G05.4 - Civil Works

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RFx No.: 2131600023

Jebel Ali Power Station ‘K’ Phase III

Volume II

(GENERAL PROJECT REQUIREMENTS)

Part G05.4

Civil Works

Dubai Electricity and Water Authority P.O. Box 564

Dubai

United Arab Emirates

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RFx No.: 2131600023

Jebel Ali Power Station ‘K’ Phase III

Issue and Revision Record

Rev Date Originator Checker Approver Description

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Table of Contents

1 General ... 7

1.1 Scope of Work, Completeness ... 7

1.2 Civil Design/Engineering ... 7

1.3 Codes and Standards ... 7

1.3.1 American Standards: ... 7

1.3.2 European Standards: ... 8

1.3.3 Local Standards and Regulations ... 8

1.3.4 Other Standards ... 9

1.4 Design Criteria for Layout, Arrangement, Drawings, Execution ... 9

1.4.1 Basic Requirements for All Civil Works ... 9

1.4.2 Design Loads / Load Assumptions ... 11

1.4.3 Tolerances ... 14

1.4.4 Special Requirements for Materials To Avoid Corrosion Problems – Reinforced Concrete ... 15

1.4.5 Special Requirements for Materials to Avoid Corrosion Problems – Steel Structures ... 16

1.5 Materials (Quality, Delivery, Storage, Handling) ... 17

1.5.1 General ... 17

1.5.2 New /Unused Materials ... 17

1.5.3 NA ... 18

1.5.4 Samples ... 18

1.5.5 Supplier/ Material Approval Procedure ... 18

2 Site Installation and Demobilisation ... 19

2.2 Execution (Assembling, Installation) ... 19

3 Site Supervision/Survey/Investigations ... 20

3.1 Site Supervision: ... 20

3.2 Survey and Investigations ... 21

4 Dewatering During Construction ... 22

4.1 QA/QC ... 22

5 Site Clearance and Earth Work ... 24

5.1 Site Clearance- General ... 24

5.2 Earth Works, Completeness ... 24

5.3.1 Select Fill ... 25

5.3.2 Ordinary Fill ... 25

5.3.3 Special fill ... 25

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5.4.1 Safety Precaution ... 25

5.4.2 Stockpiles and Disposal ... 26

5.4.3 Preparation of Foundations ... 26

5.4.4 Backfilling ... 26

5.4.5 Soil Replacement ... 27

5.4.6 Pipe Bed Preparation ... 27

5.4.7 Protection of Existing Utilities and Services ... 27

5.4.8 Deep Vibratory Techniques ... 28

5.4.9 Dust Control ... 28

5.5 QA/QC, Test and properties ... 28

5.5.1 General ... 28

5.5.2 Quality Assurance for Vibro Techniques ... 29

6 Piling Works ... 30

6.1 Documents to Be Submitted ... 30

6.2 Design Criteria, Arrangement Drawings ... 30

6.2.1 Bored Cast-In-Place Piles and Driven Piles ... 30

6.3.1 Steel Reinforcement and Concrete ... 31

6.4.1 Program ... 32 6.4.2 Qualification ... 32 6.4.3 Staking-Out Tolerances ... 32 6.4.4 Cut-off ... 32 6.4.5 Working Platform ... 32 6.4.6 Concreting... 33 6.5 QA/QC ... 33 6.5.1 Piling Record ... 33

6.5.2 Test Piles, Static Loading Tests ... 34

7 Concrete Work ... 36

7.2 Civil Design/Engineering ... 36

7.3 Dimensional tolerances ... 36

7.4 Concrete with Special Properties ... 36

7.4.1 General Requirements ... 36

7.5 Finishing Of Concrete Surfaces ... 38

7.6 Bar-bending Schedules ... 38

7.7 Crack Widths of reinforced Concrete Structures ... 38

7.8.1 Quality of Materials ... 38

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7.8.3 Cement ... 39

7.8.4 Water ... 39

7.8.5 Aggregates ... 39

7.8.6 Reinforcement, Treatment and Coating of Reinforcement ... 41

7.8.7 Concrete mixes ... 42

7.8.8 Transport of Concrete ... 43

7.8.9 Concreting Operations ... 44

7.9 QA/QC ... 47

7.9.1 Trial Mixes ... 47

7.9.2 Quality and Testing ... 48

7.9.3 Strength of Concrete ... 48

7.9.4 Reinforcement – Certificates ... 49

7.9.5 Shuttering and Scaffolding Works ... 50

8 Pre-cast Concrete ... 51

9 Grouts ... 52

10 Masonry, Mortar, Plaster ... 53

10.1.1 Cement Mortars ... 53 10.1.2 Masonry ... 53 10.1.3 Plaster ... 54 10.2 Execution ... 55 11 Steel Work ... 56 11.1 Civil Design/Engineering ... 56

11.2.1 General ... 56 11.3 Materials ... 57 11.3.1 General ... 57 11.3.2 Steel Specifications ... 57 11.3.3 Galvanizing ... 58 11.4 Execution /Workmanship ... 58 11.4.1 Tolerances ... 58 11.4.2 Connections ... 58 11.4.3 Painting ... 61 11.4.4 Erection ... 61 11.5 QA/QC ... 63

12 Small Non-Structural Steel Parts ... 64

12.1 General ... 64

12.2 Design /Engineering ... 64

12.2.1 Steel Sections and Plates ... 64

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12.2.3 Metal Flooring ... 65 12.2.4 Steel Grating ... 65 12.2.5 Ladders ... 65 12.2.6 Steel Stairs ... 66 13 Waterproofing ... 67 13.1 General ... 67 13.2 Roof drains ... 67

13.3 Rainwater/Gutter down pipes ... 68

14 Metal Works – Roof and Wall Cladding Systems ... 69

14.2 Warranties ... 69

14.3 Codes and Standards ... 69

14.4.1 Wall and Roof Cladding System ... 70

14.4.2 Requirements for Walls ... 71

14.4.3 Requirements for Roofs ... 72

14.5.1 Sunshades ... 73

14.6.1 Supporting Structure ... 74

14.6.2 Fasteners ... 74

15 Metal Works /Joiner’s Work – Doors ... 76

15.1.1 General ... 76

15.1.2 Fire Steel Doors ... 76

15.1.3 Roller Shutter Doors ... 77

15.1.4 Profile Cylinders ... 78

15.1.5 Master-Key System ... 78

15.1.6 Building and Room Designation Signs ... 78

16 Metal Works /Joiner’s Works – Windows and Doors ... 80

16.1.1 Aluminium windows ... 80

16.1.2 Ventilation louvers... 80

17 Glazing ... 81

17.1.1 Noise levels ... 81

17.2.1 General ... 81

17.2.2 Double Glazing Units ... 81

17.2.3 Seal Strips ... 82

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18 Suspended Ceilings ... 83

