBR value of less than 2 % shall not be considered suitable

(3) Embankment materials classified as Selected Material Type A and Selected

Material Type B, if required, shall be constructed to the thicknesses shown on the Drawings and shall meet all the following material requirements

Selected Material Type A - shall consist of naturally occurring soil aggregate free of topsoil and all other organic matter The soil aggregate shall consist of sound durable particles which do not breakdown under compaction or repeated wetting/drying cycles All sizes greater than 50 mm shall be handpicked and removed from the working layer

The fraction of material passing the No 40 sieve shall have a liquid limit, as determined by AASHTO Test Method T89, of not greater than 40 % and a plasticity index, as determined by AASHTO Test Method T90, of not greater than 20 % The fraction passing the No 200 sieve shall be more than 10 % but not greater than

30 % Shale material and sand shall not be used for Selected Material Type A The

minimum required CBR values indicated on the Drawings shall be on soaked samples compacted to 95 % of the maximum dry density in a moisture range of 3%

as determined in AASHTO Test Method T99

Selected Material Type B - shall consist of naturally occurring soil aggregate, sand

or other materials free from topsoil and all other organic matter The material shall consist of sound durable particles which do not breakdown under compaction or repeated wetting/drying cycles All sizes greater than 50 mm shall be handpicked and removed from the working layer

The fraction passing the No 200 sieve shall not be greater than 35 % The minimum required CBR values indicated on the Drawings shall be on soaked samples compacted to 95 % of the AASHTO Test Method T99

(4) Where sand embankment is specified on the Drawings, such materials shall consist

of river or pit-run sand whose properties shall meet the following requirements:

- Gradation : Maximum particle Size: 3/8 inch

Material finer than No.200 sieve: 25 % maximum

- Plasticity : Material shall be generally non-plastic and free from clay

lumps

- CBR strength: When compacted to 95 % of AASHTO Test Method T99

density, the material shall have minimum soaked CBR of 10 %

(5) Materials for earthfill, landscaping and islands shall consist of clay, laterite, land

deposit sand or river or beach sand, unless otherwise shown on the Drawings, shall comply with the requirements of Section 2.4: Fill of these Specifications

2.6.3 Execution

(1) Preparation of foundation for embankment

(i) Prior to placing any embankment upon any area, all clearing and grubbing

operations shall have been completed in accordance with Section 2.2: Clearing and Grubbing of these Specifications

(ii) Natural ground (including slopes of existing road) situated less than 1.5 m

below surface of the road or side slopes shall, after proper clearing and grubbing or scarifying of existing road surface, be compacted to a depth of

150 mm, measured from original ground as shown on the cross-section sheet, to not less than 95 % of the maximum dry density of the material as determined by AASHTO Test Method T99 Compression of existing soil which may result from this compaction will not be measured and backfilling

of the corresponding volume of earth fill is considered incidental to other items of work and will not be separately paid for

(iii) Where embankments are to be constructed on slopes or existing

embankments are to be widened or included in new embankment, the existing slopes (or slope of the existing embankment) shall be loosen by

scarifying to a depth of not less than 100 mm, to ensure a good bond between the embankment and the embankment foundation, or where this is impracticable, steps in vertical and horizontal face shall be cut in the existing slopes and the embankment built up in successive layers Material which has been loosened shall be re-compacted simultaneously with the first level of embankment material placed

(iv) Unless otherwise shown on the Drawings, where existing unpaved roads

are to be covered with less than 300 mm of fill, excluding pavement, the top

of the old road bed shall be scarified and re-compacted with the next layer

of the new embankment The total depth of the scarified and added material shall not exceed the permissible depth of layer

(v) Embankment in swamps or water shall be constructed by sand

embankments The Contractor shall, when ordered by the Employer’s Representative, excavate or displace swamp ground and backfill with suitable material Backfill will be in accordance with the same provisions as for embankment unless otherwise directed by the Employer’s Representative

