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GREATER KANDY WATER

SUPPLY PROJECTPRESENTATION

TO

GREATER COLOMBO WATER REHABILITATION PROJECT

STAFF

THINGS TO DO IN WATER RETAININGRESERVOIR CONSTRUCTION

18THSEPTEMBER 2009

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INTRODUCTION

Construction Backwash Recovery Facility

This Is not a presentation on Design or Construction of Water RetainingStructures

Very briefly few problems encountered in the administration of theabove contract will be discussed

Insurance Day works Attendance to contractor Payment for preparation of Method Statements Water Bar in Concrete joints Shoring during Excavation

Rock Blasting Laying of Hume pipes Use of Collars Marker Tapes Drawing Errors Safety Officer Quality Control Formworks

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INSURANCE

Contractor shall take full responsibility for care of works andmaterials and plant from commencement until hand over

Provisional sum or to be quoted in BOQ Employers risks Insurance of works and contractors equipment Scope of cover

Shall be in the joint names of the contractor and employer

Shall cover employer and contractor against all loss or damage

from what ever cause arising until take over

Third party Insurance Contractor shall insure in the jointnames of employer and contractor

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DAY WORKS

When ever necessary any varied work may beexecuted on a day work basis on receivinginstruction from the Engineer

Normally day work schedules for labour, materialsand construction plant is included in the BOQ

in the NWS&DB it has own standard ratesestablished for Day works. These rates will coveroverheads and profit.

Generally in most of the other contracts contractoris required to enter the rates for labour,equipments etc. and the contractor will not beentitled to overheads or profits.

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INSTALLATION OF WATER BARS

In all large concrete water retaining structure it isnecessary to provide construction joints as it maynot be possible to complete concreting in onepouring of any base or wall.

It is necessary to make the joints watertight. It isthe normal practice to install Water Bars at thejoint to make these watertight.

General and particular specifications gives the

approved specifications for water Bars

Methods statement should describe and explainthe placing of Water Bars

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USE OF BONDING AGENT

Bonding agents are classified in tocategory of construction chemicals

These are used to bond two surfaces ofconcrete

Method statement should Cleary state theuse of Bonding Agent

These are important points to look for

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Applying Bonding Agent in concrete surfaces

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SHORING

Shoring is required where ever deep excavations

are carried out.

It is found that the specification of shoring isincluded in the specification, but not clearly

referred in BOQ

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Inadequate Protective System

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Properly Shored Trenches

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ROCK BLASTING

Proper planning of supply of BlastingMaterials and detonators required.

Safety Measures

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MARKER TAPE

Relevant Specification

Including as a BOQ item

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SAFETY AT SITE

PPE for workers

Ensuring facilities for prevention ofaccident

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Inappropriate Safety tools

No goggles .?No helmets..?

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