18.2 Material ... 83

19 Flooring ... 84

19.2.1 Bonded Cement Screed ... 84

19.2.2 Raised Floors ... 84

19.3.1 General ... 86

19.3.2 Protection of Flooring ... 86

20 Tiling ... 87

20.1.1 Ceramic floor and wall tiles ... 87

20.1.2 Acid-proof Tilling Material ... 88

20.2.1 Preparation of Surface ... 88

20.2.2 Placing ... 88

21 Painting ... 90

22 Plumbing and Drainage Installation ... 91

22.1 General ... 91

22.2 Materials ... 91

22.2.1 General Requirements ... 91

22.2.2 Drainage Wares & Fittings ... 92

22.3 Execution of Work ... 93

22.3.1 General ... 93

22.3.2 Pipes and Fittings ... 93

22.3.3 Jointing of Pipes ... 94

22.3.4 Placing of Sanitary Fixtures ... 94

22.3.5 Earthing of Metal Parts ... 94

23 Roads and Pavements, Outdoor Facilities ... 95

23.2 Sub-grade ... 95

23.3 Sub-Base ... 95

23.4 Wet Mix Road Base ... 96

23.5 Bitumen Macadam Layers – General... 97

23.5.1 Design of Bitumen Macadam Layers ... 98

23.5.2 Mixing and Placing of Bitumen Macadam Layers ... 100

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23.7 Hard Shoulders ... 101

23.8 Testing of Material, Field Tests ... 101

23.9 Jointing New to Existing Pavement ... 101

23.10 Fencing and Gates ... 102

23.10.1 Steel Fencing Posts ... 102

23.10.2 Chain Link Wire-Mesh ... 102

23.10.3 Gates ... 102

23.11 Landscaping ... 103

23.11.1 Products and Material (NOT APPLICABLE) ... 103

23.12 Interlocking Paving Blocks ... 103

23.13 Kerbs ... 104

23.14 Traffic Signs ... 104

23.15 Carriageway Markings ... 105

23.16 Guard Rails ... 105

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1 General

The Tenderers are requested to propose high energy efficiency buildings and shall propose energy saving constructions for slabs, walls, windows, doors and roofs according to local or international standards whichever is more stringent and with special reference to Green Buildings Regulations and Specifications. The requirements stated herein are to be followed together with all the relevant de-tailed specifications in civil-, electrical-, mechanical- and I&C-disciplines.

1.1 Scope of Work, Completeness

This specification covers the general technical requirements of civil works. The design and execution shall be state of the art, functional and complete in all parts.

1.2 Civil Design/Engineering

The design and engineering shall be state of the art in accordance with all relevant codes and stand-ards, functional and complete in all aspects. .

Before starting the design works, the Contractor shall submit to the Employer/Engineer for review the project design manual containing design data, and detailed design criteria for all civil works. Design works shall commence only after review of the project design manual by the Employer/Engineer. The reinforced concrete design and working drawings of main structures (concrete buildings and steel structures including shop drawings and connection details) shall be submitted by the Contractor for approval by the Employer/Engineer. Soft copies of all designs and structural calculations shall be sub-mitted along with all models and diagrams.

All main routings (culverts /tunnels /trenches /duct banks /ducts) shall be submitted by the Contractor for approval by the Employer/Engineer.

1.3 Codes and Standards

The design, all materials, civil works constructions and installations, tests and investigations , must be as a minimum conform to the latest edition of the following Codes and Standards (listed in alphabetical order) as far as these standards, codes and regulations are available in an English language edition.

1.3.1 American Standards:

American National Standard Institute (ANSI) American Society for Testing and Materials (ASTM) American Concrete Institute (ACI) American Institute of Steel Construction (AISC) American Iron and Steel Institute (AISI)

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American Water Works Association (AWWA)

Uniform Building Code (UBC)

American Welding Society (AWS)

American Association of State Highway and (AASHTO) Transportation Officials

National Plumbing Code (NPC)

American Society of Civil Engineers (ASCE)

Portland Cement Association (PCA)

National Concrete Masonry Association (NCMA) Occupational Safety & Health Administration (OSHA)

1.3.2 European Standards:

European Norm (EN)

International Organization for Standardization (ISO)

British Standards

British Standard (BS)

British Standard Code of Practice (BS CP)

German Standards

Deutsches Institut für Normung eV (DIN)

Verein Deutscher Ingenieure (VDI)

1.3.3 Local Standards and Regulations

Construction Industry Research and Information Association (CIRIA) Dubai Municipality Coastal Zone Regulations

Other local standards and national regulations, if any

Building regulations and guide lines by the Dubai Municipally, if any Local Green Buildings Regulations

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1.3.4 Other Standards

Other internationally accepted standards which ensure a quality equivalent to or higher than the standards listed above may be used for specific works, but only if these are submitted in an English language edition and approved by Employer/Engineer.

Japanese Industrial Standards (JIS)

Swedish Standards for sand blasting of steel parts

Center for Civil Engineering Research and Codes (CUR) CUR /CIRIA Reports and Manuals

If any standard contains a provision which is inconsistent with a provision in another standard, the more stringent shall apply.

1.4 Design Criteria for Layout, Arrangement, Drawings, Execution

1.4.1 Basic Requirements for All Civil Works

The design of all structures shall be such that differential and total settlements or other movements shall not exceed the limits given by specifications or with the applicable codes, and standards and full provision shall be made for all expansion and other joints.

Safety against uplift has to be guaranteed during all execution stages, especially when ground water lowering is terminated. The factor of safety (FoS) against uplift shall be not less than 1.2.

Structural members subjected to flexure shall be designed to have adequate stiffness to limit deflec-tions or any deformadeflec-tions that affect strength or serviceability of a structure adversely as per the spec-ified criteria or the limits prescribed by the machinery manufacturers (whichever is less).

The superstructures and foundations subjected to vibrations (the primary source of these vibrations being the unbalanced forces generated by rotating or reciprocating equipment) shall be designed such that vibrations will be neither intolerable nor troublesome to personnel, and will not cause damage to the machine or structure.

The natural frequency of the whole of the superstructures and foundations or parts thereof and all structures adjacent thereto shall not coincide with the operating frequency of the vibrating plant. The differences between frequencies and the dynamic analysis of the superstructures and foundations shall be in accordance with the relevant design standard.

The dimensions of all the buildings shall be such as to provide adequate space for the safe installation and proper operation, maintenance and repair of all plant and equipment.

Throughout the works all floor slabs above rooms containing electrical equipment shall be watertight. No drain pipes or water pipes are permitted to pass through these rooms. If this cannot be avoided civil design shall consider double slab with enough accessible space in between.

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All materials used in the Works shall be of the best quality of their respective kinds as specified herein, obtained from sources and suppliers approved by the Employer/Engineer or his representative and shall comply strictly with the tests prescribed hereinafter or, where tests are not laid down in this Specification, with the requirements of the latest issue of the relevant American, British, German Standards or other Standards agreed by the Employer/Engineer. Samples of all materials proposed to be used in the works shall be collected from site for testing at any time by the Employer/Engineer. Access roads with footpaths shall be provided to bring in all the equipment and to take it out in case of maintenance. These access roads shall be suitable for the vehicles which will be used (cars, forklifts, trucks/trailers acc. DIN 1072) to reach up to the point of unloading of the equipment.