(vi) If unsuitable materials occur in some areas under the embankment or in

existing embankments, such materials shall be removed to levels as directed in writing by the Employer’s Representative, the bottom of the excavation shall be compacted, as described above, and the areas backfilled and compacted layer by layer with suitable material Fill material replacing unsuitable materials being excavated on the written instruction of the Employer’s Representative will be measured and paid for under Item

“Embankment”, unless the excavation was performed on a localized soft spot, pothole or failed area in an existing pavement, in which case both excavation of soft or unsuitable material and replacement with either Selected Material, Type A or subbase will be paid for under Item “Soft Spot Excavation and Replacement”

(vii) All compaction shall conform to the requirements in following “(3)

Compaction of embankment other than rock embankment” of this Specification Where an existing surface of a road is situated at subgrade level or lower, the surface shall be scarified, except where otherwise shown

on the Drawings, to a depth of 150 mm, graded, spread and compacted, to the density prescribed for layers at the depth concerned below subgrade, in the full width of the new embankment No materials shall be removed from these areas unless ordered in writing by the Employer’s Representative (viii) Where the surface of an existing road is above the required subgrade, the

existing road shall be removed to new subgrade level, except where otherwise shown on the Drawings, where after shaping and compaction shall be carried out in accordance with following “(3) Compaction of embankment other than rock embankment” of this Specification

(ix) On pavement rehabilitation where selected material and/or subbase layers

are to be placed directly on an existing pavement surface which is in a good condition, the existing surface shall not be scarified and re-compacted, except where otherwise shown or unless otherwise directed by the Employer’s Representative

(x) In landscape areas topsoil shall be removed to a depth as directed by the

Employer’s Representative and in accordance with these Specifications Fill shall be placed in the same manner as for embankments to lines and levels as directed by the Employer’s Representative

(xi) Clay berms or dike placed next to the ditch or channel as indicated on the

Drawings shall be constructed by the excavated clay from the ditch or from borrow pit The suitable material shall be specified on the Drawings (2) Placing embankment

Embankment shall be placed in accordance with the following requirements: (i) General

Except as otherwise required by the Employer’s Representative, all embankments shall be constructed in layers approximately parallel to the finished grade of the road bed During construction of embankment, a smooth grade having an adequate crown or superelevation shall be maintained to provide drainage Embankment shall be constructed to the required grade, and completed embankment shall correspond to the shape

of the typical sections shown on the Drawings

(ii) Earth Embankment Earth embankment shall be defined as those principally of material other than rock, and shall be constructed of consented material from designated

or other consented sources

Except as specified for embankment in swamps, earth embankment shall

be constructed in successive layers, for the full width of the cross-section and in such lengths as are suited to the compaction and watering methods used Prior to compaction the layers shall not exceed 200 mm in depth unless otherwise directed by the Employer’s Representative

(iii) Placing over Swamp Ground Embankment in or over swamps or in water shall be placed as indicated on the Drawings and as specified in the Special Provisions, and as required by the Employer’s Representative

(iv) Adjacent to Culverts and Bridges Embankment adjacent to culverts and bridges which cannot be compacted

by use of equipment used in compacting the adjoining section of embankment shall be compacted in the manner prescribed under the Section 2.5: Excavation and Backfill for Structures Embankment placed round spill through type abutments shall be compacted in 150 mm layers

(measured before compaction) of uniform suitable material placed in such

a manner as to maintain approximately the same elevation on each side of the abutment and each layer of material shall be mixed, wetted and compacted as specified herein Material placed adjacent to any portion of any structure shall be Selected Material Type A or Type B as consented by the Employer’s Representative

(v) Preparation of Subgrade

- The surface of the finished subgrade shall be neat and workmanlike

and shall have the required form, super elevation, levels grades, and cross-section The surface shall be constructed to sufficient accuracy to permit the construction of subsequent layers of material to the thickness, surface tolerance, and compaction specified

