First Web Edition 2006, Devoted to Engineering Community
Taweelah Unit III Um Al Nar Water Transmission Scheme
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- Procedures / Method for one reservoir construction
- Structural construction activities
- General activities post structural construction
- Detailed activities prior to structural construction
- Construction of peripheral retaining walls- major elements
- Preparatory works for the base slab- non propriety formwork
- Preparatory works for baffle walls- propriety formwork
- L shape wall
- Base Slab bay / Floor slabs
- Straight walls
- Columns
- Inlet chamber
- Roofing
- Other General activities
Taweelah Unit III Um Al NarWater Transmission SchemeWater ReservoirConstruction Method Statement ScopeThe purpose of this document is to define the construction procedures to be adopted for the construction of typical reservoirs. Four number reservoirs are to be built at one location. This statement is meant only for general description of the procedures for various operations involved. Other detailed typical statements shall be produced during the real execution of the works for each activity as standard procedures applicable to the project. The project duration is 20 months Period for the tanks construction considered 14 months (60 weeks). Two tanks to be constructed simultaneously. Ref. DocumentsDrawings A1/71341/00/1142203 to 5, 1143201 to 16 all schematic Reference Attached from Doka Formwork G A Walls & Columns Top 50 systems Formwork D 2 Tables Specification For Concrete W-C-SS-005 Specification For Concrete Reservoirs W-C-SS-007 DesignPrior to the construction of the reservoir, all proposed forms shall be designed to the final requirement & calculations with drawings submitted for approval. The construction execution of the reservoir RCC structures shall be carried out based on the AFC drawings. Existing servicesRecords shall be checked for the possibilities of any running service. Any existing services so located shall be informed to the relevant authorities as well as company for necessary actions. Trial pits shall also be excavated to scan whether or not any service exists. Supervision & ControlConstruction manager, Site engineer, construction foreman & charge hands shall control all activities on site according to the relevant job descriptions. SurveyAccording to the AFC drawings, the surveying team shall locate the setting out lines, coordinates as well as the surrounding circulation area for the construction purpose. Since the dimension of the built up reservoir are given around 130 M x 90 M, proper arrangement shall be made to carry out the mass excavation works. Topographical levels shall be recorded. The site shall be graded to the required ground level. All survey documents shall be prepared for the purpose of verification. Around the area, guide barricades shall be erected for the purpose of locating the grids & reference site levels. Benchmarks shall be established on all corners for the purpose of flying and reestablishing any of working locations. The establishment of the base corners points as well as the base level benchmark shall be conducted by licensed land surveyor & documents submitted to the engineer for approvals & records references. SafetyAll safety measures shall be taken according to the excavation requirement. Warning tapes Safety cones shall be provided around the defined working area. All safety signboards meant for the excavation safety shall be provided. Warning night-lights reflectors shall be provided around. Ladders shall be provided for the access into the working area located not more than 8 m spacing. Pouring platform for the people to work safely shall be constructed. For convenient access of heavy equipment into the formation area, ramps shall be provided from the existing or graded level from 2 opposite ends. If so required, dewatering arrangements shall be carried out continuously until the foundation slab is constructed. Toolbox talks shall be imparted daily for all the important operations involved. A safety officer shall inspect the works every day, during all concreting activities, form erection activities etc. MaterialsConcrete source- Ready mix concrete from an approved supplier shall be used. Rebar fabrication- Rebar shall be fabricated on the steel yard located elsewhere on the site. All fabricated bars shall be tagged according to the BBS (Bar Bending Schedule) references
Fabrication of the plywood forms shall be carried out on site based on the specialist formwork vendor details. The supporting system shall be provided by the form vendor based on the detailed design approved by the engineer. On site, the form works shall be erected according to the vendor drawings. The scope of the vendor formwork system shall be confined to retaining walls, baffle walls, columns, flat slab.