All platform, galleries and stairways will be provided with guard rails and kick plates on all sides. No flights will have more than fourteen (14) risers. Where a stairway height exceeds 14 risers, it shall be divided in to equal flights separated by a landing. The minimum clear width of staircase is 100 cm. Suitable access to the roofs of the buildings by means of galvanized and painted steel stairs shall be provided for maintenance and repair of any installation.

All rooms subject to fire hazard shall be provided with emergency exits in accordance to local laws, NFPA regulations and/or the applicable codes and standards. Hindrance free fire escape paths will not be longer than 30 m nor less than 1.0 m wide to the nearest fire escape exit. However, erection routes and doors will be dimensioned in all directions 0.3 m greater than the biggest part which has to be transported, together with its transportation means.

Safe, convenient and straight forward accesses and means are to be provided to take equipment in and out of all rooms, at all levels using suitable stair wells and suitable electric hoists. The dimensions of rooms, stairwells, doors and corridors shall be designed to suit the above mentioned transport con-cept. Storage of cylinders or any other equipment in corridors and along any access route is not per-mitted.

Roof parapet height of all steel or concrete building structures shall be designed for a minimum height of 1.2 meters.

If a culvert(s), and /or tunnel(s), trench(es) or any other underground services are crossing roads, the road shall be suitably constructed for truck loading according to DIN 1072 without affecting the under-ground structures.

All pipe penetrations through water retaining structures/cable trenches/cable tunnels/cable pits and manholes shall be furnished with buddle flanges. Approved type of PVC water bars shall be provided for any underground construction/expansion joints.

All civil designs and drawings, inclusive all steel designs and drawings shall be approved by the Dubai Municipality before start of construction. If the Contractor and/or his Subcontractor(s) starts with the production of constructive elements off site and/or on site, before that approval was given, all changes in Contractor’s work caused by disapproval and/or remarks will be fully on Contractor’s risk in costs and time delay.

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Pedestals and foundations of outdoor equipments or partially shaded shall be designed minimum 0.30m above finished ground level.

All outdoor equipment shall be provided with sunshade as specified hereafter.

Before commencing the works the Contractor shall ascertain the locations and nature of all existing underground services and shall take every possible precaution against any damage occurring to them or interference therewith, during the execution of the works.

1.4.2 Design Loads / Load Assumptions

The following design loads shall be considered for the design of buildings and structures:

Area Value Unit

Live load for building roofs

(A/C equipment and foundations to be considered additionally)

2.5 kN/m2

Sloping Roof-sheet metal construction 1.5 kN/m2

Operation Floors- Ground Floor 35.0 kN/m2

Operation Floors- Upper Floor 17.5 kN/m2

Switchgear Rooms, etc. 10.0 kN/m2

Battery Rooms 15.0 kN/m2

Workshop Floors- Ground Floor 25.0 kN/m2

Workshop Floors- Upper Floor 15.0 kN/m2

Light platforms, Walkways, Stairways : Concrete Steel

5.0 5.0

kN/m2 kN/m2 Additional dead load for suspended ceiling, pipes, AC system, etc. 1.0 kN/m2

Traffic Loads SLW 60, DIN 1072

Roads and pavements, gutters SLW 60, DIN 1072

Underground water tanks, septic tanks, etc. covered by road areas SLW 60, DIN 1072

Areas designated for different loadings on the same floor shall be clearly and permanently marked.

1.4.2.1 Dead Load

Dead load is defined as the weight of all permanent construction including walls, foundations, floors, roofs, ceilings, partitions, stairways, and fixed service equipment.

For heavy industrial work, this would include equipment, vessels, including internals, pipes, valves, and accessories, electrical and lighting conduits, switchgear, instrumentation, fireproofing, insulation; lad-ders, platforms, and other similar items.

Equipment and piping should be considered empty of product load when calculating dead load. The gravity weight of soil overburden shall be considered as dead load.

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1.4.2.2 Erection Dead Load

The erection dead load is the weight of the equipment at time of erection plus the weight of the foun-dation. The foundation weight is the combined weight of the footing, pedestal, and overburden soil.

1.4.2.3 Live Load

Live load is defined as the weight superimposed by the use and occupancy of the building or other structure, but not permanently attached to it. For industrial design, live load can be defined as the load produced by personnel, moveable equipment, tools, and other items placed on the structure, but not permanently attached to it.

Crane loads shall be considered as live load. Unless specified otherwise, the minimum live load values given in Table 1 below shall be considered.

The loads assumptions quoted in Table 1 below have proved useful in the construction of numerous power stations and are to be regarded as minimum requirements.

The Employer/Engineer's consent is required in all cases for reductions of load carrying capacities and for exceeding the permissible stresses.

1.4.2.4 Product Load

The load shall be defined as the gravity load imposed by liquid, solid, or viscous materials in vessels, tanks, equipment or piping during operation.

1.4.2.5 Test Load

The test load shall be defined as the gravity load imposed by any method necessary to test vessels, tanks, equipment or piping.

1.4.2.6 Thermal Load

Thermal loads shall be defined as forces caused by changes in temperature. The primary source of thermal loads in an industrial plant is the expansion or contraction of vessels and piping. Another source of thermal loads in a redundant structure is the expansion or contraction of the entire structure or individual structural components.

1.4.2.7 Impact Load

Any live load that can produce a dynamic effect (such as a moving load) shall be increased by an impact factor.

1.4.2.8 Truck Load

Structures accessible to trucks shall be designed to withstand the gravity, lateral and impact effects of truck loading. Truck loading shall be SLW 60 as defined by DIN 1072. However, when actual expected

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vehicles produce more severe load conditions (heaviest loads of equipment that will be transported) they shall govern.

1.4.2.9 Soil Load

Soil loads shall consist of lateral earth pressures. Active and passive coefficients for lateral pressures shall be obtained from the project soils report. The weight of soil shall be considered as dead load.

1.4.2.10 Hydrostatic Load and Buoyancy

Hydrostatic load is the load due to water pressure. The design of structures shall include hydrostatic loads when applicable. The buoyancy load is equal to the weight of the volume of displaced water.

1.4.2.11 Wind Load

All wind calculations shall be made in accordance with the relevant British Standard using the following factors:

 Basic wind speed at 10 meters above ground = 160 km/h (100 mph)

 Exposure Category = D

 Importance factor, I = 1.15

1.4.2.12 Earthquake Load

All buildings and structures shall be verified against earthquakes considering seismic zone 2B of UBC or any latest local regulations requirements.

1.4.2.13 Dynamic Loads

Each structure shall be designed to withstand the effects of vibration and impact to which it may be subjected. Each structure and foundation supporting a compressor, turbine, pump or other machinery having significant dynamic unbalance shall be designed to resist the peak loads specified by the man-ufacturer. Vibration amplitudes of the supporting structure or foundation shall be kept within accepta-ble limits for dynamic forces that occur during normal machine operation. In the case of a tall and slender structure, there may be a need to investigate the dynamic effects of wind gusts.

1.4.2.14 Surge Load

Surge loads may occur in some vessels or equipment. In such cases, the magnitude and direction of the load shall be given by the equipment supplier.

