Method Statement Of Pipeline Works 17691q
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Tianjin-Raman t Venture
Method Statement Project Management This project is “Laying of Bulk Distribution System and Construction of Reservoirs (Package-3) Contract No: KUKL//BDS-SRT/01/03”. This chapter describes the construction method of this BDS project including pre-construction survey and setting out, working area clearance, general precaution before excavation, civil concrete works, DI pipe, HDPE pipe and fittings transportation and storage, trench excavation dewatering and bedding extra soil stock and disposal, pipeline laying, valve fittings service installation, backfill, water pressure test, pipeline clean and disinfection, related sewer pipeline removal and re-installation manhole and different chamber works in detail reinstatement, construction of reservoirs and undertake different civil works. The Contractor’s Works are expected, as a minimum, to comprise the following steps: Survey of Existing Service Connections Pipe works o Installation of Di pipes from dia 1000 `mm to 500 mm. o Bulk distribution system between branch reservoirs. o Install bulk meters and valves at all needed cross connections in pipes. Repair / rehabilitation or replacement of sewer pipes according to design. o Extension of network to areas not adequately served. Other works: Construction of reservoirs at Balaju(Capacity of 7000 cum). o Repair roads according to given requirements wherever needed. o Repair other utility lines in case they are damaged during the work. o Provide alternative sources of water for people while being disconnected from water supply system during the implementation and hydrostatic testing. 1. Pre-Construction Surveys and Setting Out We shall all measurements and be responsible for their correctness. Any differences which may be found between actual measurements and the dimensions given in the Contract Documents shall be submitted to the Engineer. Site bench marks shall be accurately and safely established, maintained and removed upon completion of the Work, before the Work, or any part thereof, are commenced, shall make a complete survey, and take levels, of the Site and agree on the dimensions and elevations upon which setting out of the works shall be based. These levels shall be related to the bench marks and shall be plotted and drawn up .After agreement of the drawings, these levels shall form the basis of setting out of the Works. 1.1.a.i.1.1 2. Clearance of Work Areas and Protection of overhead underground and surround service Prior to the start of any work, lay-out the right-of-way, working areas, clearing, and pavement cutting to insure a proper recognition and protection of the adjacent properties. Ensure that the general shape, profile, and levels of the area are not materially altered during clearing and grubbing operations. In order to avoid re-clearing or to control dust or erosion may have to clear and grub at the latest practicable stage of construction. As technical requirement clearance including The removal of all trees and bushes (complete with roots), other vegetation, rubbish, fences, and all other material that may interfere with the construction of the Work. The disposal of all material resulting from the clearing The removal of all rocks and boulders of size up to 0.2 m 3 that are lying on the surface to be 1
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture cleared or exposed during the clearing operation. Breaking, Dismantling, Cutting of Brick, Interlocking tiles, stone pavement, PCC, Asphalt Road/ Side walk along the pipeline Where fences have to taken down, the sorting, coiling, and stacking of the material, and The removal and stacking of other re-usable materials, demolition of structures Before commencing work in any particular area, the position of all underground services and all other obstacles and existing construction overhead service on the Site, take all measures necessary for the and protection of these services. 3. General precaution before excavation a) Responsible for obtaining temporary way leaves including crop compensation, for temporary working areas, additional working easement and for any additional areas b) If the work will cause unavoidable interference with access to ading property, convenient access to driveways, houses and buildings ading the work shall be maintained and temporary approaches to intersecting streets and alleys shall be provided and kept in good condition. c) Provide and maintain access to the various sections of the Works requires for the proper execution of the work. , Existing roads and bridges shall be upgraded for the construction transport purposes and site roads, loading and turning areas shall be so arranged as to minimize inconvenience to ading landowners or occupants and to the general public. d) Any detour and traffic control will take approval from engineer and road department, once carry traffic control will follow the road department relies for traffic safe. e) When the execution of the Works requires the temporary disconnection of existing public utilities, the Contractor shall provide the affected s with temporary services in at least the same standard as the original services. For water supply install temporary lines or arrange for regular supply by tankers. f) When disconnect existing sewers, shall install temporary pipes of adequate size to carry off sewage from any private sewer facilities cut off by construction work. When forced to disconnect power or telephone connections the relevant authority shall provided temporary connections at the Contractors expense. g) Protection of Ading Property, Responsible directly to the tenant / land owner for any excessive or avoidable damage to crops or lands resulting from his operations whether on lands adjacent to right-of-way or on approved access road h) Responsible and take all measures in order to protect ading property including buildings and other structures. i) Coordination with Other Authorities to take all approval for commences the work. 4. DI/HDPE pipes and fittings manufacture and transportation, storage, loading and unloading method a) Manufacturer will manufacture DI pipe as per ISO standard 2531 with cement lining and zinc coating and bitumen coating , fittings and valves also will produce according related standard .will transport pipe to pipe store yard and stacking as operation manual as per construction schedule in one lot or several lots. b) From store yard will transport the pipe to secondly yard nearest site area by crane truck, normal truck or tractor, then will make special trailer to bring pipe from secondly yard to the site by excavate or tractor. c) The pipe shall lay along the trench on good and stable condition to protect the surface of the pipe. d) Pipe and fittings loading and unloading shall use special hoist belt, lightly and carefully to protect the surface. e) The ground of storage should be soft, and no corrosively chemical near the storage. f) All kinds of valves and pipe fittings should be store in dry rainproof area, classified and mark, easy checking and loading. 5. Trench excavation shoring dewater and bedding backfill and compact and reinstatement of 2
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture surface a) Prepare before excavation, make site investigation, to make sure the underground soil condition, the structure distribution condition on the ground and under the ground, discuss with the engineer or related authorities about the treatment measure. To confirm the position and level of old pipeline and structure and new pipeline center etc. Make proposal for the excavation and disposal surplus soil and take safety measure. Before excavate, the operator shall know the trench excavating section and depth of trench b) Earthwork excavate and shoring The trench mainly excavated by excavator equipment with manual cleaning the bottom of trench. If there is rock, the hydraulic hammer or exposing will take .before excavation, the 15cm depth shall leave for manual excavate. As per design drawing and site visit ,the excavate will take necessary protection measure according different soil condition ,depth of trench and building condition along the pipeline. In case the deep trench and soil condition unstable or the building exit along the pipe line , the trench shoring measure use H type steel pile with steel sheet. Once trench is excavated, the traffic control and safeguarding shall take. As per traffic condition and shopping business condition, we shall make temporary bridges on difference place to reduce the inconvenience. The bridge made by steel plate timber and steel fence. The trench excavate soil shall stack along the pipeline trench. The upper layer sand or aggregate shall stack difference; the height shall not exceed 1.5m. The disposal of extra soil shall be carried out or transport to special place storage. When backfill may shall return. The foundation treatment shall comply with design request. The trench bottom shall be flat and no collapse no water, the turning shall meet requirement. After excavate the quality inspection shall carry out and accept by the engineer. 6. Underground Pipeline and Surround Structure Protection Measure Technology preparation Before construction, project manager department shall study the underground pipeline drawing and know the location of the pipeline and depth and function. Before construction detail investigation at site about the surround structure shall execute .Before construction detail detection of electrical cable underground or telephone communication cable ,underground pipeline ,if find any difference between drawing shall make report to related department and take approval from them and take measure to protect. Make protection and emergency program for underground pipeline and surround structure during excavation and make safe protection .meanwhile make all persons and construction team to study and discuss the construction deg and good education for all person to protect the pipeline. Due to the heavy duty truck entry the site always, the ground shall put steel plate for protection the road surface. If find old pipeline ing through the trench during excavating, when the excavate near the bottom of the old pipeline, shall hanger the old pipe and , then continue excavate during construction, always inspection no collision and no damage to pipeline, during backfill the soil under the pipe shall be compacted if equipment cannot work, the manual is applicable and compacted strongly to escape the future segmentation. If the electrical steel pole shall move or as above Protection for electricity steel pole. Any service or structure or material found undescribed in the technical specification and drawing, shall protect it and report the engineer and take necessary measure to carry out next step. 7. Trench dewater and bedding Before excavate, study the soil quality and water lever underground, make program and prepare the equipment. 3