Summary of the activitiesGeneral activities prior to structural construction 300 mm compacted granular sub base 75 mm concrete blinding 2 layers bituminous membrane 50 mm screed
Periphery retaining walls, Base slab, baffle walls, columns with heads, suspended slab, all components of the inlet & outlet chambers, components of the overflow chambers. Intermediate suspended slabs & walls, sump elements. Box outs, construction joints, expansion joints, stair structure, Roof up stands General activities post structural constructionFilling the PVC pipes inserts within the walls with approved propriety material. Fixing of Manholes covers & frames on roof. Roofing & waterproofing Roof handrails External Walls pattern formation. 1200 mm wide interlocking paving around reservoir construction. Detailed activities prior to structural constructionExcavation & Sub GradeAfter the clearance from the engineer, excavation shall be started using heavy equipments removing the excavated material directly into the truck & transporting to the tip off stock piles or in case the material not to be used for the filling purpose, to a designated dumping area. During excavation, dust control shall be carried out by conventional means. Excavation shall be carried out approximately to the formation sub grade level only all according to the profile shown on the approved drawings. The surveyor shall control the levels to avoid over excavation. The excavated formation shall be dressed manually as well as using light rollers & after the formation profile is established, heavy rolling shall be carried out over the entire are to reach field compaction to 95 % of dry density. Field compaction test shall be conducted according to the standards & specification requirements. Quality Engineer shall inspect the profile 300 mm compacted granular sub base Approved granular sub base is spread over the entire area in 2 layers. 1st layer shall be laid in a thickness so that after the rolling, the compacted thickness in both the courses is 300 mm. Thereafter, 2nd course construction shall be carried out. The top profile of the sub base shall be given according to the details which indicates a fall 1 in 500. Site sample testing shall be conducted according to the specification requirement for both courses. 75 mm concrete blinding & mass concrete to requirement Blinding shall be done in stages parallel to the width of the reservoir. The whole blinding shall be divided into 6 bays each 20m wide & 90 m long. The one stage quantifies to about 135 cum which is feasible for a convenient casting. If so required, further formation of baying compartments could be established within each bay for alternative laying. Low profile strip formwork for the controlling sides shall be prepared. A concrete laying team shall be grouped for the purpose such that concrete received from the transit mixer is immediately pumped into the location & spread using teeth shovel / garden racks, to the strip profile level. Proper leveling shall be carried out using wooden float edge by the masons. The whole area shall be laid, profiled to true levels & given wooden float after the concrete is ready to receive the float. Polythene sheet shall be spread over the entire area. Curing shall be carried out for 3 days only. Before laying new concrete at the set edge of the previous blinding at the edge, cement slurry shall be applied to the edge so that new & old concrete is properly bonded. Mass concrete shall be carried out as shown on the approved contract drawings 2 layers bituminous membrane At the end of the curing, the surface shall be cleaned of all dust particles, debris, water etc & inspected. Any cracks appearing or any damaged portion located shall be repaired. According to the manufacturer’s instruction, bituminous membrane shall be applied over the blinded surface. 50 mm screed The membrane shall be protected by an application of 50 mm screed layer as soon as possible & cured accordingly by the repetition of the foregoing activities in sequence but in alternate bays. Construction of peripheral retaining walls- major elementsPreparatory works for one corner L shape – 1 set, 4 stages in repetition (Ref to attached drg GA walls from DOKA) Preparatory works for straight walls – 1 set 40 m long, 6 repetitions (Ref to attached drg GA walls from DOKA) These elements comprise of the base slab, shear key & upright RCC structures Preparatory works for the base slab- non propriety formwork384 repetitions of each bayEach bay comprises of 4 sides Preparatory works for the columns- propriety formwork40 sets, 10 repetitionsEach column comprises of 4 sides (Ref to attached drg Column top 50 from DOKA) Preparatory works for baffle walls- propriety formwork10 sets, 4 repetitions Each wall comprises Preparatory works for the inlet / outlet chamber as well as overflow1 set, 2 repetitions These comprise of base slab, walls, suspended slabs Preparatory works for the suspended slab - propriety formwork 1 set, 2 repetitions Flat