- As far as is practicable and when directed by the Employer’s

Representative, the Contractor shall construct bridge approach fills

as early in the Contract period as possible to allow for consolidation

of the embankment during the remainder of the Contract period

- Where new embankment is to be compacted against existing

embankment with side slopes as specified on the Drawings or where embankment is built one-half width at a time, the slopes of old or new embankment shall be cut into a minimum of 2 m horizontally to provide a working platform as the work is brought up

in layers

- Material thus cut out shall be re-compacted along with the new

embankment material at the Contractor's expense

- Clods or large lumps of earth over 150 mm in greatest dimension

shall be broken up before compacting the material in embankment

- Where streams or ditches are to be diverted, or abandoned, their

beds should be filled up to a level Within the limits of earthwork, such fill shall be placed and compacted to the requirements as specified in this Section Filling shall be performed well ahead of the construction of roadway embankments, and all other works involved such as pumping, damming, etc Embankment fill placed against the sides of pipe culverts shall be placed in such manner as

to maintain the same elevation on both sides of the culvert

- The Employer’s Representative may request the installation of

settlement plates, piezometers, lateral movement stakes, inclinometers or other settlement control devices or as required by the Employer’s Representative

- All settlement occurring in embankment construction shall be

corrected by the Contractor by providing additional layers of embankment or selected material The Contractor shall be fully

responsible for the stability and integrity of the embankment during the Contract and Maintenance periods

- If a soil failure either occurs or becomes imminent during the

construction of the embankment, the Employer’s Representative shall have the authority to suspend all embankment construction in the affected area until corrective measures can be determined and implemented Any delay in the embankment construction schedule and any other effects caused by implementation of the above clause shall not constitute grounds on the part of the Contractor for

a claim for extension of the Contract and/or financial compensation

(3) Compaction of embankment other than rock embankment

(i) Before compaction, each layer shall be processed as required to bring the

moisture content to within + 1 % and – 2 % of optimum moisture content as determined in AASHTO Test Method T99 or directed by the Employer’s Representative with respect to the type and size of the compactors being utilized The material shall be so worked as to have uniform moisture content throughout the layer Full compensation for any additional work involved wetting or drying embankment material to the required moisture content shall be considered as included in the contract price paid for embankment and no additional compensation will be al owed

(ii) Each layer of material shall be compacted uniformly by use of adequate and

appropriate compaction equipment The compaction shall be done in a longitudinal direction along the embankment and shall generally begin at the outer edges and progress toward the centre in such a manner that each section receives equal compactive effort

Hauling equipment shall be operated over the full width of each layer in so far as practicable

(iii) Embankments shall be constructed in layers of uniform thickness not to

exceed 150 mm in thickness after compaction and compacted to the requirements of this Section Each layer of the embankment shall be compacted to a dry density equal to at least 95 % of the maximum dry density of the material as determined by AASHTO Test Method T99, except the top 150 mm of the embankment shall be compacted to 95 % of the maximum dry density as determined by AASHTO Test Method T180 The in-place dry density shall be tested in accordance with AASHTO Test Method T191

(iv) Embankments shall be maintained to the grade and cross-section shown on

the Drawings throughout the contract period

(v) The Contractor shall protect the prepared subgrade from both his own and

public traffic The Contractor shall maintain the subgrade by watering and rolling as frequently as necessary to preserve the subgrade in a completely

satisfactory condition as specified above

(vi) The compaction of the subgrade shall, in cut areas, including areas of

existing road where surface layer have been removed, extend to a minimum depth of 150 mm and the compaction shall attain not less than

95 % of the maximum dry density determined by AASHTO Test Method T180 The in-place dry density shall be tested in accordance with AASHTO Test Method T191

(vii) Attention is drawn to the fact that the general compaction requirements

shall at any level apply to the full width of the embankment Slopes to be covered with topsoil and grassing shall have a firm surface before topsoil is placed

(4) Preparation of subgrade surface

The subgrade shall be shaped to correct line and level and the Contractor shall at all times ensure that the subgrade is well drained and protected against damage from public as well as construction traffic The finished subgrade surface shall at no point deviate more than 15 mm from the cross-section shown on the Drawings The surface shall be maintained in this state, with a regular light sprinkling of water to prevent a dusty condition until the pavement layers are spread

