First Web Edition 2006, Devoted to Engineering Community



Download 2.87 Mb.
Page10/27
Date26.04.2018
Size2.87 Mb.
#46813
1   ...   6   7   8   9   10   11   12   13   ...   27

Primer


QC inspections shall be conducted to ascertain the true profile of the aggregate base course & corrections applied if so required

All surfaces planned to be primed shall be barricaded & cleaned of all dirt & any objectionable material

Bituminous material shall be applied evenly on the dry surface by means of a pressure distributor spray tanker within a temperature 30 deg to 70 deg C

Surfacing Binder Course

QC inspection shall be conducted prior to the commencement of binder course laying to make sure that the surface is satisfactorily clean, well dried & even to the specified priming conditions as well as to receive binder course.

The material upon arrival at the location shall be spread & struck off to the prepared profile by means of self-poared spreading & finishing equipment attached with a strike off assembly distributing the mixture to a strip 3 m wide

Rolling Steel Roller’s # of passes 6 to 8 depending on the surface condition Steel rollers 10 T capacity equipped with adjustable wheel scrapes, water tanks & sprinkling apparatus to keep the wheel sufficiently wet to prevent the bituminous mixture from sticking to the steel surface shall be employed to roll the profiled material immediately after the material is laid to the acceptable profile to prevent the formation of undue displacement or hair cracking

The roller wheels shall be kept properly moistened without excess water or oil

Rolling shall be commenced from the side and proceed towards the centre each trip overlapping the previous by at least 300 mm with keeping alternate trip not more than 5 km/h & it shall continue until the surface is impression free.

Mechanical compactors shall be engaged to compact the roll inaccessible area layers.

Pneumatic tyres rollers shall be engaged only after the compaction by wheel roller is over.

It is significant to make sure that the asphalt temperature does not fall below 80 deg C prior to full compaction is achieved

Roller shall not pass over the edges of the freshly laid material generally except when the edge is located at a discontinuation for that day

QC inspection shall be conducted throughout the above operations to make sure that the material is compacted to the standards and the temperature remains within limits mentioned as well as levels are maintained within specification tolerances particularly over the areas involving shoulders

At the commencement of the work on the area involving the compacted & chilled edge, a bevel shall be cut out, cleaned & tack coat applied to receive adjoining material

No traffic shall be permitted until 12 hours lapse post-rolling completion



Wearing Course

The planned surface shall be cleared of all dust & dirt using power broom or blowing

Tack coat shall be applied to the specification requirement

Immediately upon arrival, the material shall be spread & rolled similarly as described in the foregoing.

QC inspection shall be conducted throughout the above operations to make sure that the material is compacted to the standards and the temperature remains within limits mentioned as well as levels are maintained within specification tolerances
Reinforcement Fabrication

When reinforcement is to be “cut and bent,” the foreman shall be issued with a current rebar schedule. The foreman shall review the schedule and allocate the fabrication process to the relevant fabricator/steel fixer. Material required shall be sourced from the yard storage facilities.


The correct bar diameter shall be cropped into the specified length as given on the bar schedule. The cropper operator shall crop the required bars of each diameter.

Upon bending of the first of each bar type, it shall be checked by the foreman for correctness. This bar if correct, shall be utilized as a check sample for all concurrent bars of that type. The bending operator shall fabricate the required number of bars of each shape code checking against the check sample when each bar is completed. Any error in bending of the bars shall be corrected prior to placement in storage.


The correct bent bars shall be stored in bundles & protected against ingress of moisture.
The bundles shall be tagged with a suitable label that indicate the relevant bar reference and BBS document reference from which these have been fabricated.
The completed bundles shall be stored within the reinforcement yard until such time as those are required upon site. Storage shall be in accordance with the procedure for store control.
Reinforcement Placement Typical

The relevant reinforcement bars, spacer blocks, chairs, stirrups and tie wire, shall be collected from the stores as well as fabrication yard and made available at the work site. The material shall be stored at the worksite, in accordance with the storage procedure pertaining fabricated & non-fabricated re-bars.


The current revision of the reinforcement drawing that applies to the structure being constructed shall be checked by the Project Engineer, Site Engineer, Q A for validity.

The steel fixers shall place and tie, reinforcement bars and accessories, in accordance with the current reinforcement drawing under direct supervision of re-bar charge hand or foreman.

Particular attention to the following items shall be monitored by the charge hand steel fixer and foreman:
Lap length of bars.

Tie wire protrusions into cover areas.

Appropriate concrete cover to formwork and outside faces.

Placement of adequate support chairs and stirrups.

Spacing of bars.
The Site Engineer & charge hand steel fixer/foreman shall check the fabricated reinforcement when all the placement of the reinforcement bars is complete. The result of this inspection shall be recorded upon Pre concrete inspection checklist by Site Engineer & QC.
The foreman steel fixer shall ensure that the reinforcement has been correctly placed prior to informing the Site Engineer & QC.
QC shall check all items of different shapes, spacing & numbers, spacer blocks, additional chairs if required.
Should any inserts, conduits, pipes, bolts etc, require fixing within the structure according to design details or shop drawings, the steel fixer foreman shall arrange for the placement of these items according to directions by Project Engineer/Site Engineer. Where a reinforcement bar clashes with such items, based on the decision of Engineer, Project or Site Engineer, the steel fixer shall move the relevant bar. An additional bar may be required to offset this moved bar. Should any doubt arise about moving bars, the charge hand shall inform the foreman & Site Engineer to resolve the issue with the engineer.

The foreman shall inform the Site Engineer when these activities are complete.


The QC shall inspect the re-bars placed in the structure for compliance with the design drawings and details as well as other working and shop drawings.
Formwork Erection Typical

Based on site engineer’s instruction, the formwork foreman shall review the drawing of the structure to be formed & shall decide together with the site engineer, the most suitable method of formwork erection.

