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Saturday, May 5, 2012

Site preparation


1.1 Description
Site preparation work consists of site clearance, survey, cutting, imported fill, embankment and construction of ditches for drainage. Work of this section includes all measurement and materials required to complete the supply, execution and construction of site preparation.
1.2 Site Clearance
The contractor shall clear, from all areas planned for the work, all buildings, materials, debris, etc, prior to the cutting and filling work taking all necessary precautions to prevent damage to the existing road structures and buildings or other facilities, in the area, which shall not be demolished.
1.3 Survey
Prior to commencement of the work, the contractor shall check the existing bench marks and reference points located on or out of the site as indicated. The contractor shall establish newly standard bench marks and points for the works within the site with the agreement of the Engineer.
a. Traversing
Prior to execution of the works the contractor shall check the existing reference points, and the results shall be submitted to the Engineer for approval.
b. Principal points
Principal points shall be established taking advantage of the existing reference points.
Individual principal point posts shall be of wood, 15cm x 15 cm size, with an indicating nail on the top, the surface of the post above the ground shall be painted white.

c. Bench marks
When establishing bench marks within the site, a minimum



2.1 Scope of Work
Earth work consists of excavation, back filling and disposal of surplus Material. Work of this section includes all measures and materials required to
complete the design supply, support, use, construction, removal of earth work.
2.2 Excavation
The ground shall be excavated to the lengths, widths and exact depths required for the construction of the works. The contractor shall examine any unsuitable or weak ground material, standards of which are given below and shall report the situation in writing to the Engineer before executing concrete or any other Works.
if the surface of a subgrade is found to be unstable or to include any type of refuse subject to removal in the opinion of the Engineer, the contractor shall excavate and remove such unsuitable Material to the width and depth required by the Engineer. Any excavation to a level lower than that indicated on the drawings shall be compensated for filling with concrete mix (1:4:8)



3. 1 Preamble 3.1.1 Scope of work
The work comprises supplying of labor, materials, plants, equipment, temporary huts and all other items necessary for the design and installation of the piles as shown on the drawings and described in these specification.
The work is to be executed in accordance with specification and contract documents and to the satisfaction of the Engineer. All tenders shall therefore furnish information about the type of piles they specialize in and other relevant details of design, execution, equipment, testing, etc, complete, in support of their capabilities.

The whole of the work and materials shall conform to the current edition of relevant British standards and codes of practice.

3. 1. 2 Responsibility for design and workmanship
The piling contractor will be responsible for designing and


4.1 Description
Concrete work shall consist of mixing, conveying, placing of concrete , for work and reinforcement Work, (it is inclusive of all measures and materials required removal of concrete forms and reinforcement).

4.2 Material
All materials used in the work shall be the best of their kind and shall conform in quality and treatment to the conditions herein specified. The contractor shall submit to the Engineer when required and at his own expense, samples of all materials to be used in the works. The quality of the samples so provided being representative of the Bulk of such materials. The construction of all concrete and reinforced concrete work shall commence at points approved by Engineer and shall be continued and completed in accordance with the

Fixing of reinforcement

4.10.2   Fixing of reinforcement

The steel  reinforcement  shall  be  assembled  to  the  exact  shapes  and dimensions   as   approved  by  the  Engineer.  The  rods  shall  have  the approved cross-sectional area and shall be fixed accurately in the moulds. The ends of all tying wires shall be  turned into the main body of the concrete and shall not be allowed to project towards the surface. Spacing blocks shall be used to ensure accurate cover to the reinforcement, where necessary, and these blocks shall be of precast concrete of a strength at least equal to that of the concrete being placed. They shall be as small as possible in view of  practicality and shall be securely fixed in position by means of wires to be cast into them.

No  temporary  supports  for  the  reinforcement  shall  be  allowed  to  be incorporated  into  the  finished  concrete.  At  the  time  of  concreting  all reinforcement shall have been thoroughly cleaned and made free

of all loss rust (crude oil or any other coatings that might destroy or reduce the bond).

Unless otherwise specified or shown on the drawings, minimum cover shall be  determined  in  accordance  with  ACI  318-  77  as  indicated  on  the following table:


Min. cover thickness

Cast against and permanently exposed to earth

75 mm

Exposed to earth and weather

D16 and smaller

40 mm

D19 - D 25

50 mm

Not     Exposed to weather and

Slabs and walls

D25 and smaller

20 mm

not  in  contact with   earth

Beams,     girder, columns

main   bars    ,    ties, stirrups

40 mm



5. 1    General

5.1.1      Scope of Work

Provide precast  concrete  panels,  materials  equipments,  and  ,  labors, complete, in  place, as shown on the drawings, specified herein, and as evidently  required  for  a   complete  and  proper  installation  of  precast concrete work .

5.1.2 Related work Described


a. Cast in place concrete b. Concrete reinforcement
5.1.3 Quality Assurance

The manufacture should demonstrate the ability to provide the required quality as specified on the drawings or as directed by the Engineer.

The installers must not have less than



6.1     Scope of work

Furnish all labour, material and equipment for the complete building of brick and concrete block work as shown on the drawings, as specified herein and as evidently necessary to complete the work.

6.2     Submittals

Before starting the work the contractor shall submit the following to the Engineer and receive his written approval.