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture During construction on foundation of pipe trench ,open one temporary water drainage ditch width 300mm depth 300mm along the pipeline ,and several wells 500x500x1000mm for colleting the water , all underground water shall go to well through this drainage ditch , in the well will install sewage submersible pump and discharge the water. The well numbers shall accord the volume of the water underground and rain. The underground water level shall less than 500mm from bottom of trench and make the bottom of trench keeping dry. The water from trench shall be treatment then discharged During dewatering, look after the surround building and structure segmentation or reforming, anything happen shall take necessary measure and discuss with engineer. The technology of reirrigation of the old building base may be taken. During rainy season, enough discharge equipment shall prepare. Some area the water volume is very big, shall consider the bigger well diameter 500mm and depth as per trend depth. To always keep the bottom of trench dry condition. Once the trench excavation and foundation ready, the pipeline bedding shall made. As per the technical specification three kinds of bedding type is used class B class S and concrete surroundings for pipe at different section of pipeline as described in the drawing. 8. Trench back fill, compact and reinstatement Backfilling of pipe trenches shall commence as soon as possible after the pipe has been laid and firmly bedded in the specified cradle and the blanket has been placed over the top of the pipe to the height of blanket cover specified. Backfilling shall be carried out as described below and over the full extent of the actual trench excavation and to original ground level, except where otherwise directed. Unless prior approval has been obtained, no filling shall be placed in water. Excavated material from the trench, which is unsuitable or has become surplus because of bulking, displacement by the pipe and importation. Any deficiency of backfill material from trench excavations because of removal of organic or other unsuitable material shall be made up from suitable surplus material from other excavations on the Site. If, insufficient or no suitable material is available for this purpose from such excavations, shall import sufficient suitable material. Complete backfilling of trenches expeditiously and in reasonable length. At the meantime the backfill material shall compacted layer by layer as specification. In all cases, reinstate surfaces over the full extent of the top of the actual excavation, as well as the entire width of all roadways where the pipeline is laid. The reinstatement shall reach all kind road standards as per Nepal road department specification. 9. Ductile pipeline laying, cleaning and testing Familiar with the manufacturer's instructions/pipeline construction manuals for the laying and ting of pipes and that these instructions are strictly adhered to, if request, may employ the manufacturer to demonstrate laying and ting. Pipe lying shall not commence until the bottom of the trench and the pipe bed has been approved by the Engineer's representative. The trench bottom shall be prepared, Trenches shall be kept dry to allow proper and safe bedding, laying, ting of pipes and construction of the selected fill blanket over the pipes. The pipeline shall be tape wrapped or sheathed in polythene sleeve for protection. i. The laying process Checking the pipe surface inner lining and out coating quality ,clean the socket and spigot ,check the quality of rubber ring ,check the lubricated flux quality Before loading the pipe inside the trench, the pipe shall be tape wrapped or sheathed in polythene sleeve for protection. Use excavator to load the pipe inside the trench with manual assistance. For tighten type ting, clean the socket and spigot and rubber ring again, install the rubber ring, press the rubber ring, by rubber hammer to keep the rubber ring flat in socket exactly, brush the lubricate flux 4
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture (like plant oil or soap water) on the rubber ring and spigot, by the hoist push the spigot into the socket to reach the position line on the spigot. Check the t, the gap between socket and spigot shall be average circled. Also check the front and next t under good condition. Once the pipeline turning, the turning angle shall less than 1 degree. At the close of each day's work or at any time when work is suspended for a significant period, the last laid pipe shall be plugged, capped, or otherwise tightly closed until lying is recommenced. For bolted gland ts the ts ring shall be pushed into place by the gland ring using only hand pressure, fixing nuts and bolts should then be fitted and first tightened to finger pressure. Thereafter tightening shall be in the sequence proposed by the manufacturer and to the torque recommended. In the ting of pipes with flanges, special care shall be taken to align, grade, and level the pipes, specials, and valves to avoid straining of the flanges. All bitumen and paint shall be removed from the mating face of each flange immediately before ting. Bolts shall be tightened up evenly in opposite pairs to ensure uniform bearing; the final tightening shall be to the torque specified by the manufacturer. For flanged ts the gasket shall be fitted smoothly to the flange and the t made by tightening the nuts to finger pressure first. Thereafter the final tightening of the nuts shall be made by gradually and evenly tightening bolts in diametrically opposite positions using only standard spanners of a type approved by the Engineer. Graphite grease shall be applied to the threads of bolts before ts are made. A care shall be taken to avoid damage to the internal surface of the pipes during assembly of the pipeline. Once ts are made they shall be protected to a level appropriate for the pipe by: polyethylene sleeving and tape wrapping. Pipes shall be cut by a method which provides a clean square cut of the pipe and of the lining, without damage to pipe or lining. All cut or trimmed ends and the parts of any pipe on which the coating may have suffered damage shall be re-coated as specified before the pipes are laid. The external area at cut spigot ends of ductile iron pipes shall be ground smooth for a distance of at least 125 mm, and then chamfered or otherwise made suitable for ting as recommended by the pipe manufacture. Unless otherwise shown on the drawings, or directed by the Engineer, gate valves shall be set upright and butterfly valves shall be set with the main shafts horizontal. All valves, specials, and fittings shall be located in the exact positions shown on the drawings or otherwise directed. , the prepared fitting shall then be wrapped in protective tape At tees, bends, terminal valves, end caps, and where otherwise directed, anchor/thrust blocks shall be constructed to dimensions ordered or shown on the drawings. Unless otherwise indicated on the drawings, anchor/thrust blocks and pedestals shall be constructed of C20 concrete. The concrete shall be well punned around the pipe, if in trenches, against the undisturbed faces and bottom of the trench. Backfilling behind or under thrust faces will not be permitted. Excess excavation shall be replaced with the prescribed mix concrete given above at the Contractor's expense. Care shall be taken to leave all ts accessible. No anchor/thrust block and pedestals shall be concreted before the approval of the Engineer has been obtained. All washout valves, pressure reducing valves, and air valves in pipelines shall be housed in a chamber as shown on the drawings or directed by the Engineer. All covers and frames shall be manufactured, from cast grey or ductile iron, All covers shall be fitted to the frames and tested at the manufacturer's works and covers and frames shall be similarly numbered in a legible and permanent manner in a position which will not be visible when fitted in place, and shall be of such construction as to minimize the ingress of sand. The Contractor shall ensure that the covers are fitted to the appropriately numbered frames after the frames have been fitted. The name of the Employer and year of manufacture shall be embossed in all covers. 5
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture The connection point shall be provided at the location specified. The flange shall be installed so that it is vertically plumb and its face is perpendicular to the axis of the pipeline. The flange shall be covered by a PN 16 blank flange; the flange shall be installed in the specified manner. The flange shall be backfilled and the location marked with a marker post. All connection shall work as the drawing showing. Permanent pipeline marker posts shall be installed at all changes of horizontal alignment and at 200m intervals along the straight lengths of pipe. Marker posts shall be positioned as close as possible to a 2 m offset from the pipe centre line. Pipelines are shall be manually cleaned internally of all debris, stones and sand prior to testing. The internal surfaces of all pipelines and pipe work including all equipment incorporated in a pipeline or pipe work through which water will shall be disinfected after they have been cleaned ii.
Construction of Valve/meter/fire hydrant/wash out chambers It includes the chamber construction works- excavation, backfilling, shoring, dewatering etc. testing and disinfection and supply, store and deliver of relevant pipes, fittings, specials, manhole covers, surface boxes and necessary accessories. Unless otherwise indicated on the drawings, anchor/thrust blocks and pedestals shall be constructed of C20 concrete. The concrete shall be well punned around the pipe, if in trenches, against the undisturbed faces and bottom of the trench.
iii.
Cleaning and testing Disinfection shall be effected by filling the pipeline with water heavily dosed with chlorine, and shall be carried out when filling the pipeline with water for carrying out the hydraulic test on completion. The level of the chlorine dosing shall be such as to make available 50 mg/l of free chlorine throughout the pipeline. The water, heavily dosed with chlorine, shall stand in the pipeline for a period of 24 hours or for such longer period as the Engineer shall require and all valves in the system shall be operated at least once during this period At the termination of the required period, chlorine residual tests shall be taken at the end of the pipeline farthest from the point of injection and the test shall be repeated if necessary until the residual is not less than 10 mg/l. Test pressures are to be measured at the centre of the blank flange situated at the lowest end of the pipeline under test. All pipelines shall be tested to a pressure corresponding to a hydraulic grade of 1452. The Sectional Hydraulic Test shall be carried out after the pipeline or pipe work section to be tested has been laid, ted and backfilled to a depth sufficient to prevent flotation of the pipeline. The sections to be tested shall be to the approval of the Engineer and shall be not longer than 2,000 m or 500 m when either the pipeline is laid adjacent to or underneath the carriageway. Before Sectional Hydraulic Test, the pipe line must fill back and compacted, check all fitting and pipeline thrust and anchor, all tested section ,the tee air release valve and valve shall closed by blind flange or plug. Check the highest air valve is open, check the pipe line can air release and water can discharged. Check the test water, test station and water discharge system. Filling the water inside the pipeline until the air release the finish. Stay a period 24 hours let the water absorber by all t then close the air valve. Rising the pressure and check always rising shall step by step. After reach the setting pressure, keep in static and same period, check the pressure gauge movement. After acceptance, then slowly reduce the pressure, slowly open pressure reduce valve open air release valve. After that can discharge the water to point area.
iv.