Where pre-fabricated formwork can be assembled in the carpentry workshop, fabrication shall be carried out.

The surveyor shall establish the lines and levels for the erection of the formwork. These lines and levels shall be explained to the foreman and supervisor in charge/charge hand of the formwork activity.

The foreman shall check that the preceding activities have been approved, so that this activity may commence. The sections of formwork required to form the structure, shall be taken to the work site.

The form carpenters shall ensure that the formwork faces are clean, in good condition for the type of finish required & applied over with shutter form oil.

The form carpenters shall assemble and fix the formwork in accordance with the current drawing.

The charge hand of carpenters shall monitor particular issues such as:

Sealing of joints between formwork has been applied properly

Verticality of formwork is according to requirement. Tie bolts are in proper positions & snug tight.

Adequate bracing and supports are in tact

Provision where applicable for box outs and inserts have been applied

Provision where applicable of chamfer and channels have been fixed

The supervisor and surveyor shall check the lines and levels of the formwork when all bracing and strutting have been completed. Wherever required, the formwork shall be adjusted to conform to the required lines and levels.

The supervisor shall ensure that any damaged face of the formwork is repaired.

The foreman shall review the formwork when completed.

Where anchor bolts or embedded plates are to be suspended in the structure, the supervisor shall ensure that these arrangements are adequately supported as well as securely braced. All inserts and bolt groupings shall be checked for location and level prior to the placement of concrete as well as after the concrete is placed.

When the formwork activity is complete, the supervisor shall inspect the formwork and associated works, recording his observations on approved formats, formwork checklist and insert check list.

The QC inspector shall confirm the acceptance of this activity after review of the items.

Where large formwork elements are encountered, the QC inspector shall review the formwork bracings and supports with the engineer.


Concreting Typical sample

The supply order for estimated quantity may be placed in advance but real confirmation shall be done based on the pour approval.

After the inspections of the preparatory works pertaining to any element namely footings, stubs, columns, suspended slabs etc & the relevant approval, the order for the release of concrete from the batching plant shall be placed.

The required quantity shall be sequenced depending on the consumption frequency on site.

The concrete shall be poured either by the concrete pump or by the mobile crane depending on the necessity & convenience.

Necessary access to the location shall be prepared using proper supports or platforms duly inspected by the safety officer in charge.

Immediately, at the arrival of the truck mixer of concrete on site, slump, temperature, air contents etc all test samples to the specification requirement shall be taken by the ready mix supplier in the presence of the QA engineer.

In case the concrete does not meet the specification requirement, the truckload shall be rejected.

Arrangement shall also be made for the filling of the concrete cubes/cylinders on site & number of specimen to specification requirement.

After the truck is approved by the QA to be transported to the site location, the concrete pump, which should already be located in proper position, shall receive the load & pump out to the in situ delivery location.

The concrete laying gang already present on the site location shall receive & pour the concrete mix into the prepared elements from a height not more than 2 m from the edge of the boom chute pipe.

As soon as enough mix is available in the element to compact the mix conveniently, insertion vibrator shall be used by a trained operator to compact the mix till no more bubbles appear. Foreman shall direct the pump remote control operator about the boom movement & stop & hold points or stages during concreting.

Vibrator shall not be allowed to touch the forms side or re-bars. Over vibration shall not be permitted

Each Footing shall be poured in one go if not more than 500 mm in depth.

The widened portion of the stub in touch with soil shall also be poured in strips not more than 450 mm deep

Into columns the mix depth at one rotation shall be 450 mm & in different strips vertically, pouring shall be completed avoiding formation of cold joint

Top level of the concrete shall be levelled & the columns form top covered with plastic sheet

The portion of the pipe chute shall be inserted into column preparatory works to allow for a 2 m vertical fall maximum. Vertical forms of the columns shall be struck after 48 hours.

Inspection shall be made immediately post form striking & any defect in concrete shall be brought to QA Engineer notice for deciding remedial action.

Vertical surface shall be covered with saturated Hessian, further covered with polythene sheet cover or alternatively curing compound shall be sprayed over the water-wet surface to form a impermeable membrane not to permit evaporation.

The grade slab shall be poured in one go in depth bay wise between ground beams or walls.

For the suspended slabs, beams shall be poured first around the slab & prior to the formation of cold joint, the slab concrete shall be poured & the whole slab completed.

The joints if so required, shall be agreed in the beginning of the pour with the engineer. Water shall be sprayed over the form during hot weather prior to pouring to avoid flash setting of concrete with re-bars.

In case some plant break down is reported, immediately the last poured line shall be stopped by a formed surface & concrete terminated at that point & in no way shall recommence prior to 24 hours with further approval obtained. In such case previous formed joint shall be scabbled/hacked to expose all aggregate by removing laitance completely, washed with cement slurry & new concrete commenced making proper bond with old concrete.

Due care shall be taken that no spacers, electric conduits or any other insert is disturbed from its design or worked location. If so disturbed, it shall be immediately relocated according to the engineer site approval.
Immediately after the compaction of concrete is over & concrete starts setting in, arrangements for applying U1 finish to the top of slab surface shall be done by timber tamper.

Immediate curing shall be applied by spreading polythene sheet cover on slabs & footing.

Then after about 2 hours, polythene sheet shall be withdrawn temporarily & saturated hessian placed over concrete & recovered with polythene sheet & the concrete cured for specified period

If so, repair to hardened concrete is required, approved repair material shall be used according to manufacturer’s instructions.


Concrete Paving Typical

All the relevant underground services shall be laid in all respects prior to the commencement of the pavement work

The area to be paved shall be made ready by clearing all weak soil & by scarifying.
Approved sub base material 150mm thick or as specified, shall be filled up to the bottom of the concrete slab following the profile given on the drawing and compacted to 95 % dry proctor density.

Weed killer chemical shall be applied to the soil to prevent the organic growth if so specified.