6.2.1 Manufacturer and sample blocks

Before precasting concrete block, the name and official address of the concrete block manufacturer,  if  the contractor intends to use a sub, contractor, sample block and sources of cement and aggregate making up the concrete block shall be submitted to the Engineer for his written approval.


Test required and as specified here in after    shall be executed by the contractor and test results shall be submitted to the Engineer for his written approval.

6.3 Materials

6.3.1     Masonry brick

Brick shall be locally available products conforming to D.S. 3921 or equivalent and be hard,  well  baked  and  shall  have  a  uniform  and  sufficient  compressive  strength appropriate            to the use. The shape of the bricks shall be rectangular. Brick used in foundation shall be misakhraj brick or equivalent.

6.3.2 Concrete blocks

All concrete blocks shall conform to ASTM C129, B.S 2028 or equivalent unless otherwise specified as follows:

a.    Concrete block shall be manufactured in accordance with the specification stated herein,

b.    block shall be manufactured of Portland cement and locally available aggregate by mixing and compacting using an electric machine,

c.    block shall be reasonably uniform in compressive strength and in all dimensions and shall be straight and free from cracks, chips or other defects.

Specification of the materials shall be in accordance with section ( 4_2), " Concrete work "

6.3.3 Joint mortar materials

a. cement

cement shall be specified in section 4_2_1 ( concrete work)

b. Sand

Sand shall be clean sharp,   coarse, well _ graded and shall conform to ASTM C-144 ( Aggregate for Mrrary jortar ) or B»S. 1200 ( Building sand from Natural aourcec)

c.    additive

water proofing additive shall conform to B.S 3826 or equivalent, other admixtures, such as a type which reduces early water loss from the masonry units and produces an expansion action in the  plastic grout sufficient to off_set initial shrinkage and promote bonding of the grout , may be used when approved by the Engineer.

6. 4  Workmanship

6.4.1 The contractor shall provide a masonry foreman who is thoroughly experience, competent and skilled in masonry construction .

The foremen shall personally supervise the mixing and placing of all mortar. Masonry reinforcing and  anchoring must be done in strict accordance with the drawing and specifications.

6.4.2 Scaffolding and Equipment

The contractor shall furnish, erect and maintain as long as necessary and remove when  no  longer  required,  safe  and  adequate  scaffolding  and  other  equipment required for the proper execution of the work. All equipment for the mixing, transpo- rtation and handling of mortar shall be clean and kept clear of set mortar, dirt or other foreign matter. Etoffaluiag or other objects shall not bump or rub against masonry.

6.4.3 Mixing of joint  Mortar

a. Standard proportion of mortar mix for the joint of bricks and blocks shall be: cement to sand = 1:3, or as directed by the Engineer, sulphate resisting cement shall be used in mortars below damp proof course

b. Mixing

i. Mix mortar by mechanical mixer or by hand on a clean level board.

ii. mix thoroughly so that all individual constituents are incorporated evenly but do not over-mix mortars containing plasticizers.

iii. Keep mixer clean at all times.

iv. Use mortar with in one hours of discharge from mixer at normal taaporturo . In no case chalj nortor be used after the initial set has taken place. Reconstitution of mortar will not permitted.

6.4.4       Laying units

All work shall be laid true to dimensions and be plumb, square in bond and properly anchored with vertical and horizontal straight  joints that are in line,  plumb, horizantal and true . Brick laying for protective chin for waterproofing memberane shall be laid in running bond with standard 2_3mm joints horizontally and vertically. All surfaces of waterproof memberane to receive briek laying shall  be throughly domed masnory mortar shall be spead over the cntir surface of joints.  laying out of the bricks shall be arranged so that vertical joint are staggered Salf bricks or other shapes shall be used where  required,  All  hollow  block  shall  be  laid  cells  vertical  and  with  full  nortar coverage on all top and side faces,  horizontally and vertically.  Cells of hollow blocks to be grouted with concrete or nortar are those carrying the horizontal and vertical reinforcement and also abutting cells, with or  without reinforcing,                                     cells of hollow block forming the cider, of entrances and doorways and cantilevered fins of walls and those so indicated on the drawings or so required by the Engineer.

In Icying concrete solid blocks,      pounding of comers and   jambs after units liave been set in position shall be avoided, where an adjustment must be made after the mortar lias startde to cat, the mortar shall be removed and replaced with fresh mortar, colls  of  unfinished  ends  shall  not  exposed,  Bond  all  interesting  masonry  walls together  as  indicated  or  a  approved  by  the  Engineer,  When  necessary  to  out masonry units, preference must be given to the use of                                                              power oquipreiit . Cutting shall be kept to a minimum.

A protective covering of mortar shall be fornecl around the reinforcing bars at a minimum depth of 20 mm, laying for brick work shall be as shown on the drawings. when it in not specified on the drawings, the contractor shall follow the instruction of the Engineer.

6.4.5   Joints in brick and concrete block work.

Joints, both vertical and horizontal,    shall be 1 cm thick and not staggered. Nortar shall be flushed with the corrent tool where planter is to be applied.

Joints of masonry units which will be exposed or painted. form a concave joint section.

Joints which are not to bo visible in the finished work to be dtruck off with the trowel as the work proceeds.

joints on the oufaces of fair_faced work shall be finished to provide as mooth surface flush with the brick and or block

face or a keyed joint of approved profile aa the work proceeded

All hole in corposed rjasomy shall be repaired, and the walls pointed. Defective joints shall be trowelled out and repointcd with nortar.


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