Sewers and Storm water Drainage Within a portion of the pipeline alignment along the existing roadway, an existing combined sewer is located approximately in the middle of the road. This sewer shall be reconstructed at a new location, 6
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture as part of the Works. The sewer reconstruction shall be undertaken in stages, commencing from the upstream side, so as to maintain the sewer flow during construction, as follows: a) The new sewer and manholes are reconstructed at a minimum clearance of 3m from the proposed water pipeline location, in segments. b) New house connections shall be provided r to each new segment as it is constructed. c) A temporary tap from the new segment to the downstream existing sewer shall be provided d) The old house connections and sewer segments shall be removed. e) The next segment of the reconstructed sewer shall be connected to the previously constructed upstream segment, without disrupting sewer service. f) The process described above shall be repeated until it is no longer necessary to reconstruct any segment of the sewer, i.e., until a minimum clearance of 3m is maintained between the proposed water pipeline location and the sewer. Sewer service to existing residences and businesses shall not be disrupted during the sewer reconstruction process. Because of the narrow width of the roadway over a large portion of the area of required sewer relocation, the Contractor shall be required to perform much of the reconstruction work prior to construction of the water pipeline. Pipe material is RCC pipe. Excavate, bedding, laying backfill etc as specification, will made technical proposal before commence. Cross river pipe line lying v.
Bridge/river/culvert bed crossing After the site visit, we will take method as following a) Check the river water flow rate and speed, made dam to stop water from both pipeline side 20 meters and set guiding pipe to let water . b) Before build dam shall clean the river bed c) Dam section diameter upper width less 2 meter ,dam slop 1:0.2 .make pile and fill the soil to build dam, the height of dam shall be 1m high than water. Dam shall protect by bag fill of soil or sand .dam shall less leakage and strong. d) Setting guiding pipe for water e) Pipeline cross river construction try to arrange at dry season with little water flow rate. f) Open excavate g) Here pipe bedding by concrete surround. After pipe lying, pay attention for backfill and press the pipeline and take special measure to pipeline floating protection.
1. Project camp Provide adequate housing with all necessary amenities and facilities for his staff and labor. The type of housing, as accommodation containers, pre-fabricated or in-situ buildings or even rental. During the whole period of existence, from setting up through operation to final removal upon completion of the Works, fully responsible for constantly carrying out all measures necessary for safeguarding the natural environment affected by camp or camps. Cause the least possible interference with existing amenities, whether man-made or natural. No trees shall be felled. Latrine and ablution facilities and first-aid services shall be provided in sufficient type and numbers to the satisfaction of the Engineer and shall be maintained in a clean and sanitary condition at all times. On completion of the Works or as soon as the facilities provided by the Contractor are no longer required, the Contractor shall remove such facilities and clear away all surface indications of their presence. Each camp area shall be reinstated to the satisfaction of the Engineer. 7
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture Provide, erect, construct, maintain and subsequently remove proper offices, stores, workshops, laboratories, storage and parking areas for his own use. Such facilities shall be sufficiently sized and equipped to enable him to manage his operations and those of his Subcontractors in a professional manner and to enable him to carry out all his obligations under the Contract. Within his offices a meeting room shall be available for site meetings with the Engineer and the Employer. These Contractor's facilities shall be subject to the same stipulations regarding sitting, interference with amenities and environmental protection as the Contractor's camp. 2. Preparation of the Stockyard for Pipes, Valves and Fittings The preparation of the stockyard for pipes valves and fittings shall include: Clearance of the Site Construction of side drains around the stockyards to avoid water logging Construction of access tracks. Covering of pipe and fittings storage areas with a 150mm thick layer of granular material that will discourage the growth of vegetation and plus any additional provision to carry the loads from the pipes and fittings. Erection of a security fence. Construction of a guard house / store keeper’s office. Erection of stores for ting material etc. including the provision of air-conditioning where necessary.
Hydrostatic Testing assessment The proposal contains the following working packages: Bulk distribution Design Develop hydraulic model Monitoring Hydrostatic testing and determine real losses Bulk distribution design The technique of leakage monitoring requires the installation of flowmeters at strategic points throughout the distribution system, each meter recording the flows into a discrete area with a defined and permanent boundary. Such an area is called a Distribution area. The design of a leakage monitoring system has some aims: 1) To manage the pressure in each district or group of districts so that the network is operated at the optimum level of pressure The BDS meters can be linked (in the future) to a central control station via telemetry so that the flow data are continuously recorded. Analysis of these data, particularly of flow rates during the night, determines whether consumption in any one distribution has progressively and consistently increased, which would indicate a burst or undetected leakage. Each leak location area is then closed off in turn, allowing the flow into each area to be monitored via the distribution meter. It is important to understand that night flow comprises customers’ use as well as losses from the distribution system. Where all customers are metered this does not pose much of a problem. In a telemeter distribution system, night flow data can be received and analyzed regularly. This enables changes in the night flow of each distribution to be quickly identified, reducing the awareness time. When compared with previous readings and with other BDS, it enables the leakage control team to prioritize inspection. The logger software typically contains an “error table” which identifies those distribution areas where night flows have increased above a pre-set alarm level. The leakage control team is able to scan the error table daily to identify unreported bursts or, in response to poor pressure complaints, to confirm a reported burst. Detection and control of leakage varies from one case to another, and the choice of methodology is largely dependent on local conditions, number of available measurements, 8
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture and type of water supply e.g. 24/7 supply versus intermittent water supply, financial constraints on equipment and other factors. DHI will establish the optimum approach to hydrostatic test based on the local conditions. Develop hydraulic model The hydraulic model of each BDS areas will be developed in order to the design of each BDA and that it is hydraulically isolated and functions properly. The hydraulic modelling will be also used to that the network will function adequately under predicted 2015 and 2025 supply and demand scenarios. A combination of measurements and mathematical modeling application will be applied through a numerical model in order to describe in detail hydraulic processes in the distribution network. The resulting calibrated mathematical model is used for evaluation of the existing water supply system and the reasons for identified system bottlenecks. The hydraulic model will be developed based on pipe networks design.
Monitoring Minimum pressure requirements Pressure loggers will be installed within each BDS area that will continuously record the pressure in the network. The location of loggers will be determined in consultation with the Engineer. The pressure data will be collected and provided to Engineer for validation. The pressure loggers will be et to record at time intervals of no more than 10 minutes and the data will be ed at intervals of 7 days of less and the total duration of the monitoring within each BDS will be 30 days, the analysis will be carried out at intervals of 7, 14, and 30 days. The pressure monitoring will be used to analyze the average pressure within each BDS as well as pressure fluctuation during 24 hours. The pressure monitoring will be used for the network function compliance along with the assessment of physical losses that are defined either as 15% or less of the volume (flow monitoring) or an average of 100 liters per connection per day when the system is pressurized at 10m average (pressure monitoring). Maximum real loss requirements Flow monitoring will be used for assessment of real losses and BDSwater balances. There will be three methods conducted such as full BDS pressure test, night flow monitoring, and water balance. The real losses will be determined based on the recorded readings of the bulk flow meters recording the flows in and out of the BDS, and the domestic consumption meters installed at each house connection. The readings will be taken over the period of 30 days and they will be verified by the Engineer.
Hydrostatic assessment of the constructed system and determine real losses NRW assessment in each BDS is a part of the step-wise Commissioning Plan and the determination of real losses is on of the key success indicators. NRW assessment will be done based on the pressure and flow monitoring within each BDS and three will be used, such as 1) full DMA pressure test, 2) night flow monitoring, and 3) BDS area water balance. In case that the 24/7 water supply cannot be arranged for 30 days alternative adjustments to these methods will be done. The main objective in physical losses is to guarantee that: Real loss is 15% or less of supplied volume, or An average of 100 litres per connection per day when the system is pressurized at 10m average is not to be exceeded The methods below along with the data collected through pressure and flow monitoring as well as from spreadsheets, databases etc. will be used to prove the compliance. Full pressure test
9
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture Network is pressurized during the full pressure test BDS area outlets are closed. Due to leakage, expansion and contraction of pipes, measurement inaccuracies, some pressure loss will occur. Evaluation methods described in the Section 6 of the “Bidding documents” will be used to determine whether pressure falls within the allowable limits and whether the BDS area can be further verified using night-flow analysis or water balance calculation.