The whole area shall be divided into parts to suit the services and the contraction joints formations & as shown on drawings

On the ’compacted filled area’ to be paved, polythene sheet 0.25mm shall be placed with end overlaps at least 150mm at all joints and intersections.

End forms shall be fixed on sides allowing a provision to place 20 dia MS dowel bars 650mm long & 300mm centres half painted with 2 coats bit mastic paint with 100mm long cardboard cap containing compressible material such as cotton waste at the
Expansion joint to the details shown on the drawing. The thickness of the expansion joint shall be 20mm

At contraction joints 25 x 25 mm plastic crack inducer shall be provided as shown in the detail & the joints cut for a depth of 20mm with a concrete cutting machine. Welded wire fabric mesh dia 6mm – 200# shall be placed in the bay centrally located with concrete spacers below.

Forms shall be set to correct levels so that the total thickness of the concrete is as indicated on the drawings.

QC inspection shall be conducted for the pour approval.


Concrete shall be poured in one layer and compacted using vibrators & given brush finish to correct levels.

Curing compound shall be spread on the surface for immediate curing covered with polythene sheet and later within 2 hours damp hessian added by removing polythene sheet temporarily and recovered thereafter.


The expansion joints between the two adjacent slabs shall be filled with elastic joint filler and sealed with a chemical resistant sealant complying with the details shown on the drawings.

QC inspection shall be conducted.


Concrete Lined Trapezoidal Ditches

Earth sectional depth dimension as included within specifications Depth 300 to 500 mm; 501 to 1000mm; 1000 to 1500mm.

Setting out dimension about the proposed ditches shall be marked.

Excavation shall be started & shaped to the design profile.

Compaction shall be done to the non-structural requirement.

Proper gradient as indicated on the design drawings shall be maintained.

Isolation layer shall be applied if so provided within the specification.

Blinding shall be applied on the compacted base to the design thickness.

Preparation for the lining concrete shall be carried out by placing in pre fabricated reinforcement to design details & sides formed at edges parallel to the ditch as well as at the construction joints.

After the inspection, concrete pour shall be carried out in alternate bays with unformed horizontal as well as sloping surfaces finished smooth. Remaining bays shall be carried out in the next day operation.

Curing shall be carried out accordingly to the approved procedures.

Expansion Joints between ditches

Size of the proposed joints to be filled/sealed is 15 mm wide x 15 mm deep.

The surface shall be cleaned of all dirt, dust and loosely adhering materials.

All grease and oil contamination shall be removed using hard small brushes, compressed air etc.

The fibreboard shall be removed to the required depth.

Under normal circumstances priming is not required.

Masking tape shall be used to confine the joint borders keeping the adjoining concrete surfaces clean.

The contents of the Can shall be removed by a Trowel or a Spatula.

The Bit mastic shall be applied to the prepared and masked portions.

In case of the vertical joints, bottom to top application sequence using a spatula or a trowel, shall be followed ensuring that the entire volume of the joint is filled in to effect a total contact with joint surfaces.

After application, the sealant shall be smoothened and compressed into the joint using a spatula or a putty knife moistened with cleaning solvent.

Masking tape shall be removed immediately after the application is completed to keep the concrete surface clean.

A full cure (a stage when the solvent evaporation is completed) shall normally consume

4 to 6 weeks post application of the sealant.

Painting over concrete surface if so required, shall be carried out only after full cure has taken place.


Concrete Lined Rectangular Ditches

Setting out dimension about the proposed ditches shall be marked.

Excavation shall be started & shaped to the rectangular design profile.

Compaction shall be done to the non-structural requirement.

Proper gradient as indicated on the design drawings shall be maintained.

Isolation layer shall be applied if so provided within the specification.

Blinding shall be applied on the compacted base to the design thickness.

Preparation for the lining concrete shall be carried out by placing in pre fabricated reinforcement to design details & sides formed at edges parallel to the ditch as well as at the construction joints.

After the inspection, concrete pour shall be carried out in alternate bays with unformed horizontal surface finished smooth. Remaining bays shall be carried out in the next day operation.

Curing shall be carried out accordingly to the approved procedures.


Expansion Joints between ditches

Size of the proposed joints to be filled/sealed is 15 mm wide x 15 mm deep.

The surface shall be cleaned of all dirt, dust and loosely adhering materials.

All grease and oil contamination shall be removed using hard small brushes, compressed air etc.

The fibreboard shall be removed to the required depth.

Under normal circumstances priming is not required.

Masking tape shall be used to confine the joint borders keeping the adjoining concrete surfaces clean.

The contents of the Can shall be removed by a Trowel or a Spatula.

The Bit mastic shall be applied to the prepared and masked portions.

In case of the vertical joints, bottom to top application sequence using a spatula or a trowel, shall be followed ensuring that the entire volume of the joint is filled in to effect a total contact with joint surfaces.

After application, the sealant shall be smoothened and compressed into the joint using a spatula or a putty knife moistened with cleaning solvent.

Masking tape shall be removed immediately after the application is completed to keep the concrete surface clean.

A full cure (a stage when the solvent evaporation is completed) shall normally consume

4 to 6 weeks post application of the sealant.

Painting over concrete surface if so required, shall be carried out only after full cure has taken place.

Galvanized grating shall be placed on the ditch later.


Termination Details to protective membrane

The following operational sequences shall be involved


Case 1 Concrete surface shall be cleaned of all dirt & dust using a brush.

Application of the waterproofing membrane according to the specifications to the defined levels keeping the top 200 mm or variable dimension according to the drawing above the finished ground level.

Lines shall be marked on all sides to correct level as per drawing.

Bead Lengths to exact site dimensions shall be cut to suit a close fit between the ends.


Every bead shall be provided with a minimum 3 # screws to be drilled and fastened into the concrete penetrating the membrane using an electrical operated Drill.

After the screws have been fastened and the beads are in proper alignment, approved sealant shall be applied to top of the bead keeping about 5 mm above the bead with a down ward lap as follows.