1.4.2.15 Bundle Pull Loads

The force requirements to remove the tube bundle from a shell and tube heat exchanger may vary from zero for those vessels in which the removal is done by application of hydraulic pressure resulting in no external reaction to 1 - 1/2 times the weight of the bundle for external pull. The variation is due

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to the unpredictable coefficient of friction existing between the shell and the tube supports after the exchanger has been in operation. The usual practice, if applicable, is to use one-half the weight of the bundle for exchangers in clean service, but not less than 1,000 kg.

1.4.2.16 Future Load

Loads from future expansion shall be considered when so directed by the Employer/Engineer. Future loads may include any of the loads listed above.

1.4.2.17 Miscellaneous Loads

Miscellaneous loads shall be defined as loads that do not fit into the categories listed in this clause. Typical miscellaneous loads are loads, during erection, maintenance and repair or forces due to creep, shrinkage, or settlement.

For the design of the individual structural components load combinations in accordance with the rele-vant design standards shall be considered.

All loadings considered in the design shall be justified with supporting details.

1.4.3 Tolerances

The following tolerances for buildings and structures are binding:

For dimensional tolerances of structures BS ISO 1803: 1997, DIN 18 201, DIN 18 202, and DIN 18 203 are binding.

The maximum allowed settlement under buildings shall not exceed 2.5 cm. In case of soil improve-ments or deep foundations works, specified allowable settleimprove-ments under the relevant sections shall be followed.

For equipment foundations OEM requirements shall be followed. For deflection of structural steel members the following shall be applied:

Type of members Deflection Remarks

Simple / continu-ous beam

Cantilever beam

Girder-beams supporting floors, walkways 1/300 L 1/250 L DL + LL + W

Pipe rack beams 1/300 L 1/200 L DL + LL + W

Crane-track or trolley beams (exc. impact) 1/1000 L 1/350 L DL + LL Monorail girders (crane loads need not be

com-bined with wind or seismic loads)

1/500 L

Wall stanchions and girders 1/300 L Only for wind

force

Roof girders or purlins 1/300 L DL + LL + W

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1.4.4 Special Requirements for Materials To Avoid Corrosion Problems – Reinforced

Concrete

1.4.4.1 General

Due to very severe climatic conditions in the project area, special measures are necessary to protect the different materials from corrosion. In this context the following materials need protection measures:

1.4.4.2 Reinforced Concrete

The following special design aspects have to be considered by the Contractor:

Top surfaces of all indoor and outdoor equipment foundations and slabs where surface wa-ter/fuels/chemicals might accumulate (due to leakages or similar), shall be provided with a slope. to-wards drain channels/drain pits.

For the same reason as above, the exposed concrete edges shall be chamfered.

In order to control the size and mitigate the occurrence of cracks and to ensure concrete durability, the Contractor shall implement the following design requirements:

Use smaller reinforcing bars well distributed over the zone of maximum concrete tension. Use Portland cement conforming to the requirements of ASTM C150, Type II.

Using blended cements or adding materials such as pulverised fuel ash, ground granulated blast fur-nace slag or silica fume in order to increase the density of the concrete mix.

Use very dense, low water/cement ratio (not exceeding 0.40) concrete.

Use synthetic fibres to minimize surface shrinkage cracks (Synthetic fibres shall not be used in rein-forced concrete structure).

Provide foundation tanking and/or surface coating.

Provide strict measures for concrete curing to prevent plastic shrinkage and thermal gradients result-ing from early age heat of hydration of fresh concrete.

Protect inserts, anchor bolts and all steel items embedded in the concrete from corrosion. Prevent the usage of steel profiles in small concrete sections.

Identify clearly the locations of the construction joints as well as their surface preparation in the draw-ings.

Incorporate other factors to increase concrete durability in concrete specifications, such as special measures for concrete protection in the Gulf region, especially for hot weather concreting etc.

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Give special consideration for the protection of concrete surfaces subject to high temperatures during plant operations.

Water retaining structures as tanks, manholes, pits including cable trenches shall be designed to BS 8007/BS EN 1992-3, where crack widths are not to exceed 0.2 mm.

Depending on the place of use, the special corrosion protection measures for reinforced concrete shall be as follows:

 Buried concrete or concrete within the groundwater capillary zone: ○ Minimum concrete cover 75 mm

○ Measures as outlined above and use of microsilica

○ Outside protection by tanking membranes and protection boards, with membranes extend-ing 15 cm above ground level.

 Concrete above ground

○ Minimum concrete cover 50 mm.

○ Measures as outlined above and use of microsilica

○ Outside protection and coatings as specified in Tender Document Volume II, Part G05.5 “Cor-rosion Protection and Painting”

 Concrete exposed to chemicals:

○ same measures as for item (2) above

○ In addition finished surface to be protected with appropriate finishes as acid/alkali resistant tiles. GRP lining (neutralization pit, tanks) as applicable. Coating as specified within Tender Document Volume II, Part G05.5 “Corrosion Protection and Painting”.

1.4.5 Special Requirements for Materials to Avoid Corrosion Problems – Steel

Structures

The following steel structures shall be hot dip galvanized and painted according to Tender Document Volume II, Part G05.5 “Corrosion Protection and Painting”:

 Steel structures and structural members inside buildings /open air arrangement  Structures with chemical exposure

 All secondary steels (pipe racks, platforms, stairs, railings, ladders) and equipment supports/skids  All bolts /nuts (if not of stainless steel). Embedded parts of bolts/anchors inside concrete need

not to be painted.

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The Contractor shall provide all technical information and a complete list of all parts to be galvanized for the Employer/Engineer’s approval.

Galvanizing shall be carried out in accordance with BS 729/ BSEN 10143, and shall be smooth, contin-uous and free from flux stains. The minimum average coating weight of galvanising shall be as follows, if not higher values are specified elsewhere,

Thickness of steel articles Minimum average coating weight

5 mm thick and over 610 g/m²

Under 5 mm but not less than 2 mm 460 g/m²

Under 2 mm but not less than 1 mm 335 g/m²

Note: 610 g/m² is equal to a thickness of 86 µm.

Small areas of galvanised coating damaged by welding, cutting, or during transport shall be repaired by applying at least two coats of zinc-rich paint.

1.5 Materials (Quality, Delivery, Storage, Handling)

1.5.1 General

Only approved construction materials shall be used. Material that has not been approved by Em-ployer/Engineer must be removed and disposed of at the Contractor’s own expense. For this purpose, Contractor shall establish at site a quality control procedure for material delivery and notify Em-ployer/Engineer for inspections and witnessing of sampling for testing. All sampling works shall be done by the third party specialist/technician. All tests reports along with analysing of results and com-parison with the specified/standards criteria shall be submitted as soon as possible results are availa-ble.

1.5.2 New /Unused Materials

Only new /unused materials shall be used and no recycled material is allowed. All materials must be proofed and tested by an independent approved third party firm accredited by DM with design certi-fication from the manufacturer. All proposed materials intended to be used for construction shall have a record of previous approvals (mainly from local authorities) and usage in similar projects and under the same environmental and harsh weather conditions. Services of testing shall be extended to earth works/soil properties, concrete, steel and other materials whenever called by Employer/Engineer on the account of the Contractor.

