Method Statement for Construction of AGL Ducts and Installation of Precast AGL Lighting Pits

CONTENTS

1. Scope of Work

• Definitions

• References

• Subcontractors

• Materials

• Plant  & Equipment

• Safety

• Prior Activities

• Procedure

1. Responsibilities

1. Attachments

1. Scope of Work

1. This procedure is applicable to the following works associated with the project titled, “New 2k Runway- Main Runway Works” – Contract Number NRTW-1008-CN.

1. This method statement outlines the procedures to be followed in the construction of AGL future ducts & installation of precast AGL pits at locations shown in the contract drawings and as directed by the Engineer.

The following six sizes of ducts shall be constructed in this contract, with the ones underneath the pavements surrounded by concrete of grade 40/20/S and the ones at all other locations by concrete grade 30/20/S.

                        –           1 Way x 50mm diameter PVC duct

                        –           1 Way x 100mm diameter PVC duct

                        –           2 Way x 100mm diameter PVC duct

                        –           4 Way x 100mm diameter PVC duct

                        –           10 Way x 100mm diameter PVC duct

                        –           15 Way x 100mm diameter PVC duct

• Definitions

• CM                              Construction Manager
  • SE                               Site Engineer
  • CS                               Chief Surveyor
  • ME                               Material Engineer

            2.5                   ESHO              Environmental, Safety and Health Officer

            2.6                   ITP                              Inspection Testing Plan

            2.7                   PPE                 Personal Protective Equipment

            2.8                   AHA                 Activity Hazard Analysis

            2.9                   JHA                 Job Hazard Analysis

• References

3.1                   Specifications:             Volume 3 – Section 9 – Part A

3.2                   Drawings:                                Volume 2 – Section 8 – Parts B and F

3.3                   BOQ:                                       Bill No. 5

• Subcontractors

None

• Materials

• U-PVC Pipes

5.2                   Concrete grades 50/20/R, 40/20/S, 30/20/S, & 45/10/C

5.3                   Draw ropes

            5.4                   End caps

            5.5                   Polythene sheet

            5.6                   Formwork/Shuttering

            5.7                   Warning tapes

            5.8                   Traffic cones

            5.9                   Traffic signs

            5.10     Safety barrier

            5.11     AGL Pits

• Tools, Plant & Equipment

6.1                   Excavator

            6.2                   Lifting equipment IT-28 with hydraulic boom

            6.3                   Hand shovel

            6.4                   Small generator

            6.5                   Concrete plant

            6.6                   Transit mixer

            6.7                   Concrete vibrator

            6.8                   Air compressor

            6.9                   PPE (Personal Protective Equipment)

• Safety

• Prior to the commencement of any activities, the workforce will receive an induction talk on the project site safety requirements. This induction talk will include both activity safety issues, as well as general safety requirements.

• Where possible hazards may arise from erecting scaffolding and concreting activities, the necessary safety measures will be taken to prevent accident or injury at all times.  This may include barriers, warning tape/net, signage, watchman, and proper lighting.

• Where work upon existing services may be required, the necessary work permits and safety equipment should be obtained prior to the activity commencement.

• Front line supervisor will ensure that Personal Protective Equipment is worn by site personnel at all times during construction activities.

• Heat Stress Training will be provided.

• Provisions of adequate cool drinking water, shade and salt tablets and/or lemon will be in place.

• Plant and Equipment will be provided with back-up alarms, lights, and all other applicable safety devices.

• For AOA work, safety requirements as defined per Section 107 will be implemented.  Specific safety training will be provided to personnel for AOA work.

• Prior Activities

• Before commencing any part of the works, the CM/SE shall ascertain the actual locations of all existing services. If the works conflict with any existing service or road, he should obtain the Engineer’s approval for protection or relocation method before commencing the work.

• Final approval of the AGL future duct and AGL lighting pit layout should be obtained from the Engineer, through the shop drawings submittal process.

• After the shop drawings approval, checking requests for site activities are submitted to the Engineer.

• All the pipes delivered to the site shall be stored in shaded area and covered with polythene sheets, until use.