Sealant shall be applied using a gun fitted with conical nozzles adjustable to suit the width into the corner using an even trigger pressure & cleaning the nozzle occasionally to avoid contamination. A smaller timber spatula soaked in soapy water shall be used to compact the sealant into the joint/junction for a smooth polish finish formation. The mixing and application equipment shall be cleaned immediately after use.

QC inspection shall be conducted & the relevant ITP signed off


Case 2 Where grooves have already been chased, the waterproofing membrane shall be tacked in & sealant applied to the space left in the groove according to specifications and the manufacturer’s instructions. No Aluminium bead shall be used in this case. Sealant shall be applied around bead continuously. AJES QC inspection shall be conducted & the relevant ITP signed off
Case 3 In gravel or soil area, membrane shall be terminated at a level ‘150mm plus’ below the footing top level keeping Aluminium bead details typical. All other details shall remain as in ‘case 1’ if no rebate has been chased. QC inspection shall be conducted & the relevant ITP signed off
Case 4 In the paved area, membrane shall continue up to the termination level but the protection board cease at 20 mm below the paving level filled with mastic on top keeping all other details as in case 1 if not chased for rebate. QC inspection shall be conducted & the relevant ITP signed off
Ignore if not applicable
Grouting to pipe rack bases typical

The surface to be grouted shall be chipped / scabbled without using mechanical bush hammer, to expose the aggregate and remove the laitance. The finished surface shall be free from oil, dust, dirt, paint, curing compounds etc and be soaked in with water for 24 hours prior to grouting to minimize the localized absorption as well as to assist the free flow of the grout.


The bolt holes/pockets shall be made water free prior to placement of grout.

The base plates/ bolts shall be clean and free of oil, grease and paint and correctly aligned according to the approved drawings.

The stainless steel shims 50x50x10 mm thick shall be in correct locations covered with mortar so as to allow at least 50 mm grout cover on shim sides.
The forms on the essential sides shall be erected at locations with chamfers.

An electric drill fitted with a paddle shall be used for the grout mixing purpose using water @ 3.5 to 4.5 litres per 25 kg bag of Master flow 928 or any other approved grouting material depending on to requirement.


The mixer shall be clean with no standing water.

90 % of the measured quantity of water required to achieve the desired consistency according to the batch volume be added to the mixer before adding the grout and the Masterflow 928 or any other approved grouting material be added gradually, simultaneously pouring in the remaining 10 % water quantity during mixing, which has to be kept on for at least 3 to 5 minutes until a uniform lump free consistency is achieved.


Then the grout shall be poured continuously using the grout pour cone with a constant hydrostatic head of at least 15 cm.
Having poured the grout Masterflow 928 in place, all exposed grout shall be covered with clean dampen Hessian and be kept moist until grout is firm enough to accept a curing membrane.

The temperature range 4 to 32 degree C shall be maintained for the 3 post pour continuous days.

The grout thickness varies between 25 to 50 mm.
Ignore if not applicable
Water Tightness Test of RCC Structure typical Sump

The structure to be tested shall be completed of all RCC constructions according to the specified and agreed procedures.

Complete filling of the tie rod holes with MBT Master Flow 544 or Conbextra GB or an equal approved shall be carried out according to the manufacturer’s instructions.
Inlet shall be laid in place to the levels shown on the drawings as reflected on the water quantity schedule i.e. the Invert levels at maximum supply elevations.
The external surfaces of the structure shall be prepared & applied with the specified protective system.
QC Inspection shall be conducted for the approval of the membrane.

Structural backfilling shall be carried out externally to the project specifications & necessary field density tests conducted to the requirement.


Application of the floor screed as specified shall be carried out

The entire surfaces of structure to be tested shall be sweep blasted removing all loose spalls, dust dirt etc. The prepared internal surfaces shall be inspected by QC for approval.


The following operations shall be involved to conduct the water tightness test according to the BS 8007: 1987 Section 9.1 applicable to liquid retaining structures.
A graduated stick shall be provided on wall top to show the water levels to a ’mm’ count.
Potable water shall be filled into the respective pit structure at a rate 2 m per 24 hours for which the attached ‘filling scheduled quantities ‘shall apply. Attached schedule shall depend on the structure volume.
After water is filled in to the required level, it shall be allowed to stay for a period of 7 days for stabilisation, absorption and autogeneous healing. If so required, water shall be added to maintain the maximum test level in case it is lost during this period.
Test shall commence from 8th day and continue for 7 days for a design crack width of 0.1 mm according to specification requirement.

Observations regarding water level drops shall be recorded every 24 hours by visual measurements on mm scale.


The test records shall be documented on the approved form.

‘ Structure Leak Test ‘and the judgement on the test made accordingly.

During this 7 days period, the total permissible loss in level shall not exceed 1/500 of the average water depth of the full tank or 10 mm.
After the test is successfully completed, water shall be pumped out either to the other structure for testing should that be ready to receive it or if not, to the other construction areas for curing or any other purpose as agreed leaving the pit empty.
Remedial Work if required.

In case of unsatisfactory performance of the water tightness test and upon the agreement with Technip, injection-grouting method may be adopted to seal the seepage routes.


Should the structure not satisfy the 7 days test, then after the completion of the remedial work, it should be refilled and if necessary left for a further stabilising period; a further test of 7 days’ duration should then be undertaken in accordance with this clause.
Concrete Protection Coating Typical

The method involves the following sequences in general.

Surface preparation, Mixing, Application Details- All grease, oil, dust, residual curing compound, mould release agent or other contaminants, which could impair adhesion, shall be removed from the surface by degreasing and washing.
The whole surface to be coated shall be cleaned using water jetting and visually inspected to ensure that the roughness does not exceed grade 80 sandpaper. All the holes, voids, depressions, spalls etc. shall be filled with Masterseal 550 or an equal approved mixed to a trowel consistency, scraped lightly into the surface, allowed to dry and later roughened by hand wire brush on the small areas and gently water jetted on the larger areas.