For testing of these works, sampling, handling, transport to the laboratory, reporting and analysing of the test results shall be by Third Party specialized laboratories. The reporting and analyzing of the test results shall be submitted to the Employer/Engineer.

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1.5.3 NA

1.5.4 Samples

The Contractor shall provide samples of all materials, embedded parts and installations, for the Em-ployer/Engineer’s review before start of construction. Three samples of each main construction mate-rial shall be submitted for Employer/Engineer selection.

All approved samples shall be collected and stored in a “sample room” and all approvals shall be con-secutively recorded.

1.5.5 Supplier/ Material Approval Procedure

The Contractor shall supply, as far as is practical, the following information:

On supplier or source a review of previous performance in supplying to similar specifications, evidence that he can legally supply to UAE, capacity of plant, other ongoing commitments, details of main items of plant and key personnel, independent references (if any and preferably unsolicited), test reports on similar products (again preferably independent).

On materials or products a copy of drawings, design calculations, supplementary specifications, and previous test results, inspection, taking samples and tests according to the specification. All that is necessary and sufficient information to demonstrate conformance with this specification.

Approvals previously granted for any materials etc. shall be withdrawn if they are not properly trans-ported, handled or stored and otherwise protected against weather or contaminants, which may ad-versely affect their properties. The Contractor has the option of removing such materials or having them retested for approval.

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2 Site Installation and Demobilisation

2.1 Scope of Work, Completeness

Refer to Tender Document Volume I, Part G03 “General Project Requirements”. Due to the limited space on the plot area, it is not allowed to use it for long term storage of any equipment and/or mate-rial.

Areas allocated by Employer, for the site installations shall be utilized in an optimized manner for of-fices workshops and stores. All site ofof-fices shall be built as multi storey buildings.

The Contractor, if requiring additional area, shall look for sufficient lay down areas, storage space and facilities, labour camps, parking places off site. The Contractor shall be responsible for obtaining all No Objection Certificates (NOC) of various authorities without additional cost borne by the Employer All construction areas, storage areas and any other temporary site installations shall be surrounded by temporary fences as per local authorities requirements. All underground services crossing the access roads to the construction areas shall be protected by Contractor by means and structures approved by Employer/Engineer.

2.2 Execution (Assembling, Installation)

All works for site installation must be executed in accordance with latest Health, Safety and Environ-mental rules (HSE)

Basic cleaning includes all floors, walls, ceilings, built-in fittings and equipment, including the furnish-ings. The basic cleaning operation must result in a degree of cleanness which permits the fully equipped buildings and rooms and associated outdoor installations and secured surfaces to be taken over without complaint. The Contractor shall be responsible that all cleaned areas and facilities will be conserved at a complete clean stage till to the final handing over to the Employer.

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3 Site Supervision/Survey/Investigations

3.1 Site Supervision:

The Contractor shall establish at Site a team of experienced civil engineers dedicated for review and checking of civil design and drawings only. Team leader shall be an Engineer from home office organi-sation of the Contractor with minimum 10 years experience in the field and shall be responsible for the correctness of design and its conformity with the specifications. Documents and drawings shall be forwarded to the Employer/Engineer for his approval only after being reviewed and signed by the as-signed team leader. The same team shall be also capable to make minor changes and corrections in design drawings during the construction stage.

Contractor shall establish another team of experienced civil engineers dedicated for checking of site works of civil sub-contractor. As above, team leader shall be an Engineer from home office organisation of the Contractor with minimum 10 years experience in the field and shall be responsible for the con-formity of the sub-contractor’s works with the design and the specifications and for the quality of workmanship. The Employer/Engineer shall be called for inspection only after the assigned team leader confirms his checking by signing in the inspection sheets.

Prior to release for pouring of concrete for floors, walls and roof of buildings, structures and founda-tions at site, each sub-contractor is responsible for checking of formwork and reinforcement as well as his latest requirement concerning the location/projection of anchor bolts and embedded items, the location and size of equipment pads and foundations, the location and slope of piping, conduits, cables, wiring and accessories, location and size of floor, wall and roof penetrations. After checking for cor-rectness of the concerned disciplinary Contractor shall sign a "Free for Casting Certificate" which per-mits the Civil sub-contractor to proceed with casting of concrete and/or constructing after release of the same by the Employer/Engineer.

The Contractor shall submit individual inspection sheets to the Employer/Engineer 24 hours prior to the commencement of the works such as excavation, backfilling, concreting and structural steel erec-tion etc., Works shall commence only after Employer/Engineer’s approval the inspecerec-tion sheet. Em-ployer/Engineer’s approval shall, however, not relieve the Contractor of any of his obligations under this Contract. Form of the inspection sheet shall be proposed by the Contractor and approved by the Employer/Engineer.

It is to be noted that should the Contractor repeatedly fail to notify or inform the Employer/Engineer of inspections, sampling or testing (if any) then the Employer/Engineer may carry out independent checks without informing the Contractor and reject parts of the works should the results of such in-spection or testing merit. As far as is practicable the Employer/Engineer shall have free access to the site, fabrication areas and suppliers work at all times without notice. Should he discover unsatisfactory work then he will invite a formal joint inspection. Either after such an inspection or if the Contractor declines the invitation the Employer/Engineer shall issue instructions with regard to the faults and their reparation.

The Employer/Engineer may select the sampling point at no cost. The Employer/Engineer may instruct tests at no cost provided either the overall frequency governed by the specification is not exceeded and the notification given to the Contractor is equal to that currently being provided by the Contractor

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for his normal testing in formality and warning, or the Employer/Engineer has due cause to suspect a change in the quality, such concern having been advised to the Contractor.

The Employer/Engineer may instruct sampling, testing or both which satisfy only some or none of the above criteria.

3.2 Survey and Investigations

To enable the Contractor to carry out his survey and construction work, he will be furnished by the Employer with the bench marks showing their description, number, co-ordinates and levels to an ex-tent necessary for the work. These information are preliminary and the Contractor is responsible to check, verify and correct, if required, these data before starting his work and he must forward a written notification concerning the discrepancies to the Employer/Engineer and obtain his approval.

All surveys required for construction of the works shall be performed by the Contractor as construction work proceeds. Survey points distributed at different locations established by contractor shall be du-rable and suitably protected to avoid any damage through out the construction period.

Levelling bolts according to DIN 18708 shall be installed by contractor for the RCC foundations and structures immediately after construction and protected from damages till handing over.

In all buildings and major foundations at least 4 levelling bolts shall be installed at 1.00 m above floor surface.

The position and the total number of surveying points shall be finally decided by the Employer/Engi-neer in co-operation with the Contractor, on the basis of the settlement report.

Measurements of all levelling bolts are to be executed:  immediately after setting of the bolt

 prior to the erection of mechanical equipment

 several times during the erection period of the mechanical equipment  after completion of the buildings/structures and erection of all equipment  Once before the plant is handed over to the Employer.

All reports shall be submitted on regular basis as agreed by EMPLOYER/ENGINEER.