slab construction (Ref to attached drg D2 Tables from DOKA) L shape wallSetting out for each L shape wall at the corner shall be carried out on the screed for the base slab (Toe + Heel) portion. Re-bars shall be placed according to the details provided with due spacers. Chairs shall be provided between the top & bottom rebar layers. At the end of the every day work, polythene membrane shall be spread over the placed & fixed rebars for protection from humidity. Vertical forms shall be prepared at site using plywood & wooden battens all to approved methods. Arrangement for the construction joint shall be made for the insertion of approved water bar so that lower half of the bar is in the retaining wall base slab concrete. The retaining wall base slab shall be continuous without any joint. It shall be ensured that the set lines of the forms are in true alignment & plumb. All vertical sides shall be well supported so that 1 m high concrete pressure is sustained by the supporting system adequately without bulging. After the clearance by the site engineer, QC inspection shall be conducted & engineers approval obtained for pouring concrete. About 500 cum of pour is in this programme that may take about 16 hours. The pouring shall be done in 3 layers so that cold joint is avoided. Two pumps shall be used for this pour. Concrete delivery shall be continuous. The portion of the green concrete at the wall junction shall be roughened before the concrete is hardened, The exposed portion of the concrete shall be properly finished to the defined levels & immediate / instant as well as specified duration curing shall be continuously carried out. Following preparatory works for the upper wall portion shall be continued. Upright wallScaffolding shall be erected on both sides for accessing the workers to fix the rebars & erect the formworks for the upright wall. Rebars shall be placed properly in compliance with the design details & engineers approval obtained prior to the closure of the forms. At the end of the every day work, polythene membrane shall be spread over the placed & fixed rebars for protection from humidity. According to the formwork vendor’s design, the sides of the forms shall be erected & fixed. It shall be ensured that the erected forms are in true alignment & plumb as well as outer wall forms in designed profile. The anchoring arrangements sleeved in shall be fastened properly. All supports as shown on the details shall be provided. A platform shall be built on top for the workers safe access & working. Water bar shall be inserted in all vertical positions duly welded using cross as well as Tees wherever required. Permanent bars shall also be inserted as shown on the vendor’s design. Outer forms shall be checked for the correctness of its compliance with design profile while vertical forms for verticality as we as alignment. QC inspection shall be conducted & engineer’s approval obtained Programme shall be charted out for pouring about 250 cum in one go. The concrete pouring chute pipe shall be inserted vertically into the prepared works so that the net drop of concrete is not more than 2 m. Pour shall be carried out in layers not exceeding 450 mm so that vibrator nozzles penetrates internally. This pour shall consume about 10 hours. At the end of the pour, the top surface shall be properly floated & either curing compound instantly sprayed or covered with polythene sheet. Side supports shall be struck only after 48 hours.
Base Slab bay / Floor slabsSize of the bay is 5 m x 5 m, 500 mm thick i.e 12.5 cum. Total number 384 bays. Preparation for 40 bays shall be done in one go i.e 500 cum pour. Construction joints to be prepared around to detail requirement. Preparation of forms to be carried out around in general keeping in view that it allows for the continuation of rebars and also the insertion of water bar. At the end of the every day work, polythene membrane shall be spread over the placed & fixed rebars for protection from humidity. Rebar placement to be done continuously to the details Rebars for the starter bars shall be placed for the baffle walls in the correct positions wherever defined Rebars for the starter bars shall be placed for the columns in the correct positions wherever defined Provision of surface water strip shall be made according to details. Provision of rebar chairs for the top & bottom rebars supports shall be made. Proper placement of concrete spacers shall be made. All the bars shall be properly bound to avoid any kind of slip or dislocation even though steel fixers shall be available to attend the pour to control the bars positions. Form carpenters shall also be available to control the alignment & levels. Two pumps shall be used for the pour for 16 hours programme. Immediately after the finishing of the top surface to the defined profile, instant curing shall be carried out. After the concrete is set, curing shall be carried out as approved. Repetition of the bays shall be done accordingly to complete