The filled areas shall be visually inspected to ensure that the correct mechanical key is achieved.



Mixing Master seal is supplied in the pre-measured units and shall be mixed on site using clean containers. The powder shall be slowly added to the liquid component and agitated /mixed for 2 minutes by using a slow speed hand power drill fitted with a suitable paddle attachment, until a homogeneous lump free consistency is obtained. The mix quantity shall be such that it could be consumed in one hour during application without allowing any retempering with water.

Application Coverage 1.8 Kg / sqm at 1 mm thickness.

The coating shall be 1 mm thick applied in one coat. In hot weather the surface to be coated shall be shaded from direct sunlight. The areas to be coated shall be saturated with fresh and clean water.

The prepared and the saturated surface shall be inspected by QC.

The mixed material shall be applied while the surface is visibly damp without standing water using short stiff brush or roller. (Roller shall be used in major /large areas). The evenness and the thickness of the applied coating shall be regularly checked during application while the material is still wet.

The materials shall be allowed to dry and visually inspected.
QC inspection shall be conducted.

Any missed areas shall be saturated and then touched up.


Ignore if not applicable
Lighting Poles Foundations Typical

Pre casting Area-The existing yard being used for the pre casting of manholes, catch basins etc. shall be employed for this purpose also.
The following operations are involved to carry out the production of the light poles foundation bases Pre installation operations
Fabricate and erect the side forms 4 #s to the specified dimensions.

Fabricate the rebars according to the specified details.

Provide the non-critical cathodic protection.

Provide the PVC cable duct.

Provide the bolt assembly to the requirement and location.

Provide the lifting lugs to carry a gravity load of at least 3 tonnes + handling stresses.

Pour the concrete. Cure the concrete immediately after pouring Post casting operations. To cure for the specified period.

Excavate the location to the required formation level. To blind the area to be founded with concrete.

Waterproof the blinding as specified. Keep the area ready in all respects well oriented & aligned to receive the foundation directly to be offloaded. Apply the water proofing membrane around as specified.

Provide the protection board as specified

Back fill the surrounding space to the relevant grade level Details.

The typical size of the foundation may be 1000x1000mm in plan and 1100mm deep.

A possible of 10 units may be produced by pre casting every day on an average.

The forms to the exact size with the preformed chamfers shall be prepared and erected.

The steel rebars shall be cut, bent to the required shape, placed and the cage prepared holding 75mm concrete spacers, be positioned into the forms.

1 # 350 mm internal radius 100 mm dia PVC cable duct formed to the dimensions shall be anchored by binding wires to the exact locations shown on the drawing keeping the upper end flush with the concrete top.

The Lifting lugs as shown on the sketch shall be fixed in to the correct locations.

The forms for the block outs for the lifting lugs shall be fixed in to the correct locations as shown without clashing with the duct or the rebars allowing a protrusion of the hook.

The bolt assembly shall be fixed in exact position according to the design details.

The non-critical cathodic protection shall be arranged using a metallic continuous binding wire connecting all horizontal rebars terminating into a boss fixed at one location near the top in the middle of the side opposite the duct-carrying portion. All the supports and the dimensions shall be checked and the plumb monitored.

QC inspection shall be conducted.
The concrete shall be poured to all the prepared units in 3 layers in vertical sequence.

The appropriate vibrator shall be used for the compaction of the concrete. During concreting, care shall be taken to keep the anchor bolts’ position undisturbed and the intermittent checks be continuously made to monitor the spacing /centres between the bolts. After the concrete is poured in full & well compacted, the surface shall be levelled using a wooden float followed by light steel trowel. Immediately after the concrete starts setting, approved curing compound shall be sprayed on the surface forming a continuous membrane which be covered over with a polythene sheet according to the specifications.


After 2 hours, the polythene sheet shall be temporarily removed to spread over the concrete surface the saturated burlap cloth or hessian, and recovered immediately.

The side forms shall be removed within the specified period. The vertical concrete surfaces shall be spread with the curing compound immediately after striking the forms and covered with the polythene sheet according to requirement. The curing shall be continued for the specified period.

The relevant locations shall be made ready to receive the pre-cast units by completing the excavation, blinding, the horizontal waterproofing and forming the correct alignment.

QC inspection shall be conducted.


The unit shall be lifted by a mobile crane, loaded gently onto a trailer and transported to the location for offloading on to the prepared ‘location to receive’ the unit. The unit shall be installed on the marked location according to the correct orientation to the lighting layout drawing.

QC inspection shall be conducted.

The protruding lifting lug eyes shall be cut to 60 mm inside the block out, the void filled with concrete by first scabbling the internal surface followed by cement slurry grouting and pouring concrete.

The external surfaces of the foundation shall be applied with the concrete protective membrane according to the specifications.

QC inspection shall be conducted
The membrane protection board shall be provided covering the surface to the specified details.

The back filling shall be carried out according to the specification up to the required levels in layers and up to the required ground grade or the pavement. The points to locate the cathodic protection shall be provided with a marker to trace the boss. The sequence shall be repeated for all the lighting poles foundations.


Pull Pits Typical

Operations in Pre casting Yard Pre casting Area.

The existing yard being used for the pre casting of manholes, catch basins and lighting poles foundations etc. shall be employed for this purpose also Form work.
The typical size of the Pit type shall be taken from the drawings.

On an average, 20 units shall be produced by pre casting every day The wooden forms to the exact dimensions with pre -formed chamfers shall be prepared and erected.

Rebars placement

The steel rebars shall be cut, bent to the required shape, placed with 75mm concrete spacers and positioned into the forms according to the details provided.

The Lifting lugs shall be fixed in to the correct locations.

All supports and dimensions shall be checked and corrected if required.