2.7.1 General

(1) Scope

This work shall consist of the satisfactory removal and disposal or salvage, wholly

or in part, of all the existing structures, substructures, buildings, culverts, walls, fencing, old pavements, platforms, other obstructions, etc., within the right-of-way

as indicated on the Drawings or as required by the Employer’s Representative This work shall also include the provision of all labor, supervision, materials and plant and equipment for the demolition of all structures including substructures, but not piles, identified on the Drawings for demolition, removal of resulting rubbish and debris from the Project area

Provision and maintenance of safety protection including hoardings, temporary footpath surfaces, road traffic protection and warnings and canopies for the protection of the public property and also protection of existing work that will remain

in place shall be considered incidental to this Section and will not be measured for payment

(2) Demolition of structures

(i) Quality assurance

- The Contractor shall maintain adequate records in accordance with

the requirements of his consented quality assurance program These records shall provide the objective evidence of compliance with the requirements of the Contract

- Dust Control The amount of dust resulting from demolition shall be controlled to prevent the spread of dust to occupied portions of the construction site and to avoid the creation of nuisance in the surrounding area Use of water will not be permitted when it will result in, or create, hazardous or objectionable conditions such as flooding and pollution

- Protection of the Public The Contractor shall provide hoardings, screens and protective canopies around the structures being demolished and care shall be taken to ensure that no people or adjacent land is harmed by falling debris or dust Where rail necessary, barricades, flashing lights and flagmen shall be employed to protect people and road traffic from harm

Floors, roofs, walls, columns, pilasters, and other structural components that are designed and constructed to stand without lateral support or shoring, and are determined to be in a stable condition, shall remain standing without additional bracing, shoring

or lateral support until demolished, unless otherwise directed by the Employer’s Representative The Contractor shall ensure that

no elements determined to be unstable are left unsupported and shall be responsible for placing and securing bracing, shoring, or lateral supports as may be required as a result of any cutting, removal, or demolition work performed under this Contract

- Protection of Personnel During demolition work the Contractor shall continuously evaluate the condition of the structure being demolished and take immediate action to protect all personnel working in and around the demolition site No area, section, or component of floors, roofs, walls, columns, pilasters, or other structural element will be al owed to be left standing without sufficient bracing, shoring, or lateral support to prevent collapse or failure while workmen remove debris or perform other work in the immediate area

- Protection of Existing Property

Before beginning any demolition work, the Contractor shall survey the site and examine the Drawings and Specifications to determine the extent of the work The Contractor shall take necessary precautions to avoid damage to existing items to remain in place, to

be reused, or to remain the property of the Employer; any damaged items shall be repaired or replaced as consented by the Employer’s Representative The Contractor shall co-ordinate the work of this Section with all other work and shall construct and maintain shoring, bracing, and supports as required The Contractor shall ensure that the structural elements are not overloaded and shall be responsible for increasing any structural supports or adding new supports as may be required as a result of any cutting, removal or demolition work performed under this contract

- Environmental Protection The work shall comply with the requirements of the Outline Design Specifications

(ii) Submittals Method statements for each type of structure to be demolished at each location, which shall include the procedures for the accomplishment of the work shall be submitted to the Employer’s Representative for consent The procedures shall provide for the safe conduct of the work, including procedures and methods to provide necessary supports, lateral bracing and shoring when required, protection of property which is to remain undisturbed, co-ordination with other work in progress The procedures shall include a detailed description of the methods and equipment to be used for each operation Procedures shall include all safety measures to

be taken to protect the general public, highway traffic, from harm during the demolition and site clearance activities

(iii) Burning The use of burning at the site of demolition for the disposal of refuse and debris shall not be permitted

2.7.2 Execution

(1) Removal of existing structures - General

(i) Existing structures upon or adjacent to the proposed haul road,

reconstructed road, elevated viaduct and stations shall be removed by the Contractor, as indicated on the Drawings or as required by the Employer’s Representative Where existing bridge structures may be used as a temporary crossing or detour, no part of the removal shall be performed unless otherwise indicated on the Drawings, nor shall structure be closed

or obstructed until the detour or new work is opened to traffic by the Employer’s Representative