all 384 bays. Side supports shall be struck only after 24 hours. Straight wallsBase Slab preparatory works shall be carried out similarly as given in the foregoing L shape pattern excepting that the forms are straight. Upright wall Each pour about 100 cum. In this case also, Scaffolding shall be erected for accessing the workers to fix the rebars & erect the formworks for the upright wall. Rebars shall be placed properly in compliance with the design details & engineers approval obtained prior to the closure of the forms. At the end of the every day work, polythene membrane shall be spread over the placed & fixed rebars for protection from humidity. According to the formwork vendor’s design, the sides of the forms shall be fixed. It shall be ensured that the erected forms are in true alignment, profile & plumb. The tie rods sleeved in shall be fastened properly. All supports as shown on the details shall be provided. A platform shall be built on top for the workers safe access & working. Water bar shall be inserted in all vertical positions duly welded using cross as well as Tees wherever required. Permanent bars shall also be inserted as shown on the vendor’s design. QC inspection shall be conducted & engineer’s approval obtained. Programme shall be charted out for pouring about 250 cum in one go. The concrete pouring chute pipe shall be inserted into the form so that the net drop of concrete is not more than 2 m. Pour shall be carried out in layers not exceeding 450 mm so that vibrator nozzles penetrates internally. This pour shall consume about 5 hours. At the end of the pour, the top surface shall be properly floated & either curing compound instantly sprayed or covered with polythene sheet. Side supports shall be struck only after 48 hours. ColumnsAbout 75 cum in one go for 40 columns. In this case also, Scaffolding shall be erected for accessing the workers to fix the rebars & erect the formworks. Rebars shall be placed properly in compliance with the design details & engineers approval obtained prior to the closure of the forms. At the end of the every day work, polythene membrane shall be spread over the placed & fixed rebars for protection from humidity. According to the formwork vendor’s design, the sides of the forms shall be fixed. It shall ensured that the erected forms are in true alignment & plumb. The fixing arrangements shall be fastened properly. All supports as shown on the details shall be provided. A platform shall be built on top for the workers safe access & working to allow for comfortable & safe circulatory movement for the crew. design. QC inspection shall be conducted & engineer’s approval obtained. Programme shall be charted out for pouring about 75 cum in one go. The concrete pouring chute pipe shall be inserted into the form so that the net drop of concrete is not more than 2 m. Pour shall be carried out in layers not exceeding 450 mm so that vibrator nozzles penetrates internally. This pour shall consume about 8 hours. At the end of the pour, the top surface shall be properly finish rough & covered with saturated Hessian & polythene sheet. Continuous curing shall be conducted thereafter. Side supports shall be struck only after 48 hours. Baffle wallsEach pour about 75 cum. In this case also, Scaffolding shall be erected for accessing the workers to fix the rebars & erect the formworks for the upright wall. Rebars shall be placed properly in compliance with the design details & engineers approval obtained prior to the closure of the forms. At the end of the every day work, polythene membrane shall be spread over the placed & fixed rebars for protection from humidity. According to the formwork vendor’s design, the sides of the forms shall be fixed. It shall ensured that the erected forms are in true alignment & plumb. The fixing arrangements shall be fastened properly. All supports as shown on the details shall be provided. A platform shall be built on top for the workers safe access & working to allow for comfortable & safe circulatory movement for the crew. QC inspection shall be conducted & engineer’s approval obtained. Programme shall be charted out for pouring about 75 cum in one go. The concrete pouring chute pipe shall be inserted into the form so that the net drop of concrete is not more than 2 m. Pour shall be carried out in layers not exceeding 450 mm so that vibrator nozzles penetrates internally. This pour shall consume about 5 hours. At the end of the pour, the top surface shall be properly floated & either curing compound instantly sprayed or covered with polythene sheet. Side supports shall be struck only after 48 hours. Inlet chamberBase slab of this chamber is at a lower level & 1 m thick. It also has walls & intermediate cantilever structure to be connected to the roof suspended slab. This shall be separately carried out in two stages. Outlet chamberThis has a basement sump in stepped profile. Base slab of this chamber is at a lower level & 1.2 m thick. It also has grade level suspended slab. This shall be separately carried out in three stages. Access stairs to roof 2 numbers These stair structures are to be constructed on 3 columns on isolated footings. The columns have to carry cantilevered steps & on landing Stages