The Contractor shall establish and mark one reference permanent survey point with co-ordinates and elevation at each floor level (preferable at column face) within all buildings and structures. This refer-ence survey point shall be used by the electrical/ mechanical Contractor for the equipment erection work.

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4 Dewatering During Construction

This section applies to the methods and techniques of ground water control. All costs for ground water control for keeping the construction pits and areas at least 500 mm below formation level dry shall be included in the lump sum.

The method and technique shall be based on the British Standard BS.8004 or any equivalent agreed with the Employer/Engineer. NOC shall be obtained from Dubai Municipality prior to installation of dewatering system.

The scope of supply includes the installation of all equipment, plants, pipes, machinery and its removal after completion including operation and maintenance of the equipment during the construction pe-riod. All equipment, instruments, machinery, tools, pipelines, required for execution of the water con-trol shall be in good repair and shall be kept in good working condition throughout the operation pe-riod.

Where necessary, cofferdams, sheet piles, pump sumps, equipment and channels, troughs, inlet gut-ters, pipes and any other works required for the water control and discharge shall be part of the scope of supply. The dewatering system shall be designed and installed in such a way that alteration and extensions can be made at any time throughout the operating time, if necessary. Reserve units shall be kept ready for service when failure of any of the installed units occurs.

The Contractor shall submit to the Employer/Engineer, the detailed method of the envisaged pumping system for dewatering, the pump capacity and the standby reserve units.

The Contractor must ensure that any dewatering works will not cause any interference to his own work and to those of other Contractors working elsewhere on site or at structures under construction or existing structures and facilities. Any damage occurring during the above mentioned period shall then be made good by the Contractor at his own expense.

Routing and location of water discharge lines shall be submitted to the relevant authorities and to the Employer/Engineers review. The disposal of water shall be in accordance to the local environmental laws and regulations. If applicable according to the local laws and regulations the pumped water has to be treated accordingly before disposal.

The Contractor shall maintain ready-for-service and regularly clean all dewatering equipment and ac-cessories and shall keep all access clear so that they can safely be used without risk of accident. Any requirements made by the Employer/Engineer in this matter shall be carried out immediately.

4.1 QA/QC

The Contractor shall keep records of all data of importance occurring during operation of the water control system. The records shall be submitted to the Employer/Engineer for information and checking every working day. For that purpose, the lowering of the water table shall be controlled by piezome-ters. The numbers and position of them shall be submitted to the Employer/Engineer's for approval. The Contractor shall provide and maintain these piezometers at his own expenses during the dewater-ing works or as long as the Employer/Engineer requires it.

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Pump operations shall not be stopped nor pipes, channels and equipment for dewatering and water control removed or altered in any way, except with the express permission of the Employer/Engineer. The Employer/Engineer will stipulate the time of removal. Until then, the pumps and water drainage facilities shall be kept in proper working order without extra payment being granted.

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5 Site Clearance and Earth Work

5.1 Site Clearance- General

The exiting ground level of the site area is about + 3, 00 m DMD and plot area is partially covered with trees that shall be treated as per Tender Document Volume III, Part P20 “Civil Works”. Due to the high ground water level the site area shall be backfilled up to a level of + 4.00 m DMD by selected fill mate-rial with properties specified here down and approved by Employer/Engineer. Elevated plant area shall be coordinated with surrounding structures/facilities/services/roads and shall be well designed for smooth transition at road connections. Soil embankments shall be protected against soil movement by suitable stone pitching of size at least 200 mm laid on a well prepared and compacted surface and above a 100 mm thick concrete blinding layer. Joints of stones shall be filled and grouted with blended cement and additives that will guarantee a durable construction with minimum maintenance. The final finished ground level of buildings shall be +4.20 m DMD.

This work consists of clearing, grubbing and stripping the area of the work of stumps, bushes, roots, down timber, rotten wood, rubbish, debris, humus, swamp material and any other vegetation or un-acceptable materials as ordered by the Employer/Engineer.

Disposal of excess soil and unusable waste materials shall be the responsibility of the Contractor. The Contractor shall transport the materials to a suitable dumping area and obtain the necessary approval from the municipal authorities at his own expense. Stacking of all materials shall follow the Green Buildings Regulations regarding segregation

Burning and blowing off of any material and use of explosives is not permitted.

Prior to start clearing or filing works, contractor shall locate any existing underground services and protect or relocate as per Employer/Engineer approval at his own cost.

5.2 Earth Works, Completeness

The Contractor shall satisfy himself as to the ground conditions on the site including the nature of the strata to be excavated, obstructions, possibilities of flooding and such like and shall allow for all provi-sions necessary to carry out the work in the most suitable manner when submitting his tender. Generally all buildings and structures must be founded on bearing strata which means that all excava-tion work for foundaexcava-tions shall meet the requirements of structural analysis based on the results ob-tained from the soil investigation and of the available information and instruction given in writing by the Employer/Engineer.

Excavation shall be done to the required dimensions including required working spaces and shall be finished according to the specified lines and slopes. All necessary precautions shall be taken to cause the minimum possible alteration or disturbance to the material lying under and adjacent to the exca-vation final lines.

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5.3 Materials (Quality, Delivery, Storage, Handling)

The fill materials used are to be examined and approved. Excavated materials can be used if they fulfil the requirements.

5.3.1 Select Fill

Select fill shall have the following properties:

Well graded (uniformity index not less than 5), non-cohesive and nearly silt free (silt content not greater than 5%; up to 10% tolerated, except below footings of structures) and plasticity index not exceeding 6, liquid limit not exceeding 40 %, salt free (content less than 3%), soils free of organic mat-ter (limit 2%). Decomposing or compressible mamat-terials shall not be used.

All material shall be of such nature and character that it can be compacted to the specified densities in a reasonable length of time. It shall be free of highly plastic clays, of all materials subject to decay, decomposition or dissolution, and of cinders or other materials which will corrode piping or other metal.

The intention is to use select fill below structures, roads, parking areas.

5.3.2 Ordinary Fill

Ordinary fill shall have the following properties:

Natural inorganic soils: salt content not greater than 3%, organic matter less than 3%. For other prop-erties see under 'Select fill'.

The intention is to use ordinary fill for non-built areas.

5.3.3 Special fill

Special fill material shall be gravel or crushed rock (for other properties see under 'Select fill'). The intention is to use special fill e.g. as sub-base material for tanks and roads.

5.4 Execution (Assembling, Installation)

The works shall be excavated either by hand or by use of excavating plant and tools acceptable to the Employer/Engineer. Method statement for earth works shall be submitted for approval by Em-ployer/Engineer.

5.4.1 Safety Precaution

The Contractor shall be responsible for all necessary safety measures.

Proper strutting, sheeting and bracing, including re-arrangement of the installations when necessary, stabilization and protection of slopes by hessian and cement, methods of excavation to reduce risks of

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slides shall be to the Contractor's debit. The additional moving of soil resulting from such damages will not be paid for.

5.4.2 Stockpiles and Disposal

The construction and lay down areas are limited. Excavated material from the Works selected by the Employer/Engineer for re-use shall be placed immediately in its final position, if possible, or otherwise may be stockpiled or deposited on Site or carted away as directed by the Employer/Engineer. It is the responsibility of the Contractor to determine the location of an off-site disposal area. Stockpiling is accepted for short periods only and in any case it shall not obstruct the construction and progress of site works.