B) Reservoirs & other works 1. TOPSOIL EXCAVATION AND STOCKPILING/PRESERVATION: In the area where most of the available embankment materials are not conducive to plant growth or where directed by the Engineer, the soil existing over the embankment foundation shall be stripped to specified depth usually not exceeding 150mm. and stored for covering embankment slope, cut slopes and other disturbed areas where re-vegetation is required. Top soil removal can be done through use of grader or other heavy earth moving equipment depending upon site requirement. 2.
EARTH EXCAVATION AND DISPOSAL OF EXCESSIVE CUT MATERIAL: Structures excavation shall consist of excavation, removal and satisfactory disposal of all materials necessary for the construction of reservoirs indicated by the Engineer. The work shall include hauling and stacking of hauling to sites of embankment construction as required as also the disposal of unsuitable cut materials in specified manner, and the trimming and finishing of site. All excavation shall be carried out in conformity with the directions laid in the contract and in a manner approved by the Engineer. The work shall be so planned that the suitable materials available from excavations are satisfactory utilized as decided before hand.
3.
EMBANKMENT FILLING AND COMPACTION: Embankment and miscellaneous back-fills will be constructed with approved material obtained either from excavation or borrow pits or other sources. Embankments will be constructed in accordance with the requirement of the specification and in conformity with the lines, grades and cross sections shown on the drawing. Materials used in embankment shall be earth, gravel, a mixture of these or any other materials approved by the Engineer. Such materials shall be free from logs, stumps, roots, rubbish or any other ingredient likely to deteriorate or affect the stability of the embankment. Only the materials satisfying the density requirement given in specification shall be employed for embankment construction. The materials for embankment shall be obtained from approved sources. After the site has been cleared the work shall be set out as specification. The limits of the embankments shall be marked by fixing pegs as guides before commencing earthwork. The top soil existing over the embankment foundation shall be stripped to specified depth. The original ground shall be consolidated by rolling. The embankment material shall be spread uniformly over the entire width of embankment in specified depth. The successive layers of embankment shall not be placed until the layer under construction has been thoroughly compacted to the requirement set out in the specification. Moisture content of the materials shall be checked and if found less than that specified for compaction, the same shall be made good either at the source or after spreading the soil in loose thickness for compaction. Water shall be sprinkled from a lose line or from a truck mounted water tank. Flooding shall not be permitted. Only the compaction equipment approved by the Engineer shall be employed to compact the different material types encountered during construction. Each layer of the materials shall be thoroughly compacted to the densities specified. Subsequent layers shall be placed after finished layer has been tested as required.
4.
SUB BASE, BASE AND SHOULDER: Following construction of the embankment or excavation for structures will be prepared to line lever 10
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture and grade, using excavator. Sub-base will be added to the designed thickness, moisture added as shown by the lab report and the material consolidated with the use of appropriate road roller. Finished layer of sub-base will be checked for line, level and grade and any deficiency corrected by adding or removing excess material as appropriate. Density tests as per frequency requirement will be conducted. Any rectification required in the light of the lab test will be carried out. After sub-base the base course will be laid to required depth. Compaction carried will be with the appropriate type of road roller, resulting surface checked for line, level and grade. Excess material if indicated after checking will be removed/trimmed. If deficiency is found, the material will be added. Re-rolling done where appropriate. Any correction dictated by the test will be carried out. During construction traffic will use the diversion where dictated by the site condition. 5.
BITUMINOUS SURFACING: Before the asphalt concrete works starts the base surface will be cleaned of dust with air compressor. Where required wire brush will be used. Appropriate type of bitumen will be heated to required temperature in the decanter machine, carried to the site in bitumen distributor kerosene added for cut back in appropriate follow and bitumen sprayed at required rate for prime coat. Traffic movement will not be allowed for minimum 24 hours of applying prime coat or as permitted by the site condition and with the approval of the Engineer. Operation for asphalt concrete works will commence. Surface will be cleaned with air compressor. Bitumen binder of appropriate grade (cut back bitumen binder, 80/100 bitumen and diesel or kerosene oil cutter) will be sprayed at specified rate with the help of bitumen distributor.This will immediately follow by rolling through pneumatic road roller. Necessary es of road roller will be applied to achieve compaction.. Any excess material will be removed or deficiency added and surface brought to required level with further rolling where required. The heating temperature of bitumen and quantity of adhesive agent will be determined by trial with approval of the Engineer.
6.
KERBSTONE After the main works are completed the Kerbstone works, sign boards, sign board posts etc. will be fixed. On issue of taking over certificate equipment, surplus materials, rubbish and temporary work of every kind shall be cleared and removed. The site will be left clean and in a workman like condition to the satisfaction of the Engineer.
7.
FORM WORK: Forms for concrete shall be constructed of metal or timber suitably lines where required and be of a substantial and rigid construction to shape and dimensions shown on the drawing. Where metal forms are used bolts and rivets shall be countersunk and will grounded to provide smooth and plane surface. Where timber is used it shall be seasoned. Forms shall be mortar tight and shall be made sufficiently rigid by the use of ties and bracings to prevent any displacements or sagging between s. It shall be strong enough to with stand all pressures, ramming and vibration. Immediately before concreting all forms shall be thoroughly cleaned. Removal of the form-work will be affected as per specification. The period shall be suitable increased in case of temperatures lower than specified and for any other conditions tending to delay the setting of concrete.
8.
REINFORCEMENT: Steel shall be clean and free from loose rust and loose will scale at the time of fixing in position and subsequent concreting. Reinforcement steel shall conform accurately to the dimensions given in the bar bending schedule shown on relevant drawing. Bars will be bent cold to the specified shape and dimensions operated by hand or power to attain 11
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture proper radii of bends. Bars will not be bent or straightened in a manner that will injure the material. Hooks shall be suitable encased to prevent any splitting or concrete. All reinforcement bars shall be accurately placed in exact position and shall be securely held in position during placing of concrete by annealed binding wire meeting the requirement of the specification and by using stay blocks or metal chairs, spacers or other approved devices at sufficiently close intervals. Bars crossing each other, where required shall be secured by binding wire (annealed) of size specified). As far as possible, bars of full length shall be used. In case this is not possible, overlapping of bars shall be done as directed by the Engineer. When practicable, overlapping bars shall not touch each other, but kept apart by 25mm. or 1.25 times the maximum size of the aggregate. The overlaps shall be staggered for different bars and located at points, along the span where neither shear not binding moment is maximum. 9.
MIXING TRANSPORTING, PLACING AND COMPACTION OF CONCRETE: Concrete shall be mixed in mechanical mixer using appropriate size and quantity of the ingredients Quantity of water shall be just sufficient to produce a dense concrete of required workability for the job. Mixing shall be continued till materials are uniformly distributed and an uniform color or entire mass is obtained and each individual particle of the coarse aggregate shows complete coating of mortar. The method of transporting and placing concrete will be as approved by the Engineer Concrete shall be so transported and placed that no contamination, segregation or loss of its constituent materials take place. All formwork and reinforcement contained in it shall be cleaned and made free from standing water, dust immediately before placing of concrete. The concrete will be deposited between a minimum and maximum temperature as specified in the specification. It shall be compacted in final position within half an hour of its discharge from the mixer. The concrete shall be deposited in horizontal layer to a compacted depth of usually not exceeding 45cm. Vibrators will be used for compaction. When the concreting is to be resumed on a surface which has hardened it shall be roughened, swept clean, thoroughly wetted and covered with a mortar layer of same concrete mix. Vibration shall not be applied through reinforcement. In case of vibrators of immersion type, with reinforcement shall be avoided as far as practicable.
10. CURING: Immediately after compaction concrete shall be protected against harmful effects or weather including rain, running water and drying process. It will be covered with wet sacking, Hessian or other similar material approved by the Engineer soon after the initial set and shall be kept continuously wet for a period of not less than 14 days from the date of placement or as directed by the Engineer. 11. FINISHING: Immediately after removal of forms all fins caused by form ts, all cavities produced by the removal of form ties and all other holes and depressions, honey comb sports, broken edges or corners shall be thoroughly cleaned and carefully pointed and rendered true with mortar of cement and fine aggregate mixed in the proportions used in the grade of concrete. 12. SAFETY: Safety will receive due attention. Work force will be provided with helmet, gumboot, hand glove, mask, and special dress appropriate with the nature of the work. Fire extinguisher and first aid requirements will be available stand by. For pedestrians and vehicular traffic, control will be achieved through traffic sign, flag man, road barrier as required. 13. EMPLOYMENT OF LOCAL LABOUR AND WOMEN LABOUR: Local labors will be employed. Timetable will be fixed for local labour and overtime facilities will be granted if necessary. Local labour will be used as much as possible. 12
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture Women labour will also be employed accordingly as per local labour. Women labour will be engaged for the easy work. Fixed time schedule will be given. Mainly the women labour will be engaged for Gabion work, Masonry work, Bioengineering work etc.