• Procedure

9.1                   Installation of Precast AGL Pits

• Once the top layer of selected fill at the inner shoulder is laid and compacted, CS shall mark the locations of AGL pits and the excavation shall be conducted with a small excavator to the approved levels.

• The foundation level shall be watered, leveled and compacted by the Contractor and inspected by the Engineer.

• Blinding concrete grade 30/20/S shall be cast to the levels indicated on the approved shop drawings.

• The precast AGL pits shall be installed in place by a hydraulic crane as per the approved coordinates and levels.

• The AGL pits shall be provided with U-PVC pipes in the sides, to be connected with the ducts.

9.2                   Construction of AGL Ducts

• Main Ducts between the Pits (2, 4, 10 & 15 Ways – 100mm Diameter)

• When the top layer of selected fill at the inner shoulder is compacted, CS shall mark the setting out and provide levels for AGL main ducts between the installed pits as per the approved shop drawings.

• The excavation shall be carried out with Excavator to a width equal or greater than the duct width. There is no need to use shutter when the trench sides are verticals.

• The duct foundation shall be leveled, compacted, tested by the Contractor and inspected by the Engineer.

• Polythene sheet shall be laid in the trench.

• Position pipes on concrete spacers or square blocks spaced at three (3) meter intervals.

• Draw ropes shall be provided for each pipe and tied with step- irons inside the pits.

• Concrete grade 40/20/S shall be cast, vibrated and leveled to the approved levels.

• Curing of concrete shall be carried out.

• The concrete top level shall be the same top level of selected fill at the inner shoulder, 365 mm from finished level.

• Crossing Ducts under the Runway and Taxiway (1Way 50mm Diameter and 1Way 100mm Diameter)

• After laying and compacting the sub base layer, all the crossing ducts shall be excavated by using an excavator. There is no need to use shuttering when the trench sides are verticals.

• The duct foundation shall be leveled, compacted and inspected by the Engineer.

• Polythene sheet shall be laid in the trench.

• Position pipes on concrete spacers or square blocks spaced at three (3) meter intervals.

• U-PVC Pipes should be fixed in their exact locations (coordinates and levels) as shown in the approved shop drawings.

• 1 Way x 50mm diameter & 1 Way x 100mm diameter pipes should be fastened in place by using nylon ropes tighten with steel U-shape bars, 8mm in diameter, nailed into the ground to prevent any movement of the pipe during concrete casting.  This procedure will consequently enable the AGL contractor to locate the exact location of the pipes while coring for fixing the lights.  All of these activities will be done in coordination with the AGL Contractor.

• Immediately after installation, open ended pipes must be covered with end caps and should not be left open.
  • Concrete grade 40/20/S shall be cast, vibrated and leveled to the approved levels.

• The top levels of concrete and sub base will be the same i.e. 325mm from the top of the Finished Pavement Level.

• Curing of concrete shall be carried out.

• In case of conflict between 1 Way x 50mm diameter duct & 1 Way x 100mm diameter duct or between 1 Way x 50mm diameter duct and 1 Way x 50 mm diameter duct, one of the pipes shall cross under the other (in touch with it) maintaining the minimum duct depth of 325mm. The concrete shall be poured at the same time for both conflicted ducts.

Note    

In other locations, except beneath all pavements, the standard duct bank details shall be used as shown in the drawings and the surround concrete shall be grade 30/20/S.

1. Responsibilities

1. The CM will coordinate with SE and ensure that the necessary resources to implement the approved method statement, Job and Activity Hazard Analysis have been allocated to the task.

1. The SE will ensure that the site preparation activities are conducted according to the approved method statement, JHA, AHA and all in-situ tests as required in the ITP are implemented.

1. The ME will ensure that the materials being used are in accordance to the project specifications, the approved method statement and the ITP.

It is the Front Line Site Supervisor’s responsibility to organize the work in a safe manner to ensure that safety and protective equipment are properly utilized.  He must also assure the AHA and JHA are implemented and the method statement procedure is followed and the ITP is applied.