Construction of footings shall be carried out comprehensively according to conventional trade practices. Construction of columns shall be carried out comprehensively according to conventional trade practices. Construction of waist slab & steps shall be carried out comprehensively according to conventional trade practices. Preparatory works shall be similar to as defined in the foregoing excavation, blinding, formwork, steel fixing, pouring etc. (all shall be carried out comprehensively according to conventional trade practices) Suspended SlabHalf portion in one go about 1400 cum. This is a flat structure transferring loads on the column heads. In one go half portion of the slab is intended to be poured as shown on drawing. The arrangement of the supporting system shall be strictly adhered to vendor’s instructions as shown on the attached drawing. Preparation & erection of forms shall be done following all approved details. Rebar placement shall be done to the details & the spacers provided accordingly. At the end of the every day work, polythene membrane shall be spread over the placed & fixed rebars for protection from humidity. The location of the movement joints shall prepared so that 50 mm thick joint filler is fixed in position correctly as well as supported to remain so during concrete pouring. The forms for the up stands shall also be erected for monolithic pour with slab concrete for which the fixing arrangements be made accordingly. All block outs for the openings shall be prepared to the defined locations & properly anchored to remain in position. The following quality checks shall be conducted prior to pouring is commenced Slab alignment Levels Profile of the column head / drop heads Alignment of the up stands & verticality Re-bars placement as well as locations & centering Proper fixing of concrete spacers All inserts or services fixes if so required, shall be placed in & approved. It shall be ensured that no rebar is susceptible to any possible displacement any time or a possibility to correction must exist during pour. Certification of the supporting system by the form vendor engineer All access routes shall be properly tagged & certified by safety officer. During concrete delivery slump, temperature, air voids tests etc shall be recorded. For pour, minimum 2 pumps shall be required for continuous placement of concrete & 1 pump to remain standby. Keeping a speed of 10 minutes for each truck, 60 cum each hour, 2 pumps shall pour the prepared portion in 10 hours followed by another overlapping 10 hours required for the wooden finishing of the unformed surface. Instant curing shall be carried out by spraying curing compound aver the area to control shrinkage cracks. Later, after final profile & finishing the surface, polythene layer shall be spread over the saturated Hessian to keep wet for at least 10 days continuously. Striking of the forms shall be carried out only after 8 days. Whole exercise shall be repeated for the second half of the slab. Reservoir testingThe structure when completed according to BS 8007 provisions water test shall be conducted to check any leakage. After closing all openings, water shall be filled gradually to the required level. The fall in the water level shall be monitored regularly at defined intervals according to the code provisions. The loss of the water should be within prescribed limits Though not necessary in this case since the water is in cover, for the comparison of the loss by evaporation, a separate small container shall be kept which indicate the loss in level due to weather & the fall of the reservoir level corrected accordingly to reach net loss in level. After successful completion of the water test, water used for the test shall be pumped out to the other reservoir for testing of that reservoir in sequence. RoofingAfter the curing is completed, the whole surface shall be scabbled properly to expose the aggregate to meet the bonding requirement of foam concreting. The surface shall be prepared & any services plinth required shall be constructed to the details. True profile required for the drainage shall be prepared for foam concrete over the entire area. Foam concrete shall be produced on site & laid by specialist roofing sub contractor All other roofing operations shall be carried out accordingly to the approved method statement Roof waterproofing shall be tested by flooding with water for 48 hours Any leak detected shall be made good according to the agreed procedures. Other General activitiesRoof handrails shall be fixed to the required locations. Adequate arrangements shall be made to keep the internal space of the reservoir well ventilated during performing the application of concrete protections. All other activities about the concrete