13
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Method Statement Project Management This project is “Laying of Bulk Distribution System and Construction of Reservoirs (Package-3) Contract No: KUKL//BDS-SRT/01/03”. This chapter describes the construction method of this BDS project including pre-construction survey and setting out, working area clearance, general precaution before excavation, civil concrete works, DI pipe, HDPE pipe and fittings transportation and storage, trench excavation dewatering and bedding extra soil stock and disposal, pipeline laying, valve fittings service installation, backfill, water pressure test, pipeline clean and disinfection, related sewer pipeline removal and re-installation manhole and different chamber works in detail reinstatement, construction of reservoirs and undertake different civil works. The Contractor’s Works are expected, as a minimum, to comprise the following steps: Survey of Existing Service Connections Pipe works o Installation of Di pipes from dia 1000 `mm to 500 mm. o Bulk distribution system between branch reservoirs. o Install bulk meters and valves at all needed cross connections in pipes. Repair / rehabilitation or replacement of sewer pipes according to design. o Extension of network to areas not adequately served. Other works: Construction of reservoirs at Balaju(Capacity of 7000 cum). o Repair roads according to given requirements wherever needed. o Repair other utility lines in case they are damaged during the work. o Provide alternative sources of water for people while being disconnected from water supply system during the implementation and hydrostatic testing. 1. Pre-Construction Surveys and Setting Out We shall all measurements and be responsible for their correctness. Any differences which may be found between actual measurements and the dimensions given in the Contract Documents shall be submitted to the Engineer. Site bench marks shall be accurately and safely established, maintained and removed upon completion of the Work, before the Work, or any part thereof, are commenced, shall make a complete survey, and take levels, of the Site and agree on the dimensions and elevations upon which setting out of the works shall be based. These levels shall be related to the bench marks and shall be plotted and drawn up .After agreement of the drawings, these levels shall form the basis of setting out of the Works. 1.1.a.i.1.1 2. Clearance of Work Areas and Protection of overhead underground and surround service Prior to the start of any work, lay-out the right-of-way, working areas, clearing, and pavement cutting to insure a proper recognition and protection of the adjacent properties. Ensure that the general shape, profile, and levels of the area are not materially altered during clearing and grubbing operations. In order to avoid re-clearing or to control dust or erosion may have to clear and grub at the latest practicable stage of construction. As technical requirement clearance including The removal of all trees and bushes (complete with roots), other vegetation, rubbish, fences, and all other material that may interfere with the construction of the Work. The disposal of all material resulting from the clearing The removal of all rocks and boulders of size up to 0.2 m 3 that are lying on the surface to be 1
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture cleared or exposed during the clearing operation. Breaking, Dismantling, Cutting of Brick, Interlocking tiles, stone pavement, PCC, Asphalt Road/ Side walk along the pipeline Where fences have to taken down, the sorting, coiling, and stacking of the material, and The removal and stacking of other re-usable materials, demolition of structures Before commencing work in any particular area, the position of all underground services and all other obstacles and existing construction overhead service on the Site, take all measures necessary for the and protection of these services. 3. General precaution before excavation a) Responsible for obtaining temporary way leaves including crop compensation, for temporary working areas, additional working easement and for any additional areas b) If the work will cause unavoidable interference with access to ading property, convenient access to driveways, houses and buildings ading the work shall be maintained and temporary approaches to intersecting streets and alleys shall be provided and kept in good condition. c) Provide and maintain access to the various sections of the Works requires for the proper execution of the work. , Existing roads and bridges shall be upgraded for the construction transport purposes and site roads, loading and turning areas shall be so arranged as to minimize inconvenience to ading landowners or occupants and to the general public. d) Any detour and traffic control will take approval from engineer and road department, once carry traffic control will follow the road department relies for traffic safe. e) When the execution of the Works requires the temporary disconnection of existing public utilities, the Contractor shall provide the affected s with temporary services in at least the same standard as the original services. For water supply install temporary lines or arrange for regular supply by tankers. f) When disconnect existing sewers, shall install temporary pipes of adequate size to carry off sewage from any private sewer facilities cut off by construction work. When forced to disconnect power or telephone connections the relevant authority shall provided temporary connections at the Contractors expense. g) Protection of Ading Property, Responsible directly to the tenant / land owner for any excessive or avoidable damage to crops or lands resulting from his operations whether on lands adjacent to right-of-way or on approved access road h) Responsible and take all measures in order to protect ading property including buildings and other structures. i) Coordination with Other Authorities to take all approval for commences the work. 4. DI/HDPE pipes and fittings manufacture and transportation, storage, loading and unloading method a) Manufacturer will manufacture DI pipe as per ISO standard 2531 with cement lining and zinc coating and bitumen coating , fittings and valves also will produce according related standard .will transport pipe to pipe store yard and stacking as operation manual as per construction schedule in one lot or several lots. b) From store yard will transport the pipe to secondly yard nearest site area by crane truck, normal truck or tractor, then will make special trailer to bring pipe from secondly yard to the site by excavate or tractor. c) The pipe shall lay along the trench on good and stable condition to protect the surface of the pipe. d) Pipe and fittings loading and unloading shall use special hoist belt, lightly and carefully to protect the surface. e) The ground of storage should be soft, and no corrosively chemical near the storage. f) All kinds of valves and pipe fittings should be store in dry rainproof area, classified and mark, easy checking and loading. 5. Trench excavation shoring dewater and bedding backfill and compact and reinstatement of 2
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture surface a) Prepare before excavation, make site investigation, to make sure the underground soil condition, the structure distribution condition on the ground and under the ground, discuss with the engineer or related authorities about the treatment measure. To confirm the position and level of old pipeline and structure and new pipeline center etc. Make proposal for the excavation and disposal surplus soil and take safety measure. Before excavate, the operator shall know the trench excavating section and depth of trench b) Earthwork excavate and shoring The trench mainly excavated by excavator equipment with manual cleaning the bottom of trench. If there is rock, the hydraulic hammer or exposing will take .before excavation, the 15cm depth shall leave for manual excavate. As per design drawing and site visit ,the excavate will take necessary protection measure according different soil condition ,depth of trench and building condition along the pipeline. In case the deep trench and soil condition unstable or the building exit along the pipe line , the trench shoring measure use H type steel pile with steel sheet. Once trench is excavated, the traffic control and safeguarding shall take. As per traffic condition and shopping business condition, we shall make temporary bridges on difference place to reduce the inconvenience. The bridge made by steel plate timber and steel fence. The trench excavate soil shall stack along the pipeline trench. The upper layer sand or aggregate shall stack difference; the height shall not exceed 1.5m. The disposal of extra soil shall be carried out or transport to special place storage. When backfill may shall return. The foundation treatment shall comply with design request. The trench bottom shall be flat and no collapse no water, the turning shall meet requirement. After excavate the quality inspection shall carry out and accept by the engineer. 6. Underground Pipeline and Surround Structure Protection Measure Technology preparation Before construction, project manager department shall study the underground pipeline drawing and know the location of the pipeline and depth and function. Before construction detail investigation at site about the surround structure shall execute .Before construction detail detection of electrical cable underground or telephone communication cable ,underground pipeline ,if find any difference between drawing shall make report to related department and take approval from them and take measure to protect. Make protection and emergency program for underground pipeline and surround structure during excavation and make safe protection .meanwhile make all persons and construction team to study and discuss the construction deg and good education for all person to protect the pipeline. Due to the heavy duty truck entry the site always, the ground shall put steel plate for protection the road surface. If find old pipeline ing through the trench during excavating, when the excavate near the bottom of the old pipeline, shall hanger the old pipe and , then continue excavate during construction, always inspection no collision and no damage to pipeline, during backfill the soil under the pipe shall be compacted if equipment cannot work, the manual is applicable and compacted strongly to escape the future segmentation. If the electrical steel pole shall move or as above Protection for electricity steel pole. Any service or structure or material found undescribed in the technical specification and drawing, shall protect it and report the engineer and take necessary measure to carry out next step. 7. Trench dewater and bedding Before excavate, study the soil quality and water lever underground, make program and prepare the equipment. 3