QC inspection shall be conducted before pouring concrete and signatures appended to ITPs
Pouring concrete & finishing

The concrete shall be poured into all the approved preparatory works in 1 layer by directly delivering from the concrete truck / transit mixer through the chute 1 # ¾” needle vibrator shall be used to compact the concrete and 1 # reserved standby.

After the concrete is poured in full & well compacted, the surface shall be levelled using a wooden float followed by light steel trowel.

Curing


Immediately after the concrete is finished, the surface shall be covered with polythene sheet with the edge lapped or tied down to exclude air circulation without permitting the membrane to be in touch with concrete surface according to the specifications.

After the concrete has stiffened but no longer than 2 hours, the polythene sheet shall be removed followed by immediate covering the surface with saturated (soaked with mix quality water) hessian and recovered with polythene sheet to prevent evaporation from the hessian. Throughout the curing period the hessian shall be maintained in a permanent wet condition using mix quality water.

The side forms shall be removed after the specified period of 24 to 36 hours as agreed.

The vertical concrete surfaces shall be draped with the saturated hessian immediately after striking the forms and covered with the polythene sheet held firmly in place along all edges & kept continuously wet for duration of curing.

The curing shall be continued for the agreed number of days.

QC inspection shall be conducted from time to time throughout the operations.

Lifting, loading & transportation

The covers shall be lifted by a mobile crane, loaded gently onto a trailer and transported to the area concerned to offload on to the prepared ‘location to receive’.

On site operations- post laying of Cable ducts.

The area around the excavation coverage shall be barricaded to the site requirement.

Setting out

The setting out shall be carried out by the surveyor to the required co-ordinates.

QC inspection shall be conducted throughout the operation and ITP for the survey check signed off
Excavation

Excavation shall be carried out (manually if the ducts are not encased in concrete) to the specified formation levels i.e. 1300 mm (varying from area to area) from the finished grade monitored by surveyor

Compaction and the tests if so required, shall be carried out accordingly.

Mass concrete base

The formwork for the mass concrete that may 500mm wide and 150mm deep shall be prepared and erected to the settings.

AJE QC inspection shall be conducted from time to time throughout the operations and concrete pour ITPs signed off

Concrete shall be poured to the exact levels, finished properly and cured to the specified procedures

Concrete protection

Concrete protection shall be applied to the mass concrete to the details & specifications.

Block work in walls

200mm Block work shall be constructed according to details to the required levels so that the cover top level is 100mm from the finished grade/ground level. In case the ducts are not laid in, opening shall be provided in the wall

QC inspection shall be conducted from time to time throughout the operations


Compacted sand fill

Uncompacted sand shall be filled as indicated on the drawing & in accordance with the specifications.

Compacted backfill

The remaining portion shall be backfilled and compacted to the specification requirement.

The top surface shall be well prepared, compacted and levelled to receive pre cast covers.

Placing the pre cast covers

The covers shall be offloaded by a crane from a trailer as transported from the pre casting yard to the relevant locations ready with one layer 0.25mm thick polythene sheet with laps 300mm, spread over.

The covers shall be properly spaced and levelled to the details shown on the drawing.

Sand fill

300mm deep sand backfill shall be carried out over the laid ducts not encased in concrete.

Backfill

As dug compacted backfill shall be carried out above the sand fill to the specifications.

AJE QC inspection shall be conducted from time to time throughout the operations with the relevant ITPs signed off

Lugs Fill

The sand shall be filled in the lifting lugs recess.

Concrete Protection

The exposed concrete surface is a part of pavement and therefore no protection shall be applied.
Massive Block Foundation- Thick Element – Typical

Wherever specified any reinforced concrete structure more than 800 mm in thickness & more than 8 cum of RCC quantity, the following procedure shall be followed.

Excavation shall be carried out to approved procedures. Blinding shall be carried out to approved procedures. Reinforcement & formwork fixing shall be carried out to approved procedures. Cathodic protection if so specified shall be fixed to design details & continuity checked. Specific attention shall be given to the concrete pour sequence. Since the quantity of the pour element & depth shall be considerably greater, concrete should be poured in continuous stepping fashion forming an acute angle with the vertical so that the formation of cold joints is completely avoided. The portion poured previously after vibration must receive over pour within the concrete setting time. A sketch shall be issued to site giving complete sequence of pouring. Concrete foreman must adhere to that & complete the pour successfully. Massive pour requires thermal curing as explained somewhere else in this document that shall be applicable here as well.
Foundations connected to paving concrete

These considerably small foundations shall be placed on the pavement concrete to transfer minor equipment stresses. Construction shall include erection of forms & reinforcement placement duly connected to paving.

Setting out shall be done & forms erected. Set out location area shall be roughened by scabbling.

Rebars shall be fixed to the details. Concrete spacers installed to sides & bottom. Any electrical insert placed in. Top-level line fixed with plastic chamfers. After inspection, concrete poured & curing effected to approved procedures.


Duct banks

Excavation shall be carried out to the defined sectional size. Proposed formation area shall be compacted to receive the concrete. Blinding concrete shall be placed to the required thickness. Forms for the sides of the duct bank concrete shall be erected. Nominal rebars shall be placed to the details. Design ducts shall be placed & fixed in defined positions using proper supporting arrangements so that during concreting operation these ducts remain in the set positions. Ends shall be closed properly allowing the ducts protrusion from the end forms. Ducts ends shall be closed preventing the ingress of dust or any foreign material. Inspections shall be conducted & concrete poured & cured accordingly to the specified colour. After the concreting is completed, marker shall be placed over the duct concrete & over backfill done.


Cable Trenches

Dummy / walled trench section Typical

The following operational sequences in brief are involved. Setting out to the exact alignment the route of the trench to the specified co-ordinates. Barricading the involved area to the safety department direction and requirement. Excavating the trench to the specified levels and sectional details. Preparing the formation to achieve the required levels and dimensions. Form work for the sides of the mass concrete strip beams. Pouring the mass concrete to the strip beam forms. Setting out the alignment for the trench block walls.