The Contractor shall not have the right either to additional payment or to claim because of work in-volved in stockpiling materials, re-use of for carting to the waste disposal areas. Necessary approvals shall be obtained from concerned authorities for waste disposal areas.

5.4.3 Preparation of Foundations

For all types of foundations and immediately after excavation the formation level of foundations shall compacted up to 98% (degree of compaction) , and then protected by means of a lean concrete layer, 7.5 cm in thickness over a layer of plastic sheet. No concrete is to be poured until formation level is inspected and agreed by the Employer/Engineer. Plate load test shall be conducted at site under areas agreed by Employer/Engineer in order to verify the parameters considered in design.

For all foundation works, formation level shall be at least 1.0m below the finished ground level.

5.4.4 Backfilling

Foundations and structures shall be backfilled as shown on the drawings with agreed material com-pacted in layers by suitable equipment until optimum stability has been obtained to the satisfaction of the Employer/Engineer. Compacting shall be carried out with special care by means of pneumatic or mechanical rollers or other compactors of a type previously agreed by the Employer/Engineer. Density requirements shall be as follows by tests per modified AASHTOT-180 Method D, at optimum moisture content

 Under buildings and structure foundations and slabs - 98%  Under roadways and parking areas - 98%

 Embankment - 95%

Backfilling of foundation work with agreed materials shall be carried out only after foundations have been inspected by the Employer/Engineer.

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5.4.5 Soil Replacement

The material to be used for replacement of soil shall not contain soluble or swelling components such as clays, or organic matters. Sand gravel mixtures of agreed grain size distribution shall be used in exchange.

The fill material shall be placed in horizontal layers of no more than 25 cm thickness. The fill moisture content shall be controlled and adjusted in order to achieve a maximum of compaction. Fresh water shall be used for watering of soils. The foregoing shall be confirmed by Tests mentioned in Tender Document Volume III, Part G05.6 “Inspection and Testing”. One Modified AASHTO or Proctor and three (3) density tests shall be made at every second fill layer prior to continuation of filling work. The testing location will be indicated by the Employer/Engineer. The results of the tests shall be made available to the Employer/Engineer within 24 hours of the tests. Filling work may be continued in case all tests performed show satisfactory results.

5.4.6

Pipe Bed Preparation

Pipe beds shall be constructed to guarantee the uniform transmission of loads. The bearing section for supported profiles shall cover at least an arc of 90°.

Pipes shall be bedded in an earth foundation of uniform density and carefully shaped by means of a template supported at the desired grade, to fit the lower part of the pipe exterior.

Where a firm foundation is not possible at the grade established due to soft, spongy or other unstable soil, all such unstable soil under the pipe and for a width of at least one diameter on each side of the pipe shall be removed and replaced with suitable selected materials as agreed by the Employer/Engi-neer, properly compacted to provide adequate support for the pipe.

5.4.7 Protection of Existing Utilities and Services

During construction the Contractor shall provide all protection for existing utilities and services as may be required by his construction operations. Permanent protection of certain items shall be as included under other clauses or as instructed by the Employer/Engineer.

In addition to the requirements as specified, herein the Contractor shall comply with the following requirements.

Use all necessary precautionary and protective measures required to maintain existing utilities, ser-vices and appurtenances that must be kept in operation. In particular the Contractor shall take ade-quate measures to prevent undermining of utilities and services presently in services.

Protect existing or new utilities and services where required by the Contractor’s operations and/or as directed by the Employer/Engineer. The Contractor shall be responsible for bracing and supporting utilities and services to prevent settlement, displacement or damage.

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5.4.8 Deep Vibratory Techniques

Loose or soft soils in the natural or existing stage unsuitable for foundation purposes can be improved by deep vibratory techniques in order o maintain the settlement of structures within the allowable limits. The technique by vibro compaction or vibro displacement, material and design/details of the deep vibration are subjected to Employer/Engineer approval. All works shall be executed by an ap-proved specialist in this field of works. Contractor is responsible to prove that those works does not affect the operating power plant in any aspect.

By any approved technique, all layers between foundation level and bearing soil are to be compacted to a relative density of at least 80% and prepared for an admissible soil pressure of at least 250 kN/m2. And settlement of structure/foundation is limited to 1.5 cm.

The final foundation level shall be covered with at least 50 cm crushed stone or gravel fill and com-pacted to 95% relative density with a 10 ton vibrating roller (at least two layers performing 6 passes); All water used in construction and soil improvement shall be fresh water.

5.4.9

Dust Control

The Contractor shall use all means necessary to control dust on roads, construction areas and borrow pits. Surfaces shall be regularly on daily basis and when required, watered to prevent dust becoming a nuisance for the public and have impact on the nearby installations and services or interfering with the proper execution of the works. Waste oil is not permitted for the use as dust control. Temporary roads and access ways may be covered with suitable gatch materials to reduce the development of dust. Sand and dust (especially cement dust) shall be contained with in the construction site. Method state-ment for dust control shall be approved by Employer/Engineer.

5.5 QA/QC, Test and properties

5.5.1 General

The Control of working and tests operations shall be carried out by the Contractor in the presence of the Employer or Engineer.

The Contractor shall prepare sheets for statistical analysis of the field and laboratory tests, and shall submit the sheets to the Employer/Engineer for approval. Controlling will consist of field and labora-tory tests, such as:

 One (1) test analyzing the chemical ingredients of the water used for performance of the work and the soil.

 One (1) test for bearing capacity of soil for static load as per ASTM D 1194 - 57.

 Three (3) tests for density of soil in place of sandcone method for each second layer of "Backfilling and/or replacement of material and/or roadwork" are required as per ASTM D 1556 - 64.

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All tests shall be recorded in forms acceptable to the Employer/Engineer. Tests shall be performed for each 500m3 of fill but not less than once per shift.

5.5.2 Quality Assurance for Vibro Techniques

Before starting the compaction works, the Contractor has to prove by tests whether he is able to im-prove the underground to the above requirements. The test program and vibro pattern is to be pro-posed by the Contractor and to be agreed by the Employer/Engineer, and shall contain a trial compac-tion, dutch cone tests (before and after the treatment) and big scale load tests comprising at least 4 compaction points covered by a concrete footing.

By the vibro compaction or vibro replacement, the soil is improved to meet the following Dutch cone resistance requirements below the foundation level (in addition to other requirements):

 from 0 to 3 metres: cone resistance increasing linearly to 10 MN/m2

 from 3 to 5 metres: 10 MN/m2

 from 5 to 7 metres: 15 MN/m2

 beyond 7: 20 MN/m2

The resistance for the first 3 m shall be 10 MN/m2, when the tests are done from a level more than 2 m above the foundation level. The results are judged to be successful if not more than 10% of the measured values are below the above requirements. The tests will be performed in the most unfa-vourable location of a probe group. The number of sounding tests shall be at least 5 for one structure. Big scale plate load tests shall be performed, for quality control purposes, at least two for each struc-ture . These tests shall cover an area of 4 compaction points/stone columns in addition to the spacing (in both directions) and shall be loaded to twice the permissible soil pressure.