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture During construction on foundation of pipe trench ,open one temporary water drainage ditch width 300mm depth 300mm along the pipeline ,and several wells 500x500x1000mm for colleting the water , all underground water shall go to well through this drainage ditch , in the well will install sewage submersible pump and discharge the water. The well numbers shall accord the volume of the water underground and rain. The underground water level shall less than 500mm from bottom of trench and make the bottom of trench keeping dry. The water from trench shall be treatment then discharged During dewatering, look after the surround building and structure segmentation or reforming, anything happen shall take necessary measure and discuss with engineer. The technology of reirrigation of the old building base may be taken. During rainy season, enough discharge equipment shall prepare. Some area the water volume is very big, shall consider the bigger well diameter 500mm and depth as per trend depth. To always keep the bottom of trench dry condition. Once the trench excavation and foundation ready, the pipeline bedding shall made. As per the technical specification three kinds of bedding type is used class B class S and concrete surroundings for pipe at different section of pipeline as described in the drawing. 8. Trench back fill, compact and reinstatement Backfilling of pipe trenches shall commence as soon as possible after the pipe has been laid and firmly bedded in the specified cradle and the blanket has been placed over the top of the pipe to the height of blanket cover specified. Backfilling shall be carried out as described below and over the full extent of the actual trench excavation and to original ground level, except where otherwise directed. Unless prior approval has been obtained, no filling shall be placed in water. Excavated material from the trench, which is unsuitable or has become surplus because of bulking, displacement by the pipe and importation. Any deficiency of backfill material from trench excavations because of removal of organic or other unsuitable material shall be made up from suitable surplus material from other excavations on the Site. If, insufficient or no suitable material is available for this purpose from such excavations, shall import sufficient suitable material. Complete backfilling of trenches expeditiously and in reasonable length. At the meantime the backfill material shall compacted layer by layer as specification. In all cases, reinstate surfaces over the full extent of the top of the actual excavation, as well as the entire width of all roadways where the pipeline is laid. The reinstatement shall reach all kind road standards as per Nepal road department specification. 9. Ductile pipeline laying, cleaning and testing Familiar with the manufacturer's instructions/pipeline construction manuals for the laying and ting of pipes and that these instructions are strictly adhered to, if request, may employ the manufacturer to demonstrate laying and ting. Pipe lying shall not commence until the bottom of the trench and the pipe bed has been approved by the Engineer's representative. The trench bottom shall be prepared, Trenches shall be kept dry to allow proper and safe bedding, laying, ting of pipes and construction of the selected fill blanket over the pipes. The pipeline shall be tape wrapped or sheathed in polythene sleeve for protection. i. The laying process Checking the pipe surface inner lining and out coating quality ,clean the socket and spigot ,check the quality of rubber ring ,check the lubricated flux quality Before loading the pipe inside the trench, the pipe shall be tape wrapped or sheathed in polythene sleeve for protection. Use excavator to load the pipe inside the trench with manual assistance. For tighten type ting, clean the socket and spigot and rubber ring again, install the rubber ring, press the rubber ring, by rubber hammer to keep the rubber ring flat in socket exactly, brush the lubricate flux 4
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture (like plant oil or soap water) on the rubber ring and spigot, by the hoist push the spigot into the socket to reach the position line on the spigot. Check the t, the gap between socket and spigot shall be average circled. Also check the front and next t under good condition. Once the pipeline turning, the turning angle shall less than 1 degree. At the close of each day's work or at any time when work is suspended for a significant period, the last laid pipe shall be plugged, capped, or otherwise tightly closed until lying is recommenced. For bolted gland ts the ts ring shall be pushed into place by the gland ring using only hand pressure, fixing nuts and bolts should then be fitted and first tightened to finger pressure. Thereafter tightening shall be in the sequence proposed by the manufacturer and to the torque recommended. In the ting of pipes with flanges, special care shall be taken to align, grade, and level the pipes, specials, and valves to avoid straining of the flanges. All bitumen and paint shall be removed from the mating face of each flange immediately before ting. Bolts shall be tightened up evenly in opposite pairs to ensure uniform bearing; the final tightening shall be to the torque specified by the manufacturer. For flanged ts the gasket shall be fitted smoothly to the flange and the t made by tightening the nuts to finger pressure first. Thereafter the final tightening of the nuts shall be made by gradually and evenly tightening bolts in diametrically opposite positions using only standard spanners of a type approved by the Engineer. Graphite grease shall be applied to the threads of bolts before ts are made. A care shall be taken to avoid damage to the internal surface of the pipes during assembly of the pipeline. Once ts are made they shall be protected to a level appropriate for the pipe by: polyethylene sleeving and tape wrapping. Pipes shall be cut by a method which provides a clean square cut of the pipe and of the lining, without damage to pipe or lining. All cut or trimmed ends and the parts of any pipe on which the coating may have suffered damage shall be re-coated as specified before the pipes are laid. The external area at cut spigot ends of ductile iron pipes shall be ground smooth for a distance of at least 125 mm, and then chamfered or otherwise made suitable for ting as recommended by the pipe manufacture. Unless otherwise shown on the drawings, or directed by the Engineer, gate valves shall be set upright and butterfly valves shall be set with the main shafts horizontal. All valves, specials, and fittings shall be located in the exact positions shown on the drawings or otherwise directed. , the prepared fitting shall then be wrapped in protective tape At tees, bends, terminal valves, end caps, and where otherwise directed, anchor/thrust blocks shall be constructed to dimensions ordered or shown on the drawings. Unless otherwise indicated on the drawings, anchor/thrust blocks and pedestals shall be constructed of C20 concrete. The concrete shall be well punned around the pipe, if in trenches, against the undisturbed faces and bottom of the trench. Backfilling behind or under thrust faces will not be permitted. Excess excavation shall be replaced with the prescribed mix concrete given above at the Contractor's expense. Care shall be taken to leave all ts accessible. No anchor/thrust block and pedestals shall be concreted before the approval of the Engineer has been obtained. All washout valves, pressure reducing valves, and air valves in pipelines shall be housed in a chamber as shown on the drawings or directed by the Engineer. All covers and frames shall be manufactured, from cast grey or ductile iron, All covers shall be fitted to the frames and tested at the manufacturer's works and covers and frames shall be similarly numbered in a legible and permanent manner in a position which will not be visible when fitted in place, and shall be of such construction as to minimize the ingress of sand. The Contractor shall ensure that the covers are fitted to the appropriately numbered frames after the frames have been fitted. The name of the Employer and year of manufacture shall be embossed in all covers. 5
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture The connection point shall be provided at the location specified. The flange shall be installed so that it is vertically plumb and its face is perpendicular to the axis of the pipeline. The flange shall be covered by a PN 16 blank flange; the flange shall be installed in the specified manner. The flange shall be backfilled and the location marked with a marker post. All connection shall work as the drawing showing. Permanent pipeline marker posts shall be installed at all changes of horizontal alignment and at 200m intervals along the straight lengths of pipe. Marker posts shall be positioned as close as possible to a 2 m offset from the pipe centre line. Pipelines are shall be manually cleaned internally of all debris, stones and sand prior to testing. The internal surfaces of all pipelines and pipe work including all equipment incorporated in a pipeline or pipe work through which water will shall be disinfected after they have been cleaned ii.
Construction of Valve/meter/fire hydrant/wash out chambers It includes the chamber construction works- excavation, backfilling, shoring, dewatering etc. testing and disinfection and supply, store and deliver of relevant pipes, fittings, specials, manhole covers, surface boxes and necessary accessories. Unless otherwise indicated on the drawings, anchor/thrust blocks and pedestals shall be constructed of C20 concrete. The concrete shall be well punned around the pipe, if in trenches, against the undisturbed faces and bottom of the trench.
iii.
Cleaning and testing Disinfection shall be effected by filling the pipeline with water heavily dosed with chlorine, and shall be carried out when filling the pipeline with water for carrying out the hydraulic test on completion. The level of the chlorine dosing shall be such as to make available 50 mg/l of free chlorine throughout the pipeline. The water, heavily dosed with chlorine, shall stand in the pipeline for a period of 24 hours or for such longer period as the Engineer shall require and all valves in the system shall be operated at least once during this period At the termination of the required period, chlorine residual tests shall be taken at the end of the pipeline farthest from the point of injection and the test shall be repeated if necessary until the residual is not less than 10 mg/l. Test pressures are to be measured at the centre of the blank flange situated at the lowest end of the pipeline under test. All pipelines shall be tested to a pressure corresponding to a hydraulic grade of 1452. The Sectional Hydraulic Test shall be carried out after the pipeline or pipe work section to be tested has been laid, ted and backfilled to a depth sufficient to prevent flotation of the pipeline. The sections to be tested shall be to the approval of the Engineer and shall be not longer than 2,000 m or 500 m when either the pipeline is laid adjacent to or underneath the carriageway. Before Sectional Hydraulic Test, the pipe line must fill back and compacted, check all fitting and pipeline thrust and anchor, all tested section ,the tee air release valve and valve shall closed by blind flange or plug. Check the highest air valve is open, check the pipe line can air release and water can discharged. Check the test water, test station and water discharge system. Filling the water inside the pipeline until the air release the finish. Stay a period 24 hours let the water absorber by all t then close the air valve. Rising the pressure and check always rising shall step by step. After reach the setting pressure, keep in static and same period, check the pressure gauge movement. After acceptance, then slowly reduce the pressure, slowly open pressure reduce valve open air release valve. After that can discharge the water to point area.
iv.