protection shall be carried out for the above ground concrete on the inner as well as on the external surfaces. All operations of the backfilling of the walls up to the formation levels shall be carried out according to the standard approved methods & field samples tested accordingly. Preparation of the walkways around shall be carried out for receiving the interlocking blocks. Compaction shall be done for the formation of the walkway area. Works for the kerbstone shall be carried out. Laying of the interlocking blocks shall be carried out to the given profile & levels. EquipmentShovel. Excavator, tipper trucks, Roller, Compactor, Concrete pumps, Truck mixers as & whenever required, concrete vibrators, centrifugal pumps to boost out water from the reservoir etc --------------------------------------- Chapter 13
----------------------------------------------------------------------------------------------------------------- The Environmental Guidelines & Environmental Protection Criteria (EG&EPC) for Plant Industrial City, National Environmental Protection Law, and Environment and Natural Reserves standards, shall be complied with by Contractor and its Sub-Contractors operating within the boundaries of PLANT. Contractor shall comply with all applicable rules and regulations of all relevant agencies having jurisdiction, which now exist or which may come into effect during the course of the Work, relating to environmental protection and management. Contractor warrants that it shall use its best endeavours to protect and to take care of all environmental and natural resources in order to prevent environmental pollution of any kind resulting directly or indirectly from the Work performed under the Contract. Notwithstanding any provisions contained within the Contract, the Contractor shall assume all liabilities for environmental and human health damage of any kind arising directly or indirectly from the Work, and shall indemnify Company / Client and hold them harmless from and against any and all losses, claims, demands, costs, proceedings, damages, charges and expenses howsoever arising therefrom, whether or not caused by negligence, in whole or in part. Without relieving the Contractor of any of its obligations detailed herein or as imposed by any relevant agency, authority, or any other body having jurisdiction, Company/Client may take part to any degree it deems necessary, in the control, removal and remediation of any pollution or contamination which is the responsibility of the Contractor, under the foregoing provisions or which is due to any act or omission, directly or indirectly, of the Contractor. The Contractor shall reimburse Company/Client for the cost thereof provided always that the amount of any such cost may be deducted by Company / Client from any money due or becoming due to the Contractor. Contractor shall furnish the following documents for the approval of Company/Client at least four (4) weeks prior to the commencement of the Work at the construction site. Waste Management Plan Environnemental Management Plan Spill Contingency Plan Contractor shall provide Company / Client with Material Safety Data Sheets (MSDS) for all chemicals / materials (where applicable) it shall use or supply prior to shipment. Contractor shall dispose of all waste including but not limited to packaging, discarded material, unspent and serviced material in an environmentally acceptable and approved manner. Contractor shall take immediate corrective action(s) to remedy any and all occurrence(s) of environmental pollution and report such incident(s) as per the environmental incident reporting requirement for PLANT. Company / Client is entitled to impose such penalty as specified in the Environmental Guidelines & Environmental Protection Criteria for Plant Industrial City (PLANT) should the Contractor fail to take the appropriate corrective action (s) or to report such incident. In case of an environmental incident Company / Client may take action to investigate the incident, assess its impact and/or take necessary corrective action and recover the cost involved by such action from the Contractor. Contractor shall complete and submit an Environmental Discharge Form (in accordance with relevant EXHIBIT) to Company / Client prior to the commencement of any demobilisation. Demobilisation may only commence upon authorization / approval of this form by Company / Client.
Health, Safety, Environmental & Security Standard Procedures / Hazard Control This procedure is applicable to all projects construction site activities. Directory: forum -> files forum -> Cross country forum -> ComboFix 14-01-23. 01 Vanessa Benko 23/01/2014 14: 13: 05 4 x86 forum -> C:\documents and settings\איה\Application Data\drivers\downld\576046. exe forum -> Kognitio Limited 2015 Kognitio jdbc/odbc bridge Installation and Configuration Guide files -> Required: rct3, Soaked & Wild! Download 2.87 Mb. Share with your friends:
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