Block work 150mm thick in walls to the specified levels up to the pavement down stand beam soffit level.

Preparation and concreting the pavement portion monolithic with the down stand beam extended up to the top of the block wall. Backfilling the trench with the excavated earth to the specifications. Placing the pre cast coloured concrete covers in 1m or 3m standard lengths on the relevant compacted area. Sealing the joint between the pavement and the trench cover. Cable marker shall be provided.


Details about the above operations in general

The surveyor shall set out the alignment of the trench concerned according to the relevant details given on the paving and underground services location plans to the reference Co-ordinates.

QC shall conduct the inspection

The safety arrangement shall be discussed with the safety department and implemented accordingly to control the trench excavation, to provide barricades, night-lights, to divert the traffic if so required, and to adopt any other necessary measure. The excavation shall be carried out by an excavator to the lines and the levels. The surveyor shall monitor all stages of excavation to achieve the required profile. The excavated material shall be transported immediately by a dump truck to the earth stockpiles temporarily. After the excavation is over, the formation levels shall be well dressed and compacted to the specification requirement

The forms shall be fabricated for the mass concrete section. The fabricated forms of width 350mm and depth 100 mm shall be erected/ fixed on the prepared compacted formation duly aligned and levelled.

QC shall conduct the inspection throughout the stages of construction
The mass concrete shall be poured to the marked levels and tamped by wooden float. The forms shall be struck after the specified period. The curing of the mass concrete shall be carried out according to approved procedures and for the specified period. The alignment of the block walls 150 mm thick shall be set out and the block work carried out in courses in a straight line and plumb.

The whole number of courses shall be laid. The fractional block course if so remained to make up the required wall height, shall be constructed as a part of the pavement down beam concrete by extending the bottom to the top of the block walls. The pavement /down beam monolithic pouring shall be carried out to the specified details according to the procedures.

QC shall conduct the inspection throughout the stages of construction
The backfilling shall commence and the trench filled according to the specifications.

The pre cast covers of 1m or 3 m standard length shall be placed on the filled trench internal surface to the specified levels. The concrete shall be coloured to the specification requirement.

QC shall conduct the inspection throughout the stages of construction

Where the dummy trench runs over the duct bank Typical

All the operations described in general shall be applicable herein as well with the following amendments/additions to certain activities. Excavation shall be carried out to the top of the duct concrete only. The walls shall be started from the duct top level. Additionally, where the underground pipe runs crossing the Trench, the specified pipe shall be laid prior to the block work is commenced or openings shall be formed in the walls (Pipe laying operation by others). Flat width of the crossing shall be in size equal to the value given by the equation “Duct Bank length + 300x2 “.



Where the dummy trench and the direct buried trench run parallel

Typical

All the operations described in general shall be applicable herein as well with the following amendments / additions to certain activities. While constructing the buried trench, the profile of the dummy trench shall dictate the profile of the buried trench. Sloping profile to a grade 1 in 2 shall be formed as shown on the drawing.



Where the cable trench crossing with the closed drain pipe trench

Typical

All the operations described in general shall be applicable herein as well with the following amendments / additions to certain activities to be supplemented. The profile of the cable duct trench shall dictate the profile of the direct buried trench. The transition of the formations between the trenches and the crossing shall be in grade 1 in 2 as shown on the drawing. The length of the duct bank shall be equal to the value given by the equation. Width of the closed drain trench in mm + 2x100. The crossing flat width shall be the duct bank length + 2x300. A gap of 100mm shall be kept between the duct bank top and the closed drain bottom surfaces. The duct bank shall be constructed according to the details. Cable tiles under the closed drain trench shall be provided in the direct buried trench only. A joint shall be provided between the pavement and the closed drain trench wall.



Where direct buried trench crossing under dummy trench

Typical

All the operations described in general shall be applicable herein as well with the following amendments / additions to certain activities to be supplemented. A level difference of 350mm shall be kept between the elevations of the crossing formation and the dummy trench. The level transition shall be established by grading 1 in 2. The cables passing under the dummy trench shall be protected by cable tiles (By others) . The trench corner wall shall be constructed to the details showing the corner length on the trench internal face.



Where trench with dummy Trench crossing under direct buried cable trench

Typical

All the operations described in general shall be applicable herein as well with the following amendments / additions to certain activities to be supplemented. The profile of the cable duct trench shall dictate the profile of the direct buried trench. The transition of the formations between the trenches and the crossing shall be in grade 1 in 2 as shown on the drawing. The length of the duct bank shall be equal to the value given by the equation. Width of the direct buried cable trench in mm + 2x100. The crossing flat width shall be the duct bank length + 2x300. A gap of 100mm shall be kept between the duct bank top and the closed drain bottom surfaces. The duct bank shall be constructed according to the details.

Cable tiles under the closed drain trench shall be provided in the direct buried trench only.

Where direct buried trench crossing under direct buried cable trench

Typical

All the operations described in general shall be applicable herein as well with the following amendments / additions to certain activities to be supplemented. A level difference 700 mm shall be kept between direct buried trench and the crossing formation level. The crossing formation width shall be equal to the value from the equation in mm. (direct buried cable trench width + 400x2). The transition of the formations between the trenches and the crossing shall be to grade 1 in 2 as shown on the drawing.

Cable tiles shall be provided in unpaved areas and at trench crossing.

Electric Trench Layout at Pumps Typical

All the operations described in general shall be applicable herein as well with the following amendments / additions to certain activities. The pump base shall be constructed to the details. The trench walls shall be continued to the shape as shown.

Option

If so required and felt convenient for certain uniform section reaches, pre cast concrete units 100 mm thick may be utilised to substitute 150 mm thick walls directly resting on the prepared formation.


Underground Piping

In the scope, the following types of pipes are indicated to be included.