Sewers and Storm water Drainage Within a portion of the pipeline alignment along the existing roadway, an existing combined sewer is located approximately in the middle of the road. This sewer shall be reconstructed at a new location, 6
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture as part of the Works. The sewer reconstruction shall be undertaken in stages, commencing from the upstream side, so as to maintain the sewer flow during construction, as follows: a) The new sewer and manholes are reconstructed at a minimum clearance of 3m from the proposed water pipeline location, in segments. b) New house connections shall be provided r to each new segment as it is constructed. c) A temporary tap from the new segment to the downstream existing sewer shall be provided d) The old house connections and sewer segments shall be removed. e) The next segment of the reconstructed sewer shall be connected to the previously constructed upstream segment, without disrupting sewer service. f) The process described above shall be repeated until it is no longer necessary to reconstruct any segment of the sewer, i.e., until a minimum clearance of 3m is maintained between the proposed water pipeline location and the sewer. Sewer service to existing residences and businesses shall not be disrupted during the sewer reconstruction process. Because of the narrow width of the roadway over a large portion of the area of required sewer relocation, the Contractor shall be required to perform much of the reconstruction work prior to construction of the water pipeline. Pipe material is RCC pipe. Excavate, bedding, laying backfill etc as specification, will made technical proposal before commence. Cross river pipe line lying v.
Bridge/river/culvert bed crossing After the site visit, we will take method as following a) Check the river water flow rate and speed, made dam to stop water from both pipeline side 20 meters and set guiding pipe to let water . b) Before build dam shall clean the river bed c) Dam section diameter upper width less 2 meter ,dam slop 1:0.2 .make pile and fill the soil to build dam, the height of dam shall be 1m high than water. Dam shall protect by bag fill of soil or sand .dam shall less leakage and strong. d) Setting guiding pipe for water e) Pipeline cross river construction try to arrange at dry season with little water flow rate. f) Open excavate g) Here pipe bedding by concrete surround. After pipe lying, pay attention for backfill and press the pipeline and take special measure to pipeline floating protection.
1. Project camp Provide adequate housing with all necessary amenities and facilities for his staff and labor. The type of housing, as accommodation containers, pre-fabricated or in-situ buildings or even rental. During the whole period of existence, from setting up through operation to final removal upon completion of the Works, fully responsible for constantly carrying out all measures necessary for safeguarding the natural environment affected by camp or camps. Cause the least possible interference with existing amenities, whether man-made or natural. No trees shall be felled. Latrine and ablution facilities and first-aid services shall be provided in sufficient type and numbers to the satisfaction of the Engineer and shall be maintained in a clean and sanitary condition at all times. On completion of the Works or as soon as the facilities provided by the Contractor are no longer required, the Contractor shall remove such facilities and clear away all surface indications of their presence. Each camp area shall be reinstated to the satisfaction of the Engineer. 7
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture Provide, erect, construct, maintain and subsequently remove proper offices, stores, workshops, laboratories, storage and parking areas for his own use. Such facilities shall be sufficiently sized and equipped to enable him to manage his operations and those of his Subcontractors in a professional manner and to enable him to carry out all his obligations under the Contract. Within his offices a meeting room shall be available for site meetings with the Engineer and the Employer. These Contractor's facilities shall be subject to the same stipulations regarding sitting, interference with amenities and environmental protection as the Contractor's camp. 2. Preparation of the Stockyard for Pipes, Valves and Fittings The preparation of the stockyard for pipes valves and fittings shall include: Clearance of the Site Construction of side drains around the stockyards to avoid water logging Construction of access tracks. Covering of pipe and fittings storage areas with a 150mm thick layer of granular material that will discourage the growth of vegetation and plus any additional provision to carry the loads from the pipes and fittings. Erection of a security fence. Construction of a guard house / store keeper’s office. Erection of stores for ting material etc. including the provision of air-conditioning where necessary.
Hydrostatic Testing assessment The proposal contains the following working packages: Bulk distribution Design Develop hydraulic model Monitoring Hydrostatic testing and determine real losses Bulk distribution design The technique of leakage monitoring requires the installation of flowmeters at strategic points throughout the distribution system, each meter recording the flows into a discrete area with a defined and permanent boundary. Such an area is called a Distribution area. The design of a leakage monitoring system has some aims: 1) To manage the pressure in each district or group of districts so that the network is operated at the optimum level of pressure The BDS meters can be linked (in the future) to a central control station via telemetry so that the flow data are continuously recorded. Analysis of these data, particularly of flow rates during the night, determines whether consumption in any one distribution has progressively and consistently increased, which would indicate a burst or undetected leakage. Each leak location area is then closed off in turn, allowing the flow into each area to be monitored via the distribution meter. It is important to understand that night flow comprises customers’ use as well as losses from the distribution system. Where all customers are metered this does not pose much of a problem. In a telemeter distribution system, night flow data can be received and analyzed regularly. This enables changes in the night flow of each distribution to be quickly identified, reducing the awareness time. When compared with previous readings and with other BDS, it enables the leakage control team to prioritize inspection. The logger software typically contains an “error table” which identifies those distribution areas where night flows have increased above a pre-set alarm level. The leakage control team is able to scan the error table daily to identify unreported bursts or, in response to poor pressure complaints, to confirm a reported burst. Detection and control of leakage varies from one case to another, and the choice of methodology is largely dependent on local conditions, number of available measurements, 8
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture and type of water supply e.g. 24/7 supply versus intermittent water supply, financial constraints on equipment and other factors. DHI will establish the optimum approach to hydrostatic test based on the local conditions. Develop hydraulic model The hydraulic model of each BDS areas will be developed in order to the design of each BDA and that it is hydraulically isolated and functions properly. The hydraulic modelling will be also used to that the network will function adequately under predicted 2015 and 2025 supply and demand scenarios. A combination of measurements and mathematical modeling application will be applied through a numerical model in order to describe in detail hydraulic processes in the distribution network. The resulting calibrated mathematical model is used for evaluation of the existing water supply system and the reasons for identified system bottlenecks. The hydraulic model will be developed based on pipe networks design.
Monitoring Minimum pressure requirements Pressure loggers will be installed within each BDS area that will continuously record the pressure in the network. The location of loggers will be determined in consultation with the Engineer. The pressure data will be collected and provided to Engineer for validation. The pressure loggers will be et to record at time intervals of no more than 10 minutes and the data will be ed at intervals of 7 days of less and the total duration of the monitoring within each BDS will be 30 days, the analysis will be carried out at intervals of 7, 14, and 30 days. The pressure monitoring will be used to analyze the average pressure within each BDS as well as pressure fluctuation during 24 hours. The pressure monitoring will be used for the network function compliance along with the assessment of physical losses that are defined either as 15% or less of the volume (flow monitoring) or an average of 100 liters per connection per day when the system is pressurized at 10m average (pressure monitoring). Maximum real loss requirements Flow monitoring will be used for assessment of real losses and BDSwater balances. There will be three methods conducted such as full BDS pressure test, night flow monitoring, and water balance. The real losses will be determined based on the recorded readings of the bulk flow meters recording the flows in and out of the BDS, and the domestic consumption meters installed at each house connection. The readings will be taken over the period of 30 days and they will be verified by the Engineer.
Hydrostatic assessment of the constructed system and determine real losses NRW assessment in each BDS is a part of the step-wise Commissioning Plan and the determination of real losses is on of the key success indicators. NRW assessment will be done based on the pressure and flow monitoring within each BDS and three will be used, such as 1) full DMA pressure test, 2) night flow monitoring, and 3) BDS area water balance. In case that the 24/7 water supply cannot be arranged for 30 days alternative adjustments to these methods will be done. The main objective in physical losses is to guarantee that: Real loss is 15% or less of supplied volume, or An average of 100 litres per connection per day when the system is pressurized at 10m average is not to be exceeded The methods below along with the data collected through pressure and flow monitoring as well as from spreadsheets, databases etc. will be used to prove the compliance. Full pressure test
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Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture Network is pressurized during the full pressure test BDS area outlets are closed. Due to leakage, expansion and contraction of pipes, measurement inaccuracies, some pressure loss will occur. Evaluation methods described in the Section 6 of the “Bidding documents” will be used to determine whether pressure falls within the allowable limits and whether the BDS area can be further verified using night-flow analysis or water balance calculation.
B) Reservoirs & other works 1. TOPSOIL EXCAVATION AND STOCKPILING/PRESERVATION: In the area where most of the available embankment materials are not conducive to plant growth or where directed by the Engineer, the soil existing over the embankment foundation shall be stripped to specified depth usually not exceeding 150mm. and stored for covering embankment slope, cut slopes and other disturbed areas where re-vegetation is required. Top soil removal can be done through use of grader or other heavy earth moving equipment depending upon site requirement. 2.