All test results shall be compiled in test reports, where values obtained are compared with requested values (in diagrams as far as possible, Es- values derived via settlement calculation from test results). A method statement and quality control program shall be prepared by the Contractor and agreed by the Employer/Engineer prior to start of vibro works containing at least the above requirements and information about the following:

Description of large scale load test including load steps/waiting time

Data recording of probe number and depth, date and time of execution, installation time for every probe, gravel consumption (if applicable), power consumption versus time or depth (automatically recorded) etc.

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6 Piling Works

These specifications cover the requirements for the materials, the installation and the realization of bored cast-in-place concrete piles and driven cast in place piles with grouting at the base. The scope shall include the preparatory works for piling, design, construction works, testing, pile head cutting, pile head treatment (waterproofing, grouting), cleaning, etc.

6.1 Documents to Be Submitted

The following documents shall be submitted by the Contractor to the Employer/Engineer in due time and are to be approved before starting the piling works:

Design calculations of the proposed type of piles and detailed drawings including the typical reinforcing details.

Design of the concrete mix as per Clause 7 specified herein. Method statement for preparation, construction and testing.

Detailed description of the plant and equipment along with the pre-qualifications of the piling works subcontractor.

Piles record book and concrete control record.

6.2 Design Criteria, Arrangement Drawings

The piling works and design shall be in accordance with the latest editions of internationally accepted standards. Copies of codes and standards used for design and construction shall be furnished by con-tractor if requested by Employer/Engineer.

Two (2) types of piles foundation can be proposed and quoted by the Contractor: cast-in place driven piles or cast-in-place bored piles. Grouting of the rock below the piles shall be considered if dictated by soil conditions. The pile bases shall be embedded in the rock level, determined by the soil investi-gations made at the beginning of the works by the Contractor. The net vertical pile capacity computed from the soil investigation report is used to determine the maximum test load in case of piles testing. The net compressive stress within concrete shall not exceed 5 MPa. The net tensile stress within steel reinforcement shall not exceed the allowable values furnished in the standards and norms.

6.2.1

Bored Cast-In-Place Piles and Driven Piles

Bored cast in place piles are drilled up to the depth indicated by the pile drawing submitted by the Contractor and agreed by the Employer/Engineer. For each pile, the Contractor draws up the geotech-nical profile of the drilling with description of the strata and samples taken for each stratum as men-tioned in the piling record item of these specifications. A representative sample from each stratum will be kept in tight packing until the end of the works.

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Generally drilling operations shall be carried out in such a way as to avoid any disturbance of the soil. A temporary casing shall be installed to the full depth of the borehole (except in stable rocks). The bottom of the casing shall always be kept sufficiently below the excavated borehole bottom, in order to prevent inflow or loosening of the adjacent soil.

Just before reinforcing and start of concreting the pile foot is to be cleaned out so that no disturbed, loose or weak soil remains below the pile tip.

For driven cast in place piles, the Contractor shall provide to the Employer/Engineer all data proving the suitability, efficiency and energy of the driving equipment.

Comprehensive details and method statements for construction shall be submitted by Contractor for Employer/Engineer approval. Anchorage in the Rock

When different top levels of the rock are encountered during the pile borings, the anchorage levels will be adopted and submitted for review by the Employer/Engineer but the minimum embedment shall not be less than 3 times the pile diameter.

When the bedrock is reached, the steel casing has to be pushed as far as possible into it, in order to avoid penetration of sediments by any possible space between the rock and the bit of the steel casing.

6.3 Materials (Quality, Delivery, Storage, Handling)

6.3.1 Steel Reinforcement and Concrete

The piles shall be longitudinally reinforced on the whole length with high steel yield epoxy coated bars. The minimum ratio of longitudinal bars is 0.8% of the pile cross section, with a minimum of 6 bars not less than 12 mm in diameter. The minimum spacing between longitudinal bars is 15 cm (DIN 1045). Helical binding shall be used with a minimum diameter of 10 mm and a maximum pitch of 15 cm. Reinforcing cage shall be stable and bars properly tied with the helical stirrup at all joints with plastic coated wires. It shall be perfectly centred within the borehole by the aid of concrete spacers distrib-uted every 1000 mm centres along the vertical bars and has same properties as for the pile. The concrete cover to reinforcement shall be not less than 75 mm and not more than 100 mm. The rein-forcement cage is put into the hole in only one operation. The cage must remain stable during con-creting and removal of the temporary casing. The handling of the cage during loading, unloading and installation within the holes has to be made with care in order to reduce the deformation and to avoid the breaking of the binding wires. Cages shall be held firmly in position by the aid of rigid hangers. Proprietary PVC pipes shall be used to protect part of main bars that will be anchored inside the foun-dations/pile caps. Connections for main rebar splicing area shall be properly design to avoid settlement during concrete pouring operation.

Concrete mix design for piling works shall be submitted for review by the Employer/Engineer. The concrete shall be as per Clause 7. The water/cement ratio shall not exceed 0.40.

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6.4

Execution (Assembling, Installation)

6.4.1 Program

The program of piling work is to be submitted for approval by Employer/Engineer four weeks before the start of the piling works. Sequence of piling shall be stated including adequate notice of his inten-tion to work outside normal hours and at weekends. Daily reports shall be submitted showing the actual accumulated progress and the plan for next day.

6.4.2 Qualification

The piles installation shall be undertaken using proven techniques and equipment and shall be imple-mented by specialist personnel who have extensive experience in carrying out such work. The Contrac-tor shall provide qualified personnel i.e. a foreman for every piling crew, who shall always be present during the works, as well as a professional engineer, well experienced in piling works, for supervision.

6.4.3 Staking-Out Tolerances

The maximum allowed deviation of the piles centre from the theoretical location shown on the setting out drawing is 50 mm in any direction. The maximum permitted deviation of the completed pile from the vertical is 20 mm per meter (2.0%). Contractor shall establish the reference bench marks, grids and coordinates which shall be used for inspection and setting of piles.

6.4.4 Cut-off

The piles are to be concreted up to a minimum of 60 cm above the cut-off level.

The cut-off must eliminate all polluted or poor characteristics concrete at the top of the pile and should be carried 50 mm into sound concrete. When this sound concrete is found below the cut-off level, the Contractor must realize, at his own expenses, a new concreting up to the cut-off level with a full con-nection to the pile. Any repair must be agreed by the Employer/Engineer. Prior to proceed with raft/pile cap foundations, pile head shall be wrapped with an approved swelling unit water bar, water proofing membrane and grouted.

Rejected piles due to quality of concrete, or non compliance with design criteria shall be replaced by the contractor on his own cost.

6.4.5 Working Platform

The areas where piling operations are to be carried out is to be levelled and kept clear of water to provide a dry stable working platform for the plant and equipment operation which shall be 1 to 1.5 metres above the designed cut off level.

After completion of the piling works the project site is to be cleaned and all excavated material due to these works is to be removed by the Contractor.