Carbon steel pipes gravity network 4” dia to 14” dia, coating material & welding, flange, gasket, bolting, testing, valve & flanges, sand filling, back filling/ pressure network etc.

Non reinforced concrete pipes, cutting, jointing, sand bedding, anchor blocks 200 to 500mm etc.

Reinforced concrete pipes, cutting, jointing, sand bedding, anchor blocks 200 to 2000 mm etc.

Ceramic gres pipes & fittings, sand bed, Y, T, cuts, leak test, 100 to 500 mm dia etc.

Bonna type pipes & fittings, sand bed, T, Y, anchor blocks 250mm to 2500mm dia etc.

Plastic pipes PVC gravity network 110 mm to 410 mm dia etc.

Polythene pipes gravity Y, T reduction piece, cuts, sleeves, leak test etc.

Plastic pipes pressure network 110 mm to 410 mm sand bed etc.

PVC pipes heavy-duty 110 mm to 410 mm send bed etc.

Polythene pipes pressure Y, T reduction piece, cuts, sleeves, leak test etc.

Cast iron cement lined pipes gravity etc.

RTRP pipes pressure+ gravity 100 to 800 mm etc.

The following activities are typically involved to carry out underground piping system etc.

Ensure no underground existing services exist in the area concerned.

Setting out the alignment of the proposed route according to survey details.

Providing safety control barriers on both sides of the excavation allowing enough clearance for the excavator & truck to work without hindrance.

After approval of the setting out, excavate the set out portion as trenching & continue up to the design depth according to the formation level of the pipe bedding following the approved excavation procedures.

The pipes & fittings shall be stacked properly on both sides of the trench according to the manufacturer’s instruction.

Prepare the bedding formation to the design levels & longitudinal profile specifically for gravity system.

Surveyor shall monitor the levels throughout

QC inspection shall be conducted to check the bedding

Bed shall be filled with sand up to the pipe external surface level.

Proper arrangement shall be made to down take the pipes. After down taking the pipes & fittings to the trench bed & placing roughly into set out alignment, surveyor shall give the exact alignment of the route.
After the route has been aligned truly & fittings included, counter weight using sand on the pipe surround shall be applied temporarily to avoid pipe uplift during pressure testing or mechanical anchors employed depending upon dia of the pipe & the quantum of water pressure. All joints shall be connected or filled according to specifications.
Wherever specified, for the steel flanges, bolting shall be carried out

Wherever specified, for the plastic or p v c pipes, push fit system of jointing shall be applied

Wherever specified, for the plastic pipes, joints shall be glued using tangit

Wherever indicated, to anchor the bend etc at turning using thrust block, block shall be constructed of concrete to resist the, resultant pressure during pressurizing.

Wherever specified, for the concrete or r c c pipes, special jointing material shall be applied to meet the requirement.

Wherever required, to use cut pipes to complete the length, pipes either Bonna or carbon steel or concrete or any other make, pipe shall be cut to the actual length of the piece required.


After all jointing has been completed, pressure testing shall be conducted for the ready portion with application of required bar pressure. Risers of the pipes shall be installed on both ends of the pipe line, filled with water under pressure which shall continue for the specified period of 24 to 72 hours during which period, observations of the water levels falling & the leak detection be conducted & recorded. Any leak detected in any part, that pipe part shall be removed & re installed & test repeated all according to approved ITPs
After the test has been successful, pipe service marker shall be placed for identification purpose & granular material filled on the pipe & its surround so that at least 200 mm layer is established on the crown of the pipe. This fill shall be compacted lightly. Later from this level to the ground, granular fill material shall be used to backfill the remaining section duly compacted in layers all according to approved procedures.
Ignore if not applicable

Epoxy grouting to vibrating machine bases Typical

Thin section - A gap between a base plate and substrate below 25 mm

Thick section- A gap between a base plate and substrate above 80mm

Normal thickness- In between the thin and the thick sections

The following activities are involved for normal thickness

Surface preparation

Metal parts that should not be bonded to the grout like jack screws of the reciprocating machinery and part of the foundation bolts shall be sealed with tape prior to grouting.
Base plates and equipment bases shall be uniformly supported in order to eliminate sag, distortion and levelled using both anchor bolts and jackscrews. Stainless steel shims 50x50x10 mm thick shall be placed in correct locations covered with mortar so as to allow at least 50 mm grout cover on shim sides.

Full extent of the foundation surface under the base plate or equipment to be grouted shall be chipped / scabbled & brushed to remove the weak upper layer of concrete and any oil soaked concrete areas prior to the installation of the base plate. Base plate surfaces in contact with epoxy grout shall be grit blasted so as to expose white metal. All surfaces and bolt pockets to receive grout must be clean & free of rust, oil, dirt, paint and residual curing compound. All base plate holding down bolts etc must be free of rust, oil, dirt or contaminants that could impair bond Formwork Unless otherwise shown on design drawing, the entire area under the base plate shall be grouted and the forms fixed around the plate keeping a minimum of 25 mm clearance from the plate edge and at least 50 mm from the edge of the pouring side so that total grout able area is equal to underside of the plate and the clearance around the plate.


Before the form work is fixed, it shall be ensured that the foundation area to be grouted and the bolts holes are clean A liquid tight formwork as practicable, shall be fixed around the base plate to prevent the leakage of the resin keeping the top of the forms 25mm above the underside of the base plate A chamfer 25mm x 25mm shall be provided on the sides so that top of the chamfer and the top of grout are in one level in case the whole of the foundation area around the plate is to be grouted, A 45 degree sloping surface above the form on the pouring side shall be constructed to create a pressure head to enable the grout material flow to cover full width of the pour. A coating of an approved release agent shall be applied to the formwork.

QC inspection shall be conducted to ascertain the form profile and general preparatory works





Download 2.87 Mb.

Share with your friends:
1   ...   6   7   8   9   10   11   12   13   ...   27




The database is protected by copyright ©ininet.org 2022
send message

    Main page