EARTH EXCAVATION AND DISPOSAL OF EXCESSIVE CUT MATERIAL: Structures excavation shall consist of excavation, removal and satisfactory disposal of all materials necessary for the construction of reservoirs indicated by the Engineer. The work shall include hauling and stacking of hauling to sites of embankment construction as required as also the disposal of unsuitable cut materials in specified manner, and the trimming and finishing of site. All excavation shall be carried out in conformity with the directions laid in the contract and in a manner approved by the Engineer. The work shall be so planned that the suitable materials available from excavations are satisfactory utilized as decided before hand.
3.
EMBANKMENT FILLING AND COMPACTION: Embankment and miscellaneous back-fills will be constructed with approved material obtained either from excavation or borrow pits or other sources. Embankments will be constructed in accordance with the requirement of the specification and in conformity with the lines, grades and cross sections shown on the drawing. Materials used in embankment shall be earth, gravel, a mixture of these or any other materials approved by the Engineer. Such materials shall be free from logs, stumps, roots, rubbish or any other ingredient likely to deteriorate or affect the stability of the embankment. Only the materials satisfying the density requirement given in specification shall be employed for embankment construction. The materials for embankment shall be obtained from approved sources. After the site has been cleared the work shall be set out as specification. The limits of the embankments shall be marked by fixing pegs as guides before commencing earthwork. The top soil existing over the embankment foundation shall be stripped to specified depth. The original ground shall be consolidated by rolling. The embankment material shall be spread uniformly over the entire width of embankment in specified depth. The successive layers of embankment shall not be placed until the layer under construction has been thoroughly compacted to the requirement set out in the specification. Moisture content of the materials shall be checked and if found less than that specified for compaction, the same shall be made good either at the source or after spreading the soil in loose thickness for compaction. Water shall be sprinkled from a lose line or from a truck mounted water tank. Flooding shall not be permitted. Only the compaction equipment approved by the Engineer shall be employed to compact the different material types encountered during construction. Each layer of the materials shall be thoroughly compacted to the densities specified. Subsequent layers shall be placed after finished layer has been tested as required.
4.
SUB BASE, BASE AND SHOULDER: Following construction of the embankment or excavation for structures will be prepared to line lever 10
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture and grade, using excavator. Sub-base will be added to the designed thickness, moisture added as shown by the lab report and the material consolidated with the use of appropriate road roller. Finished layer of sub-base will be checked for line, level and grade and any deficiency corrected by adding or removing excess material as appropriate. Density tests as per frequency requirement will be conducted. Any rectification required in the light of the lab test will be carried out. After sub-base the base course will be laid to required depth. Compaction carried will be with the appropriate type of road roller, resulting surface checked for line, level and grade. Excess material if indicated after checking will be removed/trimmed. If deficiency is found, the material will be added. Re-rolling done where appropriate. Any correction dictated by the test will be carried out. During construction traffic will use the diversion where dictated by the site condition. 5.
BITUMINOUS SURFACING: Before the asphalt concrete works starts the base surface will be cleaned of dust with air compressor. Where required wire brush will be used. Appropriate type of bitumen will be heated to required temperature in the decanter machine, carried to the site in bitumen distributor kerosene added for cut back in appropriate follow and bitumen sprayed at required rate for prime coat. Traffic movement will not be allowed for minimum 24 hours of applying prime coat or as permitted by the site condition and with the approval of the Engineer. Operation for asphalt concrete works will commence. Surface will be cleaned with air compressor. Bitumen binder of appropriate grade (cut back bitumen binder, 80/100 bitumen and diesel or kerosene oil cutter) will be sprayed at specified rate with the help of bitumen distributor.This will immediately follow by rolling through pneumatic road roller. Necessary es of road roller will be applied to achieve compaction.. Any excess material will be removed or deficiency added and surface brought to required level with further rolling where required. The heating temperature of bitumen and quantity of adhesive agent will be determined by trial with approval of the Engineer.
6.
KERBSTONE After the main works are completed the Kerbstone works, sign boards, sign board posts etc. will be fixed. On issue of taking over certificate equipment, surplus materials, rubbish and temporary work of every kind shall be cleared and removed. The site will be left clean and in a workman like condition to the satisfaction of the Engineer.
7.
FORM WORK: Forms for concrete shall be constructed of metal or timber suitably lines where required and be of a substantial and rigid construction to shape and dimensions shown on the drawing. Where metal forms are used bolts and rivets shall be countersunk and will grounded to provide smooth and plane surface. Where timber is used it shall be seasoned. Forms shall be mortar tight and shall be made sufficiently rigid by the use of ties and bracings to prevent any displacements or sagging between s. It shall be strong enough to with stand all pressures, ramming and vibration. Immediately before concreting all forms shall be thoroughly cleaned. Removal of the form-work will be affected as per specification. The period shall be suitable increased in case of temperatures lower than specified and for any other conditions tending to delay the setting of concrete.
8.
REINFORCEMENT: Steel shall be clean and free from loose rust and loose will scale at the time of fixing in position and subsequent concreting. Reinforcement steel shall conform accurately to the dimensions given in the bar bending schedule shown on relevant drawing. Bars will be bent cold to the specified shape and dimensions operated by hand or power to attain 11
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture proper radii of bends. Bars will not be bent or straightened in a manner that will injure the material. Hooks shall be suitable encased to prevent any splitting or concrete. All reinforcement bars shall be accurately placed in exact position and shall be securely held in position during placing of concrete by annealed binding wire meeting the requirement of the specification and by using stay blocks or metal chairs, spacers or other approved devices at sufficiently close intervals. Bars crossing each other, where required shall be secured by binding wire (annealed) of size specified). As far as possible, bars of full length shall be used. In case this is not possible, overlapping of bars shall be done as directed by the Engineer. When practicable, overlapping bars shall not touch each other, but kept apart by 25mm. or 1.25 times the maximum size of the aggregate. The overlaps shall be staggered for different bars and located at points, along the span where neither shear not binding moment is maximum. 9.
MIXING TRANSPORTING, PLACING AND COMPACTION OF CONCRETE: Concrete shall be mixed in mechanical mixer using appropriate size and quantity of the ingredients Quantity of water shall be just sufficient to produce a dense concrete of required workability for the job. Mixing shall be continued till materials are uniformly distributed and an uniform color or entire mass is obtained and each individual particle of the coarse aggregate shows complete coating of mortar. The method of transporting and placing concrete will be as approved by the Engineer Concrete shall be so transported and placed that no contamination, segregation or loss of its constituent materials take place. All formwork and reinforcement contained in it shall be cleaned and made free from standing water, dust immediately before placing of concrete. The concrete will be deposited between a minimum and maximum temperature as specified in the specification. It shall be compacted in final position within half an hour of its discharge from the mixer. The concrete shall be deposited in horizontal layer to a compacted depth of usually not exceeding 45cm. Vibrators will be used for compaction. When the concreting is to be resumed on a surface which has hardened it shall be roughened, swept clean, thoroughly wetted and covered with a mortar layer of same concrete mix. Vibration shall not be applied through reinforcement. In case of vibrators of immersion type, with reinforcement shall be avoided as far as practicable.
10. CURING: Immediately after compaction concrete shall be protected against harmful effects or weather including rain, running water and drying process. It will be covered with wet sacking, Hessian or other similar material approved by the Engineer soon after the initial set and shall be kept continuously wet for a period of not less than 14 days from the date of placement or as directed by the Engineer. 11. FINISHING: Immediately after removal of forms all fins caused by form ts, all cavities produced by the removal of form ties and all other holes and depressions, honey comb sports, broken edges or corners shall be thoroughly cleaned and carefully pointed and rendered true with mortar of cement and fine aggregate mixed in the proportions used in the grade of concrete. 12. SAFETY: Safety will receive due attention. Work force will be provided with helmet, gumboot, hand glove, mask, and special dress appropriate with the nature of the work. Fire extinguisher and first aid requirements will be available stand by. For pedestrians and vehicular traffic, control will be achieved through traffic sign, flag man, road barrier as required. 13. EMPLOYMENT OF LOCAL LABOUR AND WOMEN LABOUR: Local labors will be employed. Timetable will be fixed for local labour and overtime facilities will be granted if necessary. Local labour will be used as much as possible. 12
Method Statement: Contract No. KUKL/BDS-SRT/01/03
Tianjin-Raman t Venture Women labour will also be employed accordingly as per local labour. Women labour will be engaged for the easy work. Fixed time schedule will be given. Mainly the women labour will be engaged for Gabion work, Masonry work, Bioengineering work etc.
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Method Statement: Contract No. KUKL/BDS-SRT/01/03
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